Nerve Cells and Nerve Impulses Flashcards
The nervous system is composed of two types of cells: ______ and _____.
neurons and glia
Which part of an animal cell is a network of tubes that modifies & transports proteins?
a) Nucleus
b) Ribosomes
c) Endoplasmic reticulum
d) Plasma membrane
e) Mitochondrion
c) Endoplasmic reticulum
A network of thin tubes that transports newly
synthesized proteins to other locations. Ribosomes may be attached.
What is the nucleus?
a) structure that contains DNA; genetic material
b) synthesizes new proteins
c) network of tubes that modifies & transports proteins
d) separates the inside of the cell from the outside
e) performs metabolic activities (makes energy)
a) structure that contains DNA; genetic material
The structure that contains the chromosomes
What does a neuron do?
Receive information and transmit it to other cells.
What is the mitochondrion?
a) structure that contains DNA; genetic material
b) synthesizes new proteins
c) network of tubes that modifies & transports proteins
d) separates the inside of the cell from the outside
e) performs metabolic activities (makes energy)
e) performs metabolic activities (makes energy)
Mitochondrion: The structure that provides the cell with energy. It requires
fuel and oxygen to function
Approximately how many neurons are in the human brain?
100 billion neurons
The human brain contains approximately 100 billion neurons (though that
estimate varies from person to person).
Which part of an animal cell synthesizes new proteins?
a) Nucleus
b) Ribosomes
c) Endoplasmic reticulum
d) Plasma membrane
e) Mitochondrion
b) Ribosomes
Site of protein synthesis in the cell
What are the four major components of larger neurons?
dendrites, cell body, axon, and presynaptic terminal.
Larger neurons contain four major components: dendrites, cell body, axon, and presynaptic terminal.
The tiniest neurons may lack axons and well-defined
dendrites
Branching fibers that extend from the cell body and get narrower at their end are: a) Dendrites b) Dendritic spines c) Cell body (soma) d) Axon e) Myelin sheath: f) Nodes of Ranvier g) Presynaptic terminal
a) Dendrites
Dendrites: Branching fibers that extend from the cell body and get
narrower at their end. The dendrite’s surface is lined with specialized
synaptic receptors, at which the dendrite receives information from
other neurons.
List five types of glia.
Astrocytes Microglia Oligodendrocytes Schwann cells Radial glia
What kind of neuron Conducts impulses to muscles and glands from the spinal cord? a) Purkinje cell b) Motor neuron c) Sensory neuron d) Pyramidal cell
b) Motor neuron
Swelling at the tip of the axon is the:
a) Dendrites
b) Dendritic spines
c) Cell body (soma)
d) Axon
e) Myelin sheath:
f) Nodes of Ranvier
g) Presynaptic terminal
g) Presynaptic terminal
Presynaptic terminal (end bulb): Swelling at the tip of the axon. The
part of the neuron that releases chemicals that cross the junction between
one neuron and the next.
Define nodes of Ranvier.
Interruptions along the myelin sheath
Glia are _______ and ________ than neurons:
a) larger and less numerous
b) smaller and less numerous
c) larger and more numerous
d) smaller and more numerous
d) smaller and more numerous
Glia are smaller and more numerous than neurons.
Which neuron is sensitive to certain kinds of stimulation (e.g., light, touch, etc.)? a) Purkinje cell b) Motor neuron c) Sensory neuron d) Pyramidal cell
c) Sensory neuron
A long, thin fiber, which is the information-sending part of the neuron, sending an electrical impulse toward other neurons, glands, or muscles is the: a) Dendrites b) Dendritic spines c) Cell body (soma) d) Axon e) Myelin sheath: f) Nodes of Ranvier g) Presynaptic terminal
d) Axon
Axon: A long, thin fiber (usually longer than dendrites), which is the
information-sending part of the neuron, sending an electrical impulse
toward other neurons, glands, or muscles.
What brings information into a structure?
a) Afferent axons
b) Efferent axons
c) Interneurons
a) Afferent axons
Which type of glia absorbs chemicals released by axons and later returns those chemicals back to the axon, remove waste products, cause blood vessels to dilate and recycles glutamate?
Astrocytes: A type of glia that absorbs chemicals released by axons and later
returns those chemicals back to the axon to help synchronize the activity of
neurons. Astrocytes remove waste products as well, particularly those created
after neurons die. Astrocytes also cause blood vessels to dilate to bring in more nutrients at times of increased brain activity. They act as a recycling system for glutamate released by neurons (absorbing excess glutamate then converting it
to glutamine and passing it back into the neurons).
What is the cell body (soma) of a neuron?
Cell body (soma): Contains the nucleus, ribosomes, mitochondria, and other structures found in most cells
Neurons entirely located within a single structure of the nervous system are said to be:
a) Afferent
b) Efferent
c) Interneurons
c) Interneurons
Why do we need a Blood-Brain Barrier? (5 reasons)
- The blood-brain barrier is needed because the brain lacks the type of immune
system present in the rest of the body. - Because neurons cannot be replicated and replaced, the barrier is in place to
minimize the risk of irreparable brain damage. - A wall is formed that keeps out most viruses, bacteria, and harmful chemicals.
- When viruses do enter, like the rabies virus, it can infect the brain and lead to
death. - A virus that enters your nervous system probably stays with you for life (e.g.,
chicken pox and shingles)
What is the refractory period?
The refractory period is a period immediately after an action potential occurs
when the neuron will resist the production of another action potential.
Which two glia build the myelin sheaths around certain neurons, and where is each located?
a) Astrocytes
b) Microglia
c) Oligodendrocytes
d) Schwann cells
e) Radial glia
CNS Oligodendrocytes: A type of glia that builds the myelin sheaths around certain
neurons in the brain and spinal cord.
PNS Schwann cells: A type of glia that builds the myelin sheaths around certain
neurons in the periphery of the body.
What do efferent axons do?
Sends information away from a structure