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Anatomy Chapter 7 Terms

Terms in this set (74)

Functions of the Nervous System
Sensory Input - gathering information
Integration
Motor output
Sensory Input
Gathering information
*to monitor changes occuring inside and outside the body
*changes = stimuli
Integration
to process and interpret sensory input and decide if action is needed
Motor Output
*a response to integrated stimuli
*The response activates muscles or glands
Structural Classification of the Nervous system
*Central nervous system (CNS)
*Peripheral Nervous system (PNS)
Central Nervous System (CNS)
Brain
Spinal cord
Peripheral Nervous System (PNS)
Nerves outside the brain and spinal cord
*Spinal nerves
*Cranial nerves
Functional Classification of the Peripheral Nervous System
Sensory (afferent) division
Nerve fibers that carry information TO the CNS
Motor (efferent) division
Nerve fibers that cary impulses AWAY from the CNS
Functional Classification of the Peripheral Nervous System
Motor (efferent) division
* Two Subdivisions
Somatic nervous system = voluntary
Autonomic nervous system = involuntary
Nervous Tissue: Support Cells
*Support cells in the CNS are grouped together as "neuroglia"
*Function: to support, insulate, and protect neurons
Nervous Tissue: Support Cells
Astrocytes
Microglia
Ependymal
Oligodendrocytes
Satellite cells
Schwann cells
Astrocytes
*Abundant, star-shaped cells
*Brace neurons
*Form barrier between capillaries and neurons
*Control the chemical environment of the brain
Microglia
*Spider like Phagocytes
*Disposal of debris
Ependymal Cells
*Line cavities of the brain and spinal cord
*Circulate cerebrospinal fluid
Oligodendrocytes
*Wrap around nerve fibers in the central nervous system
*Produce myelin sheaths
Satellite Cells
*Protect neuron cell bodies
Schwann Cells
*Form myelin sheath in the peripheral nervous system
Nervous tissue: Neurons
*Cell Body
Neucleus
Large nucleolus
*Processes outside the cell body
Dendrites - conduct impulses TOWARD the cell body
Axons - conduct impulses AWAY form the cell body
Nervous Tissue: Neurons
*Myelin Sheath - whitish, fatty material covering axons
*Schwann Cells - produce myelin sheaths in Jelly roll like fashion
*Nodes of Ranvier - gaps in myelin sheath along the axon
Nervous Tissue Neaurons
*Axons end in axonal terminals
*Axonal terminals contain vesicles with neurotransmitters
*Axonal terminals are separated from the next neuron by a gap
Synaptic cleft - gap between adjacent neurons
Synapse - junction between nerves
Neuron Cell Body Location
Most neuron cell bodies are found in the central nervous system
Gray matter - cell bodies and unmyelinated fibers
Nuclei - clusters of cell bodies within the white matter of the central nervous systyem
Ganglia - collections of cell bodies outside the central nervous system
Functional Classification of Neurons
Sensory (afferent) neurons
Motor (efferent) neurons
Interneurons (association neurons)
Sensory (afferent) neurons
*Carry impulses from the sensory receptors to the CNS
Cutaneous sense organs
Proprioceptiors - detect stretch or tension
Motor (efferent) neurons
*Carry impulses from the central nervous system to viscera, muscles, or glands
Interneurons (association neurons)
*Found in neural pathways in the central nervous system
*Connect sensory and motor Neurons
Structural Classification of Neurons
Multipolar neurons - many extensions from the cell body
Bipolar neurons - one axonand one dendrite
Unipolar neurons - have a short single process leaving the cell body
Functional Properties of Neurons
Irritability - ability to respond to stimuli
Conductivity - ability to transmit an impulse
Nerve impulses
*Resting neuron
The plasma membrane at rest is polarized
Fewer positive ions are inside the cell that out
*Depolarization
A stimulus depolarizes the neuron's membrane
*The exchange of ions initiates an action potential in the neuron
Nerve Impulses
*Action Potential
If the action potential (nerve impulse) starts, it is propagated over the entire axon
Impulses travel faster when fibers have a myelin sheath
Nerve Impulses
*Repolarization
Potassium ions rush out of the neuron after sodium ions rush in, which repolarizes the membrane
The sodium-potassium pump, using ATP. restores the origional configuration
Nerve Impulses: Transmission of a Signal at Synapses
*Impulses are able to cross the synapse to another nerve
*Neurotransmitter s released from a nerve's axon terminal
*The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter
*An action potential is started in the dendrite
The Reflex Arc
*Reflex - rapid, predictable, and involuntary response t a stimulus
Occurs over pathways called reflex arcs
*Reflex arc - direct route from a sensory neuron, to an interneuron, to an effector
Simple Reflec Arc
Types of Reflexes and Regulation
*Somatic Reflexes
*Autonomic Reflexes
*Patellar - knee jerk, reflex is an example of two-neuron reflex arc
Somatic reflexes
Activation of skeletal muscles
Example : When you move you hand away from hot stove
Autonomic reflexes
Smooth muscle regulation
Heart and blood pressure regulation
Regulation of glands
Digestive system regulation
Central Nervous System (CNS)
*CNS developes from the embryonic neural tube
The neural tube becomes the brain and spinal cord
The opening of the neural tube becomes the ventricles
*Four chambers within the brain
*Filled with cerebrospinal fluid
Central Nervous System: Regions of the Brain
*Cerebral hemispheres (cerebrum)
*Diencephalon
*Brain Stem
*Cerebellum
Regions of the Brain: Cerebrum
*Cerebral Hemispheres (Cerebrum)
Paired (left and right) superior parts of the brain
Includes more than half of the brain mass
The surface is made of ridges (gyri) and grooves (sulci)
Regions of the brain: Cerebrum: Lobes of the cerebrum
*Lobes fo the Cerebrum
Fissures (deep groves)divide the serebrum into lobes
Surface lobes of the cerebrum
*Frontal lobe
*Parietal lobe
*Occipital lobe
*Temporal lobe
Specialized Areas of the Cerebrum
*Primary somatic sensory area
*Primary motor area
*Broca's area
Primary Somatic Sensory Area
*receives impulses from the body's sensory receptors
*located in parietal lobe
Primary Motor Area
*Sends impulses to skeletal muscles
*Located in frontal lobe
Broca's area
*Involved in our ability to speak
Cerebral Areas involved in special senses
*Gustatory Area (taste)
*Visual area
*Auditory Area
*Olfactory Area
Interpretation areas of the Cerebrum
*Speach/language region
*Language comprehension region
*General Interpretation area
Layers of the Cerebrum
*Gray Matter - outer layer in the cerebral cortex composed mostly of neuron cell bodies
*White matter - fiber tracts deep to the gray mater
Corpus callosum contects the hemispheres
Basal nuclei - islands of gray matter buried within the white matter
Regions of the Brain: Diencephalon
*Sits on top of brain stem
*Enclosed by the cerebral hemishphers
*Made of 3 parts
*Thalamus
*Hypothalamus
*Ephithalamus
Thalamus
*Surrounds the third ventricle
*The relay station for sensory impulses
*Transfers impulses to the correct part of the cortex for localization and interpretation
Hypothalamus
*Under the thalamus
*Important autonomic nervous system center
*Helps regulate body temperature
*Controls water balance
*Regulates metabolism
*an important part of the limbic system (emotions)
*The pituitary gland is attached to the hypothalamus
Ephithalamus
*Forms the roof of the third ventricle
*Houses the pineal body (an endocrine gland)
*Includes the choroid plexus - forms cerebrospinal fluid
Brain Stem
*attaches to the spinal cord
*Parts of the brain stem
*Midbrain
*Pons
*Medulla oblongata
Midbrain
*Mostly composed of tracts of nerve fibers
*Has two bulging fiber tracts - cerebral peduncles
*Has four rounded protrusions - corpora quadrigemina
Reflex centers for vision and hearing
Pons
*The bulging center part of the brain stem
*Mostly composed of fiber tracts
*Includes nuclei involved in the control of breathing
Medulla Oblongata
*The lowest part of the brain stem
*Merges into the spinal cord
*Includes important fiber tracts
*Contains important control centers
Heart rate control Blood pressure regulation Breathing Swallowing *Vomiting
Reticular Formation
*Diffuse mass of gray matter along the brain stem
*Involved in motor control of visceral organs
*Reticular activating System (RAS) plays a role in awake/sleep cycles and consciousness
Cerebellum
*Two hemispheres with convoluted surfaces
*Provides involuntary coordination of body movements
Name the structures that make up the CNS and those that make up the PNS:
CNS - brain and spinal cord
PNS - nerves that extend to and from the CNS
Which glial cells are most abundant in the body:
Which produce the insulating material called myelin;
Astrocytes are the most numerous glial cells
Oligodendrocyes produce myelin
Why is a brain tumor more likely to be formed from glial cells than from neurons:
Because Glial cells can divide; most neurons cannot. A criteria of cancer cells is their uncontrolled division
How does a tract differ from a nerve:
A Tract is a bundle of nerve fibers in the CNS.
A Nerve is a bundle fo nerve fibers in the PNS.
How does a ganglion differ from a nucleus:
A Ganglion is a cluster of nerve cell bodies in the PNS.
A Nucleus is a cluster of nerve cell bodies in the CNS.
Which part of a neuron conducts impulses toward the cell body:
Which part releases neurotransmitters:
Dendrites conduct impulses toward the nerve cell body.

