#33

Question 1

Where is the thyroid gland located?

Answer 1

above the trachea and below the larynx

Question 2

Thyroid stimulating hormone

Answer 2

targets thyroid gland

stimulates secretion of thyroid hormones and growth of thyroid gland

regulation: stimulated by TRH, inhibited by thyroid hormones

Question 3

mechanism of thyroid hormone synthesis

Answer 3

TG is iodized (3 times on T3, 4 on T4), in colloid cell

TSH binds to G protein, Pka stimulates endocytosis into follicular cells, T3/4 are released into the bloodstream

Question 4

difference between t3/t4

Answer 4

t4 has four iodines t3 has 3. t4 eventually becomes t3

Question 5

what happens if iodine is not in diet?

Answer 5

hypothyroidism

Question 6

WHich thyroid gland is most acive?

Answer 6

T3. Its mostly secreted as T4 but is turned into T3 in the tissues

Question 7

actions of thyroid hormone

Answer 7

increases metabolic rate and heat production, by enhancing sympathetic activity

stimulates protein synthesis and growth through increased gene expression, stimulation of growth hormone

Question 8

purpose of t4

Answer 8

negative feedback on hypothalamus

Question 9

hypothyroidism

Answer 9

caused by thyroid gland failure, deficiency in TRH or TSH, iodine deficiency, autoimmune disease

Question 10

cretinism

Answer 10

hypothyroidism in infants and young children

low metabolic rate, growth retardation, mental deficits, hypothermia

Question 11

myxedema (hypothyroidism in adults)

Answer 11

Low BMR
weight gain
cold sensitivity
dry rough skin
scanty hair
sluggish mental activity
puffy eyes and lips

Question 12

why does goiter happen?

Answer 12

no iodide, so thyroid hormone can’t be synthesized. This means T4 can’t put negative feedback, so TSH stimulation increases and makes the thyroid huge

Question 13

causes of hyperthyroidism

Answer 13

Thyroid stimulating immunoglobins bind to TSH receptor and stimulate the thyroid

autoimmune production of TSH or TRH, thyroid tumor

Question 14

graves disease

Answer 14

Thyroid stimulating immunoglobins bind to the TSH receptor and stimulate the thyroid

high metabolic rate, poor heat tolerance, weakness, low body weight, bulging eyes, goiter

Question 15

adrenal cortex secretes

Answer 15

steroids

Question 16

adrenal medulla secretes

Answer 16

cattecholamines, release contolled by sympathetic NS

Medulla made of modified post ganglionic sympathetic neurons

Question 17

epinephrine effects

Answer 17

increases free fatty acids, blood glucose, conversion of glycogen to lactate in muscle, and glucagon secretion.

Question 18

Pheochromocytotoma

Answer 18

adrenal tumor causing a heightened sympathetic state (high bp, tachycardia, pain, constipation, rage) triggered by physical exertion, anxiety, and bowel movements

Question 19

Three categories of corticosteroids

Answer 19

Mineralocorticoids (aldosterone)

Glucocorticoids (cortisol)

Sex hormones (DHEA)

Question 20

cortisol general actions

Answer 20

increase blood glucose, protein degradation, lipolysis,

Question 21

cortisol secretion regulation

Answer 21

stimulated by corticotropin releasing hormone from hypothalamus and adrenocorticotropic hormone from AP

circadian rhythm causes cortisol fluctuations throughout day

Question 22

long term cortisol exposure

Answer 22

increases appetite and promotes lipogenesis and fat deposition. Promotes glucose liberation

Question 23

short term stress symptoms

Answer 23

increased heart rate, blood pressure, bronchiole dilation

glycogen breakdown, blood flow to muscles, metabolic rate increases

Question 24

long term stress response

Answer 24

kidneys retain sodium and water, blood volume and pressure rise, proteins and fats converted to glucose, blood glucose increases, suppressed immune system

Question 25

cushings disease

Answer 25

cortisol hypersecretion

too much CRH, ACtH, or cortisol.

abnormal fat deposits (buffalo hump and moon face), muscular weakness, stretch marks, poor wound healing, mental retardation in children

Question 26

_____ is the common precursor for all steroid hormones

Answer 26

cholesterol