NS 1 - Intro and MP Flashcards
(7 cards)
Define a Neurotransmitter, and describe its function (where released, what it affects, how its bd and reassembled)
Chem messenger. Released at presyn membrane. Affects Posyn receptors. Bd by enzymes. Reassembled at axon terminal
Explain ion movements and electrical signals, and list 3 NB concepts
All pc prod electrical signal by ion movements. Mp is NB to neuron
1- ecf and icf differ greatly in ionic comp
2- cells have selectively perm membrane
3- membrane perm change by ion
List 5 membrane processes in Membrane potential
1- rest potential = mp of resting cell
2- graded potential = temp, localized change in RP caused by
3- action potential = electrical impulse prod by GP that propagates along surface of axon to synapse
4-synaptic activity = release NT @ presyn membrane, prod gp in Posyn membrane
5-Info processing = response (integration of stim) of Posyn cell
List and explain 2 passive forces acting across a plasma membrane, and explain the electrochem gradient
1- chem grad= concentration gradients of ions
2- electro grad = separate charges of ions, result in potential difference
Electrochem grad - sum of chem and electro forces across membrane, forms potential energy
List and explain 2 active forces across the PM
Na-K exchange
- powered by ATP
- 3na for 2k
- maintain RP at -70mv
RP
- highly perm to k+ RP at -70 to -90mv
- na has large gradient but low perm = only makes RP slightly less negative
List the mechanisms for na-k exchange, states of the channels and 3classes of gated channels
Membranes either passive channels(leak, always open, perm changes w/ conditions) or active (voltage gated, open/close irt stim, at RP most gated channels are closed)
Closed, capable of opening
Open / activated
Closed not capable opening / inactive
3 classes
- chem gated
- > open in presence of chems (Ach) at a binding site
- > found on neuron cell body + dendrites
- voltage gated
- > respond to mp changes
- > active and inactive gates
- > chars of excitable membrane
- > found in neural axons, skm sarcolemma, cardiac muscle
- mechanically gated
- > respond to membrane distortion
- > found in sensory receptor (touch, psi, vibration)
Provide the definition of a synapse, and describe 4 areas of the synapse as well as the 2 types of synapses
Area where neuron comm w/ another cell
SynTerminal - expanded area of presyn axon containing synaptic vessels
Syn cleft - gap separates pre and post syn membranes
Posyn cell - receives message
Presyn cell - sends message
Types
- nmj = synapse bw neuron and muscle
- neuroglandular = bw gland + neuron
