Biology 255 Exam 3 Study Guide (Human
Anatomy) Questions And Answers (Verified
And Updated)
Central nervous system structures
Brain and spinal cord
Nervous system general functions
Collect information, process and evaluate information, and initiate response to information
Peripheral nervous system structures
Cranial nerves, spinal nerves, and ganglia
Sensory (afferent) nervous system
Detects stimuli (receives sensory input/information from receptors) and transmits information from
receptors to the CNS
Somatic sensory
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
Transmits input from blood vessels and viscera
Motor (efferent) nervous system
Signals move away from the CNS to the effector organs, glands, etc. Output
Somatic motor
Aka voluntary nervous system; transmit voluntary output to skeletal muscle
Autonomic motor
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
Short processes that branch from cell body of a neuron
Cell body
Summation of signal from dendrites; contains typical organelles (largest part of a typical neuron)
Axon (nerve fiber)
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
Region where body is connected to axon
Axon terminal/synaptic end bulb (synaptic bulbs, axon terminals)
Expanded regions at tips of telodendria that secrete neurotransmitter
Multipolar
Many dendrites and one axon; most common
Bipolar
Two processes, one dendrite, and one axon (most rare - in the eye and olfactory)
Unipolar
Single, short process that branches like a T
Sensory (afferent) neuron
Transmit impulses from sensory receptors (e.g., in skin) to the CNS
Motor (efferent) neuron
Transmit impulses from CNS to muscles of glands
Interneuron (association)
Facilitate communication between sensory and motor neurons; only within CNS
Astrocyte
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
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
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
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)
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
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
Describe composition of the myelin sheath
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?
- 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
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
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
Bundles of afferent and efferent fibers (axons) within CNS
Anatomy) Questions And Answers (Verified
And Updated)
Central nervous system structures
Brain and spinal cord
Nervous system general functions
Collect information, process and evaluate information, and initiate response to information
Peripheral nervous system structures
Cranial nerves, spinal nerves, and ganglia
Sensory (afferent) nervous system
Detects stimuli (receives sensory input/information from receptors) and transmits information from
receptors to the CNS
Somatic sensory
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
Transmits input from blood vessels and viscera
Motor (efferent) nervous system
Signals move away from the CNS to the effector organs, glands, etc. Output
Somatic motor
Aka voluntary nervous system; transmit voluntary output to skeletal muscle
Autonomic motor
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
Short processes that branch from cell body of a neuron
Cell body
Summation of signal from dendrites; contains typical organelles (largest part of a typical neuron)
Axon (nerve fiber)
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
Region where body is connected to axon
Axon terminal/synaptic end bulb (synaptic bulbs, axon terminals)
Expanded regions at tips of telodendria that secrete neurotransmitter
Multipolar
Many dendrites and one axon; most common
Bipolar
Two processes, one dendrite, and one axon (most rare - in the eye and olfactory)
Unipolar
Single, short process that branches like a T
Sensory (afferent) neuron
Transmit impulses from sensory receptors (e.g., in skin) to the CNS
Motor (efferent) neuron
Transmit impulses from CNS to muscles of glands
Interneuron (association)
Facilitate communication between sensory and motor neurons; only within CNS
Astrocyte
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
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
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
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)
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
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
Describe composition of the myelin sheath
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?
- 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
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
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
Bundles of afferent and efferent fibers (axons) within CNS
