Endocrine System-2 Flashcards
The cortex releases some 2 dozen steroid hormones collectively called
Corticosteroids
The adrenal medulla is
Derived from embryonic nervous tissue and contains sympathetic nerve fibers
What is under control of the sympathetic nervous system
Adrenal medulla
The sympathetic nervous system…
Results in secretion of norepinephrine and epinephrine from the adrenal medulla
What does the zona glomerulosa release
Aldosterone
The release of aldosterone is controlled by the…
Kidneys renin-angiotensin system
The Renin-Angiotensin system is activated when…
Blood pressure drops or when NA+ levels in the blood drop
What is aldosterone’s main target organ and what is it’s main effect?
Kidney; to increase sodium and water absorption and increase K+ excretion
What is under control of the anterior pituitary?
Zona fasciculata
CRF=
ACTH=
Corticotropin releasing factor
Adrenocorticotropic hormone
What is released throughout a normal person’s day?
Cortisol
When are cortisol levels the highest/lowest?
Highest-in the morning
Lowest- throughout the day
Cortisol…
- released in circadian rhythm
- increases blood sugar levels
- releases a lot when stressed
What are characteristics of acute major depression and other forms of chronic stress?
Dysfunction of the HPA axis (hypothalamic pituitary adrenal) with elevated plasma cortisol levels
What does cortisol do to the body?
- Cortisol raises blood sugar levels by stimulating the conversion of FA and AA to glucose
- Cortisol raises blood glucose levels by stimulating breakdown of glycogen in liver
- cortisol has a vasoconstriction effect
- cortisol has an anti-inflammatory effect
Cushing’s disease (hypersecretion of cortisol)
Causes:
1) pituitary tumor
2) adrenal tumor
3) large doses of glucocorticoid drugs
Symptoms:
- hyperglycemia (steroid diabetes)
- round face
- fat deposition around midline
- weak bones and thinning muscles
- water and salt retention (hypertension)
Addison’s disease (hyposecretion)
Hyposecretion of hormones from adrenal cortex. Affects both aldosterone and cortisol
Symptoms
- weight loss
- low NA+ and glucose levels in blood
- high K+ levels in blood
- weakness or fatigue
- severe dehydration and hypotension
- salt craving
Addison’s disease may be caused by…
1) the immune system mistakenly attacking the adrenal gland (autoimmune disease)
2) infections (such as tuberculosis, HIV, fungal)
3) tumors
What is used to treat Addison’s disease
Corticosteroid replacement therapy
What is the main androgen secreted by the adrenal gland?
Testosterone
Target tissues…
Contain an enzyme called aromatase which converts some testosterone to estrogen
Aromatase
This enzyme becomes important when females are diagnosed with estrogen receptor and breast cancer
What is the function of estrogen and testosterone from the adrenal?
Sex hormones promote bone growth and to maintain muscle mass in both males and females
Pineal gland is involved in what
Awake/sleep cycles
What hormone does the pineal gland secrete
Melatonin
