Hypothalamus & Pituitary

Hypothalamus Function

Links brain to endocrine system, regulates (water, body temp, etc.)

What hormones does the hypothalamus secrete? (targeting anterior pituitary)

GnRH, TRH, CRH, GHRH, PIH, Somatostatin

What hormones does the hypothalamus secrete? (targeting posterior pituitary)

OT, ADH

What does GnRH stand for?

Gonadotropin releasing hormone

What does TRH stand for?

Thyrotropin releasing hormone

What does CRH stand for?

Corticotropin releasing hormone

What does GHRH stand for?

Growth hormone releasing hormone

What does PIH stand for?

Prolactin inhibiting hormone

What does OT stand for?

Oxytocin

Anterior Pituitary’s Hormones (response to hypothalamus)

FSH, LH, TSH, ACTH, PRL, GH

Posterior Pituitary’s Hormones (response to hypothalamus)

OT, ADH

What does FSH stand for?

Follicle stimulating hormone

What does LH stand for?

Luteinizing hormone

What does TSH stand for?

Thyroid stimulating hormone

What does ACTH stand for?

Adrenocorticotropic hormone (

What does PRL stand for?

Prolactin

What does GH stand for?

Growth hormone

What is the Hypothalamic-hypophyseal portal system?

Blood vessels (venules) connect hypothalamus and anterior pituitary (communication)

GnRH portals

1.) GnRh → FSH → gonads make gametes

2.) GnRh → LH → gonads make sex hormones

TRH portal

TRH → TSH → Thyroid secretes thyroid hormones

CRH portal

CRH → ACTH → adrenal cortext secretes glucocorticoids

PIH portal

PIH → inhibit PRL production

Somatostain portal

Inhibit GH and TSH

What is the Hypothalamic-hypophyseal tract?

Hypothalamic hormones travel down axons to terminals (herring bodies), connected to posterior pituitary

OT Tract

OT → uterus contracts, mammary glands eject milk

ADH Tract

ADH → Kidneys increase water reabsorption

Homeostasis

Negative feedback (self-regulating, common, ex: hormones)

Positive feedback (self-reinforcing, rare, ex: blood clots, childbirth)

Growth Hormone Effects

Directly effects chondrocytes, osteocytes, myocytes, adipocytes

Indirectly effects insulin-like growth factors

What things can effect how body makes growth hormone?

Sleep (elevates it),

Exercise and food (elevates it),

Age (decreases it)

Pituitary GH disorders

Gigantism - Hypersecretion of GH during childhood

Dwarfism - Hyposecretion during childhood

Acromegaly - Hypersecretion during adulthood

GHRH Portal

3.) GnRh → GH → mitosis (make cells) and differentiation (cell duities)