Chapter 3 Flashcards
What is neurophysiology
study of life processes of neurons
What is an ion?
atom or molecule that has an electrical charge by gaining or losing one or more electrctrons
What is an anion?
negatively charged ion (protein or chloride)
What is a cation?
a postivitively charged ion (potassium or sodium)
Explain the intracellular fluid and extracellular fluid
Intracellular is watery and found within cells; extracellular the fluid in the spaces between cells and in the vascular system
What is a cell membrane?
a lipid bilayer that ensheathes a cell
Whats a microelectrode?
small electrode used to record electrical potentials in cells
What is resting potential?
a difference in electrical potential across the membrane of a nerve cell
What is a millivolt?
a thousandth of a volt
What is an ion channel?
a pore in the cell membrane that alllows certain ions through
What is potassium K+
a potassium atom that carries a positive charge because it lost one electron
What is selective permeabilty
property of membrane that allows substances to pass through but not others
What is diffusion
Spontaneous spread of molecules until uniformed concentration is achieved
What is electrostatic pressure?
charged molecules or ions to move via diffusion toward areas with the opposite charge
What is a sodium potassium pump?
expensive mechanism that pushes sodium ions out of a cell and potassium in
What is a sodium ion Na+
sodium atom that carries a positive charge because it lost one electron
What is equilibrium potential?
movement of icons across the cell membrane is balanced, as the electrostatic pressure is pulling ions in one direction is offset by the diffusion force by pushing them in the opposite direction
What is the axon hillock?
area on the cell which the axon originiates
What is hyperpolorization/ depolarization?
increase in membrane potential (interior of of neuron)/ decrease in membrane potential
What is local potential?
electrical potential initiaed by stimulation at a specific site, decreasing with strength in time
What is threshold?
stimulus intenstiy that is adequate to trigger an action potentialat the axon hillcock
What is all or non property?
the amplitude of the action potential is independent of the size of the stimulus
What is action potential?
spike. quick reversal of membrane potential that makes up the insdie of the membrane positive
What is voltage gated Na+ channel?
selective channel that opens or closes in response to changes in voltage of the local membrane potential; it mediates action potential
What is refractory?
temporarily unresponsive or inactivated
What is abosolute refractory phase?
period of complete insensitivity to stimuli
What is relative refactory phase?
period of reduced sensitivity in which strong stimulation produces an action potential
What is conduction velocity?
speed at which an action potential is propogated along the length of an axon
What is myelyn?
fatty insulation around the axon formed by the glial cells
What is the node of Ranvier?
gap between successive segments of the mylen sheath where the axion membrane is exposed
What is salatory conduction?
form of conduction that is like myelinated axons
What is multiple sclerosis?
scars, widespread degeneration of myelin
What is a neurotransmitter?
synaptic transmitter/chemical transmitter. chemical released from presynaptic axon terminal that serves as the basis for communication between neuons
What is pre/postsynaptic?
the region of a synapse that releases the neurotransmitter/ the region that receives and responds to the neurotransmitter
What is postspynaptic potential?
a potential that can vary in amplitude and spreads passively across the cell membrane–decreases in strength in time
What is excitatory postsynaptic potential?
depolorizing potential in the post synaptic neuron that is caused by pre synaptic potentials
What is synaptic delay?
delay between the arrival of an action potential at the axon terminal and creation of a post synaptic potential
what is inhibitory postsynaptic potential?
hyperpolarizing potential that is caused by inhibitory connections
What is chloride ion CI-?
chlorine atom that carries a negative charge because it gained one electron
What is a spatial summation?
sumation of postsynaptic potentials that reach the axon hillcock from different locations across the cell body
What is the temporal summation?
summation of post synaptic potentials that reach the axon hillcock at different times
What is synaptic vesicle and synaptic cleft?
small, spherical structure that contains molecules of neurotransmitter/space between presynaptic and postsynaptic neurons at synapse/
What is calcium ion Ca+
calcium atom that carries a double positive charge because it has
What is a ligand
substance the binds receptor molecules such as a neurotransmitter or drug that binds postsynpatic receptor
What is acetylcholine?
neurotransmitter that is produced and released by a parasympahetic postganglonic neurons
What is a neurotrasmitter recpetor?
receptor. a protein that captures and reacts to molecules of a neurotransmitter or hormone
What is a curare?
Neurotoxin that cauces paralysis by blocking acetylcholine receptors in muscle
What is a bungarotoxin?
neurotoxin isolated from the venom of the banded krait that blocks Ach recptors
What is antagonist?
molecule (drug) that interfers with or prevents the action of a neurotransmitter
What is a agonist?
molecule (drug) that binds a receptor molecule and initiates a response of another molecule/transmitter
What is cholinergic?
cells that use ACH as their synaptic transmitter
What is degradation?
chemical breakdown of a neurotransmitter into active metabolites
What is acetycholinestrase (ache)
enzyme that inactives the transmitter acetycholine
