Lecture 23 Unit 3 Flashcards
does the posterior pituitary synthesize hormones
no
what type of neurons foes the posterior pituitary gland consist of
hypothalamic neurons
what do hypothalamic neurons release?
ADH and Oxytocin
what does the posterior pituitary gland contain
resembles neural tissue with glial cells, nerve fibers, nerve endings, and neurosecretory vesicles
where are ADH and oxytocin stored after being made in the hypothalamus?
neurosecretory vesicles
Where is ADH produced and why?
in supraoptic nucleus in the hypothalamus in response to signals from osmoreceptors
what does ADH do
- prevents diuresis
- prevents water loss in sweat glands
- causes constriction of arterioles
what is diuresis
decreased urine production by stimulating the kidneys to return more water back to the blood
when is ADH released from posterior pituitary
dehydration or high osmolarity of blood
when is ADH inhibited from leaving the posterior pituitary
over hydration or low osmolality of blood
what is ADH release inhibited by?
alcohol
what does lack of ADH result in
diabetes insipidus
what happens in diabetes insipidus
- inability of the kidney to conserve H2O
- excessvie urination
where in the hypothalamus is oxytocin produced
cells in the paraventricular nucleus of the hypothalamus
what are the target tissues of oxytocin
uterus during labor and mammary glands after delivery
what causes the stretch of cervix
stimulation of uterus by babys head
what happens to the positive feedback loop after the baby is born
it ceases
what happens as the baby pushes further and further out
more and more oxytocin is released
what is oxytocin effect on mammary glands
- suckling and hearing babys cry stimulates oxytocin release
- oxytocin causes muscle contraction and milk ejection
what is T3/T4 transport in blood attached to
thyroxine binding globulin
what do thyroid hormones do
- increase basal metabolic rate by stimulating the cellular use of O2 to produce ATP
- increase synthesis of Na+/K+ ATPase
- enhance some actions of sympathetic nervous system by up regulating beta receptors
- stimulates growth during development
what happens when thyroid hormones increase basal metabolic rate?
increased cellular catabolism of glucose, fatty acids, and triglycerides
what happens when thyroid hormones increase synthesis of Na+/K+ ATPase?
more ATP is used to pump ions, so it produces heat raising body temp (called calorigenic effect)
what happens when thyroid hormones enhance actions of sympathetic nervous system
increased heart rate, contractility, and blood pressure
