animal mt 1 Flashcards
what is the resting potential value of the membrane?
-65 mV
what two refractory periods cause an action potential to be unidirectional?
1) absolute refractory period - Na channels inactivate after use
2) relative refractory period - hyperpolarization drives voltage below resting potential and requires a stronger stimuli to reach threshold
what is locomotion?
an animal moving itself based on its own power
how does an action potential trigger muscle contraction?
- action potential triggers release of ACh into synaptic cleft
- ACh opens ligand channels by binding to postsynaptic receptors
- action potential in muscles is triggered
- action potential propagates into T-tubule channels in muscle
- action potential moves from T-tubules into sarcoplasmic reticulum, opening Ca channels
- Ca ions bind to troponin freeing up actin for myosin to bind
what are the main characteristics of cardiac muscle?
- striated + branched
- few nuclei
- involuntary movement
- sarcomeres
what happens when a synapse is used repeatedly?
signal becomes stronger over time and memories become more common (synaptic plasticity)
what effect did neurotoxins have on Na/K ion channels?
Na: blocked ion flow
K: not affected
what two hormones control the movement within the digestive system?
- ACh (parasympathetic “rest and digest”) activates contraction
- epiniphrine (sympathetic “fight or flight”) inhibits contraction
define learning
enduring change in behaviour due to a prior experience
what are the four parts of the brain?
- cerebellum
- cerebrum
- brain stem
- diencephalon
what is an integral/transmembrane protein?
a protein that has segments that face both the inside and outside of the plasma membrane
how do actin and myosin initiate muscle movement?
- ATP binds to myosin and releases the head from actin
- ATP –> ADP, myosin head straightens out
- myosin reaches forward and binds to a new actin subunit, head curls back to original position
- ADP released and myosin is open for new binding
what were three key findings from patch clamping experiments?
- voltage channels are either open or closed at a given time
- Na channels open quickly after depolarization and creates a positive feedback loop for more Na to enter
- K channels open with delay and then alternate between open and closed until hyperpolarization
what are the two divisions of the autonomic system?
1) parasympathetic - “rest and digest”
2) sympathetic - “fight or flight”
(roughly) what is the equilibrium potential for sodium?
60 mV
what are the three components of the cytoskeleton?
- actin/microfilaments (muscle contraction)
- microtubules (chromosome division)
- intermediate filaments (cell structure)
what are inhibitory post synaptic potentials (IPSP)?
hyperpolarization of post synaptic membrane as a result of neurotransmitter activity leading to a decreased chance of action potentials
(roughly) what is the equilibrium potential for potassium?
-90 mV
describe saltatory conduction
- as an action potential propagates down an axon, it loses momentum in the form of charge
- once potential reaches nodes of ranvier, ion channels add more charge, pushing potential further down axon