The hypothalamus is an almond-sized structure located above the brainstem that maintains homeostasis by secreting hormones to the pituitary gland. The pituitary gland, or hypophysis, is a pea-sized organ that stores and releases hormones from the hypothalamus to control other endocrine glands. It has an anterior and posterior lobe; the anterior lobe secretes hormones regulating growth, metabolism, reproduction and stress responses, while the posterior lobe stores and releases oxytocin and vasopressin. Pituitary disorders commonly involve benign tumors that can cause too little or too much hormone secretion or mass effects by pressing on surrounding structures.
3. • Almond-sized and can be found
just above the brainstem
• Main goal: maintain
HOMEOSTASIS
• Structure in the forebrain
HYPOTHALAMUS
4. • Receives neuron signals from brain
and PNS
• Channels signals to pituitary gland
• Secretes hormones to the pituitary
gland for later usage
HYPOTHALAMUS
8. PITUITARY GLAND
• Controls other endocrine
glands and body’s hormonal
response to environment
• Has 2 parts: anterior and
posterior
9. PITUITARY GLAND
1. Anterior Lobe
(Adenohypophysis)
• Secretes hormones that
regulate wide variety of bodily
functions
10.
11. PITUITARY GLAND
Somatotrophs
• Secrete humangrowth hormone(hGH), aka
somatotropin, whichstimulates tissues to secrete
hormones that stimulate bodygrowth and
regulate metabolism.
12. PITUITARY GLAND
Gonadotrophs
• Secrete follicle-stimulatinghormone (FSH)and luteinizing
hormone (LH), whichbothact on the gonads. They
stimulatethe secretionof estrogen and progesterone,
maturationof egg cells in the ovaries, and stimulatesperm
productionandsecretion of testosterone in thetestes.
16. HORMONES SECRETED IN THE
ANTERIOR LOBE
• Human-growth hormone (hGH)
- Tissues
- Stimulates tissue growth in the liver, muscles, bones, as
well as protein synthesis, tissue repair, and elevation of
blood glucose levels.
• Thyroid-stimulating hormone (TSH)
- Thyroid gland
- Stimulates thyroid gland to secrete thyroid hormones.
17. HORMONES SECRETED IN THE
ANTERIOR LOBE
• Follicle-stimulating hormone (FSH)
- Ovaries and testes (gonads)
- Stimulates development of oocytes (immature
egg cells) and secretion of estrogen in females;
stimulates sperm production in the testes in
males.
18. HORMONES SECRETED IN THE
ANTERIOR LOBE
• Luteinizing hormone (LH)
- Ovaries and testes (gonads)
- Stimulates secretion of estrogen and
progesterone, including during ovulation, in
females; stimulates testes to produce
testosterone in males.
19. HORMONES SECRETED IN THE
ANTERIOR LOBE
• Prolactin (PRL)
- Mammary glands
- Stimulates milk production.
• Adrenocorticotropic hormone (ACTH)
- Adrenal cortex
- Stimulates secretion of glucocorticoids (cortisol) by the
adrenal cortex during the body’s response to stress.
20. HORMONES SECRETED IN THE
ANTERIOR LOBE
• Melanocyte-stimulating hormone
(MSH)
- Brain
- When in excess, can cause darkening of the skin;
may influence brain activity (its exact role
unknown—there is very little MSH in humans).
22. Oxytocin (OT), aka the "love" drug
• Secretes in response to uterine distention and stimulation of
the nipples.
• Stimulates smooth musclecontractions of the uterus during
childbirth, as well as milk ejectionin the mammary glands.
23. Antidiuretic hormone(ADH), or
vasopressin
• Secretesinresponsetodehydration, bloodloss,pain,stress; inhibitors
ofADHsecretion includehigh blood volumeand alcohol.
• Decreasesurinevolume toconserve water,decreases waterloss
through sweating,raises bloodpressure by constrictingarterioles
24. Pituitary disorders
• most common disorder: benign tumors
• two kind of pituitary tumors: secretory
and non-secretory
• can be removed, monitored, and
controlled with proper medication.
25. Pituitary disorders
Problems caused by tumors fall into certain
categories:
• Hyposecretion: Too little of a hormone is
produced, interfering in normal function.
• Hypersecretion: Too much of a hormone is
produced, interfering in normal function.
• Mass effects: The tumor presses on the pituitary or
other areas of the brain, causing pain, vision