Ch.10 Flashcards
What cytoplasmic extensions, together with the cell body, provide the main receptive surfaces for neurons?
dendrites
Dendrite function
receives input of communication from other neurons
Axon function
carry nerve impulse away from cell body
One function of the nervous system
controls movement of muscle
The oculomotor nerve is a cranial nerve containing nerve fibers that innate eye muscles and control eye movement. These fibers are examples of..
motor neurons
What is the function of sensory receptors
detect changes in and outside the body
Three general functions of the nervous system
sensory input, integration and processing, motor output
How many axons and/or dendrites can a neuron have?
1 axon and many dendrites
Every neuron has which of the following components
cell body, 1 or more dendrites, axon
What is. myelin
layers of lipid and protein that wrap around axon
A myelinated nerve fiber is ____, whereas as unmyelinated nerve fiber is _____
white, grayM
Myelin is rich in
lipids
In Guilian-Barre syndrome, the immune system attacks and degrades the myelin sheath of PNS axons. Predict the effect this will have on nerve impulse and motor function
lose solitary conduction resulting in poor muscle function
Which cells produce myelin in the brain and spinal cord?
ologodendrocytes
What is a reason the axons in the CNS and PNS differ in their ability to regenerate after injury?
axons in the CNS lack neurilemmae
Most of the neurons in the brain and spinal cord are ____
multipolar
In order for a severed peripheral nerve to regenerate and recover its original function, nerve fibers must sprout and enter tubes formed by what?
Schwann cells
Dendrites of unipolar neurons are parts of what type of neuron
sensory neurons
Clusters of neuron cell bodies in the PNS are called
ganglia
Which neuroglia are not part of the CNS
satellite cells
Synaptic knobs are at the ends of
axons
A test organism develops a genetic mutation that causes neurons to develop without synaptic knobs. How will this impact neuronal function?
no neurotransmitters storedPr
synaptic neurons release neurotransmitters by the process of
exocytosisW
hen an action potential passes over the surface of a synaptic knob, the contents of the vesicles within the synaptic knob are release in response to the presence of ____
calcium ions
How is an impulese transmitted from one neuron to another?
Impulse, presynaptic axon release neurons in cleft
How are action potentials related to. impulses conducted along the length of an axon?
propagation of series of action potentials along nerve fiber
If a neuron is stimulated causing changes in the membrane potential to the point where voltage-gated Na channels open and begin depolarizing the cell, the neuron is said to have reached _______
threshold
Saltatory conduction is faster than conduction on
unmyelinated fiber
The most rapid conduction of an impulse along an axon occurs on a fiber that is _______
thick and myelinated
The resting cell membrane is more permeable to which ion
potassium
If a resting potential becomes more negative, the membrane is said to be______
hyperpolarized
What is the correct sequence of events that occur along an axon after membrane reaches threshold?
Sodium channels open, membrane depolarizes, potassium channels open, membrane repolarizes
How does a neuron cell membrane become depolarized
Sodium ion channels being open and diffusing into the cell
Roughly how long does an excitatory postsynaptic potential last
15 miliseconds
Each neuron in the CNS may receive input from which structure
axons
When is an action potential triggered
SPSP exceeds IPSP
The neurotransmitter that controls skeletal muscle contraction is
acetylcholine
Which neurotransmitters are modified amino acids
dopamine, serotonin, epinephrine, norepinephrine
A drug that increases the action of serotonin by keeping serotonin in the synapse longer is most likely used to treat which disorder
clinical depression
What occurs during reputake
neurotransmitter taken back into presynaptic neuron
What types of neurons are organized into neuronal pools
interneuronsWha
t is convergence
axons from neurons in different parts of nervous system contacting same neuron
How do diverging axons amplify an inpulse
contacting many neurons (stimulating)
What disorder involving an immune response that affects the myelin coating on axons throughout the spinal cord and brain, triggering inflammation and leaving scars
multiple sclerosis
Why do opiate drugs derived from poppies relieve pain in humans
receptors for endogenous opiates
What neurotransmitter is most likely released when a person uses a drug that creates a sense of well being
dopamine
What structural type of neuron has a single process that extends from the cell body
unipolar
Axon branches are called
collaterals
Myelin is composed of
protein
Two major cell types found in nervous tissue
neurons and neuroglia
