Physiology of Endocrine System Pt 1

Question 1

hypothalamus

Answer 1

• located in brain
• regulates body’s internal environment + homeostasis (e.g. temp, water, heart rate)
• produces hormones that stimulate pituitary glands
• contains neurosecretory cells

Question 2

posterior pituitary gland

Answer 2

• located in brain
• connected to hypothalamus via stalk-like structure
• axon endings store ADH + oxytocin

Question 3

neurosecretory cells

Answer 3

• neurons in hypothalamus
• respond to neurotransmitters
• create hormones which are sent to posterior pituitary axons

Question 4

ADH

Answer 4

• antidiuretic hormone aka vasopressin
• promotes reabsorption of water from collection ducts (which receive urine from kidneys)
• secreted by posterior pituitary gland

Question 5

Oxytocin

Answer 5

• causes uterine contraction, stimulates release of milk from mammary glands
• can be used to induce labor
• secreted by posterior pituitary gland

Question 6

anterior pituitary gland

Answer 6

• located in brain
• in “3-tiered relationship” with hypothalamus and other endocrine glands
• secretes: GH, prolactin, MSH, TSH, ACTH, FSH, LH

Question 7

3-tiered relationship

Answer 7

1. hypothalamus produces hormones + sends them to anterior pituitary gland
2. those hormones stimulate anterior pituitary gland to produce hormones to control thyroid, adrenal cortex, gonads
3. those glands produce hormones that regulate the secretion of appropriate hypothalamic hormones

Question 8

GH

Answer 8

growth hormone (aka somatotropic hormone)

• determines height + bone structure
• causes cell growth + division, protein synthesis
• impacts liver and skeletal muscle
• promotes growth of cartilagenous plates, osteoblast bone formation

Question 9

Prolactin

Answer 9

• produced during pregnancy, childbirth, nursing
• causes mammary glands to develop and produce milk
• plays role in carb and fat metabolism

Question 10

MSH

Answer 10

melanocyte stimulating hormone

stimulates melanocytes in skin to increase melanin production

Question 11

TSH

Answer 11

thyroid stimulating hormone

stimulates thyroid gland to produce T3 + T4

Question 12

ACTH

Answer 12

adrenocorticotropic hormone

stimulates adrenal cortex to produce cortisol

Question 13

gonadotropic hormones:

Answer 13

FSH + LH

stimulates gonads

Question 14

Thyroid

Answer 14

• produces T3 and T4 (thyroxin), calcitonin

- needs iodine (from diet) to produce active thyroxin

Question 15

thyroxin

Answer 15

• increases metabolic rate of all cells
• increases respiratory enzymes
• increases oxygen uptake
• necessary for proper growth/development
• shuts down TSH production (via neg feedback)

Question 16

calcitonin

Answer 16

• decreases calcium in blood, deposits it in bone

- opposes action of PTH

Question 17

parathyroid glands (4)

Answer 17

• embedded in surface of thyroid

- produces PTH

Question 18

problems w/ growth hormone production

Answer 18

• too little GH during childhood –> “pituitary dwarf”
• too much GH during childhood –> “pituitary giant”
• too much GH during adulthood –> acromegaly (abnormal growth of hands/feet/face only)

Question 19

problems w/ inadequate thyroxin/PTH production

Answer 19

• low thyroid function since birth = congenital hypothyroidism –> decreased sexual growth, sexual immaturity, abnormal protein metabolism (–> intellectual disability)
• no PTH –> low blood calcium –> tetany (increased nerve excitability causing body shakes from continuous muscle contraction)

Question 20

PTH

Answer 20

• increases calcium level in blood via stimulating increased Ca absorption in intestines, promoting osteoclast activity (bone breakdown, Ca deposited in blood)
• decreases phosphate level in blood via excreting phosphate at kidneys
• neg feedback: PTH production stops once Ca blood level = sufficient