lecture 5 Flashcards
properties of hormones
- cell to cell communication molecules
- binding to target receptor initiates cellular response
- communication is eventually terminated
what is the half life of a hormone?
the time for [hormone] in the blood to reduce by 1/2
5 ways to classify hormones
- source: where does it come from? (e.g. pancreatic hormones)
- neuronal control of release?
- receptor type
- chemical type
- function (e.g. reproductive hormones)
3 chemical classes
- peptide/protein
- steroid
- amine
Peptide/protein hormones characteristics
made in endocrine cells all over the body
made in advance and stored in vesicles for release
Steroid hormones characteristics
made from cholesterol
only made in adrenal cortex, kidney, skin, gonads, placenta
can’t be stored (lipophilic)
what type of hormones need a lot of SER
steroid hormones
Amine hormones characteristics
made in pineal, adrenal medulla, thyroid
mostly made from tyrosine
Steroid hormone: speed of response based on receptors
released by simple diffusion into blood –> transported bound to carrier proteins
- intracellular receptors= slow genomic response
(regulates gene activity) - membrane receptors= fast non-genomic response
2 types of amine hormones derived from tyrosine
-catecholamines (eg. adrenaline)
-thyroid hormones
gland=
collection of secretory cells
3 ways that hormones regulate cellular processes
- rate of enzymatic rxns
- transport of ions or molecules across cell membranes
- gene expression and protein synthesis
what does the cellular mechanism of action depend on?
-presence and location (membrane, cytoplasm, nucleus) of target receptors
-specific signalling pathway
The pituitary gland is
two glands fused together
the posterior pituitary is – tissue
neural tissue
what two neurohormones are secreted by the posterior pituitary?
vasopressin (ADH, antidiuretic hormone) and oxytocin
the anterior pituitary is —- tissue
endocrine
what does the anterior pituitary secrete?
6 true hormones
what is release of hormones from the anterior pituitary controlled by?
neurohormones from the hypothalamus
the posterior pituitary is an…
extension of the brain
(it secretes neurohormones made in the hypothalamus)
the anterior pituitary is a…
true endocrine gland
portal circulatory system
specialized modification where two sets of capillaries are connected in series by a set of small veins
