If, for example, Venus was to block the sun from the Earth, that may cause some people to act strange. This may be because the brain has a lot of water in it, as does the human body. It is known that the moon is what creates the tides in the sea, so perhaps, if its gravitational pull moved the water in the body and the brain, it might create odd effects.

The symptoms I have noted from studying certain cases I know of (mild cases) are the following:

• Over-reacting to emotions.
• Over-reacting to heat.
• Over-reacting to touch.
• Fear of others ( or non-relatives ).
• Moodiness.
• Talking about non-existent things (not as a joke).
• Getting themselves into situations (such as standing on a bed sill) and then behaving as if it was terrifying.
• Getting hyper.
• Moving their bodies a lot (shaking them).

The times when this happens worst, is, of course, the full moon. However, it doesn’t affect everyone. I have seen, that it mostly affect girls. Girls, between 12 and a half years old, and 17/18 years old. This, is the time when most pubertal changes happen on the outside.

The lunacy could be a case of the increased estrogen in the blood, being moved around in the body because of the moon’s gravity. This could, instead of helping maturity, create breaks in it, i.e. the lunacy.

How the Moon Affects And When It Is Most Likely To Affect.

The moon affects people by moving the blood in the body a little. In puberty, there are an increased amount of hormones and estrogen in the body, as the graph below confirms. It goes even higher during menstruation. This, combined with the gravitational pull of the moon affecting a teenager’s brain could have some very serious effects. It might lead some people to do things they regret doing in their later years, such as crime.

By coincidence, menstruation happens roughly every month, the same time as there is a full moon. This would make things even worse.

From recent studies, I have found that during this time, teenage girls might be very responsive to:

• Light.
• Sound.
• Touch .
  

Results of Experiment 1

To test the theory I have explained in the above pages, I have placed a drop of orange juice on a slide ,on the microscope. After examining it closely, this is what I found( The experiment was done on a day when there was a full moon.

Highest resolution look 1: No particles moved. 1:30pm

Highest resolution look 2: Might have been a slow movement. 1:37pm

Highest resolution look 3: Stringy particles stayed still. 1:44 pm

Highest resolution look 4: No noticeable movement. 1:48pm

Highest resolution look 5: Almost all particles were still(smallest move) 1:53pm

Medium resolution look 1: When shadowed, movement was clearer. 1:55pm

Medium resolution look 2: The particle I could see clearly enough was rotating. 1:58pm

This shows, hat because the cell that was rotating would have behaved like cells is the bloodstream. Of course, if hormones were to rotate off-course like that, hen it would have some unusual effects on the brain.

But the theory isn’t correct without further proof. Therefore, have done a second experiment, and written down my findings below.

Results of Experiment 2

Time: 2:10. one 6 days after new moon. Dine the same as experiment1 with orange juice. ll resolutions are looked with in each one, and the most notable things are listed.

• Look 2:May be very small movement.
• Look 3:Nothing moves.
• Look 4:Nothing moves.
• Look 5: Everything stays still.

Results Of Experiment 3

For experiment 3, I dropped a ball onto the ground at different times of the month, and used a watch to record how long it took.

These are the results: (Estimated.)

Drop 1 (Beginning of the month, crescent moon)

1.15 seconds.

Drop 2: (Middle of the month, half moon)

1.22 seconds.

Drop 3: (End of the month, full moon)

1.47 seconds.

These results prove a small part of my theory, that the moon’s gravitational pull affects the gravity on Earth. However, if astronauts were to travel to a planet with a greater gravitational pull than the Earth, if they had increased levels of hormones in their blood, they might be affected by the moon, too. This would not work on the moon, as there still is gravity, so the blood doesn’t float, but it is pumped along by the heart at probably a similar speed.

There would be ways to treat such a problem. If say, a teenage girl with increased hormones were to take an anti-hormones pill just before the full moon, her hormonal imbalance would not take place, and her levels would be completely normal later. But if the strength of the drug was too much, it might kill all the hormones.

There will probably never be a long-term way to ward against this, as a drug would need to be constantly administrated to the patient. A brain or hormone blood monitor might help, as they will probably be available in the future. Until then, only for extreme cases, anti-hormone pills should be registered.

Final Theory

My final theory is that every full moon people with increased levels of estrogen or hormones in their body go a bit mad. This is because of the hormones in their brain moving out of their normal course, because of the moon’s gravitational pull moving the blood, therefore moving the hormones.

These results show that when there is not a full moon, cells do not move in water (as long as it is kept still). This shows why people (especially teenage girls) with high levels of estrogen have a bad mental state at the full moon.

One of the most plausible explanations can be offered by the idea that pheromones do exist in humans. Pheromones are chemicals emitted by living organisms used to influence the behavior of other organisms of the same species. This enables the organisms to detect each other even from far distances. Remember the male dogs that could not be contained during the rutting season of dogs? Pheromones from female dogs make them behave that way.

Types of Pheromones

In 2005, the scientific literature categorized pheromones into four classes: territorial markers, mother-infant, menstrual synchrony, and human sex-attractant pheromones. Dogs mark their territories by urinating in places they consider theirs. The smell of their urine serve as warning to other dogs that they are intruding into another's territory. Babies have been observed to show a clear preference for pieces of clothing worn by their own mothers. In humans, pheromones have been identified to influence menstrual synchrony and attract the opposite sex, especially males. We are more interested on the last two categories.

Discovery of Sex Pheromones

The understanding of pheromones date back to the 1870s. A renowned French naturalist Jean-Henri Fabre (http://www.beyonddiscovery.org/content/view.txt.asp?a=2702#A_Seductive_Scent) observed that male peacock moths flew for a long distance to visit a female moth in his lab. The male moths come from every direction no matter where in the house he moved the female. He hypothesized it must be an odor in the female, undetectable in humans, that caused attraction.

Pheromones in Humans

But are pheromones also found in humans? There is still controversy whether pheromones exist in humans but a landmark study in 1986 by Dr. Winifred Cutler codiscovered pheromones in our underarms (So that's why when we smell the underarms of the opposite sex, we either get attracted or repelled?). She also discovered that women who have regular sex with men have more regular menstrual cycles than women who have sporadic sex. And the explanation is attributed to pheromones. Somebody suggested that constant washing away or covering up of the sweaty underarms  could be the reason why many people in modern society are depressed or lonely. Well, this is a matter of hygiene, but leaving a little of the odor in the underarms could do the trick. If you don't want to attract somebody, then you have to scrub everything.

Further, research suggests that men and women choose their mates by sniffing out partners. In fact, in 2006, a research study published in Nature confirmed the presence of pheromones in humans. Receptors in the nose pick up subliminal scents. This has something to do with trying to identify compatible immune systems.

Realizing the importance of pheromones, the cosmetics industry popularized pheromone use in perfumes and lipstick. Since then, it has developed into a multi-million dollar industry.

Tip to Find Out if You Have Sex Appeal

I read in an article that an indicator of sex appeal are mosquitoes. If you noticed that mosquitoes tend to bite you more than others who do not complain they are bitten, you should be proud. You have greater sex appeal.

