Flashcards in Lecture 18- Endocrine System Deck (61)
What do all endocrine glands have in common (or what defines an endocrine gland?
They secrete hormones into the blood
What is paracrine secretion?
Hormone to a target cell
What is autocrine secretion?
Hormone to self
What makes up the posterior pituitary gland?
- infundibulum or pituitary stalk
- pars nervosa
- tissue develops from brain
What makes up the anterior pituitary gland?
- pars tuberalis
- pars intermedia
- pars distalis
- tissue derived from ectoderm
What are sinusoids?
Essentially giant capillaries
What are degranulated cells?
Cells that turn back into an acidophil or basophil
What are progenitor cells?
Cells that go on to produce other cell types
What are chromophobes?
Either degranulated cells or progenitor cells
What are the acidophils?
- somatotropes (growth hormone)
- mammotropes (prolactin)
What are the basophils?
- gonadotropes (FSH and LH)
- thyrotropes (TSH)
- corticotropes (POMC) cleaves to (ACTH)
What is the best way to differentiate these cells?
The blood supply to the median eminence, infundibulum, and anterior pituitary is a portal system? What does that mean
Two capillary beds
What does the pars tuberalis secrete?
mainly basophilic gonadotropes
What does the pars intermedia secrete?
basophilic cortico tropes. POMC cleaved to melanocyte stimulating hormone. In pars distalis POMC cleaved to ACTH
What does oxytocin do?
- milk let down
- uterine contraction during labor
What are pituicytes?
Glial cells that surround the unmyelinated axons
What are herring bodies?
Cells that store the hormone
Where are the neuronal cell bodies for the posterior pituitary?
Where are the alpha cells located in the islets of langerhans?
Along the periphery- glucagon- raises blood glucose
Where are the beta cells located in the islets of langerhans?
On the interior- insulin that lowers blood glucose
Where is the adrenal gland found?
On top of the kidney, suprarenal gland
What are the three layers of the adrenal gland?
- cortex derived from mesoderm
- medulla derived from neural crest
What are the three layers of the cortex?
- zona glomerulosa
- zona fasciculata
- zona reticularis
They precursor to hormones produced in the adrenal cortex is cholesterol. What does this tell you?
Lipid soluble, hydrophobic
What is secreted in the zona glomerulosa?
What are mineralocorticoid and give an example.
aldosterone, influence salt and water balance
What does aldosterone do?
Released from the adrenal gland under low BP to stimulate Na+ retention and for the kidney to release renin and angiotensin II
What effect does aldosterone have on blood K+ levels?
increases secretion of K+ in the collecting duct to lower blood K+