BSI 2 Lecture 48: Endocrine 2 Flashcards
What is another name for the pituitary gland?
The master gland or hypophysis
Where is the pituitary gland located?
In a protective bony cavity on the inferior surface of the midbrain called the sella turica
What connects the pituitary gland to the hypothalamus?
The pituitary stalk or infundibulum (also called hypophysial stalk)
How many parts can the pituitary be split into?
Two, the anterior and posterior pituitary gland
What is the anterior pituitary composed of?
Epithelial tissue
What is the posterior pituitary composed of?
Glial-like cells called pituicytes and neurosecretory axon terminals because it is part of the brain
What is the general process of secretion by the hypothalamus-pituitary axis?
The hypothalamus will release hormone that will cause the pituitary gland to release a hormone that acts on a target site in the body
How many hormones does the anterior pituitary secrete?
Multiple hormones because of the multiple different cell types
What does the posterior pituitary release?
Antidiuretic hormone and Oxytocin
Where is antidiuretic hormone and oxytocin made, and how does it get to the posterior pituitary?
It is made in the hypothalamic neurosecretory cell bodies and is transported down the infundibulum
What controls the release of 6 major hormones secreted by the anterior pituitary?
Releasing factors secreted by the hypothalamus
How do these releasing factors travel to the pituitary gland?
They are secreted near the primary capillary plexus in the median eminence where they travel by blood down the infundibulum to a second capillary bed which surrounds the anterior pituitary cells where is rejoins systemic circulation
All currently known releasing factors are ____ except for _____ which is a catecholamine.
Peptides; Dopamine
Which two hormones, secreted by the anterior pituitary, don’t act on secondary endocrine glands?
Growth hormone and Prolactin
What two hormones, from the hypothalamus, affect secretion of growth hormone?
Growth hormone releasing hormone and Somatostatin
What does growth hormone do?
It causes precursor cells and the liver to release IGF-1, it stimulates the production of proteins in the cell, and it causes fatty cells to be more susceptible to lipolysis while stimulating gluconeogenesis, and inhibiting the effects of insulin.
How does growth hormone effect bones?
Increases protein deposition in chondrocytes and osteoblasts and increases differentiation of chondrocytes into osteoblasts
Does growth hormone effect bones after epiphyseal fusion?
Yes, it will cause bones to thicken