If you attract somebody of the same sex, that's another story. See the article by Wolfe which prompted me to write this article.

 

It is not long ago, when people believed that through successful child rearing, a good personality can be formed. This theory is called nature vs. nurture, and states that there are certain traits that people have when they are born, but the parents, environment, and future experiences will determine who you will become. This theory seems very logical, since we all experience events and people that shape or change us. But biological evidence now shows that our whole personality is already set in the womb of our mothers. The culprits are the hormones and the brain wirings, which determine who we will be what sexual preferences we will have and most probably where we will work and what our hobbies will be (Pease p. 3-15).

Before we go into the details of the actual differences of men and women, we should take a look at the definition of hormones and what important roles they play in the human body.

A hormone is a chemical messenger that carries a signal from one cell (or group of cells) to another via the blood. All multi-cellular organisms produce hormones. Hormones generally regulate the function of their target cells, i.e., cells that express a receptor for the hormone. The action or net effect of hormones is determined by a number of factors including its pattern of secretion and the response of the receiving tissue - the signal transduction response (Wikipedia).

There are different effects hormones have on human bodies. Hormones are there for stimulation or inhibition of growth, in puberty they can affect mood and mind, they can activate or inhibit the immune system, they also regulate metabolism. Another important effect on the human body and mind is that hormones prepare the human for a new activity such as fighting, fleeing, and more importantly mating. Hormones furthermore control the reproductive cycle and prepare the human body for a new phase of life such as puberty, parenthood, and menopause (Wikipedia).

The human creation process starts with a fertilized egg that develops into an embryo. We know that the so-called “default” gender is female but the real gender will be determined through the XX chromosome or the XY chromosome. If it is a XX chromosome, the embryo will develop into a girl, and if it is a XY chromosome, it will develop into a boy. Six to eight weeks after conception, the fetus is still sexless and has the potential to develop male or female genitalia.

German scientist Dr. Günther Dorner was one of the first to advance the theory that our sexual identity is formed six to eight weeks after conception. He also discovered the influence of hormones on the gender development. A genetic boy (XY) develops special cells to direct large amounts of male hormones, particularly testosterone, to form male body parts and configure the brain for masculine traits and behaviors, which we will go to later. But let us assume that a male fetus requires four units of these hormones; one to form the male genitals and three to configure the brain with a male operating system. This male fetus receives only three out of the four, which means that the first unit is used to form genitals but the brain only receives two, which means that the brain becomes two-thirds male and remains one-third female. This will result in a boy who will grow up with a mainly male brain, but with some female thinking patterns and abilities (Allan& Barbara Pease).

If in any case the male fetus only gets two units; one for the genitals and one for the brain, then this boy will grow up with male genitals, but with a mainly female structures thinking, and in puberty will most likely to become homosexual. It is in puberty when boys and girls will have hormones racing through their body to fully develop the body and sexual organs. It is because of the additional hormones when most teenagers discover their homosexuality.

Now that we know how the gender and male and female thinking structures develop, we can now tackle the major differences between men and women. Many of us already know that our behavioral patterns and thinking structures derived from our ancestors the cave men. These patterns still hold true today and explain the most irrational behaviors of each sex. How women hate it when men do not take care of their emotional needs, and how men hate it that a women can never shut up. Here are the reasons as to why men behave the way they behave.

Let us examine the abilities of males. Have you ever wondered why men cannot find the things they look for right away? That is because they have a tunnel vision, like a pair of binoculars which only enables them to look into far distances straight ahead. Men were hunters, which means, they only had to focus on one object straight ahead. A man's brain can configure a 3 dimensional map in their brain and because of this can read maps better and hear the direction of a sound. Male brains are compartmentalized which means they can only do one thing at a time. The brain of a male also has a thinner corpus callosum than the female, which means that the male brain only works with one wide of the brain. Men have increased spatial skills thanks to the male hormones. Spatial skills are mainly located on the right brain hemisphere. When men communicate, they are direct to the point and always treat listening to a person as problem solving. Men also have fewer verbal receptors in the brain, which explains why they talk lesser than women. Testosterone, the male hormone, is the hormone of success, achievement, and aggression. Too much testosterone will lead a person to too much aggression and will result in crime (Allan & Barbara Pease).

Now we know how males are wired and we will move on to the female skills and brain wiring. The female vision is peripheral which means, she can see almost up to 180⁰. This was needed when the woman was the nest defender and needed to watch the children and possible enemies sneaking up to the cave. Women can also see more color and women's eyes have more white which allows a greater range of eye signals since close-range personal communication is an integral part of female bonding. Women have the so-called sixth sense which simply means that women can read the body language of others and can quickly detect the emotion of a person. This is also the reason why men cannot lie to women. Women are also better in distinguishing high-pitched sounds, because a women's brain is programmed to hear a baby cry at night, while a man can sleep over it. Besides having a superior sensitivity to body language and emotions, women also have superior sensitivity in differentiating tone changes in voice volume and pitch. The reason why so many women want to “just cuddle” is because women's skin is at least ten times more sensitive to touch and pressure than men's. Women also have a better sense of smell than the average men. Women's noses can detect the pheromones associated with men and unconsciously decode the state of a man's immune system. Boys and men alike like things, rather than people, compete rather than co-operate, and analyze and solve problems rather than listen to them (Allan Pease).

Women have specific areas for speech and often occupy professions that make use of such. Women are multi-trackers, which means they can jump from one topic in a conversation to another without getting lost. The same way it is with activities; women can do two or more things at the same time, because of their ability to multi-track. This multi-tracking is due to the stronger corpus callosum of women which connects both hemispheres and therefore can do more things at the same time. Women see verbal communication as a way of bonding with people, and women also need to talk in the end of the day to release stress. Women are also accused of being too emotional. This is only true because women's emotion receptors in the brain are more scattered than men's. And due to their thick corpus callosum, women can connect different activities with different emotions, while men can stay emotionless, since his brain is compartmentalized.

Oestrogen the female hormone is responsible for enhanced articulation and fine-motor skills, that is why women during the menstrual cycle on high estrogen days can behave calmly and speak with near-perfect articulation. The same it is with high testosterone days; her speech may be more erratic but her spatial ability is better. The hormones are responsible for the Pre-Menstrual-Tension (PMT) which drives women insane (Barbara &Allan Pease).

In 1998 a study by the Canadian brain research authority showed that higher testosterone level increased the spatial skills and the mathematical reasoning. Unfortunate for women, during PMT the testosterone level sinks which means it is during that time that women are more likely to score less in a mathematical exam. Testosterone makes men the aggressive hunter, but modern day and society does not very much approve of men killing everything, so the hunter substitution is commonly known as sport. This enumeration will show you the effects of estrogen, progesterone and testosterone; estrogen is responsible for an overall feeling of contentment and well-being, and plays a major role in a woman's nurturing and nest-defending behaviors. Estrogen has a calming effect and is often given to males in prisons to control violent behavior. Estrogen also helps memory, which is why during menopause, the memory level drops with the drop of hormones. The female hormone progesterone is the hormone that releases parental and nurturing feelings and its purpose is to encourage a woman to carry out her child-rearing role successfully. Progesterone is released whenever a woman sees a baby or a baby-like appearance in a toy, which is also why stuffed toys and dolls that look like babies have always sold higher than other toys (Allan & Barbara Pease).

