How Hormons Impact on Your Sexual Behaviour

  Even with what we know about hormones, it still may seem incredible that the secretion of a few molecules from a handful of glands can be responsible for something as intense as the sex drive, but sexual behavior can be understood scientifically just like any other type of human behavior.

hormones will be the key players in this realm, and these hormones orchestrate a wide variety of things.
  From conception through to adulthood, they guide the development of our primary and secondary sexual characteristics, as well as behavioral characteristics, which together distinguish us as either male or female. And once mature, these same hormones regulatethe sex drive and reproductive behavior as well. All of this activity is orchestrated by the neuroendocrine system.

Some of the glands and associated with sexual behaviar are Pineal, Pypothalamus, Pituitary, Thyroid, Parathyroid, Thymus, and Adrenal glands, all of which secrete hormones.

Of course there are several organs that are relevant to this system as well, most notably the gonads, which are the testes for a male and ovaries for a female, as well as the pancreas and other organs that secrete hormones in addition to performing their other functions.

Types of Hormons

We can also recall that hormones are of several classes, those being
• Amino acid derivatives,
• Peptides and proteins, and
• Steroids, are last of these categories is the one that all the sex hormones belong to.

These are released into the bloodstream to reach their targets, often slipping right through the membrane due to their size and structure to find receptors within the cell. They interact with these receptors to elicit a specific physiological response related to body development or behavior, typically in some manner related to gene expression. As we may recall, the sex hormones can be divided into androgens, like testosterone, and estrogens, like estradiol.

It is true that the male gonads release more androgens than estrogens, and the opposite is true for the female gonads, but all men and women have both in their bodies, so it is overly reductive to refer to them as male and female hormones.

Hypothalamic Pituitary Gonad Axis

Release of sex hormones by the gonads is regulated by the anterior pituitary gland, which releases other hormones like gonadotropin, which travels through the bloodstream to the gonads to stimulate them.

  The levels of these hormones are relatively stable for males, whereas in females they fluctuate in a cycle lasting around 28 days,which we call the menstrual cycle.

The anterior pituitary, in turn, is controlled by the hypothalamus, again through the release of other hormones, which in this case travel through the hypothalamo pituitary portal system. For example, gonadotropin-releasing hormone is released from the hypothalamus, which stimulates release of gonadotropin in the anterior pituitary, which then travels to the gonads to stimulate release of sex hormones.

Hormones Can be Released as a response to
•Other hormones,
• Non-hormonal chemicals,
• Psychosocial inputs, or even
• Direct neural regulation. The exception to this last method is the anterior pituitary, which has no neural input.

  In general, hormone release due to neural signals tends to be a response to some experience, such as arousal, or more subtle environmental factors.

How do hormons regulate human developments ?
  Humans exhibit sexual dimorphism, which means that similarly to many other animal species, males and females have very different physical features. This starts at fertilization. When a zygote is produced, it gets 23 chromosomes from each gamete, one set from the egg, and one set from the sperm.

One of the chromosomes in each set is a sex chromosome, which will be either an X or a Y chromosome. The egg always has an X chromosome, and the sperm has either an X or a Y chromosome.

If the resulting zygote has two Xs, the fetus will develop into a female. If an X and a Y, the fetus will begin to develop into a female, but at a certain point this process will be overruled due to the chromosomal difference and it will develop into a male.
  A six week old fetus possesses gonads that are essentially identical regardless of the sex, but they will develop into either ovaries or testes depending on the genetic instructions.

  On the Y chromosome, there is a gene that,when expressed, produces the Sry protein, which influences the development of the gonad such that it will develop into a testis. In the absence of Sry protein, development results in an ovary. All the features of the external genitalia develop in similar ways, from identical precursors that differentiate due to specific interactions involving the differing products of gene expression, as well as the presence or absence of hormones like testosterone.

A similar process occurs again during puberty, when the secondary sexual characteristics develop. Growth hormone, gonadotropic hormone, and adrenocorticotropic hormone cause the gonads and adrenal cortex to release other hormones which initiate the development of these characteristics, as well as the maturation of the genitals.

  In this way, while testosterone is not anexclusively male hormone, it is responsible for masculinization, and while estrogen is not exclusively female, it is responsible for feminization.

Obviously, the differences in the physical characteristics of males and females are very clearly seen, but much more subtle is the sexual differentiation of the brain. Those who place political correctness over scientific fact may not like it, but the male and female brain are quite different in a variety of ways. 

  There are differences in regional sizes, such as with the sexually dimorphic nucleus of the hypothalamus. There are differences in numbers of neural and glial cells, number and types of synapses, and more. Of course there is plenty of overlap, as weare all humans, but it is undeniable that these differences exist, and it seems clear that these differences develop at different times and by different mechanisms.

  When analysing sexual behavior, cultural factors must be taken into account, but we are also beginning to understand mechanisms in the brain that inform our sexuality. These tend to be relegated to the cortex, hypothalamus, amygdala, and ventral striatum.
•  The cortex mediates the more complex and abstract aspects of any sexual experience, including the variety of emotions that can be felt during the act.
•  The hypothalamus is home to structural differences between males and females, given the differing size of the sexually dimorphic nucleus, which influences male and female sexual behavior, and it is also involved in hormone release.
•  The amygdala, in a general sense, is responsible for our experience of emotions and social salience detection, so in this context, it would seem to be involved in mate selection.
•  The ventral striatum is involved in reward,such as the anticipation of sexual activity, and other rewarding stimuli.