BIOLOGY 255 EXAM 3 STUDY GUIDE (HUMAN
ANATOMY)
Central nervous system structures - Answers :Brain and spinal cord
Nervous system general functions - Answers :Collect information, process and evaluate
information, and initiate response to information
Peripheral nervous system structures - Answers :Cranial nerves, spinal nerves, and
ganglia
Sensory (afferent) nervous system - Answers :Detects stimuli (receives sensory
input/information from receptors) and transmits information from receptors to the CNS
Somatic sensory - Answers :Transmits input from skin, fascia, joints, and skeletal
muscle; general somatic senses: touch, pain, pressure, vibration, temperature, and
proprioception, and special senses (taste, vision, hearing, balance, and smell)
Visceral sensory - Answers :Transmits input from blood vessels and viscera
Motor (efferent) nervous system - Answers :Signals move away from the CNS to the
effector organs, glands, etc. Output
Somatic motor - Answers :Aka voluntary nervous system; transmit voluntary output to
skeletal muscle
Autonomic motor - Answers :Aka visceral motor system or the involuntary nervous
system; transmit involuntary output to smooth muscle, cardiac muscle, and glands (has
parasympathetic and sypmathetic subdivisions)
Dendrite - Answers :Short processes that branch from cell body of a neuron
Cell body - Answers :Summation of signal from dendrites; contains typical organelles
(largest part of a typical neuron)
Axon (nerve fiber) - Answers :Single, long extension that carries impulses away from
the cell body
-Typically have a single axon
-Axon transmits nerve impulses away from cell body and to other cells
Axon hillock - Answers :Region where body is connected to axon
Axon terminal/synaptic end bulb (synaptic bulbs, axon terminals) - Answers :Expanded
regions at tips of telodendria that secrete neurotransmitter
,Multipolar - Answers :Many dendrites and one axon; most common
Bipolar - Answers :Two processes, one dendrite, and one axon (most rare - in the eye
and olfactory)
Unipolar - Answers :Single, short process that branches like a T
Sensory (afferent) neuron - Answers :Transmit impulses from sensory receptors (e.g., in
skin) to the CNS
Motor (efferent) neuron - Answers :Transmit impulses from CNS to muscles of glands
Interneuron (association) - Answers :Facilitate communication between sensory and
motor neurons; only within CNS
Astrocyte - Answers :Most abundant glial cells in CNS Wrap around the capillary
Functions:
1. Keep anything from leaking
2. Maintain blood-brain barrier via regulation of blood flow
3. Regulate tissue fluid composition (control ion flow, pH)
4. Form a structural network
5. Assist neuronal development (can secrete their own neurons)
6. Help regulate synapses
7. CNS damage - formation of glial scar
Oligodendrocyte - Answers :Wrap around CNS axons like electrical tape wrapped
around a wire (it's made of their plasma membrane)
Function:
1. Produce myelin, which is an insulator of electrical activity -speeds up neural
transmission
Microglia - Answers :CNS stem cells that are motile (modified white blood cells)(move
around through the brain tissue)
Function:
1. Wander through CNS and phagocyte cellular debris from dead or dying tissue
Ependymal cell - Answers :Ciliated cuboidal epithelial cells in the CNS that line
ventricles of the brain and the central canal of the spinal cord
Function:
1. Form the choroid plexus with capillaries and produce cerebral spinal fluid (CSF)
Schwann Cell (neurolemmocyte) - Answers :Associated with PNS axons only
Functions:
1. Wrap around axons like electrical tape wrapped around a wire
2. Produce myelin, which is an insulator of electrical activity --speeds up neural
transmission
, (same function as oligodendrocytes in CNS)
Satellite cell - Answers :Flattened cells around neuronal cell bodies in PNS ganglia
(PNS ganglia are just clumps of cell bodies)
Functions:
1. Physical barrier between neural cell bodies and interstitial fluid
2. Regulates flow of nutrients and waste
Describe the process of myelination, naming the cells that make the myelin sheath in
both the CNS and PNS - Answers :
Describe composition of the myelin sheath - Answers :The overlapping inner layers of
the neurolemmocyte plasma membrane form the myelin sheath
What are the nodes of Ranvier? What is their role in the conduction of a nervous signal?
