Endocrine- Bergfelt

Question 1

Endocrine System

Answer 1

Collection of ductless glands that secrete hormones directly into the circulatory system that target distant organs

Question 2

Endocrine Glands

Answer 2

ductless glands of the endocrine system that secret heir products, hormones, directly into teh cirulatory system

Question 3

Examples of endocrine glands

Answer 3

pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland

Question 4

Hormone signaling

Answer 4

hormone-receptor interactions

Question 5

Exocrine Glands

Answer 5

glands not of the endocrine system that secret their product through a duct or canal

Question 6

Examples of exocrine glands

Answer 6

salivary, sweat, mammary glands

Question 7

What are the two major systems involved in homeostasis?

Answer 7

nervous and endocrine system

Question 8

Where is the thyroid located?

Answer 8

on either side of the trachea, below the larynx

Question 9

Where are the parathyroid glands located?

Answer 9

external and internal to the surface of each lobe of the thyroid gland in cats and dogs

Question 10

What is the function of thyroid follicles?

Answer 10

epithelial cells that produce thyroid hormones

Question 11

What is colloid?

Answer 11

intracellular fluid rich in thyroglobulin

Question 12

Where are parafollicular cells located?

Answer 12

between thryoid follicles

Question 13

What do parafollicular cells secrete?

Answer 13

produce calcitonin

Question 14

What do cheif cells produce?

Answer 14

parathyroid hormone

Question 15

What are the two main precursor substances to thyroid hormone synthesis?

Answer 15

Iodide and thyroglobulin (tyrosine aa)- from colloid

Question 16

What is the most bioactive form of thyroid hormone?

Answer 16

T3

Question 17

What is the most abundant form of thyroid hormone?

Answer 17

T4

Question 18

What produces thyroid- releasing hormone?

Answer 18

produced by the hypothalamus, binds to TRH receptors on anterior pituitary gland thyrotropes

Question 19

What is the function of thyroid stimulating hormone?

Answer 19

stimulates T3 and T4 synthesis

Question 20

How does T3 and T4 function as a negative feedback loop?

Answer 20

As T3 and T4 blood concentrations increase, inhibit TSH and TRH, inhibiting thryoid epithelial hormone production

Question 21

The T3 and T4 negative feedback loop acts on what two organs?

Answer 21

hypothalamus and anterior pituitary

Question 22

What are external control factors to the thyroid gland?

Answer 22

cold, diet and stress

Question 23

What is the effect of cold on the thyroid?

Answer 23

increases T3 levels

Question 24

What is the effect of high carb. diet on the thyroid?

Answer 24

increase in T3 levels, increase metabolic rate

Question 25

What is the effect of low carb. diet on the thyroid?

Answer 25

decrease in T3 levels, decrease in metabolic rate

Question 26

The transport of T3 and T4 requires what and why?

Answer 26

Requires the binding to transport proteins because T3 and T4 are fat soluble (hydrophobic)

Question 27

what are some examples of thyroid binding proteins?

Answer 27

thyroid binding globulin, transthyrein and albumin

Question 28

What does T3 bind to?

Answer 28

mitochondria nd nuclear receptors

Question 29

What does the binding of T3 to mitochondria create?

Answer 29

activates oxidative phosphorylation and ATP synthesis

Question 30

What does the binding of T3 to nuclear receptors create?

Answer 30

increases mRNA transcription, translation and an increase in protein synthesis

Question 31

What are the primary organs for clearance of thyroid hormones and metabolites?

Answer 31

liver and kidneys

Question 32

T4 glucuronidation is facilitated by which liver enzyme?

Answer 32

T4, UDP-glucuronyltransferase

Question 33

What can happen if you increase UDP-glucuronyltransferase production in the liver with drugs or toxins?

Answer 33

increase the loss of T4, increases loss of T3: acute hypothyroidism

Question 34

the production of calcitonin is stimulated by?

Answer 34

high extracellular or blood calcium levels

Question 35

What is the function of calcitonin?

Answer 35

decrease Ca levels

Question 36

What tissues do calcitonin target?

Answer 36

bone, kidney and digestive tract

Question 37

What is the effect of calcitonin on bone?

Answer 37

inhibits osteoclast activity, stimulates storage of Ca

Question 38

What is the effect of calcitonin on the kidney?

Answer 38

inhibits tubular reabsortion of Ca, stimulates excretion of Ca

Question 39

What is the effect of calcitonin on the digestive tract?

Answer 39

inhibits uptake of Ca, stimulates excretion of Ca

Question 40

What stimulates increased production and secretion of parathyroid hormone?

Answer 40

low extracellular or blood Ca levels

Question 41

What organs do PTH target?

Answer 41

bone, kidney and digestive tract

Question 42

what is the effect of PTH on bone?

Answer 42

stimulates osteoclast activity, increasing bone digestion

Question 43

What is the effect of PTH on the kidney and GI?

Answer 43

reabsorption of Ca and inhibiting Ca excretion

Question 44

Hypothyroidism

Answer 44

decreased synthesis and secretion of thyroid hormones, associated with decreased metabolic rate

Question 45

Primary hypothryoidism is classified as

Answer 45

thyroid gland dysfunction and is the most common

Question 46

Secondary hypothyroidism is classified as

Answer 46

pituitary gland dysfunction and is rare (pituitary gland tumor)

Question 47

Tertiary hypothyroidism is classified as

Answer 47

hypothalamic dysfunction, rare/ not described

Question 48

Congenital hypothyroidism is classified as

Answer 48

thyroid gland hyperplasia | reported in foals as a result of mares diet, low I- during pregnancy