Lecture 31 - Endocrine 1 Flashcards
(32 cards)
the endocrine system is essential is regulating what?
hormones for homeostasis
what is a hormone
chemical messenger transmitting signals from one cell to another via binding to receptors
what three ways do hormones work>
autocrine, paracrine and endocrine
true or false, cytokines are hormones
true, but are often considered a different system
where do hormones come from?
nervous system (NTs, and some bona fide hormones)
immune system (cytokines)
endocrine gland hormones
describe endocrine hormones
hormones that travel and act far from site of release
where can enodcrine receptors be located?
at cell surface (common)
in cytosol (steroids)
nucleus
- receptor must be present to initiate effect
what are the three main types of hormones?
amino acid derivatives (small)
peptide hormones (biggest)
steroid hormone
describe amino acid derivatives
modification to amino acids that lead to hormone
- serotonin, histamine, melatonin
describe peptide hormones
they are usually made as a non-functional prohormone where the endocrine cells contain proteases which cleave the pro-hormone into its final form
- require processing
what is an example of a pro-hormone?
proglucagon is cleaved by PC1, which is required in L cells to make GLP-1, which is then cleaved after its function to inactivate it.
what is an example of a steroid hormone?
testosterone, oestrogen
which 5 factors regulate functional outputs of the endocrine system?
- rate of hormone production
- rate of hormone release
- amount of sequestered hormone in blood
- rate of hormone breakdown
- location/tissue specific hormone levels
what three main reasons do endocrine disorders develop?
- abnormal endocrine glands (beta islet cells in type 1 diabetes)
- abnormal neural regulating mechanisms
- abnormal target tissue (type 2 diabetes)
describe the pineal gland
in brain, contains pinealocytes which produce melatonin
- reproductive process regulation and sleep regulation for maintaining circadian rhythyms
how does the pineal gland know when to secrete melatonin
its proximity (in brain) to the visual pathways allows it to have light-inhibited melatonin production
what is the most important endocrine gland?
hypothalamus
describe the anatomy of the hypothalamus
contain many different nuclei, containing neurons specialising in specific roles
how is the hypothalamus well placed to integrate signals and produce integrated output?
The hypothalamus is centrally located to receive signals from the brain and blood. It integrates this input and coordinates appropriate neuronal or hormonal responses via the pituitary gland.
how is ADH and oxytocin unique?
it is produced in the hypothalamus but then is transported along axons of nerves that project into the posterior region of the pituitary gland where it is secreted
how are the releasing hormones sent down to the anterior pituitary?
the hypopheseal portal system (deox blood transportation)
what do releasing hormones do?
secreted by the hypothalamus, down hypopheseal portal system, act on glands in the anterior pituitary to release their own hormones
describe the histology of the anterior pituitary vs posterior
anterior: lots of secretory glands, produce their own hormones
posterior: pale staining, no secretory glands, get delivered hormones to release
what is the pars intermedia?
a part of the anterior pituitary and secretes melanocyte stimulating hormone MSH (pigment of skin)