- Answers :- Spaces called neurofibril nodes between adjacent insulating cells
(neurolemmocytes or oligodendrocytes)
- Electrical signal "jumps" from node to node, so it travels much more quickly down the
axon
= saltatory conduction
Nerve fiber - Answers :Axons of neurons. They can be myelinated or unmyelinated
- Myelin sheath (speeds up transmission) or no myelin sheath
- Speed of transmission increases with:
Increased size of fiber - increased diameter
- Presence of myelin
Nerve - Answers :Bundles of afferent and efferent fibers (axons) in PNS, outside CNS
- Both are white matter
- Allow electrical signals to travel quickly throughout the body
Tract - Answers :Bundles of afferent and efferent fibers (axons) within CNS
Ganglia - Answers :Gray matter cell bodies in groups in the PNS
Nuclei - Answers :Gray matter masses of cell bodies and dendrites in the CNS
What is an action potential? Describe the process (in a general way) - Answers
:Electrical signals travel down the axon via action potentials (rapid flow of ions across
the cell membrane)
- Once an action potential begins, it triggers more down the axon until the signal
reaches the axon terminal
Synapse - Answers :Specialized junctions between two cells through which a signal is
passed (conductive link)
-Often between an axon and another neuron
ANATOMY)
Central nervous system structures - Answers :Brain and spinal cord
Nervous system general functions - Answers :Collect information, process and evaluate
information, and initiate response to information
Peripheral nervous system structures - Answers :Cranial nerves, spinal nerves, and
ganglia
Sensory (afferent) nervous system - Answers :Detects stimuli (receives sensory
input/information from receptors) and transmits information from receptors to the CNS
Somatic sensory - Answers :Transmits input from skin, fascia, joints, and skeletal
muscle; general somatic senses: touch, pain, pressure, vibration, temperature, and
proprioception, and special senses (taste, vision, hearing, balance, and smell)
Visceral sensory - Answers :Transmits input from blood vessels and viscera
Motor (efferent) nervous system - Answers :Signals move away from the CNS to the
effector organs, glands, etc. Output
Somatic motor - Answers :Aka voluntary nervous system; transmit voluntary output to
skeletal muscle
Autonomic motor - Answers :Aka visceral motor system or the involuntary nervous
system; transmit involuntary output to smooth muscle, cardiac muscle, and glands (has
parasympathetic and sypmathetic subdivisions)
Dendrite - Answers :Short processes that branch from cell body of a neuron
Cell body - Answers :Summation of signal from dendrites; contains typical organelles
(largest part of a typical neuron)
Axon (nerve fiber) - Answers :Single, long extension that carries impulses away from
the cell body
-Typically have a single axon
-Axon transmits nerve impulses away from cell body and to other cells
Axon hillock - Answers :Region where body is connected to axon
Axon terminal/synaptic end bulb (synaptic bulbs, axon terminals) - Answers :Expanded
regions at tips of telodendria that secrete neurotransmitter
,Multipolar - Answers :Many dendrites and one axon; most common
Bipolar - Answers :Two processes, one dendrite, and one axon (most rare - in the eye
and olfactory)
Unipolar - Answers :Single, short process that branches like a T
Sensory (afferent) neuron - Answers :Transmit impulses from sensory receptors (e.g., in
skin) to the CNS
Motor (efferent) neuron - Answers :Transmit impulses from CNS to muscles of glands
Interneuron (association) - Answers :Facilitate communication between sensory and
motor neurons; only within CNS
Astrocyte - Answers :Most abundant glial cells in CNS Wrap around the capillary
Functions:
1. Keep anything from leaking
2. Maintain blood-brain barrier via regulation of blood flow
3. Regulate tissue fluid composition (control ion flow, pH)
4. Form a structural network
5. Assist neuronal development (can secrete their own neurons)
6. Help regulate synapses
7. CNS damage - formation of glial scar
Oligodendrocyte - Answers :Wrap around CNS axons like electrical tape wrapped
around a wire (it's made of their plasma membrane)
Function:
1. Produce myelin, which is an insulator of electrical activity -speeds up neural
transmission
Microglia - Answers :CNS stem cells that are motile (modified white blood cells)(move
around through the brain tissue)
Function:
1. Wander through CNS and phagocyte cellular debris from dead or dying tissue
Ependymal cell - Answers :Ciliated cuboidal epithelial cells in the CNS that line
ventricles of the brain and the central canal of the spinal cord
Function:
1. Form the choroid plexus with capillaries and produce cerebral spinal fluid (CSF)
Schwann Cell (neurolemmocyte) - Answers :Associated with PNS axons only
Functions:
1. Wrap around axons like electrical tape wrapped around a wire
2. Produce myelin, which is an insulator of electrical activity --speeds up neural
transmission
, (same function as oligodendrocytes in CNS)
Satellite cell - Answers :Flattened cells around neuronal cell bodies in PNS ganglia
(PNS ganglia are just clumps of cell bodies)
Functions:
1. Physical barrier between neural cell bodies and interstitial fluid
2. Regulates flow of nutrients and waste
Describe the process of myelination, naming the cells that make the myelin sheath in
both the CNS and PNS - Answers :
Describe composition of the myelin sheath - Answers :The overlapping inner layers of
the neurolemmocyte plasma membrane form the myelin sheath
What are the nodes of Ranvier? What is their role in the conduction of a nervous signal?
- Answers :- Spaces called neurofibril nodes between adjacent insulating cells
(neurolemmocytes or oligodendrocytes)
- Electrical signal "jumps" from node to node, so it travels much more quickly down the
axon
= saltatory conduction
Nerve fiber - Answers :Axons of neurons. They can be myelinated or unmyelinated
- Myelin sheath (speeds up transmission) or no myelin sheath
- Speed of transmission increases with:
Increased size of fiber - increased diameter
- Presence of myelin
Nerve - Answers :Bundles of afferent and efferent fibers (axons) in PNS, outside CNS
- Both are white matter
- Allow electrical signals to travel quickly throughout the body
Tract - Answers :Bundles of afferent and efferent fibers (axons) within CNS
Ganglia - Answers :Gray matter cell bodies in groups in the PNS
Nuclei - Answers :Gray matter masses of cell bodies and dendrites in the CNS
What is an action potential? Describe the process (in a general way) - Answers
:Electrical signals travel down the axon via action potentials (rapid flow of ions across
the cell membrane)
- Once an action potential begins, it triggers more down the axon until the signal
reaches the axon terminal
Synapse - Answers :Specialized junctions between two cells through which a signal is
passed (conductive link)
-Often between an axon and another neuron
