intro to the endocrine system Flashcards
hormones types
peptides/proteins
Amines/AAs
Steroid hormones
Amines/AAs
derivatives of tyrosine
Gives rise to thyroid hormones (thyroxine, triiodothyrine) and adrenaline and noradrenaline (catecholamines- derived from tyrosine)
Indoleamines derived from tyrptophan (melatonin)
Thyroid hormones
bind to nuclear receptors and regulate gene transcription
What types of receptors do adrenaline and noradrenaline bind to
GPCR
alpha and beta
Peptides/proteins
eg insulin
Receptor tyrosine kinase
Activates intracellular signalling via phosphorylation cascade
Steroid hormones
eg sex hormones, glucorticoids, adrenal hormones
Activate nuclear receptors - work as TFs regulating gene transcription
2 endocrine glands
Parathyroid (PTH)
- stimulated by Ca
Pancreas (insulin and glucagon)
-stimulated by glucose
medulla
adrenaline, noradrenaline
Thyroid
Thyroxine (T4)
Triodothyronine (T3)
endocrine glands
ductless
extensive blood supply
may be primary glands eg pituitary, thyroid, adrenals
Other organs may have secondary endocrine function eg brain (hypothalamus), heart, kidney
intracrine
within cell signalling
autocrine
cell releases signal that acts back on the cell
paracrine
affects neighbouring cells
endocrine
releases into circulation, affects distant target cells
Neuroendocrine
modified nerve cells that secrete directly into blood and travel to distant target cells