Unit 2 - A & P Module - Neurotransmitters Synapses and Integration Flashcards
The site of information integration in a neuron is the __________.
trigger zone
What is true about graded potentials?
- Excitatory Postsynaptic Potentials (EPSPs) can make action potentials more likely to occur.
- EPSPs that reach threshold can initiate an action potential.
- The trigger zone is the integrating center for graded potentials of the neuron.
After the hyperpolarization phase of an action potential __________.
potassium channels are closing
Action potentials are unidirectional. Why do they travel only from the cell body of a neuron to the terminal and never go backward?
The sodium channel inactivation gates close once an action potential passes.
When a cell’s membrane potential becomes less negative or even positive, the cell is said to be ____________.
depolarized
The two types of electrical signals transmitted through neurons are __________.
graded potentials and action potentials
The portion of the nervous system that directly controls skeletal muscles is the __________.
somatic motor system
Nerve and muscle cells are classified as excitable tissues because they __________.
generate and propagate electrical signals
The total amount of neurotransmitter released at the axon terminal is directly related to the __________.
total number of action potentials
The membrane potential at which the electrochemical force on an ion =0 is called the __________ potential for that ion.
equilibrium
The chemical messengers released into synapses are called __________.
neurotransmitters
The myelin sheaths that surround axons in the CNS are formed by __________.
oligodendrocytes
Action potential conduction velocity is the slowest in __________.
small unmyelinated axons
Graded potentials __________.
spread through electronic conduction, can summate, and can be depolarizing or hyperpolarizing
