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Anatomy & Physiology: The Nervous System

Terms in this set (41)

What are the functions of the Nervous System
1) Sensory imput-> gather info; monitor changes (stimuli) happening inside and outside the body
2) Integration-> process & interpret sensory imput and decide is action is needed
3) Motor output-> response
What makes up the CNS?
1) Brain
2) Spinal cord
What makes up the PNS?
Nerve outside the brain and spinal cord
What is the sensory (afferent) division?
Nerve fibers that carry information to the CNS
What is the Motor (efferent) division?
Nerve fibers that carry impulses away from the central nervous system.
What are the subdivision that makes up the motor division?
-Somatic NS-> voluntary
-Autonomic NS-> involuntary
What are Astrocytes?
Abundant, start shaped cells
Function of Astrocytes
- Brace neurons
- Form barrier between capillaries
- control the chemical environment of the brain (CNS)
What's a Microglia?
- Spider-like phagocytes
Function of Microglia
Dispose of debris
What are ependymal cells?
Line cavities of the brain and spinal cord (CNS)
What are the functions of Ependymal cells?
Circulate cerebrospinal fluid
function of oligodendrocytes
Produce myelin sheath around nerve fibers in the CNS
Difference between Neuroglia and neurons
- Neuroglia divide; neurons do not
- most brain tumors are "gliomas"
- Most brain tumors involve Neuroglia cells, not neurons
function of satellite cells
Protect neuron cell bodies
Function of Schwann cells
Form myelin sheath (in jelly-roll like fashion) in the PNS
What are neurons?
Nerve cells that specialized in transmitting messages
What makes up a neuron?
- cell body -> nucleus and metabolic center of the cell
- Processes -> fibers that extend from cell body (dendrites & axons)
Functions of dendrites
Conduct impulses toward the cell body
Function of axons
Conduct impulses away from the cell body
synaptic cleft
gap between adjacent neurons
Synapse
Junction between nerves
Nodes of Ranvier
gaps in myelin sheath along the axon
What is multiple sclerosis?
- An autoimmune disease
- myelin sheath is destroyed
- hardens to a tissue called the sclerosis
What are gray matter?
Cell bodies and unmyelinated fibers
Nuclei
Clusters of cell bodies within the white matter of the CNS
Ganglia
Collection of nerve cell bodies found outside the CNS.
What's the function of sensory (afferent) neurons?
- carry impulses from the sensory receptors
- cutaneous sense organs
propriceptors
- detect stretch or tension
- Respond to skeletal muscles, tendons joints and ligaments
What's the function of motor (efferent) neurons?
Carry impulses from the CNS
What are interneurons?
- Association neurons
- found in neural pathway in the CNS
- Connect sensory cord motor neurons
Multipolar neurons
many extensions from the cell body
Bipolar neurons
one axon and one dendrite
unipolar neurons
have a short single process leaving the cell body
What are the function of neurons?
- Irritability to respond to stimuli
- Conductivity to transmit an impulse
Polarization
Plasma membrane is at rest
- fewer + ions inside the cell than outside the cell
Depolarization
More + ions flow in the membrane
What is a reflex?
a fast, unplanned sequence of events in response to a stimulus
What is a reflex arc?
Direct route from a sensory neuron, to an interneuron, to an effector
Types of Autonomic reflexes
- Smooth muscle regulation
- Heart & blood pressure regulation
- regulation of glands
- Digestive system regulation
Types of Somatic reflexes
Activation of skeletal muscles
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