Testosterone on the other hand is responsible for aggression, spatial ability; it deepens the voice, and makes men's beards grow. It is also a cause of baldness. As men reach their 50s and 60s, the level of testosterone decreases and they become less aggressive and more nurturing, but for women, the reverse happens; after menopause estrogen decreases leaving them with a bigger amount of testosterone and as a result, they become more assertive and self-reliant.

Now we know that hormones program our brains before birth, dictating our behavior and the way we think. Testosterone in teenage boys is 15-20 times higher, and when they go into puberty, the testosterone gives them a dramatic spurt of growth. The body ratio of teenage boys is 15% fat and 45% protein. He turns into an adolescent and his body physically changes to match the biological job description which is the lean, mean, lunch-chasing machine. Boys are excellent in sport because their bodies are hormonally constructed for effective breathing and they have excellent oxygen distribution via the red blood cells to allow running, jumping, and grappling. Steroids are male hormones that build additional muscle mass and give athletes extra “hunting” abilities and an unfair advantage over others.

Female hormones have a different effect on teenage girls. They are not regulated, but come in huge waves over a 28-day cycle and can cause havoc for many girls due to the rise and fall of emotions. Female hormones change a girl's body into a ratio of 26% fat and 20% protein. The purpose of the extra fat is to give additional breastfeeding energy. Female hormones fatten the body and can be used for livestock such as pigs or cows, but male hormones reduce fat and build muscle (Barbara & Allen Pease).

The big question now remains, despite all these differences between men and women, what is the key factor that still brings them together? The simple answer is reproduction; the more complex answer is companionship and relationship. Let us not go too deep into the relationship of men and women but rather analyze our reproductive relationship and find out what attracts us to each other.

Beauty they say is in the eye of the beholder. But in biology, beauty is a natural indicator of a healthy body and a healthy reproductive system. The way a person looks can get him or her into a better job, better partner, and better things in life. Whenever we say, that we find a person beautiful, then we subconsciously attracted to the person and think of the person as a possible reproductive partner.

Every study over the last 60 years reaches the same conclusion that a woman's appearance and body is more attractive to men than her intelligence or assets. Authors Allan and Barbara Pease have collected a data of 13 of men's turn-ons in priority order. This will reveal biologically why men are attracted to physical aspects. The first point is Athletic body shape, which indicated a strong, fit body and is a signal of a woman's ability to successfully bear children, flee from danger and defend the offspring if necessary. Most men prefer a heavier woman to a leaner one, because the additional fat aids breastfeeding. The list goes on will full breasts as a turn-on. Full breasts indicate a woman's sexual and reproductive peak. Another factor is long legs. Woman's legs serve as sexual signal because they draw attention to the area where the left and right legs meet. Men also prefer women with rounded thicker legs than athletic skinny legs, because additional fat highlights the sex difference and is an indicator of better lactation.

Rounded hips and a small waist in 5th on the list of turn-ons and signals high fertility, the same way a flat stomach indicates that a woman is not pregnant and available. A woman who has excellent health and is capable of bearing children has a hip-to-waist ratio of 70% that is the waist is 70% the size of her hips. If the ratio exceeds 100% it is a non-verbal indicator for low fertility, since fat is barely deposited around vital organs such as the heart, brain, testes, and ovaries (Allan & Barbara Pease). Next on the list are hemispherical buttocks. A rounded buttock is attractive because it signals that there is a large amount of fat that can be used for breastfeeding. If a woman has an arched back and an arched vulva, it means that she is fertile. Curves and arches indicate femininity and fertility, while geometric and angular shapes indicate masculinity. Long necks are another turn-on on that list. A long neck shows femininity since the shorter, thicker and stronger necks are held by men, to protect them from enemies (Allan & Barbara Pease).

Let us move to the features of women's faces that attract attention of men. The preferred features of female faces are small faces with short chins, delicate jaws, high cheekbones, full lips, and eyes that are large in proportion to the length of the face. For a woman's face to be universally classified as “pretty” it must be childlike. These kinds of faces triggers paternal reactions in the brains of men and give a powerful desire to touch, embrace and protect. One of the most attractive factors in the face is a sensual mouth. Humans are the only primates that have lips that sit on the outside of the face instead of inside the mouth. Zoologists believe a woman's lips to have evolved as a mirror of her genitals because they are the same size and thickness. This is called the “genital echo,” a reaction that transmits a powerful signal to male observers. This is also the reason why many women choose red lipstick, since red is a sexual signal. Attractive large eyes inspire protective feelings in men as well as dilated pupils, the same way it is with a small nose, which also brings out paternal feelings in men, which is why large eyes and small noses are also in the turn-on list. The last point on our list is long hair. Women with blonde hair have high estrogen levels and men are attracted to blondes more because more estrogen indicated fertility. Long shiny hair indicated a healthy and well-nourished body and therefore shows the potential fitness to produce offspring. Long hair is associated with sensual allure while short hair is associated with a more serious approach in life (Allan & Barbara Pease).

The list of what attracts females to males is considerably shorter because male physical sex appeal is much more basic and straightforward. Women have always been primarily attracted to healthy, strong men who could obtain food and protect her and her children, and that hasn't changed much. But the modern day woman wants more than her ancestors: she wants a man who will fulfill her emotional needs. Thus women look for softness and hardness in a man. On top of the attraction list for women is an athletic looking v-shaped body. A strong body is a signal of good health and the ability to catch food and fight off enemies. Turn-on number two is broad shoulders, chest and muscular arms. Men should have these features to signalize that they can lug heavy weapons over long distances and carry home their kills. The bigger a man's chest is, the more respect and power he commands. Men have longer forearms than woman which enables them to be better providers. Another attraction is a small, tight bum. The secret in this attraction is that a tight, muscular rear is necessary to make the strong forward thrusting motion during sex. Turn-on #4 is full hair or baldness. Throughout history, hair on the head has been considered a badge of raw masculinity.

Male baldness on the other hand is hereditary and is caused by an overproduction of male hormones. These hormones flood the system and switch off certain hair papillae. Because of these high hormone levels, bald men are usually more aggressive and sexually more aroused than men with hair, thus making baldness the super-male signal. Turn on #5 & 6 are a sensual mouth and kind eyes. When women describe men's mouth and eyes they refer to the attitude, which proves that men see the actual feature itself, while women look beyond to seek the emotion. A woman will show a preference for men with darker eyes, because light eyes are more infantile in appearance. The next turn-on is the nose and the chin. The male nose and chin have evolved to give a man protection from powerful blows during fighting or hunting, and thus making both a badge of masculinity. High testosterone levels give a more protruding jaw. As for the nose, common myth says that the nose shows the size of a man's penis, but there has been no research to substantiate this myth. What the nose and a man's penis have in common is that they protrude and that both expand with blood during sexual arousal (Allan & Barbara Pease).

