adrenal glands and gonads Flashcards
where are adrenal glands found
superior to the kidneys
name the 2 separate gland structures of adrenal glands
Adrenal cortex (85%)
and adrenal medulla (15%)
(neural tissue)
name the 3 zones in the Cortex-3 steroid hormones
of adrenal glands
Outer zone:
mineralocorticoids -mineral homeostasis
Middle zone:
glucocorticoids -glucose homeostasis
Inner Zone:
androgens -steroid masculinising hormones
explain the Mineralocorticoids in the outer zone of the cortex - 3 steroid hormone
Aldosterone is the major form – regulates mineral & water balance by action on kidneys
Stimulates Na+ reabsorption from urine to blood
Stimulates excretion of K + into urine
explain the steps of mineralocorticoids on mineral and water balance
- dehydration, sodium deficiency or hemorrhage
- decrease in blood volume and blood pressure
- in the kidney, renin is converted to ACE by angiotensin 1
- ACE is converted to aldosterone in the adrenal cortex by angiotensin 2
- then, in the kidneys, more sodium and water return to blood and more potassium eliminated in urine
- this causes increase in blood volume and pressure
explain the glucocorticoids in the middle zone of the cortex - 3 steroid hormone
e.g. cortisol (hydrocortisone)
Increase rate of protein breakdown
Stimulate liver formation of glucose
Breakdown of triglycerides in adipose tissue
Anti-inflammatory effects:
- Inhibit white blood cells
Depresses immune system
Regulated by negative feedback through hypothalamus
explain the links between Immune System Health and Low Cortisol
a high cortisol level suppresses the immune system
a low cortisol can result in uncontrolled immune system action.
- The immune defences become overly aggressive and not only attack invading organisms, but mount allergic reactions against many environmental agents.
“Allergic reactions” can also be directed against endogenous antigens
- the components of our own bodies.
Autoimmune conditions such as lupus & rheumatoid arthritis can activate during periods when cortisol levels are low.
explain androgens in the inner zone of the cortex - 3 steroid hormone
Small amount secreted from adrenal cortex
Contribute to libido in females
Converted to oestrogens by other body tissues
Stimulate axillary hair growth in both male & female
Contribute to adolescent growth spurt
what cells does adrenal medulla consist of
sympathetic post ganglionic cells
adrenal medulla is stimulated by what
preganglionic sympathetic neurons
what does adrenal medulla release
Epinephrine and norepinephrine
what effects does adrenal medulla give
systemic sympathetic effects
when does adrenal medulla occur
during strong physiological stress
what are gonads
ovaries and testes
what do gonads produce
Both produce gametes and release sex steroids
