Endo Lec 3 Flashcards
adrenal gland structure (2)
- cortex
- medulla
adrenal gland -cortex (structure)
- zona glomerulosa
- zona fasciculata
- zona reticularis
zona glomerulosa produces (general)
-aldosterone
zona fasciculata produces (general)
-cortisol and small amount of androgens
zona reticularis produces (general)
-androgens (DHEA & androstenedione) and small amount of cortisol
adrenal gland medulla produces
epinephrine and norepinephrine
corticosteroids (def.)
hormones produced by the adrenal cortex
hormone family produced by zona glomerulosa
mineralocorticoids
hormone family produced by zona fasciculata
glucocorticoids
hormone family produced by zona reticularis
androgens
DHEA stands for
dehydroepiandrosterone
mineralocorticoids example
aldosterone
glucocorticoids example
cortisol
androgens example
DHEA
androstenedione
corticosteroid synthesis
cholesterol –> progesterone –> mineralocorticoids, glucocorticoids, adrenal androgens
major actions of aldosterone (4)
- increased Na+ reabsorption by kidney
- increased water reabsorption by kidney (depends on Na+)
- increased K+ secretion by the kidney
- increased H+ secretion by the kidney
mechanism of aldosterone action (Na+)
aldosterone affects Na+ channel (luminal membrane), Na+/K+ ATPase (basolateral membrane)
mechanism of aldosterone action (H+)
aldosterone affects Na+/H+ carrier insertion into luminal membrane
control of aldosterone secretion (↑ aldosterone because..)
↓ vol of ECF/BP/Na+ (via renin-aldosterone system)
↑ K+ in ECF
aldosterone secretion is not under the control of
an anterior pituitary tropic hormone
cortisol general functions
-affects metabolism of glucose
cortisol secretion is increased during
stress conditions
cortisol maintain and protects
the body under stress conditions (chronic- long term)
cortisol (non-stress conditions) effect
permissive action on epinephrine and norepinephrine that exert control on vascular tone to maintain normal blood pressure
7 metabolic effects of cortisol
- increase in blood glucose (hyperglycemia)
- increase in glucose availability for CNS
- decrease in glucose utilization by peripheral tissues
- increase in glucose formation in liver (gluconeogenesis)
- increase in glycogen synthesis in liver
- increase in protein breakdown
- increase in fat breakdown
7 actions of cortisol on immune system
- decrease in lymphocyte number
- decrease in lymph node size
- reduced humoral and cellular immunity
- decreased production of inflammatory substance, such as leukotriene and prostaglandins
- decreased capillary permeability and prevention of neutrophil diapedesis to site of infection and edema
- reduction in proteolytic content release from lysosomes
- increased susceptibility to infection
pharmacological use of cortisol
suppress organ rejection after transplantation
cortisol effects during fetal and neonatal life
- required for development of CNS (brain)
- GIT, adrenal gland
- lungs (surfactant synthesis)
cortisol secretion controlled (mechanism)
stress/diurnal rhythm–> + CRH (hypothalamus)—> + ACTH (anterior pituitary)–> +cortisol (adrenal cortex)
cortisol –> - ACTH
cortisol –> - CRH
8 stress factors examples
- Heavy exercise
- Prolonged cold exposure
- Infection
- Shock
- Decreased oxygen supply
- Sleep deprivation
- Pain
- Fright
Conn’s syndrome (cause)
-too much aldosterone
Conn’s syndrome symptoms (5)
- hypernatremia (high Na+)
- increase in volume of ECF
- increase in blood pressure (hypertension),
- hypokalemia (low K+)
- metabolic alkalosis
Addison’s syndrome (cause)
- too little aldosterone
- too little cortisol
Addison’s syndrome symptoms (aldosterone) (3)
- hypotension
- metabolic acidosis
- hyperkalemia (high K+)
Addison’s syndrome symptoms (cortisol) (2)
- decrease in blood glucose
- increased skin pigmentation
Cushing’s disease (cause)
-too much cortisol
Cushing’s disease symptoms (3)
- increase in blood glucose
- muscle wasting, “MOON face”, “BUFFALO HUMP”
- decreased resistance to infection
virilization (masculinization) in females (cause)
-too much adrenal androgens
reduced hair growth, decreased sexual response in females (cause)
-too little adrenal androgens
catecholamines (def.)
hormones made by adrenal medulla hormones
synthesis of catecholamines
tyrosine–> dihydroxyphenylalanine (DOPA) —> dopamine –> noradrenaline (norepinephrine) –> adrenaline (epinephrine)
catecholamines examples
- adrenaline
- noradrenaline
___% of the catecholamines released from adrenal medulla is adrenaline
80%
regulation of catecholamine secrection
splanchnic nerve (sympathetic preganglionic nerve) simulates release of adrenaline/ noradrenaline from chromaffin cells in adrenal medulla
chromaffin cells release (two hormones)
adrenaline/noradrenaline
major actions of catecholamines (adrenaline & noradrenaline) on cardiovascular system (4)
↑heart rate
↑force of contraction
↑cardiac output
↑blood pressure
major actions of catecholamines (adrenaline & noradrenaline) on smooth muscle (3)
dilation of pupils
bronchodilation
↓ GIT motility
major actions of catecholamines (adrenaline & noradrenaline) on metabolism (3)
↑ glycogenolysis (skeletal muscle and liver)
↑ lipolysis
↑gluconeogenesis
chronic long term stress hormone
cortisol
acute short term stress hormone
medullary hormones (adrenaline/noradrenaline)