Narrow hips and muscular legs are also on the list of most attractive body parts. Men's narrow hips and muscular legs allow him to run swiftly over long distances to chase and hunt. Women find a 90% hip-to-waist ratio attractive and men's legs are attractive because they are symbols of masculine power and endurance. Turn-on #10 is the large penis. Women who appear excited about a long penis are reacting more to the perceived masculine power of the organ than to what its length will physically achieve. In fact, women in a happy relationship will rarely ever think about penis size. Evolution has not programmed women to be sexually aroused by the sight of male genitals, which is the opposite of what happens to men. The last turn-on is the tree-day beard. Male hormones cause long facial-hair growth, which means the higher a man's testosterone on a given day, the faster it grows, thus the three-day bears serves as a strong visual badge of masculinity (Allan & Barbara Pease).

Men have two lists: their first impression list, and what they seek in a long-term partner, but women only ever have one list. Women want a man to be caring, intelligent, humorous, loyal and understanding. A good body is a bonus for women, but usually ranks lowest of her priorities. Men use a female's appearance and grooming as a measure of how he feels about her. The female hormone estrogen and progesterone gives a person the nest-defending attributes and thus women all over the world are looking for the perfect provider who can stimulate us emotionally and not only physically. The male hormone testosterone makes one self-reliant and improves spatial and visual skills. This also explains why men are highly visually oriented when it comes to choosing a partner.

Hormones can make or break our lives. Too much testosterone can make us into raging beasts, while too much estrogen can make us sweet like a puppy and increases our memory. The gist of it all is to have an understanding why we function the way we function, and be able to solve our future problems with our hormones and the other sex.

The major endocrine glands include the two Adrenal glands, the Pituitary gland, the four Parathyroid glands, the Sex glands, and the Thyroid gland. A few hormones are produced by endocrine tissue present in organs that are not primarily endocrine glands. Such organs include the Brain, Stomach and Pancreas.

Generally, hormones regulate a variety of body functions. They may be grouped according to the functions that they control. These functions include:- the way the body uses food; growth; sex and reproduction; the regulation of the composition of the blood; the body's reaction to emergencies and the control of hormones themselves.

For the sake of this paper, the role of hormones will be viewed in respect of mammalian production with regard to Sex hormones.

During childhood, the features relating to sex are usually undeveloped. When an individual reaches about 14 (10-17) years of age, conspicuous changes take place that lead toward sexual maturity and the ability to reproduce. This time is known as Puberty, when the characteristics that differentiate the sexes gradually appear. In males the beard and body hair begin growth, the shoulders broaden, the voice becomes deeper-pitched, and more attention is paid to the opposite sex. In females the mammary glands and hips enlarge, subcutaneous fat is deposited, the reproductive tract begins a series of cyclic changes, and the attentions of young men becomes of interest.

At the start of Puberty, the Hypothalamus, the portion of the Brain nearest the Pituitary gland, greatly increases its secretion of a hormone called Gonadotropin releasing factor. This Growth-stimulating hormone (GSH) acts on the anterior lobe of the Pituitary. It stimulates the gland to secrete the Gonad tropic hormones - Follicle stimulating hormone (FSH) and Lutenizing hormone (LH). These hormones, in turn act on the gonads (Sex glands) - the Testes in males and the Ovaries in females. If the Pituitary is experimentally removed, the reproductive organs remain infantile, the individual is sterile, and no sexual cycle occurs.

Under the influence of FSH and LH, the Gonads grow and begin to secrete large amount of sex hormones. The male sex hormones, including Testosterone and Androsterone, are called Androgens. The female sex hormones include Progesterone and Estrogens - the most important Estrogens being Estradiol, Estriol and Estrogen. The Cortex of the Adrenal glands in both male and female also secretes some sex hormones, especially Androgens.

The sex hormones regulate the remarkable changes that occur during Puberty. The help trigger a person's rapid growth in height and weight and at the end of Puberty, the stop this growth. Androgens cause the male sex organ to mature, and the stimulate sexual behaviors. Androgens also stimulate the development of such secondary male characteristics as a deep voice and a beard.

Estrogens cause the female sex organs to develop fully, and they establish female sexual behaviors. They also stimulate the development of secondary sexual characteristics, such as full breast and wide hips e.t.c. In a woman's body, Follicle stimulating hormone (FSH), Lutenizing hormone (LH), Estrogens and Progesterone work together to control the Menstrual cycle, while Progesterone also regulates processes necessary for pregnancy.

Therefore, the whole series of events making up the breeding cycle in females under the hormones control can be summarize thus:

• A combination of internal and external factors modulated in the Hypothalamus, stimulates secretion of releasing factors. These include production of the Gonadotropins Follicle stimulating hormones (GFSH) and Lutenizing hormone from the pars anterior.
• Follicles stimulating hormone (FSH) stimulates development of the Graafian follicles and induces production of Oestrogens in the Ovary. Lutenzing hormone (LH) activates the Ovulation process, and the feed-back of Oestrogen to the Hypothalamus cuts off the supply of Follicle stimulating hormones (FSH), so that no further Follicle become mature and there is no further Ovulation.
• Lutenizing hormone (LH) stimulate lutenization of the empty Follicle while the Lactogenic hormone (LTH) component stimulates milk production in the mammary gland
• Progesterone from the Corpus luteum ( or later the Placenta) initiate the pregnancy changes and also inhibits further Ovulation, so that in the case of a successful mating, another Oestrous cycle can not commence until the effect of Progesterone ceases

The Placenta, beside serving for exchange of food, respiratory gases, and waste between parent and embryo, also produces hormones:

• Estradiol and Progesterone until near the end of pregnancy
• Gonadotropin which is usually excreted in the Urine. The modern human “Pregnancy Test” depends upon demonstrating the presence of Gonaadotropin in the Urine sample.
• Relaxine, another placental hormone relaxes Pelvic ligaments in anticipation of birth
• Oxytocin ( from Posterior Pituitary) stimulates contraction of Uterine muscle sometimes being injected after child birth for this purpose

Apart from hormones of the Pituitary and Reproductive tract, those from other Endocrine glands (Thyroid, Parathyroid, etc.) have a part in activities related to reproduction. The human Menstral cycle for instance is regulated by Follicle stimulating hormone (FSH) and Lutenizing hormone (LH), as earlier mentioned.

Consequently, in male mammals, reproductive activities also are under hormonal control. The Endocrine of the Testis responsible for Secondary sexual characters is the Testosterone evidently produced by the Leydig or Interstitial cells between the Seminiferous tubules. If this hormone is injected into a Castrated individual, the accessory sex organs enlarge,the Secondary sexual characters develop, and the behaviour becomes that of a normal (Uncastrated animal).

