ENDOCRINE SYSTEM

Endocrine System

A system of glands that secrete hormones (chemical messengers) directly into the blood stream.

Promotes growth and maintains the internal balance of the body. (Homeostasis)

Note: The hypothalamus is technically part of the nervous system(brain).

The function of the endocrine system

The system of glands, tissues, and cells that secrete hormones into the bloodstream to influence metabolism and other body processes.

Hypothalamus

A part of the brain that activates, controls, and integrates the autonomic mechanisms, endocrine activities, and many body functions.

Pituitary Gland

The “master gland,” closely linked with the hypothalamus, that controls other endocrine glands and secretes hormones that regulate growth, maturation and reproduction.

The pituitary gland may be king, but the power behind the throne is clearly the hypothalamus.

Pituitary gland secretions

ACTH- adrenocorticotropic hormone

A hormone formed in the pituitary gland, that stimulates the outer layer of the adrenal gland to secrete its hormone.

HGH- human growth hormone

Promotes growth (indirectly), control of protein, lipid and carbohydrate metabolism

Liver, adipose tissue

Pituitary gland secretions

LH- luteinizing hormone Control of reproductive

function Ovary and testes

(growth, development & function)

FSH- follicle-stimulating hormone

Control of reproductive function

Ovary and testes (growth, development & function)

In both sexes, LH stimulates secretion of sex steroids from the gonads. In the testes, LH binds to cells, stimulating synthesis and secretion of testosterone. Cells in the ovary respond to LH stimulation by secretion of testosterone, which is converted into estrogen by adjacent cells.

Pituitary gland secretions

Oxytocin- Stimulates milk ejection and uterine contractions.

Ovary and testes Oxytocin acting within the brain plays a major

role in establishing maternal behavior.

Thyroid

Control heart rate, body weight, body temperature, energy level, muscle strength and menstrual regularity.

Thyroid problems

Hypo: The thyroid gland

produces too little amounts of thyroid hormone. Hypothyroidism causes the body to function at a lower rate.

Hyper: The thyroid gland

produces too much hormone. Increases the rate at which each cell functions, increasing all the reactions that occur in the body.

Parathyroid

One of four small endocrine glands on the back of the thyroid

Secretes parathyroid hormone which regulates calcium and phosphorus metabolism.

Adrenal Glands

Endocrine glands, located over the kidneys that produce androgens (example: testosterone)

Regulated by the hormones of the pituitary gland.

Pancreas

The pancreas is a digestive gland found behind the lower part of the stomach. It discharges its juice, mixed with with bile, into the intestine.

It also produces insulin, a hormone that helps to control the level of glucose sugar in your blood

Ovaries

One of two female reproductive glands that produce ova (eggs) and sex hormones; ovaries are the female gonads.

Production of estrogen Production of

progesterone

Testicles

Site of sperm production, also known as Gonads

Produces the male sex hormone testosterone.