At the beginning of this section we mentioned that neurons pass information at the synapse with the help of neurotransmitters.
One such neurotransmitter is dopamine.
Dopamine is also known as the "happy hormone" because it plays a key role in behavior related to pleasurable or happy behaviors such as food, intercourse and social interaction.
Chemicals like dopamine which affect human body functions and behavior are known as hormones.
Our body produces a wide range of hormones, some of which you are already familiar with.
For example, hormones such as estrogen and testostorone are responsible for many of the physical changes observed in females and males during puberty.
Below you can see the chemical composition of these two hormones.
Two other kinds of hormones, which also acts as neurotransmitters are shown below.
We've already spoken about dopamine. Serotonin also plays an important role in stabilizing our mood, feelings of well being and happiness.
The collection of glands that produces hormones and regulate the body's metabolism, growth and development is known as the endocrine system.
Let's go over the major glands in our endocrine system and what hormones they release.
1. Pituitary gland
The pituitary glands acts as a link between the hypothalamus in the brain and the endocrine system.
Some of the hormones secreted by the pituitary gland include -
1.1 Oxytocin- stimulates the contraction of uterus and mammary gland cells.
1.2 Antidiuretic hormone- controls retention of water by the kidneys
1.3 Thyroid-stimulating hormone- stimulates the thyroid
1.4 Adrenocorticotropic hormone- stimulates adrenal cortex to secrete glucoctricoids.
2. Thyroid gland
The Thyroid gland releases three hormones-
2.1 Triiodothryonine (T3)
2.2 Thyroxine (T4)
Together T3 and T4maintain the body's metabolic processes.
2.3 Calcitonin- controls the blood's calcium levels.
3. Adrenal gland
The adrenal gland releases the following hormones -
3.1 Epinephrine
3.2 Norepinephrine
Together these two hormones raise blood glucose level and regulate metabloic activities.
3.3 Glucoctricoids- raises blood glucose level
3.4 Mineralcorticoids - influence salt and water balance in the body.
4. Pancreas
The pancreas releases two main hormones - insulin and glucagon. Insulin lowers our blood glucose levels, while glucagon increases blood glucose levels.
5. Ovaries
The ovaries release estrogen and progestorone. Estrogen stimulates growth of the uterine lining and promotes development of secondary sexual characteristics in females.
Progestorone promotes growth of the uterine lining.
6. Testes
The testes release a group of hormones called androgens- of which testostorone is a critical one.
Testostorone supports sperm(male gamete) formation and promotes development of secondary sexual characteristics in males.
Abnormally high or low levels of hormones can lead to health problems.
If your level of thyroxin is too low, it will lead to a lower metabollic rate - which in turn can cause weight gain.
If on the other hand your body has too much thyroxin, you can develop a goiter- which is a swelling of the neck because of an enlarged thyroid gland.
If the level of insulin in your body is too low, your body will not have enough energy to function. This is because insulin helps cells absorb sugar from the bloodstream, which is then broken down to release energy.
This condition is known as hypoglycemia.
If your body is unable to break down glucose into energy, you can develop diabetes.
If you have too much insulin, you can develop hyperinsulinemia.