Indeed, both Spermatogenesis and Oegenesis are controlled by the hormone Testosterone and Estrogen respectively. Healthy females from Puberty onward experience a recurrent discharge of blood, mucus, and epithelial cells from the lining of the Uterus, termed Menstration; on the average, this occurs every 28 days ( one lunar month) and lasts from 4 to 5 days. Menstruation is regulated by endocrine secretion (especially the Corpus luteum of the Ovary) and prepares the Uterus for implantation of an Ovum. It usually ceases during Pregnancy and Lactation and stops if the Ovaries are removed. Menstration gradually stops at about age of 45-50 years and its cessation (the Menopause) marks the end of reproduction ability. This “change of life” is a time of physiological emotional distress for many women. There is no comparable sexual cycle in male.

Each Ovary in a young female contains many thousands of immature Ova, the numbers decreasing with age i.e. as Menopause approaches. One enlarged mature Ovum (occasionally more) is released through the effect of Estrogen to pass down the Oviduct some days after each Menstation. This is called Ovulation. Possibly, 400 Ova in all during the life of an average woman are ovulated.

Indeed, .in addition, hormones may be administered to alter a function of the body in some way. Birth control pills, for example, contain synthetic female hormones. By taking these hormone, a woman alters the Endocrine balance that controls the Menstral cycle. This alteration blocks Ovulation, thus making it almost impossible for pregnancy to occur - i.e. another Oestrous cycle cannot commence until the effect of Progesterone ceases. In normal Menstrual cycle, there is first a period when the Follicle is developing up to the time of Ovulation, which corresponds to the periods of Pro-estrus and Oestrus, when the Oestrogen hormone is dominant. During this time, the Uterus lining is thin and unchanged. After Ovulation, the Corpus luteum is formed, Progesterone dominates the cycle and the Uterus wall thickens and becomes highly vascular. This is the Pre- menstrual period and corresponds to Post oestus.

Thus, each normal Oestrous cycle has four main phases:

• Dioestrus or Anoestus phase- a latent period during which there is no visible sexual activity. This may be quite prolonged in animals with a long cycle.
• Pro-oestrus phase- during which follicle develops in the Ovary
• Oestrus phase- the “Period of heat” which is often accompanied by changes in the external and internal genital parts. Only at this time is the female willing to receive male for pregnancy. Also, it is the time that Ovulation occurs in most mammals. (the Rabbit, Cat and Ferret are exceptions, since they ovulate only after copulation).
• Post-Oestrus phase - which is a time merging into pregnancy if copulation is successful, or Pseudo-pregnancy where it is not

If no fertilization is affected, no Placenta is formed, the Corpus luteum degenerates and Progesterone is not produced for long. This results in Endometrium breakdown, which causes the menstrual discharge of blood and cells. This period and the short post-menstrual period, which proceeds, the next development of a follicle corresponds to Anoestrus.

If the union has been successful, the egg or eggs will have been fertilized at the upper end of the Oviduct, cleavage will have commenced and the young embryo (or embryos) will have been implanted in the Uterus wall, which had been prepared by the Progesterone. The mother is then said to be pregnant. Changes which have commenced in the Endometrium of the Uterus soon after Ovulation, becomes very marked at this stage, and a Placenta is formed where tissue of the embryo and mother come into close contact. As the embryo develops further, the Uterus increases in size to keep pace. The high level of Progesterone in the body sustains all these. The critical stages of human development take place quite early in this respect. All the major organs of the body have been established by the end of the third month. The following six months are essentially a period of growth.

By the beginning of the second trimester, the Placenta reaches its full development and secrete Estrogen and Progesterone. During the second and third trimesters the Plasma levels of the Estrogen and Progesterone continuously, reaching a peak at the time of labor. In addition to Estrogen Progesterone, the Placenta secretes a hormone called Human Placental Lactogen (HPL). Placental Lactogen is similar to Growth hormone and Prolactin. It stimulates breast development in preparation for Lactation, supports fetal bone growth, and alters maternal metabolism by substituting Lipids for Glucose for energy. The Placenta also secretes Antidiuretic hormone, Aldosterone, and Renin.

Finally, at birth, which takes place at the end of the third trimester, some 266 days after fertilization in man, changing hormone levels in the developing fetus initiate the process. First, the fetal Pituitary gland secretes the hormone called Adrenocorticotrophic hormone (ACTH), which stimulates the Adrenal glands to release Steroid hormones that induce maternal Placental cells to manufacture Prostagladins that help induce powerful uterine muscle contractions. Acting in parallel, the pressure of the baby's head against the Cervix sends nerves impulses to the mother's Brain that trigger the Hypothalamus to release the hormone Oxytocin from the Pituitary. Working together, Oxytocin and Prostagladins stimulate contractions in the walls of the Uterus, forcing the fetus downward - thus resulting in birth.

Types of Androgens:

Testosterone is the main androgen however there are other androgens. Some of these are mentioned below:

1. Dehydroepiandrosterone (DHEA):

   This steroid hormone is produced from cholesterol in the adrenal cortex. It is the natural precursor of natural estrogens. DHEA is also known as dehydroisoandrosterone and dehydroandrosterone.

2. Androstenedione:

   An androgenic steroid Androstenedione, sometimes called Andro is produced in the testicles, adrenal cortex and ovaries. Androstenedione is converted metabolically to testosterone and other androgens. The usage of androstenedione for body building purposes is illegal internationally.

3. Androstenediol:

   is the steroid precursor which is believed to be the main regulator of gonadotrophin secretion in mammals.

4. Androsterone:

   is a chemical by-product produced by the lysis of androgens. It is also derived from progesterone. It has masculinising effect but these effects are only about one-seventh the intensity of testosterone in the human body. It can be detected easily by testing the urine and / or blood of both male and female clients.

5. Dihydrotestosterone: (DHT)

   DHT is a metabolite of testosterone. It is one of the most potent androgens. It is more potent than testosterone and is produced by the adrenal cortex. This androgen can be synthesized in the laboratory.

Functions of Androgens:

Androgens play a key role in the formation of the testicles.

During the embryonic stage of human development, the gonads are at first capable of becoming either ovaries (female sex organs) testis (male sex organs). In humans, at about the age of four weeks gonadal rudiments appear in the intermediate mesoderm immediately next to the kidneys. During weeks five and six epithelial sex cords appear within the forming testes and incorporate the germ cells as they migrate into the gonads. In male embryos specific chromosome genes regulate and control the development of the male phenotype. SRY genes are most important for this development to occur. Androgen exposure is responsible for the conversion of the early bipotential gonad into testes. In males, the sex cords fully invade the developing gonads.

Evolution of Leydig Cells and Androgen Production

During the embryonic stage mesoderm-derived epithelial cells of the sex cords develop in the testes and later become the Sertoli cells. Sertoli cells later function to support sperm cell formation. During weeks seven to nine a small amount of non-epithelial cells appear between the tubules, during fetal development. These become the Leydig cells. After appropriate differentiation and maturation the Leydig cells begin to produce androgens.

Effects of Androgens

During embryonic development androgens function as pancrean hormones. These hormones are required by the Sertoli cells in order to facilitate sperm production. Androgens are also required for masculinization of the developing male fetus, including penis and scrotum formation - this process will be discussed in more detail in another article.

