Chapter 10- Nervous system I: Basic structure and function
Indicate the four types of neuroglia (glial cells) in the central nervous system.
Astrocytes Oligodendrocytes Microglia Ependyma
Where are axon terminals located?
At the ends of axons
Select examples of effectors that can be stimulated by motor impulses.
Autonomic
The motor division of the nervous system is subdivided into _____ and _____ nervous systems
Autonomic Somatic
The part of a neuron that sends out nerve impulses is the _____.
Axon
Which three items are parts of a neuron?
Axon Cell body Dendrites
A neuron has no more than one _____, but can have many _____.
Axon; dendrites
The process called _____ transport involves the passage of proteins, organelles and other materials along an axon.
Axonal
Where is a synaptic cleft located?
Between a synapti knob and another cell
Neurons that have only two processes, one axon and one dendrite, are called _____ neurons.
Bipolar
The enlarged part of the neuron (within the circle) is the cell _____.
Body
Select examples of effectors that can be stimulated by motor impulses.
Cardiac muscle Glands Skeletal muscle
Arrow A indicates a _____. Whereas arrow B indicates a _____.
Cell body; dendrite
Within neurons, dendrites are processes extending from the _____. They function to carry signals _____ the cell body.
Cell body; toward
Structures called tracts are bundles of axons occurring within the _____ nervous system.
Central
What is the source of new neurons in the CNS?
Central nervous system stem cells
The two main divisions of the nervous system are the _____ nervous system and the _____ nervous system.
Central, peripheral
The gap between the two neurons is called the synaptic _____.
Cleft
What is the term for branches off of an axon?
Collaterals
What is a function of the nervous system?
Coordinate all other body functions
What type of process is typically more abundant in a neuron?
Dendrite
Neurons have processes called _____ that receive signals from other neurons.
Dendrites
Within a neuron, the _____ are highly branched cellular processes that carry signals toward the cell body of the neuron.
Dendrites
A neuron includes a cell body with its organelles, and cell processes called _____ and _____.
Dendrites; axons
Mature neurons _____divide.
Do not
Muscles and glands, located outside of the central nervous system, function as _____, responding to motor impulses.
Effectors
The chromatophilic substance (Nissl bodies) of a neuron is a modification of what cellular organelle?
Endoplasmic reticulum
True or false: If an axon in the CNS is damaged, it regenerates after a short period of time.
False- Regeneration is unlikely because the CNS lack neurilemma; oligodendrocytes do not proliferate after injury.
A mass of neuron cell bodies located outside the brain and spinal cord is called a(n) _____.
Ganglia
_____ matter consists of _____ axons, dendrites, and neuron cell bodies.
Gray; unmyelinated
Indicate three functions of astrocytes.
Helps repair nervous tissue Aids in the metabolism of substances (ie glucose). Forms the blood brain barrier.
The axon _____ is the region of a neuron where the axon originates.
Hillock
Sensory signals come into the central nervous system where _____ occurs. Then, signals are sent out to the body using _____ neurons.
Integration; motor
The _____ function of the nervous system is to gather _____ information and make decisions that affect _____ functions.
Integrative; sensory; motor
What is the meaning of the prefix "multi-"?
Many
Name the cell in nervous tissue that provides physical support, insulation, and nutrients for other cells.
Neuroglia
What are the two cell types in neural tissue?
Neuroglia Neurons
In the central nervous system, cells called _____ outnumber the cells called _____.
Neuroglia; neurons
Schwann cells and satellite cells are types of _____ found in the _____ nervous system.
Neuroglia; peripheral
Mature _____ do not divide.
Neurons
What is the term for biological messenger molecules that transmit a signal between two neurons?
Neurotransmitters
What is the name of the gaps found between segments of myelin along an axon?
Nodes of Ranvier
In the CNS, myelin is produced by cells called _____. In the peripheral nervous system, myelin is made by cells called _____.
Oligodendrocytes; Schwann cells
What prefix means "all around"?
Peri-
The somatic nervous system and autonomic nervous system are subdivisions of the _____ nervous system.
Peripheral
In what branch of the nervous system do the Schwann cells wrap around axons creating myelin sheaths?