The Axon terminal releases neurotransmitters
Your professor tells you that one neuron transmits a nerve impulse at the rate of 1 meter per second and that another neuron conducts at the rate of 40 meeters per second. Which neuron has the myelinated axon:
the fiber that conducts at 40 meters per second
What is the difference between a graded potential and an action potential?
A Graded Potential is a local current that dies out with distance.
An Action Potential is a current that is continuously regenerated along the length of the axon and does not die out.
How is a stimulus transmitted across a synapse:
Chemically via the release of a neurotransmitter and binding of the neurotransmitter to the postsynaptic membrane.
Which portions of a neuron are likely to be associated with a sensory receptor or a sensory organ:
Dendrites
What is a reflex:
A Reflex is a rapid, predictable, and involuntary response to a stimulus
What are the three major regions of the cerebrum:
Cerebral cortex, White matter, and basal nuclei
What is the composition of white matter of the brain:
Myelinated nerve fibers
Which brain region controls such vital activities as breathing and blood pressure: cerebrum, brain stem, or cerebellum?
The brain stem controls vital activity
What is the function of the cerebellum?
The cerebellum provides precise timing for skeletal muscle activity and helps control our balance and equilibrium
In what major brain region are the thalamus, hypothalamus and pineal body found?
Diencephalon
What name is given to the cerebrospinal fluid filled cavities within the brain:
Ventricles
What name is given to the barrier that protects the brain from toxic chemicals:
Blood-Brain Barrier
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