Embryological stages in human development.

The mesonephros is an excretory organ of the embryo. Under the influence of androgens, parts of the mesonephron and the wolffian ducts develop into male sex organs viz. the epididymis, the vas deferens and the seminal vesicles. This powerful action of mammalian androgens is supported by AMH hormone which is secreted by Sertoli cells. The key function AMH is to prevent embryonic Müllerian ducts from developing into fallopian tubes and other female reproductive tract tissues in male embryos. AMH and androgens cooperate to allow for the normal movement of testes into the scrotum.

Early Hormonal regulation

In humans Androgen action on target tissues involves conversion of testosterone to 5α-dihydrotestosterone. This is called dihydrotestosterone (DHT). In week 11 to week 12 of embryonic development human chorionic gonadotrophin (hCG) promotes the differentiation and specialization of Leydig cells and the intrinsic production of androgens. These processes take place before the production of the pituitary hormone called Luteinizing Hormone (LH).

When a male child reaches puberty androgen, Luteinizing Hormone and Follicle Stimulating Hormone production increases. The net effects of these hormones include the hollowing out of sex cords and formation of seminiferous tubules. Additionally the production of germ cells starts and these differentiate into sperm. During adulthood Androgens and Follicle Stimulating Hormone cooperatively work on Sertoli cells in the testes to support sperm production and regulate sexual drive and aggression.

Many male contraceptive methods have been tested to reduce spermatogenesis but none has been found to be effective except tubal ligation. Tubal ligation involves a surgical procedure during which the vas deferens are isolated and ligated. Vasectomies and implantation of intra vas device are other male contraceptive interventions.

Depo-Provera is a contraceptive Injection and is a brand name for medroxyprogesterone acetate for IM use. This is usually administered once every three months.

Elevated androgen levels caused by abuse of androgen supplements will stop the manufacture of LH in the pituitary gland and block production of endogenous androgens by Leydig cells.

During androgen abuse the level of androgens in testes falls and the Leydig cells stop producing Androgens. This happens because the high level of circulating androgen decreases the production of LH in the pituitary gland. This leads the seminiferous tubules to degenerate. The end result could be male infertility. It is for this reason that many transdermal androgen patches are applied to the scrotum - to maintain high Androgen levels in the testes.

Androgens Inhibit fat deposition.

Most of us are aware that males have less adipose (fat) tissue than females. This is due to the fact that androgens inhibit the ability of fat cells to store lipids. This occurs because androgens block the transduction pathway which normally supports adipocyte function in mammals.

Androgens increase Muscle mass

Generally males have greater amounts of muscle tissues than females. This is the result of higher amounts androgens. Androgens are known to promote the enlargement of skeletal muscle cells. They do this by acting in a coordinated manner to enhance muscle functions by acting on many different types of cells.

Athletes who abuse androgens seem to gain muscle mass over a short period of time. One must be alert to mood changes in such clients as hormone levels rise and fall in unpredictable patterns, so does the drive, emotional statue, motivation and aggression. Periods of aggression may be interspaced with depression when circulating androgens reach their troughs (low levels).

Androgens act on the Brain too

Circulating Androgens affect human behaviour. Higher levels of androgens are associated with more aggression, energy levels and drive to achieve goals. This happens because androgens influence human neurons by making them more sensitive to steroid hormones. Many studies show that Androgen levels are directly proportional to human aggression.

Androgens increase Male Libido.

Sexual desire or libido of male clients is increased with androgens. Androgens affect both the mental and physical components to this drive.

Insensitivity to androgen in humans.

Insensitivity to androgens is fairly rare but does occur. AIS or Androgen resistance syndrome is a disorder due to a mutation of gene encoding. It is called androgen resistance. This results in under verilization and/or infertility in XY persons of either sex. Insensitivity to androgens can also result in several types of intersex conditions.

This article is for educational use only. It must not be used as a substitute for medical opinion.

Estrogen in females works as a messenger during each mensual cycle. Estrogen together with ovarian hormones, signals cells in the breast to divide and multiply. Estrogen also signals the cells of the uterus to divide.

Other hormones signal the ovaries to make estrogen, and then the ovaries force estrogen into the bloodstream. Estrogen travels through the blood, but only travels to the cells that have estrogen receptors like the breast and uterus.

Estrogen has a shape that allows it to fit into an estrogen receptor the same way a key fits into a lock. The estrogen and the estrogen receptor bind to form a unit that enters the nucleus of the cell and this begins a series of events that turns on estrogen-responsive genes. These genes tell the cells to make proteins that signal the cells to carry out important activities. Some of these signaling proteins can tell the cell to divide.

Estrogen is mainly produced by the ovaries, the corpus luteum, and the placenta. Since men usually don't have these they have to rely on secondary estrogen producing organs to produce estrogen. This is one reason why males don't have as much estrogen as females. Secondary organs are the liver, adrenal glands, and the breasts.

Controlling the Reproductive Process

To stop the reproductive process by use of hormones people usually need to take the pill. The pill works by thinking the mucus around the cervix. This makes it difficult for sperm to enter the uterus and reach any eggs that may have been released. The pill can sometimes also affect the lining of the uterus making it difficult for the egg to attach to the wall of the uterus. The pill contains mainly the hormones estragon and progesterone.

Another kind of pill is the low-dose progesterone pill, sometimes called the mini-pill. The difference is that the progesterone pill contains only progesterone. This pill can sometimes affect ovulation as well as all the other this that the normal pill does. The problem with this pill is that it must be taken more regularly.

Taking the pill can have side effects from sitting in the sun to long. If you sit in the sun to long while taking the pill your face can go brown and takes months to fade away. Taking the pill while smoking can increase the risk of blood clots. Other side effects include moods change, breast tenderer, headaches, dizziness and weight gain.

To help the reproductive process males and females can take extra estrogen. For males this can increase the amount of sperm released and for females it can soften the fibrous tissue. Taken too much of any hormone to try and get pregnant is very stupid as it helps cancers, especially breast cancer, to grow and develop.

Progesterone helps maintain pregnancy. If the baby is heading for an early birth artificial progestin can be taken to try and encourage the baby to stay in the body.

Estrogen Imbalance

Estrogen in females is responsible for making the fibrous tissue softer. I lack of estrogen could mean that the womb wont close or fibrous tissue wont soften making childbirth impossible.

However estrogen doesn't just make childbirth possible. An excess of Estrogen in women is believed to cause the weakening of the connective tissue that allows the fat to bulge up into the skin.

Excess estrogen is thought to be one of the main causes of cellulite (the fatty, uneven and wrinkled skin), perhaps because people can blame it on poor genetic inheritance. There are several treatments for normalization of hormones. For example Vitamoor is a drug proven to balance hormones.

The effects of hormones in our body are so unpredictable doctors can't predict the outcome. Lets say you reduced the amount of Estrogen with a drug, Doctors are unable to tell if you are also reducing something like calcium absorption in the bones. How do you know that womb tissues will be softened for childbirth? Estrogen has many hundreds of roles in the body and an imbalance of Estrogen is treatable but has lots of side effects.

