Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

END 207: Physiology > Endocrine 11: Glucocorticoids > Flashcards

Endocrine 11: Glucocorticoids Flashcards

1
Q

Cells secreting Glucocorticoids

A
  • Zona Fasciculata of the Adrenal cortex
  • (small contribution from) Zona reticularis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

hormones that make up glucocorticoids

A
  • Hydrocortisone (cortisol): 95%
  • corticosterone: 4%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

describe the chemistry of glucocorticoid formation

A
  1. Cholesterol is freed from vacuoles
  2. it’s converted into pregnanolone in the inner mitochondrial membrane
  3. pregnanolone is converted in to 11-deoxycortisol in the endoplasmic reticulum
  4. 11-deoxycortisol is converted into Cortisol (glucocorticoid) in the mitcochondria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

75% of Cortisol in the plasma is transported via

A

corticosteroid binding globulin (CBG)= Transcortin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

15% of cortisol in the plasma is transported via

A

Albumin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

presentage of free (unbound) cortisol in the plasma

A

10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which form of cortisol is the active form

A

free (unbound) form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

explain why there is very few cortisol in urine

A

because most of it is bound to a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

which hormone stimulates production of CBG

A

Estrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When does CBG levels increase

A

during pregnancy

high levels of estrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When does CBG levels decrease

A

Liver Cirrhosis:
* impaired synthesis of plasma protiens (globulins)

Nephrosis:
* impaired nephron causing filtration of plasma proteins into urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe metabolism & excretion of Cortisol

A

Cortisol is conjugated into glucuronic acid, know as hepatic inactivation & excreted in urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When does impairment of Hepatic inactivation of Glucocorticoids take place

A
  • Liver disease
  • during surgeory
  • Other forms of stress
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe Mechanism of Action of glucocorticoids

A
  1. hormone passes through cell membrane (because steroid)
  2. it binds to Cytoplasmic receptor forming hormone-receptor complex (HRC)
  3. HRC enters the nucleus and binds to Hormone response element (HRE) on the DNA to facilitate mRNA transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Actions glucocorticoids are divided into

A
  • Permissive action
  • Physiological action
  • Pharmacological action
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Enumerate & describe permissive actions of Glucocorticoids

A

Allows for glycogenolysis:
* Cortisol augments activity of Glucagon hormone onto the liver to break down glycogen

Allows for Lipolytic effect of catecholamines & growth hormone

Allows Vasoconstrictor effect of Angiotensin II & Catecholamines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Effect of Cortisol on Carbohydrate metabolism

A

Hyperglycemic:

Stimulate Gluconeogenesis:
* protein catabolism to release aa in the blood
* stimulate enzymes for hepatic uptake of aa & convertion into glucose
* increase Hepatic release of glucose in the blood
* excess glucose converted into glycogen

Decrease Muscle & adipose tissue affinity to glucose (Anti-insulin):
* Decrease affinity of insulin receptors to insulin
* Decrease mobility of glucose transporters from cytoplasm to membrane
* Decrease the phosphorylation of glucose into G6P

18
Q

The only organs spared from anti-insulin effect of Cortisol are ___

A

Heart & brain

19
Q

Effect of Cortisol on protein Metabolism

A
  • Decrease protein synthesis
  • Increase protein catabolism
  • inhibit aa transportation into extraheptatic tissue
  • Increase aa transportation into Liver
20
Q

Effect of Cortisol on Fat Metabolism

A
  • Lipolytic
  • Increase FFA
  • (in diabetics) increase Ketone bodies =Ketogenic
21
Q

Effect of Cortisol on Appetite

A

Increase apetite by:
* Inducing Neuropeptide Y
* Suppressing CRH

Equivocal (decrease appetite):
* Stimulate Leptin Synthesis in adipocytes (negative feedback)

22
Q

Effect of Cortisol on Cardiovasvular system

A

Required to maintain normal ABP:
* Positive inotropic effect on the heart through Beta adrenergic receptors
* Decrease production of VD prostaglandins to maintain VC tone
* Helps maintain blood volume by decreasing permiability of Endothelium

23
Q

Effect of Cortisol on Kidney

A
  • Increase GBF to increase GFR
  • rapid excretion of water load
  • Responds to Acid load by:
    1. formation of ammonia from glutamate
    2. increase urinary phosphate excretion by reducing its reabsorption
24
Q

effect of Cortisol on CNS & Sleep

A
  • Modulates Behaviour, mood & excitability
  • Decrease REM sleep
  • Increase Slow wave sleep
  • Increase time spent awake
25
Q

Effect of Cortisol on blood cells

A

Increase all except Eosinophils & T lymphocytes (decrease):
* Increase RBCs
* Increase Platelets
* Increase Neutrophils, But inhibt its function

26
Q

Explain how cortisol decreases eosinophils

A
  • Apoptosis
  • increase their sequestration in Lung & spleen
27
Q

Explain how cortisol decreases T Lymphocytes

A

inhibts lymphocyte mitosis

28
Q

Importance of cortisol in fetal life

A

accelerate maturation of surfactant in the lungs

29
Q

Pharmacoglogical effect of Cortisol on bones

A

Inhibits bone formation:
* Decrease synthesis of type I collagen
* Decrease rate of formation of active osteoblasts
* Decrease absorption of Ca2+ & PO4- from intesine by antivitamin D
* Increase renal excretion of Ca2+ & PO4-

Increase in rate of bone resorption

30
Q

Major side effect of prescribing cortisol

A

Osteoporosis

31
Q

Pharmacoglogical effect of Cortisol on skin & Capillaries

A

Thinning

  • Fragility of Capillaries leading to easy rupture & intracutaneous hemorrhage
32
Q

Pharmacoglogical effect of Cortisol on Connective tissue

A
  • Inhibit collagen synthesis
  • Decrease prolifration of fibroblast
33
Q

Major problem facing pediatricians during corticosteroid therapy

A

Its combined effect on bone & CT antagonize growth

34
Q

Explain how glucocorticoids blocks inflammation

A
  • Stabilizing Lysosmal membranes
  • Decreases PG, IL1 & Leukotriens = inhibit VD, Capillary perimability, redness & Swelling
  • Inhibit Phagocytosis
35
Q

Pharmacoglogical effect of Cortisol on Allergy

A

Prevents histamine release & Blocks formation of leukotriens

36
Q

Pharmacoglogical effect of Cortisol on Immunity & Lymphoid tissue

A
  • Suppresses humoral immunity by Intefering with B lymphocyte antibody production & decreases Circulating Immunoglobulins
  • supress cellular immunity by blocking IL2 production thus decreasing T-lymphocyte proliferation
  • Decrease T lymphocyte production of interferon
37
Q

Explain why glucocorticoid is a double weapon in supressing immunity

A
  • Useful in prevention of rejection of Transplanted organs
  • Fulminates old infections + Carciongenic
38
Q

Describe factors affecting Hypothalamic secretion of CRH

A
  • Stress, increases CRH thus increase ACTH secretion
  • Circadian rhythm
39
Q

Cells secreting ACTH

A

basophilic Corticotrophs of anterior pituitary

40
Q

Mechanism of Action of ACTH on Adrenal Cortex cells

A
  1. Bind to G coupled receptor
  2. Activates adenyl cyclase to increase cAMP
  3. cAMP increases Protein Kinase A
  4. Ptn Kinase A phosphorylates Cholesteryl ester hydrolase enzyme
  5. Cholsteryl ester hydrolase converts cholesteryl esters to cholesterol for Cortisol synthesis

END 207: Physiology (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions