Chapter 10: Nervous System 1
Within neurons, dendrites are processes extending from the ______. They function to carry signals ______ the cell body.
cell body; toward
In the ______ nervous system, neurons are organized into neuronal pools.
central/central nervous system/CNS
The two main divisions of the nervous system are the ______ nervous system and the ______ nervous system
central; peripheral
The term indicating that charges are likely to move across the cell membrane is membrane ______.
potential
One neuron sends a signal to a nearby neuron through a structure called a(n) ______.
synapse
The space between the synaptic knob of one neuron and the receptive surface of another is called the ______.
synaptic cleft
The size and shape of neurons ______.
varies
Indicate three general functions of neuroglia.
-Carry out phagocytosis. -Produce components of myelin. -Provide structural support of neurons.
The flow of information in the nervous system involves which three components?
-Brain and spinal cord -Effectors for motor output -Sensory receptors
Identify three functions of neuroglial cells.
-Remove excess ions and neurotransmitters from areas surrounding neurons. -produce growth factors for neurons -guide neurons into position during embryogenesis
The two main divisions of the nervous system are the ______ and the _______.
-peripheral nervous system -central nervous system
The circle includes which two structures?
-synapse -synaptic cleft
A neuron has a spherical surface (labeled as B) from which root-like structures (labeled as A) extend outward. A tubular filament extends from B that branches into two at the other end. The tubular filament is segmented. One of the segments is labeled as C. At the terminal, root-like structures extend outward that is labeled as D.
A - dendrite B - chromatophilic substance C - Schwann cell D - axon
Convergence of neurons allows which function to occur in the brain?
Allows neurons to collect and process impulses from different sources.
Identify the prefix that means "two".
Bi-
What does it mean that neurons are excitable?
Local potential changes occur in the membrane due to changes in the surrounding area.
Thinking, learning, and regulating movement are functions of which organ system?
Nervous
What is a refractory period for a membrane?
Period of time after an action potential when the membrane cannot send another action potential.
For the flow of information in the nervous system, match each component with its part in the process.
Sensory Input - Receptor Integration - Brain and Spinal Cord Motor Output - Effector such as muscle
Match the function of the nervous system with the component that carries it out. Instructions
Sensory input - Receptor Integration and processing - Brain and spinal cord Motor output - Effector
Which is the correct order for transmission of a nerve impulse from a receptor to an effector?
Sensory receptor→Sensory neuron→Interneuron→Motor neuron→Muscle cell
What is the function of divergent neuronal circuits in the nervous system?
To amplify impulses.
Which neurotransmitter is responsible for skeletal muscle contraction?
acetylcholine
The neurotransmitter released at neuromuscular junctions, stimulating skeletal muscle contraction, is ______.
acetylcholine/ACh
What is the effect of a neuromodulator?
alters the response of the neuron to a neurotransmitter
As an action potential occurs in one area of the axon, an electrical current to neighboring areas of the membrane initiates ______.
another action potential
The part of the neuron surrounded by the circle is called the ______.
cell body
Where are axon terminals located?
at the ends of axons
A neuron has a cell body from which root-like structures extend outward that is labeled as B. A tubular filament extends from a portion of the cell body that is labeled as A. The tubular filament is enveloped by segments and branches at the other end. The filament between the segments is labeled as C.
axon hillock - A dedrite - B axon - C
Name the specialized endings found at the end of an axon.
axon terminals
A neuron has no more than one ______, but can have many ______.
axon; dendrites
Where is a synaptic cleft located?
between a synaptic knob and another cell
What will trigger the opening of chemically gated ion channels?
binding of neurotransmitter molecules
The enlarged part of the neuron (within the circle) is the cell ______.
body, soma, or perikaryon
Ion channels that respond to neurotransmitter molecules are described as ______ gated.
chemically
Neurotransmitters bind to ion channels that are ______-gated ion channels.
chemically
The term ______ describes an arrangement of neurons in which two or more presynaptic neurons synapse onto a single postsynaptic neuron.
convergence
What type of process is typically more abundant in a neuron?
dendrite
In this image of a neuron, the cellular processes indicated by the lines are called ______.
dendrites
Neurons have processes called ______ that receive signals from other neurons.
dendrites
A neuron includes a cell body with its organelles, and cell processes called ______ and ______.
dendrites; axons
A cell membrane is ______ if its membrane potential becomes less negative (more positive) than the resting potential.
depolarized
In the process of ______, one presynaptic neuron synapses with multiple postsynaptic neurons.
divergence
When one neuron synapses with several other neurons, this is a ______ circuit.
diverging
Since neurons can respond to changes in their surroundings, they are described as ______.
excitable
An ______ postsynaptic potential involves the opening of sodium channels, depolarizing the membrane, and bringing it closer to a threshold level.
excitatory
What are neuronal pools?
groups of neurons in the CNS with a common function
When depolarization occurs, the resting membrane potential becomes ______ negative and ______ 0mV.
less; closer to
A charge inside of a cell, indicating that there is the possibility that charges will move across the cell membrane, is called ______.
membrane potential
Which term indicates that charges have the capability of moving across the cell membrane, creating an electric current?
membrane potential
The master regulatory system that sends and receives information is the ______ system.
nervous
A molecule acting as a(n) ______ will alter the release of neurotransmitters or alter the response of the postsynaptic neuron to the neurotransmitter.
neuromodulator
Dendrites are branches off of the ______ that function to ______.
neuron cell body; receive incoming signals
The structure within the cell body that is indicated by the letter B is the cell's ______.
nucleus
Which neuron structure is surrounded by the circle in the image?
nucleus
Most cells are negatively charged on the inside but have a positively charged extracellular space outside. This difference in charges is called ______.
polarity
The water molecule shows ______ because it has negatively-charged regions in the vicinity of the oxygen atom and positively-charged regions near the hydrogen atoms.
polarity
A(n) ______ period is a brief time following a nerve impulse when the membrane is unresponsive to an ordinary stimulus.
refractory
Match the neuron type with its function.
sensory (afferent) neuron - located in PNS; carries impulses towards the CNS motor (efferent) neuron - located in PNS; carries impulses away from the CNS interneuron - located in the CNS; integrates sensory signals
Neurons carrying nerve impulses toward the CNS are ______ neurons while neurons carrying nerve impulses from the CNS to the periphery are ______ neurons.
sensory/afferent; motor/efferent
An excitatory postsynaptic potential (EPSP) occurs when neurotransmitters bind to their receptors and open chemically-gated ______ channels.
sodium
The end of an axon may have many fine extensions, each with a specialized ending called an axon ______.
terminal
The meaning of the prefix "bi-" is ______.
two
As an action potential occurs in one area of the axon, it causes nearby ______ channels to open, initiating another action potential in the neighboring membrane.
voltage-gated