Endocrine System

The Endocrine System controls conditions in the body by making and sending chemicals from one place to another. It is controlled by the nervous system. Your endocrine system works automatically without your control.

Structures and FunctionsOf Endocrine System

The main structures of the endocrine system are groups of specialized cells called glands. These glands produce hormones and release them into your circulatory system so the hormones can travel through your blood stream.These glands can be found in many parts of your body. There are different names for all of these glands.

Pituitary Gland

Director of system Located at base of brain – right above

mouth Many important types of hormones are

produced in pituitary gland including growth, sexual development, and water hormones.

Hypothalamus

Attached to pituitary gland Connects nervous and endocrine

system

Pineal Gland

Found deep in brain Sensitive to different levels of light Lets you know what is hot, cold, and

when you need to sleep or wake up

Thyroid Gland

Found by Adam’s apple in throat Releases hormones necessary for

growth and metabolism Releases hormone that is responsible

for regulation of calcium in body

Thymus

Found in chest Helps body fight disease by producing

white blood cells called T cells

Adrenal Glands

Located on top of kidneys Produces hormones that balance

carbohydrates, protein, fat, water, and salt levels

Also produces hormones that make your heart beat faster when you hear loud noises, are on a roller coaster, or if you are stressed out

Pancreas

Part of digestive and endocrine systems

Produces hormones to balance glucose in blood

Located beneath stomach – connected to small intestine

Ovaries and Testes

Produce hormones that control sexual development

Located in groin area

Some other organs produce hormones but are also parts of other systems like the kidneys and the heart.

Kidneys make hormone to balance production of red blood cells

Produced when oxygen level in blood decreases

The heart produces hormones that balance blood pressure

These hormones tell the kidneys to remove more salt

Feedback

Negative and Positive

Negative

Feedback mechanisms in the body are called negative mechanisms, because the final effect of the response is to turn off the response. When the hormone has been made to much the final response is shutting down reproduction of that hormone. When the body needs energy the thyroid gland releases thyroxine to increase cellular respiration and the more cellular respiration the more body energy is released.

Positive

The outcome of the positive feedback is not to maintain homeostasis, but makes a response that increases. For example when you cut yourself you’re bleeding is controlled by positive feedback. First the damaged area sends a signal which starts a chain of chemical reactions that leads to good blood clot, that let the scab and white blood cells heal the open skin

Hormone Balance

Balanced Hormone Action

The amount of one hormone depends on the balance or imbalance of another

For example, the pancreas produces two different hormones - one (insulin) decreases level of sugar in blood- another (gulucan) decreases level of sugar in blood

The balance of these hormones maintain a stable blood sugar

Imbalanced Hormone Action

Too little or too less of any hormone can cause disease

For example, if the pancreas produces too little insulin, sugar levels in blood rise to dangerous levels

The high blood sugar levels can damage circulatory system and kidneys