2.2 Hypothalmus + Pituitary Gland

Hypothalmus role + location

Has roles in both the nervous and endocrine systems, located at the base of the brain, below thalamus.

Hypothalmus- basic functions of the body

-body temp

-water balance

-heart rate

-increasing and decreasing the secretions of other glands

Hypothalmus- functions through the pituitary gland

Secretes releasing factors which stimulates the secretion of a hormone or inhibiting factors, which slow down the secretion of a hormone. These factors travel through the blood vessels to the anterior lobe of the pituitary gland.

Pituitary gland- location

Lies under the Hypothalmus and is joined to the Hypothalmus by the infundibulum.

Pituitary gland function

Vital to normal functioning of the body

Anterior lobe

The front lobe has no nerves connecting it to the Hypothalmus, but a complex network of blood vessels lying in the infundibulum.

Posterior lobe

the rear lobe is joined to the hypothalamus by nerve fibres that come from nerve cell bodies that pass through the infundibulum. It is not a true endocrine gland as it does not secrete substances, it simply stores and releases hormones.

Posterior lobe secretes

Anti-diuretic Hormone and Oxytocin

Anti diuretic Hormone

causes kidneys to remove water from urine that is forming. Water is then returned to the bloodstream, retaining fluid for the body. In higher concentration it can cause the constriction of small arteries.

Oxytocin

Stimulates the contraction of muscles in the uterus, released in large quantities during labour. Stimulates the contraction of cells in the mammary glands, resulting in the release of milk during breastfeeding.

Anterior lobe of the pituitary releases

Gonadotropins, FSH, LH, Growth Hormone, Thyroid stimulating hormone, Adrenocorticotropic hormone and prolactin

Gonadotropins

are hormones that affect the gonads, the ovaries and testes

Follicle-stimulating hormone

stimulates the development of the follicles that contain eggs in the ovary of the female. In the male, FSH stimulates the production and maturation of sperm in testes.

Luteinising Hormone

works with FSH in the female to bring about ovulation and to form a structure called the corpus luteum after ovulation. In the male it stimulates interstitial cells in the testes to secrete male sex hormones.

Growth Hormone

stimulates body growth, particularly growth of the skeleton. It increases the rate at which amino acids are taken up by the cells and built into proteins. GH is secreted throughout life as it helps to maintain the size of organs once maturity is reached.

Thyroid Stimulating Hormone

Stimulates the production and release of hormones from the thyroid gland.

Adrenocorticotropic hormone

Controls production and release of some of the hormones from the cortex of the adrenal glands.

Prolactin

works with other hormones to initiate and maintain milk production in females