Lecture 7 Flashcards
(18 cards)
Where is the adrenal gland located?
Cranial to the kidney
What is the adrenal gland composed of?
2 layers
Adrenal cortex (outside)
Adrenal medulla (inside)
What are the 3 zones of the cortex?
Zona Glomerulosa
Zona fasciculata
Zona reticularis
What does the zona glomerulosa secrete?
Mineralocorticoids (aldosterone)
Primary function of aldosterone?
Increase Na transport in the distal tubules and collecting ducts of the kidney
- Helps maintain plasma volume and therefore maintain blood pressure
Explain the function of aldosterone
Increases gene expression of Na transporters (apical membrane) and Na/K ATPase (basolateral membrane)
More Na is reabsorbed from urin in the ECF and plasma and K lost in urine
Water and Cl from Na
Net effect = expanded plasma volume and increase in blood pressure
What does the zona reticularis - inner layer, secrete?
Minor sex hormones
What does the zona fasciculata - middle layer, secrete?
Glucocorticoids, (mainly cortisol)
How are glucocorticoids transported in blood?
Proteins bound ~ 90%
~ 10% unbound and therefore active
5 Primary functions of glucocoticoid
- Increase blood glucose
- Long-term stress response
- Anti-inflammatory effects
- Permisive Effets
- Other
How does glucocorticoid increase blood glucose?
Increase hepatic gluconeogenesis
Decrease uptake of blood glucose into tissues
increase catabolism of proteins and lipid stores
- more a.a. availabel for gluconeogeneiss
- more a.a. and f.a. available as alternative energy source
3 reasons why cortisol might be helpful in stressful situation
Increase blood glucose (short term) for the brain
Increase blood a.a. for tissue repair (long term)
Increase f.a. as energy source of muscles
How does cortisol serve as an anti-inflammatory?
Blocks production of cytokines involved in inflamation
What does it mean that effects of cortisol as anti-inflammatory are dose-dependent?
Low (normal) cortisol concentration have little effect
High (stress) cortisol levels are anti-inflammatory
Very high concentrations can cause immune system suppresion
What are the permissive effects of cortisol?
Enhances the effect of catecholamine in the body
3 “other effects” effects of cortisol?
Induction of parturition - can cause abortions
Increase appetite in some animals
Increase urination - possible inhibition of ADH
What are some of the uses of cortisol mimicing drugs for anti-inflammatory
Reduce swelling after dificult caving
Sprains
Allergic reactions and skin conditions
Why would we use a high dose of cortisol mimicing drugs?
Immunosuppressive effects
- Immune mediated disease
