HPA pathway Flashcards
What are central endocrine glands?
Those within or in close association with the brain.
Hypothalamus
Pituitary gland
Pineal gland
The ______ and ______ are connected by the infundibulum.
Hypothalamus and pituitary gland.
The pituitary gland is two separate tissue types known as the ____ and _____ gland. Which one of these is an extension of the neural tissue?
Anterior and Posterior.
Posterior.
What are hypothalamic hormones? How are they transported an why are they transported this way?
Tropic hormones. Through a portal system so that they aren’t dilutes in the whole circulatory system.
The portal system transports hormones from which pituitary gland? Why not both?
The anterior. Posterior secretes hormones made by hypothalamus - hormones travel down neuronal axons into whole system.
What are neurosecretory neurons?
Two specific cell bodies that lie within the hypothalamus:
Supraoptic nucleus and paraventricular nucleus.
What hormones are released from the posterior pituitary?
Vasopressin - to kidneys, conserve water, stop excision of salt - increase Blood volume and pressure
Oxytocin - acts on uterus during labour for contraction and produce milk
How do hormones from the hypothalamus get to the anterior pituitary gland? What is the role of this?
Via hypothalamic-hypophyseal portal system. Prevent dilution
How is release of hormones from anterior pituitary controlled?
Negative feedback loop, hormone itself is the feedback signal.
What is the dominant form of negative feedback?
long-loop - some have short. Long loop where release of hormone (non-tropic) from endocrine gland acts back on the hypothalamus and the anterior pituitary to stop release. Short just tropic hormone from anterior pituitary back to hypothalamus.
What is prolactin?
PRL is the only anterior pituitary hormone that isn’t tropic - act directly on breast tissue.
What is the role of adrenocorticotropic hormone (ACTH and cortisol?
Acts on adrenal cortex to promote synthesis and release of cortisol.
What is the role of cortisol?
Prevents hypoglycemia - aids in breakdown of glucose from the liver.
What are causes of hyper and hypocortisolism
Hyper - tumours of adrenal gland or pituitary (cant respond to neg feedback)
Exogenous administration
Cushing’s syndrome
Hypo- Addison’s disease
congenital adrenal hyperplasia
What does the adrenal medulla release vs the adrenal cortex of the adrenal glad?
Medulla - catecholamines
Cortex - steroid
