Lecture #23: Endocrine System--Adrenal Glands and Pancreatic Hormones

Question 1

What the subdivisions of the Andrenal Glands?

Answer 1

Zone glomerulsa, Zona Fasiculata, and Zona Recturlaris

Question 2

What does zone glomerulsa secrete?

Answer 2

(where target cells for
angiotensin II secrete mineralocorticoids, mainly
aldosterone)

Question 3

What does Zona Fasiculata secrete?

Answer 3

where target cells for ACTH

secrete glucocorticoids, mainly cortisol

Question 4

What does the Zona Reticularis secrete?

Answer 4

where target cells for ACTH

[mainly] secrete androgens

Question 5

What is Mineralcorticoids?

Answer 5

Part of the Zona Glomerulosa
• The major human mineralocorticoid is
aldosterone

• Functions of aldosterone
1. increases absorption (GI) and reabsorption (kidney) of Na+ with Cl-; bicarbonate and
water following it
2. promotes excretion of K+ and H+ (secretion in kidney)

• Aldosteronism results from hypersecretion of mineralcorticoids– results in high BP caused by retention of Na+and the resultant increase in plasma volume

Question 6

What is Glucocorticoids?

Answer 6

Part of Zona Fasciculata
• Target cells for ACTH produce glucocorticoids. Cortisol is the major human glucocorticoid

Also raise blood
pressure by increasing sensitivity of blood vessels to other hormones which
cause vasoconstriction

Question 7

What is Cortisol’s main key functions in regulation of metabolism during stress?

Answer 7

1. increase rate of protein catabolism
   and lipolysis
2. promote gluconeogenesis
3. provide resistance to stress by making nutrients available

Question 8

How are glucocortoids anti-inflammatory and immunosuppressive?

Answer 8

1. by reducing release of histamine from mast cells
2. by decreasing capillary permeability
3. by depressing phagocytosis
4. by inhibiting white blood cells

Question 9

If a heart transplant patient receives predisone (a glucocorticoid) to help prevent rejection of the transplanted
tissues, will blood levels of ACTH and CRH be high or low?

Answer 9

Low! (due to negative feedback

suppression of ACTH & CRH release!)

Question 10

What happens in the negative feedback regulation of glucorticoid secretion?

Answer 10

A highlevel of CRH and a low level of glucorticoids promote the release of ACTH, which stimulates glucocortoid secretion by the adrenal corte.

Question 11

What is cushing’s syndrome?

Answer 11

Hypersecretion of glucocorticoids

Question 12

What are some of the affects of cushing’s syndrome?

Answer 12

• Redistribution of fat to face
• Spindly arms & legs due to muscle loss
• Poor wound healing
• Bruises easily

Question 13

What is Addison’s Disease?

Answer 13

Hyposecretion of glucorticoids and aldosterone

Question 14

What are the affects of addisons disease?

Answer 14

• Hypoglycemia, muscle weakness, low BP
• Dehydration due to decreased Na+ in blood
• Mimics skin darkening effects of MSH
• Potential cardiac arre

Question 15

What does Eustress mean?

Answer 15

Prepares us to meet certain challenges and is helpful.

Question 16

What does Distress mean?

Answer 16

It is harmful

Question 17

What causes a stress arise?

Answer 17

1. Increased heart rate and force of beat
2. Constriction of blood vessels of most viscera and skin
3. Dilation of blood vessels of heart, lungs, brain, and skeletal muscles
4. Contraction of spleen
5. Conversion of glycogen into glucose in liver
6. Sweating
7. Decrease in digestive activities
8. Water rentention and elelvated blood pressure
9. Dilation of airways

(Flight or flight responses)

Question 18

What is the second stage of stress response?

Answer 18

Resistance reaction, which is initiated in large part by hypothamlamic releasing hormones and is a longer lasting response.

Question 19

What hormones are included with resistance reaction?

Answer 19

Corticotropin Releasing hormone, growth homone releasing hormone, and thyrotropin releasing hormone

Question 20

How does Corticotropin Releasing hormone (CRH) contribute to resistance reaction?

Answer 20

Stimulates the anterior pituitary to secrete ATCH, which in turn stimulates the adrenal cortex to increase release of cortisol.

Cortisol then stimulates gluconegenesis by liver cells, which leads to Lipolysis, and catabolism of proteins into amino acids.

Tissues throughout the body can use the resulting glucose, fatty acids, and amino acids to produce ATP or to repair damaged cells. Cortisol also reduces inflammation.

Question 21

How does GHRH contribute to resistance reaction?

Answer 21

Stimulates lipolysis and glycogenolysis, breakdown of glycogen to glucose, in the liver.

Question 22

How does TRH contribute to resistance reaction?

Answer 22

Promotes secretion of thyroid hormones, which stimulate the increased use of glucose for ATP production.

Question 23

What are Androgens?

Answer 23

Target cells for ACTH (mainly)
produce androgens in small amounts (Zona Reticularis)

– insignificant in males
– may contribute to sex drive in females
– converted to a form of estrogen in
postmenopausal women

Question 24

What is the major adrogen that is screted into the adrenal gland?

Answer 24

dehydroepiandrosterone (DHEA)

Question 25

What type of cells are in the Adrenal Medulla?

Answer 25

• Chromaffin cells receive direct innervation from sympathetic nervous system

Question 26

How are chromaffin cells made?

Answer 26

– develop from same tissue as postganglionic
sympathetic neurons
– acts as a modified sympathetic ganglion

Question 27

What two hormones are produced in the adrenal medulla?

Answer 27

• Produce 80% epinephrine (adrenaline)
and 20% norepinephrine (noradrenaline)

• Hormones are sympathomimetic
– effects mimic those of sympathetic NS
– cause fight-flight behavior

Question 28

Draw or describe the regulation of blood glucose in the pancreas.

Answer 28

1. Blood glucose (hypoglycemia) simulates alpha cells to secrete
2. Glucagon acts on hepatocytes (liver cells) to: convert glycogen into glucose and form glucose from lactic acid and certain amino acids
3. Glucose released by liver cells raised blood glucose level to normal
4. If blood glucose continues to rise, hyperglycemia inhibits release of glucagon
5. High blood glucose (hyperglycemia) stimulates beta cells to secrete
6. Insulin acts on various body cells to:
   Accelarate facilitated diffusion of glucose into cells
   Speed conversion of glucose into glycogen
   Increase uptake of amino acids and increase protein synthesis
   Speed Synthesis of fatty acids
7. Blood glucose level falls
8. If blood glucose continues to fall, hypoglycemia inhibits release of insulin

Question 29

What is Diabetes Mellitus?

Answer 29

• Diabetes mellitus marked by hyperglycemia
– excessive urine production (polyuria)
– excessive thirst (polydipsia)
– excessive eating (polyphagia)

Question 30

What is type I and type II of diabetes mellitus?

Answer 30

• Type I –> deficiency of insulin (typically juvenile onset)
• Type II –> insulin insensitivity (typically adult onset)