2.2 hypothalamus + pituitary gland

what is hypothalamus, what does it do and where is it located

- connection between the nervous and endocrine systems

- regulates body temp., water balance, heart rate , ↑/↓ secretions of other glands

- located base of brain, below thalamus, above pituitary gland

what does hypothalamus secrete

- releasing factors → stimulate secretion of inhibiting factors (slows down secretion of a hormone)

what does hypothalamus produce

other hormones → nerve fibres → posterior lobe

pituitary gland (hypophysis)

- lies under hypothalamus, joined by infundibulum

- has anterior (front) and posterior (rear) lobe

what is anterior lobe

- no nerves connecting it to hypothalamus; connected by complex networks of blood vessels in infundibulum

- TRUE endocrine gland (secretes its own hormones)

what is posterior (rear) lobe

- joined to hypothalamus by nerve fibres (nerve cell bodies in H. → infundibulum → posterior lobe)

- NOT a true endocrine gland, as it does not secrete substances, only stores & releases hormones

what does adenohypophysis release

- releases no. of hormones that regulate bodily activities; controlled by releasing of inhibiting factors from H

- gonadtropins, growth hormone, thyroid stimulating hormone, adrenocorticotropic, prolactin

gonadtropins

FSH - development of ovarian follicles + production/maturation of the sperm

LH- brings ovulations and forms corpus luteum & stimulates interstitial cells in testes

Growth Hormone (GH)

stimulates growth of skeleton → ↑ rate at which a.a. are taken up by cells & built into proteins

thyroid stimulating hormone

stimulates production & release of some of the hormones from thyroid gland

adrenocorticotropic hormone (ACTH)

controls production & release of some hormones from cortex of adrenal glands

prolactin (PRL)

works w/ other hormones to initiate & maintain milk production

what does neurohypophysis release?

- hormones not made in PL, but in special nerve bodies of (H). → hormones move down fibres → stored in PL → released into blood → release triggered by nerve impulses from the H.

- OT and ADH

oxytocin (OT)

stimulates contraction of the muscles of the uterus (large amts. released during labour) & mammary glands → milk release

antidiuretic hormone (ADH) / vasopressin

causes kidneys to remove water from urine that's forming → water returned to the bloodstream.

helps fluid retention in the body + vasoconstriction → ↑ blood pressure.