HPA axis

Question 1

what are the 2 sections of pituitary gland?

Answer 1

anterior and posterior

Question 2

describe the path of activation of anterior pituitary

Answer 2

activation of neurons in hypothalamus > increase releasing hormones into portal circulation > these hormones bind cells in anterior pituitary > causes release of hormones into general circulation

Question 3

whats portal blood vessel and whats the point

Answer 3

it is a capillary system that is directly connected from hypothalamus to anterior pit > allows for hormones to reach directly and in relatively high concentration

Question 4

describe specificity of anatomy and function of hypothalamus > ant pit

Answer 4

anterior pit has specialized cells (yellow cells) that respond to specialized neurons (yellow neurons) from the hypothalamus
- specialized neuron releases certain hormones into the portal system and only corresponding specialize cells expresses matching receptors in the ant pit will activate and release specific hormone

Question 5

describe the path of the HPA axis

Answer 5

hypothalamus release hormone 1 > activates ant pit > it releases hormone 2 > activates peripheral endocrine gland > release of hormone 3 onto effector cells

Question 6

describe the feed backs in the HPA axis

Answer 6

short loop feedback: hormone released by the ant pit into the general circulation arrives at the hypoth and inhibit further release of hormone from hypothal
long loop feedback: hormone released by the peripheral endocrine can diffuse back and inhibit BOTH hypothal and ant pit from releasing their hormones

Question 7

what hormons are released into the general circulation by ant pit

Answer 7

• corticotrophs
• somatotrophs
• thyrotrophs
• gonadotrophs
• lactotrophs