Endocrinology - Lecture 2 Flashcards
What are the 2 different tissues of the pituitary gland?
adenohypophysis and neurohypophysis
What is the adenohypophysis tissue also known as?
anterior pituitary
What is the neurohypophysis tissue also known as?
posterior pituitary
What kind of tissue is the anterior pituitary?
endocrine tissue
What kind of tissue is the posterior pituitary?
neural tissue
What 2 hormones does the posterior pituitary produce?
vasopressin and oxytocin
What 6 hormones does the anterior pituitary produce?
- TRH
- GnRH
- somatostatin
- GRH
- PIH
- CRH
What 2 nuclei synthesize oxytocin and vasopressin?
supraoptic nucleus and paraventricular nucleus
Where do the supraoptic and paraventricular nuclei run and terminate?
run: down the pituitary stalk
terminate: in the posterior pituitary close to capillary blood vessels
What are processed in secretory granules during axonal transport of supraoptic and paraventricular nuclei?
prohormones
What is the name of the mature hormones liberated from the carrier molecules produced in the posterior pituitary?
neurophysins
What are the circulating half lives of the neurophysins produced by the posterior pituitary?
1-3 minutes
What are the 3 functions of oxytocin in females?
- parturition
- milk ejection
- behavioural effects
How is oxytocin important in parturition?
dilation of uterine cervix by fetal head causes release of oxytocin -> uterine contraction, which assists the expulsion of fetus and then placenta.
How is oxytocin important in milk ejection?
it causes milk filled ducts to contract and squeeze milk out
What are the behavioural effects of oxytocin in females and males?
it reduces anxiety and enhances bonding, pro-social behaviour
What are the 2 functions of oxytocin in males?
- ejaculation
- behavioural effects
How is oxytocin important in ejaculation?
there is a surge of oxytocin during sexual activity which assists in epididimal passage of sperm and ejaculation
What is the major component of the thyroid gland?
thyroglobulin
What hormones are present in the thyroid gland?
T4 and T3
What controls the synthesis of thyroglobulin?
TSH of pituitary gland
What does thyroglobulin provide for T4 and T3 prior to release?
storage
What is the mass of the thyroid gland and what does its size vary with?
15 to 20g, varies size with sex, age, diet, reproductive state
The thyroid gland is larger in ___ than in ___.
females, males