Chapter 2 Flashcards
(32 cards)
Electrostatic Pressure
Opposite signs are attracted and same signs are pushed away from each other
Role of Inhibition
Inhibitory signals from brain prevent withdrawal reflex so don’t drop something important
Cation
Positively charged ion
Anion
Negatively charged ion
Sodium-potassium Transporters
Protein found in membrane of all cells that extrudes sodium ions from and transports potassium ions into cell. 2 K+ in and 3 Na+ out
Diffusion
Movement of molecules from high concentration to low concentration areas
EPSP’s
Excitatory synapses produce them and after em threshold of excitation is reached action potentiometer fired
IPSP’s
Inhibitory synapses produce them which counteracts EPSP’s
Movement of ions during action potential
- Na+ channels open and Na+ begins entering
- K+ channels open and K+ begins leaving cell
- Na+ channels become refractory
- K+ continues leaving cell, causes membrane potential to return to resting potential
- K+ channels close and Na+ channels reset
- Extra K+ outside diffuses away
All-or-none Law
Once an action potential is triggered in axon, it is propagated, without decrement, to end of fiber
Rate Law
Intensity of a stimulus or other info being transmitted is determined by the rate at which the axon fired
Saltatory Conduction
In myelinated axons the action potentiometer jumps from one node of Ranvier to the next
Axodendritic Synapse
Synapse taking place on the smooth part of a dendrite or on a dendritic spine
Axosomatic Synapse
Synapse taking place on somatic membrane
Axon conic Synapse
Synapse consists of two terminal buttons connecting
Presynaptic membrane
Membrane of terminal button lies adjacent postsynaptic membrane where neurotransmitters are released
Postsynaptic membrane
Cell membrane adjacent terminal button that receives neurotransmitters
Synaptic Cleft
Space between presynaptic and postsynaptic membranes
Ionotropic Receptors
Ion channels open when a molecule of neurotransmitter attached to binding site.
Metabotropic Receptor
Has a binding site for a neurotransmitter that when activated begins a series of events opening an ion channel elsewhere in membrane of cell
G protein
Protein coupled to a metabotropic receptor, conveys messages to other molecules when ligand binds with and activates receptors
Second Messenger
In metabotropic receptors it is the chemical produced when G protein activates anymore and then carries signal to open ion channels or other events
Depolarizing
Excitatory
Hyperpolarizing
Inhibitory