L1- Introduction Flashcards
(54 cards)
endogenous
from within the body e.g. hormones
exogenous I
natural but from the outside e.g. plant based- antibiotics, morphine etc
exogenous II
synthetic- man made
main extracellular signalling groups
endocrine paracrine autocrine
endocrine paracrine autocrine defined by
distance and volume
endocrine hormones circulate
the whole body
endocrine glands are highly
potent
where will endocrine hormones act on
tissues with correct receptors
endocrine signals are subject to
tight feedback control
types of endocrine signalling molecules
Hydrophilic 1
Hydrophilic 2
Lipophilic
Hydrophilic 1
catecholamines
amines
Amino acid derivatives – small charged hydrophilic with receptors in plasma membrane
Hydrophilic 2
Peptides and proteins
Peptides and proteins receptors in
the plasma membrane
Lipophilic
steroids
steroids
common derivation from cholesterol.
- receptors are intracellular
catecholamines are
hydrophilic and act on the plasma membrane
peptides and proteins are
hydrophilic and work on the plasma membrane (more slowly than catecholamines)
steroids
lipophilic and work on cytosolic and nuclear receptors
paracrine signalling
short distance signalling e.g. from cell to cell or nearby cells
paracrine molecules are released into
the extracellular environment
paracrine molecules induce
changes in receptor cells
example of paracrine signalling
NT at synaptic junctions
neurotranmitters
electrochemical signals that travel 20nm to cross synaptic junctions in less than a msec
