Pharmacology - biochem-ish Flashcards
what is autocrine signalling
when a cell releases signal molecules that illicit response in itself
what is paracrine signalling
cell releases molecules that target neighbours
what is endocrine signalling
signalling molecules enter the blood
what 3 receptors are targeted by hydrophilic signalling molecules
ligand gated ion channels, g-protein coupled receptors, kinase-linked
what receptor is targeted by hydrophobic
nuclear
what are gated ion channels made of
glycoproteins
what signals can cause them to open and close
ligand, voltage, physical
what is signalling via 2nd messengers
signal binds to receptor on cell and activates effectors within the cell, don’t actually pass through
what are the receptors
G coupled protein receptors (GCPR)
describe GCPR (4)
1) peripheral membrane proteins 2) with 7 transmembrane a-helical spans. 3)Has a G nucleotide binding site for GTP or GDP4) has subunits (alpha, beta, gamma)
when GCPR proteins are not signalling what state are they in
receptor empty, G bound to GDP
what happens when GCPR becomes activated
binds to receptor and G protein couples with it. GDP dissociated from G and GTP binds with alpha subunit. G protein dissociates
what are the signalling molecules from GCPR
GTP bound alpha subunit and a By-dimer
what happens when GCPR becomes inactivates
a subunit hydrolysed GTP –> GDP and pi, a subunit rebinds with by-subunit
what makes up the autonomic nervous system (ANS)
CNS and peripheral nerves system (PNS)
where do efferent signals travel to and from
away from CNS
where to afferent signals travel to and from
to CNS
ANS mediates whole body except what
skeletal muscle
the ANS is divided into what 2 divisions
sympathetic and parasympathetic
what is sympathetics main functions
‘fight or flight’
what is parasympathetics main function
‘rest and digest’
where are preganglionic neurones normally located
inside the CNS
where are post ganglionic cells normally located
outside CNS –> effector cells
what are the neurotransmitters and receptors between pre and post ganglionic fibres
acetycholine (ACh) to nicotonic cholinoceptors
where do pre and post ganglionic neurones synapse in the sympathetic chain
para or prevertebral ganglia, noth are near spinal cord
where do pre and post ganglionic neurones synapse in parasympathetic chain
terminal ganglia distance to CNS, often on the walls of target organs
what are the anatomical differences between pre and postganglionic fibres
pre are myelinated and white motor B fibres. post are not myelinated and grey motor C fibres
what type of outflow is sympathetic (regions of spine)
thoracolumbar (T1-L2)
what type of outflow is parasympathetic (regions of spine)
craniosacral
what does sympathetic stimulation do to the body
increases HR and force of contraction, relaxes bronchi and decreases mucous production, relaxes GI motility, releases adrenaline from adrenal glands. ejaculation
in the sympathetic chain, what is the NT for preganglionic neurones
ACh
in the sympathetic chain, what is the NT for postganglionic neurones
normally noradrenaline NA
what are the parasympathetic cranial nerves
C3, C7, C9, C10
what effect does parasympathetic chain have on the body
decreases HR, bronchoconstriction, increases GI motility and mucous production. erections
in the parasympathetic chain, what is the NT for pre and post ganglionic neurones
ACh
describe the steps in a neurochemical transmission (7)
1) uptake of precursor 2) synthesis and storage of NT 3) depolarisation by AP 4) Ca enters nerve terminal 5)Ca releases NT 6) receptor us activated 7) enzymes break down NT and it is re-uptaken as a precursor
in the parasympathetic chain, what is ACh broken down into and by what
choline + acetate by ACh
how many subunits is the nicotinic ACh receptor
5
what are the sympathetic co-transmitters
ATP and neuropeptide Y
what are the parasympathetic co-transmitters
nitric oxide (NO) and VIP
what receptors does NA act on in sympathetic
adrenoreceptors
what receptors does ACh act on in parasympathetic
M1-M3
what is nicotine an agonist of
receptors - mimics ACh
what uptakes and what metabolised NA
U1/U2
MOA and COMT
what is the M1 ACh receptor coupled too and what does it do
q, increased acid secretion
what is the M2 ACh receptor coupled too and what does it do
i, decreased heart rate
what is the M3 ACh receptor coupled too and what does it do
q, contraction of airways and relaxation of vasculature
what is the B1 NA receptors coupled too and what does it do
s, increased heart rate
what is the B2 NA receptors coupled too and what does it do
s, relaxation of airways and vasculature
what is the a1 NA receptors coupled too and what does it do
q, contraction of vasculature
what is the a2 NA receptors coupled too and what does it do
i, decreases NA release
what does cocaine block and what does this result in
U1, leftover NA, this increases adrenoreceptor activity, increases HR
what does amphetamine do
substrate for U1, blocks MOA, NA isn’t broken down, increases HR
in what direction does sodium flow into a cell
Na - leaks in
in what direction does K flow
outwards
what is an AP
briefly depolarisation, moves along nerve axons with constant magnitude
what is the normal resting potential of a cell
-70mv
when Na channels are activated it is a knock on effect and others are activated, what is this called
positive feedback
when K channels are activated it reduces the stimuli, what is this a example of
negative feedback
what happens in the refractory period
Na channels are inactivates and no stimuli can cause a 2nd AP
what factor of nerve cells mean passive signals do not pass far from site of origin
they are leaky
what do schwann cells do
wrap around axon to provide insulation, providing a myelin sheath
what is saltatory conduction
AP’s jumping between gaps in myelinated schwann cells
