4.3 Endocrine

Question 1

TSH stimulates all activities of the ______ except?

Answer 1

thyroid EXCEPT storage

Question 2

TSH stimulates what 4 main activities?

Answer 2

1) thyroglobulin synthesis in follicle
2) iodid trapping by follicle
3) conversion of iodide to iodine (peroxidase)
4) iodination of tyrosines of thyroglobulin

Question 3

storage of iodinated thyroglobulin is in?

Answer 3

colloid

Question 4

TSH made/secreted by?

Answer 4

anterior pituitary

targets thyroid follicle

Question 5

what AA is iodated to make T3 and T4?

Answer 5

tyrosine

Question 6

iodide or iodine is used to iodinate thyroglobulin?

Answer 6

iodiNe

Question 7

Why doesn’t TSH promote storage?

Answer 7

bc once we make T3 or T4 we don’t want them to STAY in the colloid, we want them taken back up by the follicle and released into blood

Question 8

What is MIT?

Answer 8

monoiodotyrosine= tyrosine with ONE iodine bound

Question 9

what is DIT?

Answer 9

diiodotyrosine= tyrosine with TWO iodines bound

Question 10

both MIT and DIT remain linked to thyroglobylin while in the ____?

Answer 10

colloid
*Not until thyroglobulin is taken out of colloid back into follicle by penocytosis does LYSOSOMAL PROTEASE start breaking bonds to release T3 or T4

Question 11

roles of peroxidase?

Answer 11

1) convert iodide to iodine
2) coupleing of MIT and DIT into T3
and DIT and DIT into T4
3)attachment of iodine to thryroglobulin

Question 12

TSH > pinocytosis of _______ > degradation by ________ > T4 and T3 released into cytoplasm and then into circulation

Answer 12

1. TSH
2. pinocytosis of colloid droplets
3. degradation by lysosomal protease
4. T4 and T3 released into cytoplasm
5. T4 and T3 into circulation

Question 13

T4 conversion to T3 happens where?

Answer 13

liver

Question 14

90% of intracellular (in cell) thyroid is?

Answer 14

T3

Question 15

90% of thyroid hormone coming out of the thyroid is?

Answer 15

T4

Question 16

thyroid hormones are _____ of cellular activity? explain

Answer 16

modulators

*increase metabolic activity and play essential role in growth and development

Question 17

any issue with iodine causes?

Explain how

Answer 17

global detramental affects bc thyroid hormones affect so many cells
*hypothyroidism
=decrease iodine > can’t make T3/T4 > decrease - feedback inhibition of hypo and pit > increase TSH levels > excessive stimulation of thyroid = goiter

Question 18

thyroid hormones diffuse through cells membranes why?

Answer 18

so they canbind on chromatin and alter transcriptions, translation, and protein synthesis

Question 19

thyroid hormones bind to receptors on?

Answer 19

chromatin

Question 20

explain the regulation of thryoid hormone?

Answer 20

> TRH > anterior pituitary > TSH > thyroid > T4/T3

***- feedback important

Question 21

what is the most important regulator of thyroid hormone

Answer 21

negative feedback

Question 22

the cold stimulus of the hypothalamic temperature regulatory center influences what function?

Answer 22

thyroid function

• in human infants and other mammals (minimal or nonexistent in adults)
• hypothalamic secretion of TRH is initiated via neuroendocrine reflex involving peripheral cold receptors

Question 23

neuroendocrine reflex involves?

Answer 23

peripheral cold receptors of the hypothalamis; can initiate TRH secretion

Question 24

how does stress affect thyroid hormone secretion?

Answer 24

stress increases cortisol > inhibition of hypothalamus > decrease TRH, TSH, and T4/T3

Question 25

main role of cortisol

Answer 25

regulate hormone levels in the blood (brings nutrients out of storage) *also inhibits TSH secretion

Question 26

hypothyroidism

Answer 26

inadequate secretionof thyroid hormones

Question 27

hyperthyroidism

Answer 27

oversecretion of thyroid hormones

Question 28

both hyperthyroidism and hypothyroidism results in?

Answer 28

goiter

Question 29

what is goiter

Answer 29

thyroid hypertrophy

Question 30

hypothyroidism causes

Answer 30

1) tumor = compressing some structure within the hypothalamus/ ant pit/ thyroid axis 2) iodine deficiency (most common) - --usually endemic to a particular region of the world

Question 31

how does USA avoid endemic goiter?

Answer 31

we put iodine in salt to avoid hypotheyroidism

Question 32

effects of hypothyroidism?

Answer 32

``` decreasedmetabolic rate less heat production proteun synthsis nutrient utilization oxygen consumption synaptic acitivty ```

Question 33

general symptoms of hypothyroidism?

Answer 33

weight gain | decreased cold tolerance, growth rate, repisration, heart rate, cardiac output, altertness

Question 34

why would hypothyroidism decrease tolerance to cold?

Answer 34

bc lower metabolic rate so less heat production

Question 35

what is cretinism?

Answer 35

hypothyroidism in children/infants

Question 36

why is cretinism such a big deal?

Answer 36

child becomes short of stature, gains weight and can have mental retardation issues if not treated

Question 37

what does cretinism effect orally?

Answer 37

delayed primary tooth eruption, enamel hypoplasia, macroglossia *large tongue

Question 38

define macroglossia

Answer 38

enlarged soft tissue; accumulation of mucopolysaccarrides in soft tissue

Question 39

what is myxedema?

Answer 39

hypothyroidism in adults; enlarged soft tissue

Question 40

hypothyroidism in adults symptoms?

Answer 40

- myxedema - dry and/or loss of hair - subnormal body temperature, hoarse voice, muscle weakness, slow tendon jerk