Endocrine Physiology - Part 3

Question 1

What is the name of the endocrine tissue in the pancreas?

Answer 1

Islets of Langerhans

Question 2

What are the 4 cell types within the Islets of Langerhans? What do they produce?

Answer 2

a-cells: produce glucagon
b-cells: produce insulin
D-cells: produce somatostatin
PP-cells: produce pancreatic polypeptide

Question 3

What is the half life of insulin?

Answer 3

5-8 mins

Question 4

What is the effect of insulin on carb, fat and protein metabolism?

Answer 4

• stimulates glucose entry and increases glycogen storage in muscles and fat tissue
• increases glycogen production and storage in the liver
• decreases gluconeogenesis by the liver
• promotes fat synthesis
• promotes protein synthesis

Question 5

What is the general effect of insuli?

Answer 5

• decrease plasma conc. of glucose
• increase cell stores of glycogen
• decreased plasma conc. of FFA
• increased cell stores of triglycerides
• decreased plasma conc. of AAs

Question 6

What is the most powerful stimulator of insulin production?

Answer 6

rising blood glucose level above normal

Question 7

What are some stimulators of insulin production?

Answer 7

• rise in blood AA and FA levels
• vagus stimulation
• someGI hormones
• hyperkalemia

Question 8

Where is glucagon secreted?

Answer 8

by alpha cells of the pancreas

Question 9

What is the effect of glucagon?

Answer 9

• catabolism of nutrients, especially between meals.
• results in an increase in blood glucose levels
• opposite of insulin

Question 10

How is glucagon regulated?

Answer 10

• increased secretion from decreased blood glucose levels as in exercise, starvation, sympathetic activation, etc.,

Question 11

How do bird glucagon levels differ from mammals??

Answer 11

birds have nearly twice as much glucagon - presumably due to higher energy requirements

Question 12

What happens if there is too much glucose in plasma?

Answer 12

• glucosuria (in urine)
• polyuria (frequent urination) due to osmotic diuresis
• polydipsia (thirst) due to osmotic diuresis
• swelling of eye lense
• chronic bladder infections
• oxidative damage to capillaries
• poor circulation in eye
• cataracts
• ketoacidosis

Question 13

How does the body regulate glucose homeostasis

Answer 13

• insulin after feeding

- glucagon in starved state

Question 14

What is the effect of catecholamines on blood glucose level?

Answer 14

• increases blood glucose level

- helpful to combat stress situation in particular during physical activity

Question 15

What is the effect of glucocorticoids on blood glucose levels?

Answer 15

• increase blood glucose level

- necessary for long term starvation and during stress

Question 16

What is the effect of GH and Thyroid hormones on blood glucose levels?

Answer 16

• increase blood glucose level

- GH promotes fat and protein metabolism

Question 17

What is diabetes millitus?

Answer 17

lack of insulin function or glucagon excess

Question 18

What is diabete insipidus?

Answer 18

lack of ADH function

Question 19

What are the symptoms of diabetes mellitus?

Answer 19

• hyperglycemia
• glycosuria
• polyuria
• polyphagia

Question 20

What is Type I DM?

Answer 20

• total lack of insulin
• requires exogenous insulin for survival
• results from autoimmune destroying beta cells
• most common type in dogs

Question 21

What is Type II DM?

Answer 21

• non-insulin dependent DM
• insulin secretion normal or increased but target cells don’t respond
• most common type in cats

Question 22

Where are the parathyroid glands?

Answer 22

beside or within the thyroid gland

Question 23

What is secreted by the parathyroid glands?

Answer 23

parathyroid hormone (PTH)

Question 24

What is the action of PTH?

Answer 24

increase plasma Ca++ and lower (PO4)3-

Question 25

What is the target tissue of PTH?

Answer 25

bone, kidneys and intestine

Question 26

How is PTH regulated?

Answer 26

• low plasma Ca++ level triggers secretion

- parathyroid cells have Ca sensing receptors on their surface

Question 27

What is the action of Calcitonin?

Answer 27

• produced by C cells of thyroid gland

- decrease plasma Ca++ level (weak affect)

Question 28

What is the most important hormone in regulating Ca in fish

Answer 28

stanniocalcin

Question 29

What animals may require vitamin D suplementation

Answer 29

heavily furred animals, animals at high latitudes, animals kept indoors, etc.

Question 30

What is the function of Vitamin D?

Answer 30

enhances:

• intestinal absorption of Ca++ and (PO4)3-
• increased bone mineralisation

Question 31

What disease can be caused by Vitamin D deficiency in animals?

Answer 31

rickets in prepubertal animals

osteomalacia in adults

Question 32

What disease is caused by lack of Ca++ in lactating cows?

Answer 32

parturient paresis (milk fever)

Question 33

What other organs have secondary endocrine functions?

Answer 33

• intestines
• kidneys
• heart
• gonads

Question 34

What hormone is produced by the heart?

Answer 34

atrial natriuretic peptide (ANP)

Question 35

What stimulus releases ANP?

Answer 35

increased BP, increased blood volume, increased blood Na+

Question 36

What is the target tissue of ANP?

Answer 36

renal tubules mainly

Question 37

What is the effect of ANP?

Answer 37

increases Na+ secretion mainly

Question 38

What hormones are released from the kidneys?

Answer 38

1. Erythropoietin

2. Renin-angiotensin-aldosterone system (RAAS)