Peripheral nervous system
Schwann cells are neuroglia that produce myelin in the _____.
Peripheral nervous system
What division of the nervous system consists of cranial and spinal nerves?
Peripheral nervous system
The ability of damage axons to regenerate in the _____ nervous system may be due to the neuroglia cell called the _____.
Peripheral; Schawnn cell
Sensory neurons carry electrical signals from the _____ to the _____.
Periphery; central nervous system
Indicate three general functions of neuroglia.
Produce components of myelin. Provide structural support of neurons. Carry out phagocytosis.
Axonal transport is the movements of _____ up and down the _____.
Proteins and organelles; axon
What is the source of myelin, found around large axons of the peripheral nervous system?
Schwann cell membranes tightly wound around axons.
The cells that are responsible for wrapping around axons, creating myelin sheaths in the PNS, are _____.
Schwann cells
List three functions of the nervous system.
Sense the environment Integrate incoming signals Initiate changes in effectors
Nerve impulses are conducted via the _____ neurons from peripheral body parts into the brain and spinal cord.
Sensory
_____ receptors detect changes in internal and external body conditions.
Sensory
Match the neuron type with its function.
Sensory (afferent) neuron- Located in PNS; carry impulses toward the CNS Motor (efferent) neuron- Located in PSN; carry impulses away from the CNS Interneuron- Located in the CNS; integrate sensory signals
What class of neurons transmit information from the periphery to the central nervous system?
Sensory neurons
Somatic motor neurons control _____ muscles. Autonomic motor neurons control _____ muscles.
Skeletal; smooth
In the central nervous system, severed axons degenerate _____ compared to the PNS and are _____ to regenerate.
Slower; unlikely
The _____ division of the peripheral nervous system handles voluntary motor activites.
Somatic
The _____ division of the peripheral nervous system handles voluntary motor activities.
Somatic
What organs make up the peripheral nervous system?
Spinal nerves Cranial nerves
Which three of the following describe the autonomic nervous system?
Subdivision of the peripheral nervous system Controls smooth and cardiac muscle Effectors are under involuntary control
A(n) _____ is the location at which a neuron and the cell with which it communicates meet (without directly touching).
Synapse
Which two characteristics apply to cells called interneurons (or association neurons)?
They are multipolar neurons They link sensory neurons to motor neurons
The meaning of the prefix "bi" is _____.
Two
Nodes of Ranvier are narrow gaps between what two structures?
Two myelin sheath
What prefix means "one"?
Uni-
Gray matter consists of what three structures?
Unmyelinated axons Neuron cell bodies Dendrites
Within the central nervous system, tissue called _____ matter consists of bundles of _____ axons.
White; myelinated
In the peripheral nervous system, severed axons _____ regenerate under certain conditions.
May
Huntington's disease may be caused by cells of the brain called _____ releasing toxins. Cells called _____may release toxins that may be related to amyotrophic lateral sclerosis (ALS), a neurodegerative disorder.
Microglia; astrocytes
Neurons that send signals away from the central nervous system to effectors, such as a muscle (skeletal, cardiac and smooth) and glands are called _____ neurons.
Motor
What type of neuron would stimulate an effector?
Motor neurons
Nervous system damage to _____ neurons would affect skeletal muscle contration (movement); difficulty in feeling touch or pain is caused by damage to _____ neurons.
Motor; sensory
A patient is diagnosed with brain lesions caused by an immune system attack against myelin sheaths. What is most likely the diagnosis?
Multiple sclerosis
Neurons are structurally classified as unipolar, bipolar, or _____.
Multipolar
What gives white matter of the central nervous system its white color?
Myelin
The winding of Schwann cells around an axon results in the formation of what feature of a neuron?
Myelin sheath
A neurilemma surrounds the _____ and contains most of the _____.
Myelin sheath; Schwann cell cytoplasm
Myelinated axons have _____, and transmit impulses more _____ than unmyelinated axons.
Myelin sheaths; quikly
Structures within the peripheral nervous system called _____ are bundles of axons wrapped in connective tissue.
Nerves
What is the term for bundles of axons within the peripheral nervous system?
Nerves
Feeling, thinking and moving are functions of which organ system?
Nervous