Endocrine 2 Flashcards
Adrenal Medulla
Part of the sympathetic ANS
- composed of cells called chromaffin cells
Chromaffin cells -> sympathetic neurons
75% epinephrine
25% norepinephrine
Chromaffin cells
Catecholamines
- 75% epinephrine
- 25% norepinephrine
Effects of epinephrine/norepinephrine
-> fight or flight
- fight or flight controls secretion of
epinephrine/norepinephrine via direct
neural control
- increased heart rate
- vasoconstriction
(except for skel muscle, cardiac muscle,
CNS) - increased BP
- pupils dilate
- increased respiration
- bronchiodilater (lungs open up more)
- increased glucose in blood
Stress + the Adrenal
Stress
- > adrenal cortex (more sustained)
- > aldosterone - higher BP
- > cortisol - higher glucose in blood - > adrenal medulla (intense immediate stress)
- > epinephrine
- > norepinephrine
- higher BP
- higher glucose in blood
*cortisol enhances the effects of epinephrine and norepinephrine
Disorder of adrenal medulla
Hyper secretion
- > pheochromocytoma
- causes by a chromaffin tumor
- secretes epinephrine inappropriately
Pancreas
Both endocrine and exocrine glands
- 95% of cells -> acinar cells
Acinar cells
-> secrete pancreatic juice (enzymes)
- released through pancreatic duct into the
small intestine
5% of cells -> islet cells
Islet cells
- > alpha cells - glucagon
- > beta cells - insulin
Insulin
Overall effect
-> decreases glucose in blood
Specific effects:
- increased glucose absorption by all tissue cells
- increased glucose burning + atp production
- glucose —glycogenesis —> glycogen
(glycogen stored in liver and skel. muscle)
- increased rate at which:
glucose —adipocytes—> fat
- increased protein synthesis
- suppressed hunger
Disorders of pancreas
Hypo secretion
-> diabetes mellitus
Causes:
1. autoimmune
-> immune system kills beta cells
- no insulin production
- requires period injections of insulin
Three names:
- Type 1 diabetes mellitus
- juvenile onset diabetes mellitus
- IDOM
- Type 2 diabetes mellitus / adult (age over 40, obesity) onset diabetes mellitus/ NIDDM
- body still makes insulin but there is decreased tissue cell response to it
- > called insulin resistance
- controlled with diet and oral meds
Diabetes mellitus symptoms
- Hyperglycemia
(300-1200 mg%)
normal -> 100 mg% - Glycosuria -> glucose in urine
- Polyuria
-> excess urination b/c of
osmotic diuresis - Polydipsia -> excess thirst
- Polyphagia -> excess hunger
Diabetes major problem
Ketoacidosis
- glucose can’t enter the cells, so cells must burn lipids for energy
Normal:
Lipids —long chain reaction—> co2 + H2O
ADP—>ATP
—————————————
Body must burn excess lipids
(Increased lipid transport in blood)
-> hyperlipidemia
Intermediates
- > ketones + ketoacids
- acetone
- fruity breath
- > build up in blood
- > acidosis (keto)
- > CNS depression
- > coma -> death
Long term complications - diabetes
Increased glucose damages BV endothelium
-> increased progress of atherosclerosis (clogged BV’s, arteries)
- clog
- > coronary arteries - heart attack
- > cerebral BV’s - stroke (CVA)
- clog BV’s that feed extremities
- > Gangrene - amputation
- diabetic retinopathy
- > destroys BV’s that feed retina -> blind
- diabetic nephropathy
- > destroys nephron BV’s
- > renal failure (kidneys)
- > destroys nephron BV’s
- diabetic neuropathy
- destruction of peripheral nerves
- burning pain
- anesthesia -> numbness
- urinary incontinance (loss of control)
- decreased GI mobility
- impotence (no erections)
- skeletal muscle weakness
Glucagon
Overall effect:
increased glucose in blood
Specific effects:
1. Stimulates:
Glycogen —glycogenolysis—> glucose
(liver + skel muscles)
Glucose —> dumped into blood
- Stimulates
Lipids —lipolysis—> fatty acids
3. Stimulates
Fatty acids & amino acids
—gluconeogenesis—>
(Liver)
Glucose
Control of insulin + glycogen
Humoral negative feedback
If:
High glucose in blood
-> detected by
Islet cells
- > inhibit glucagon sec.
- > stimulate insulin secretion
If:
Low glucose in blood
-> detected by
Islet cells
- > stim glucagon output
- > inhibit insulin output
Thymus
Produces:
- thymosins + thymopoetins
Thymosins / thymopoetins:
-> stimulate production and maturation
of T lymphocytes
T Lymphocytes
-> active in cell mediated immunity
Pineal gland
Part of epithalamus
Secretes melatonin
Melatonin effects:
- in children -> inhibits GNRH output
- regulates sleep/wake cycles
- mood
Increased melatonin -> sleepy
Decreased melatonin -> awake
Control of melatonin secretion
If:
Increased light -> eyes -> brain
-> pineal -> decreased melatonin
If:
Decreased light -> eyes -> brain
-> pineal -> increased melatonin
