Exam 2: Endocrine Part 2

Question 1

regulation of pineal gland-melatonin

Answer 1

circadian control from light signals, pathway to SCN to inhibit release
levels inc as light dec

Question 2

action of pineal gland-melatonin

Answer 2

setting sleep patterns relax somatic muscle tone

signals sexual maturation in animals

Question 3

melatonin decreasing with age

Answer 3

older people sleep less
insomnia increases
metabolic rate also decreasing so be careful what sleep meds you are giving

Question 4

composition of thyroid gland

Answer 4

2 lobes connected by isthmus

Question 5

2 categories of hormones produced in thyroid gland

Answer 5

large follicles: metabolic hormones
- regulated by pituitary

parafollicular cells: hormones in Ca regulation
- independent of pituitary control

Question 6

regulation of T3 and T4

Answer 6

negative feedback loop with TSH
hormones produced as part of thyroglobulin in the colloid of follicle
hormones cleaved off thyroglobulin before release
- thyroid not very soluble so need T4 to be on them in bloodstream
as you release get T3 in cell

Question 7

action of T3 and T4

Answer 7

inc production of glycolytic enzymes
stimulates ATP production
calorigenic effect(inc ATPase production and action)
chronotropy inc (heart rate)
inotropy inc (contractility)
T3 stronger with 24hr half life
T4 has 7 day half life

Question 8

majority of free hormone is T4 or T3?

Answer 8

T3

Question 9

globulins have higher affinity for T3 or T4?

Answer 9

T4

Question 10

What do T3 and T4 do when hit receptor

Answer 10

extra atp made, glyoclytic enzymes made, need mitochondria to move them!!!
atpase activity enhanced
gets heart to beat faster and inc motility in digestive tract bc when depolarize you release Ca and use atpaseactivity to get into storage

Question 11

thyroid and groiter

Answer 11

groiter: due to over stimulating or insufficient production and pituitary acts normal to kickstart thyroid
need more raw material - iodide pumps

Question 12

will you get a groiter in graves, iodide deficiency, hasimotos disease, diet cruciferous, pregnancy

Answer 12

graves dsease: yes
iodide deficiency: yes
hasimotos: no
cruciferous diet: no
pregnancy: yes

Question 13

what converts T4 to T3

Answer 13

T4 deiodinase

Question 14

in starvation what does the liver do

Answer 14

downregulates type 1 deiodinase (D1) and upregulates type 2 (D2)

Question 15

what converts T4 to rT3

Answer 15

D2

Question 16

rT3

Answer 16

tricks axis into thinking you have enough T3 in blood so you do not put out TSH, pituitary does not pick up the dec in metabolic rate

Question 17

what can cause transient hyperthyroidism in first trimester of pregnancy, stimulates TSH receptors on thyroid

Answer 17

human chorionic gonadotropin

Question 18

regulation of calcitonin

Answer 18

negative feedback loop in response to increased serum Ca levels

Question 19

action of calcitonin

Answer 19

brings Ca levels down
inhibits osteoclast activity-the breakdown of bone
promotes excretion of Ca in kidney by dec Ca permeability in loop of Henle
children: stimulates osteoblast activity

Question 20

is the regulation of calcitonin overseen by pituitary

Answer 20

NO

regulation is direct with no oversight from hypothalamus/pituitary

Question 21

regulation of parathyroid hormone

Answer 21

negative feedback loop in response to decreased serum Ca levels

Question 22

action of parathyroid hormone

Answer 22

inc Ca levels
inhibits osteoblast activity
inc production of osteoclasts
inc Ca permeability and reabsorption in loop of Henle
stimulates release of calcitrol from kidney
inc Ca absorption in intestines

Question 23

chief cells vs oxyphil cells

Answer 23

chief cells: only put out active hormone

oxyphil cells: dormant

Question 24

if old man with recent spinal fusion has low serum Ca levels, what would you check to determine the cause of lower Ca?

Answer 24

calcitrol - vitamin D levels

parathyroid- since just had surgery

Question 25

regulation of thymus-thymosins

Answer 25

stimulated by prolactin,
stimulated by interleukins released in response to infection and inflammation
inhibited by steroid hormone (stress and sex hormones)

Question 26

action of thymus-thymosins

Answer 26

promotes stem cell mitosis and T cell differentiation in bone marrow
regulates T cell maturation in thymus

Question 27

as you get older does your thymus inc or dec in size?

Answer 27

dec

Question 28

regulation of heart - natriuretic peptides

Answer 28

ANP release in response to distension of atrial cells
BNP released in response to stretch receptors in ventricles
secretion of both enhanced by high sodium

Question 29

action of heart - natriuretic peptides

Answer 29

dec Na and P
promotes vasodilation
inc glomerular filtration rate in kidney
dec kidney permeability to Na and water increasing excretion of both

suppresses thirst and taste bud salt sensitivity
inhibits aldosterone, renin, ADH release
stimulates lipolysis

Question 30

half life of natriuretic peptides

Answer 30

very short

30s to minute