Vitamoore is the only proven drug to balance estrogen without many side effects. It is a natural drug so it teats the problem naturally reducing the chances of a side effect to almost 0%.

Estrogen in men is responsible for the drainage of seminal fluid. The tubes running from the testes to the epididymis, where sperm mature and acquire the ability to fertilize eggs, are unable to drain off the excess liquid. Excess fluid damages the testes and sperm is not packed densely in the seminal fluid. If sperm is not packed densely in seminal fluid fertility is impaired.

Hormone sensitive cancers such as breast cancer rely on the supply of estrogen to survive. Therefore lots of estrogen would mean a quickly growing cancer. The treatment of these cancers often includes estrogen reduction.

Estrogen plays a very important role in the reproductive system. It is just as important in the male body as the female body. Without it sperm could not reach and fertilize the egg and most animals would not exist.

Motherhood, the first warm touch of protective love and nurturance, is a nearly universal quality of all living organisms. One of the most amazing things about motherhood and maternal behavior is how much it is taken for granted. The behaviors elicited by maternal behavior are a key factor in the survival of organisms, especially more developed organisms, which due to their physical complexity must be born undeveloped and do not enjoy the relative independence of precocious organisms. Nature has equipped parents, the mother in particular, with instinctual tools for promoting the survival of their young, deeming it not practical to leave the decision of whether or not to act in this manor in the hands of individual parents. For many years, scientists who were not taking maternal behavior or maternal behavior for granted have been trying to find out what causes the dependable, persistent, and necessary behavior demonstrated by all mothers towards their offspring. Even though we usually differentiate between the biological and the emotional the most prevalent attempts to explain maternal behavior is by biological factors, due to its universality and its powerful effect on the organism.

Naturally, the study of human maternal behavior would best be researched using human subjects, but in order to conduct intrusive procedures needed for much of the research, animal subjects were used. Relative similarity to human behavior and a measurable and consistent manifestation of maternal behavior were chosen as Criteria for suitable animal subjects; following these criteria, monkeys and rats were used most often in trying to determine the foundations to maternal behavior. Rats display an extremely constant and reliable pattern of maternal behavior. “…maternal behavior in the rat is remarkably robust and reliable. By this I mean that it is really very easy to observe these behaviors under laboratory conditions”(Kenyon). The maternal behavior patterns displayed by rats are retrieving of stray pups, nursing, ano-genital licking intended to arouse defecation and urination in the offspring, maternal aggression towards perceived threats towards offspring, and nest building. These behavior patterns are not present in subjects during pregnancy, but burst out after parturition. The question at hand is what biological changes in the female body, if any, cause this behavior.

Hormones have been suspected to be the cause of maternal behavior after it was shown that blood transfusions from postpartum mother rats to virgin rats induced maternal behavior. The two major hormone candidates suspected to control maternal behavior are progesterone and estrogen. Progesterone is the female hormone that initiates sexual drive, and therefore is expected to decline in the last stages of pregnancy. Studies were done to see if there is a correlation between descending levels of progesterone and maternal behavior. In a study conducted by Siegel & Rosenblatt, pregnant rats received hysterectomies in the 10th, 13th, 16th, and 19th day of the pregnancy, and then exposed to pups. One can expect that following hysterectomy, which causes a decline in levels of progesterone, rats will display maternal behavior to pups presented to them. In order to research the effects of estrogen, some of the subjects also received ovariectomies. It turns out that ovariectomy that follows hysterectomy at any stage, reduces the effects of the hysterectomy, causing a longer period of time needed to develop maternal behavior, due to the fact that no estrogen in being produced by the missing ovaries. The results suggest that high levels of estrogen and low levels of progesterone facilitate maternal behavior in pregnant rats, an idea supported by the fact that hysterectomised and ovariectomised rats injected with replacement estrogen displayed maternal behavior at an equal delay period as control rats.

An assumption about the role of estrogen-produced prolactin in the initiation of maternal behavior was denied after blocking prolactin did not alter the effects of estrogen on mother rats. After further study it has been discovered that what was assumed to be prolactin was in fact placental lactogens produced by the developing fetus that were activating prolactin receptors; both type I and II of this substance can cross the brain-blood barrier and reduce latency in demonstration of maternal behavior. “There are two rat placental lactogens, I and II, and shown here is that they are both equally effective at significantly reducing the latency for expression of various components of maternal behavior, including both retrieval and crouching. These placental lactagens appear to be capable of readily crossing the blood brain barrier and have been found in high concentrations in the CSF of pregnant women”(McCarthy). The speed in which dropping levels of progesterone and increase of estrogen promoted maternal behavior suggested that there is another factor that causes maternal behavior but in a faster rate. ‘Oxytocin, a nine amino acid peptide synthesized in the hypothalamus and secreted to the blood from the posterior pituitary gland’ (Hypertext for Biomedical Sciences). This hormone has been shown to be necessary for several labor related contractions, and to initiate lactation, in females.

Stimulation of milk ejection (milk letdown): Milk is initially secreted into small sacs within the mammary gland called alveoli, from which it must be ejected for consumption or harvesting. Mammary alveoli are surrounded by smooth muscle (myoepithelial) cells which are a prominant target cell for oxytocin. Oxytocin stimulates contraction of myoepithelial cells, causing milk to be ejected into the ducts and cisterns. Stimulation of uterine smooth muscle contraction at birth: At the end of gestation, the uterus must contract vigorously and for a prolonged period of time in order to deliver the fetus. During the later stages of gestation, there is an increase in abundance of oxytocin receptors on uterine smooth muscle cells, which is associated with increased "irritability" of the uterus (and sometimes the mother as well). Oxytocin is released during labor when the fetus stimulates the cervix and vagina, and it enhances contraction of uterine smooth muscle to facilitate parturition or birth. (Hypertext for Biomedical Sciences)

The secretion of oxytocin is related to the hormones discussed earlier, progesterone and estrogen; “The burst of oxytocin released at birth seems to be triggered in part by cervical and vaginal stimulation by the fetus, but also because of abruptly declining concentrations of progesterone. Another well-studied effect of steroid hormones is the marked increase in synthesis of uterine (myometrial) oxytocin receptors late in gestation, resulting from increasing concentrations of circulating estrogen” (Hypertext for Biomedical Sciences). The revelation that apart from having labor related effects, oxytocin has cerebral functions, and due to its extensive activity during and after parturition, it has been hypothesized to have an effect on maternal behavior. “ …the discovery that there is also a dense network of intercerebral oxitocinergic projections and that oxytoxin can influence neural excitability, opened the possibility for a direct effect of oxitocin on behavior”(McCarthy). In a study done on the effects on oxytocin by Cort Pederson, a psychiatry professor, it has been discovered that an intracerebroventricular injection of oxytocin induced full maternal behavior in virgin rats within one hour. A linear correlation has been shown in this study between the dose of oxytocin given and the percentage of subjects demonstrating maternal behavior, starting at 50% at 200mg and going up to 90% at 400mg (Kenyon). ‘To further prove the effect on oxytocin on maternal behavior, Pederson blocked oxytocin in the brains of mother rats resulting in an immediate reduction in maternal behavior; keeping oxytocin dosed mothers away from their pups did little to reduce maternal behavior after reuniting with them, while oxytocin blocked mother did not resume care taking’ (Zubritsky). Interestingly, stress and fright reduce secretion of oxytocin, probably to prevent labor in hazardous situations. “oxytocin neurons are repressed by catecholamines, which are released from the adrenal gland in response to many types of stress, including fright”(Hypertext for Biomedical Sciences).

Other researchers concentrate on the areas of the brain that are affected by the hormones mentioned. The optimal facilitation of pregnancy requires inhibition of sexual drive in order to eliminate the chance of contesting generations. “An important recent finding is that during pregnancy those regions of the brain that mediate maternal behavior become more responsive to estrogen, while those region that mediate sexual behavior, which is difficult to elicit during pregnancy become less responsive” (Rosenblatt). The location of receptors that work with these specific hormones is as important and as reveling as the hormones themselves. “The hormones act by increasing activity in the medial preoptic area of the hypothalamus, and damage to this area eliminates rat’s maternal behavior”(Kalat 321). The specifics of estrogen and this particular region in the hypothalamus have also been proven. “…the work of Susan Fahrbach and Don Pfaff has demonstrated that estrogen action in the preoptic area is both necessary and sufficient for the hormonal induction of maternal behavior”(McCarthy). A different study done with rats by causing lesions to both medial and lateral subdivisions of the habenular complex, has shown the importance of the lateral subdivision in facilitating maternal behavior. “Complete bilateral cytotoxic lesions of the Lhb (lateral habenulaer complex)…completely prevented the hormonal onset of retrieving and severely disrupted nest building and nursing behavior for the entire ten day test period”(Corodiman at-el 838).

Twenty-four hours after giving birth, the subject that is still expressing maternal behavior, shows no sign of the hormones that initiated this behavior. “Transfusion of blood from mothers 24 hours after parturition does not stimulate maternal behavior in nonpregnant female rats… ovariectomy and adrenalectomy (removing the adrenal glands) have no effects on maternal behaviors which shows that estrogen and progesterone are not needed for maintenance of maternal behavior”(Kenyon). Having eliminated all biological causes that explain maternal behavior in the first hours after birth, another factor must be found to explain the persistence of maternal behavior. This factor is named the maintenance system because it creates maternal behavior starting a short time after birth, lasting until the offspring are independent. The hormonal system that facilitates maternal behavior patterns is merely the initiation system to arouse care taking of offspring until the mother becomes accustomed to their young. “Prior to puberty, rats behave maternally on the first day if they are exposed to pups. After puberty, 5-6 daily exposures to novel pups are required to elicit MB; that value gradually drops as rats age. This process is called sensitisation or concaveation. Pregnant rats do not show MB during most of the gestation period, but during the last 2-3 days of pregnancy there is a rapid drop in the latency to display MB in response to pups. This sensitivity to pups remains high for some weeks after weaning”(Kenyon). Preliminarily, the mother is not used to the odor of her young, and only due to the hormonal effects discussed earlier takes care of the pups. “One thing that happens during this period of being with babies is that the mother becomes accustomed to their odors. Infant rats release some chemicals that stimulate the mother’s vomeronasal organ, which responds to pheromones”(Kalat 322). Odor is only one of the stimuli factors that arouse the maintenance system to kick in; other pup behaviors are assumed to be responsible for stimulating maternal behavior in the mother. “Pederson thinks physical contact with the pups, particularly suckling, mobilizes a ‘maintenance’ system, which doesn’t depend on oxytocin”(Zubritsky). Vocal abilities of the pups are also used as a stimulus for inducing maternal behavior. “Pups are able to vocalize and emit ultrasonic signals, which are important in facilitating maternal behavior” (Levine and Stanton 180).

Learning about the maintenance system puts the initiation system in perspective, yet not diminishing its importance; “The hormonal events that occur at the end of pregnancy should not be viewed as turning on maternal behavior in an all or non fashion. Rather, they act to reduce the latency of responsiveness to pup stimulation”(Numan, at-el 56-57). It may be assumed that the evolutionary reason for the existence of these two systems is for the mother to have a head start in caring for her own pups, while still not eliminating the possibility of a surrogate mother, if the biological mother does not survive the birth. Under this assumption, the hormonal system can be viewed as an assisting procedure to warm the mother up to her offspring, promoting their survival. Some of the biological differences between sexual receptiveness and maternal behavior have proven to hold important survival techniques.

…it is interesting to contemplate the biological adaptiveness of behavior observed in this study. Normally, in the lactating rat, implantation of the fertilized egg is delayed following impregnation at postpartum estrus. As a result, the dam’s first litter is weaned some time before the arrival of the second litter. However, if the first litter were yet suckling in the period immediately prior to the second parturition, then the pups might have become undernourished or diseased, etc. under such circumstances, the female will abandon her pups, and in some instances even cannibalize them. The potential benefits of this strategy are obvious. Not only does the female conserve her energy for the forth coming (and probably healthier) litter, but resistance toward the young at this time may well function to prevent the deleterious effect of a premature delivery caused by suckling induced oxytocin action on the uterus. Additionally, cannibalization of the first litter might provide further nourishment for the mother that could be reinvested in the second litter. (Rowland 234)

After reviewing maternal behavior and its causes in rats and primates, it is easy to forget the reason of this research, the understanding of human psychological behavior and cognition. Learning about maternal behavior and its causes can enable us to aid women in and after labor when much emotional turmoil is present, especially mothers that are experiencing problems with accepting their babies. The effects of stress and drugs on maternal behavior related hormones is important when taking care of neglected children, when trying to get junky mothers to rehabilitate, and stressful mothers to relax for the sake of their babies. The mere idea that the emotion of motherly affection has biological, measurable factors, reassures us that we do have control to a certain extent, and can try through scientific procedures to further understand and improve human life.

References

Cordimas, K. P., Rosenblatt, J S., Canfield, E. M., & Morrell, J. I. (1993). Neurons in the Lateral Subdivision of the Habenular Complex Mediate the Hormonal Onset of Maternal Behavior in Rats. Behavioral Neuroscience, 107, 827-843.

Hypertext for Biomedical Sciences.

McCarthy, M. (1998). Hormonal Control of Maternal Behavior. (Nov 20, 2001).

Levine, S. & Stanton, M. E. (1990). The Hormonal Consequences of Mother-Infant Contact. In Bernard, K. E. & Barzelton, B. T. (Eds.) The Foundation of Experience. (165-191) Medison: International Universities press Inc.

Rowland, D. L. (1981). Effects of Pregnancy on the Maintenance of Maternal Behavior in the Rat. Behavior and Neural Biology. 31, 225-235.

Rosenblatt, J. S. (No date). Maternal Behavior; Behavioral Development; Mother-Young Interaction. (Nov 20, 2001).

Zubritsky, E. The Limits of Love. (Nov 20, 2001).