Lesson (Final) Flashcards
Nervous system classifications are based on!
- Structures (structural classification)
- Activities ( functional classification)
Structural Classification:
- Central Nervous system (CNS)
- Peripheral nervous system (PNS)
Organs of the Central Nervous system:
- Brain
- Spinal cord
Function of the Central Nervous system:
- Integration
- Interprets
- Issues
command center
Integration
Incoming sensory information
Interprets
Outgoing instructions
Issues
Peripheral nervous system (PNS)
Nerves extending from the brain and spinal cord:
*Spinal nerves
*Cranial nerves
Carry impulses to and from the spinal cord
Spinal nerves
Carry impulses to and from the brain
Cranial nerves
Function:
Serve as communication lines among sensory organs, the brain cord and glands or muscles
Peripheral nervous system (PNS)
Functional classification:
*Sensory (afferent) division
* Motor (efferent) division
Nerve fiber that carry information to the central Nervous system
Sensory (afferent) division
Two sensory in the Sensory (afferent) division:
- Somatic Sensory
- Visceral sensory
Fibers carry information from the skin, skeletal muscles, and joints
Somatic Sensory
Fibers carry information from visceral organs
Visceral sensory
Nerve fibers that carry impulses away from the central nervous system organs to effector organs (muscles and glands)
Motor (efferent) division
Two subdivisions of the motor division:
- Somatic Nervous system
- Autonomic nervous system
Subdivisions of the Motor division:
Voluntary
Somatic Nervous system
Subdivisions of the Motor division:
Involuntary
Autonomic nervous system
Consciously (voluntarily) controls skeletal muscle
Somatic nervous system
Automatically controls smooth and cardiac muscles and glands
Autonomic nervous system
Autonomic nervous system further divided into:
- Sympathetic
- Parasympathetic
Support cells in the CNS are grouped together as?
Neuroglia
General functions of neuroglia:
- Support
- Insulate
- Protect neurons
Nervous tissue is made up of two principal cell types:
- Supporting cells (called neuroglia, glial cells, or glia
- Neurons
CNS glial cells:
*astrocytes
* Microglia
* Ependymal cells
* Oligodendrocytes
Abundant, star- shaped cells
Astrocytes
The most abundant and versatile neuroglia
Astrocytes
Spiderlike phagocytes
Microglia
Dispose of debris
Microglia
Lines cavities of the brain and spinal cord
Ependymal cells
Cilia assists with circulation of cerebrospinal fluid
Ependymal cells
Wrap around nerve fibers in the central nervous system
Oligodendrocytes
Produce myelin sheaths
Oligodendrocytes
Functions of the nervous system:
- Sensory Input
- Integration
- Motor output
Gathering information
Sensory input
Sensory receptors monitor changes called stimuli, occurring inside and outside the body
Sensory input
Nervous system processes and interprets sensory input and decides whether action is needed
Integration
A response, or effect, activated muscles or glands
Motor output
White, fatty material covering axons
Myelin
Wrap axons in a jelly roll like fashion (PNS) to form the myelin sheath
Schwann cells
Two types of schwann cells:
- Neurilemma
- Nodes of Ranvier
Part of the schwann cells external to the myelin sheath
Neurilemma
Gaps in myelin sheath along the axon
Nodes of Ranvier
Produce myelin sheaths around axons of the CNS
Oligodendrocytes
Lack neurilemma
Oligodendrocytes
Types of terminology:
- nuclei
- Ganglia
- Tracts
- Nerves
- White matter
- Gray matter
Clusters of the bodies in the CNS
Nuclei
Collections of cell bodies outside the CNS in the PNS
Ganglia
Bundles of nerve fibers in the CNS
Tracts
Bundles of nerve fibers in the PNS
Nerves
Collections of myelinated fibers (tracts)
White matter
Mostly unmyelinated fibers and cell bodies
Gray matter
Structural Classification:
- multipolar neurons
- Bipolar neurons
- Unipolar neurons
Based on the number of processes extending from the cell body
Structural Classification
Many extensions from the cell body
Multipolar neurons
Most common structural type
Multipolar neurons
Have a short single process leaving the cell body
Unipolar
Functional properties of neurons:
- irritability
- Conductivity
Ability to respond to a stimulus and convert it to a nerve impulse
Irritability
Ability to transmit the impulse to other neurons muscles or glands
Conductivity
is the major positive ion inside the cell
K+
is the major positive ion outside the cell
Na+
Membrane permeability changes again —becoming impermeable to sodium ions and permeable to potassium ion
Repolarization
Involves restoring the inside of the membrane to a negative charge and the outer surface to a positive charge
Repolarization
PNS glial cells:
- Schwann cells
- Satellite cells
Form myelin sheath around nerve fibers in the PNS
Schwann cells
Protect and cushion neuron cell bodies
Satellite cells
Nerve cells
Neurons
Cells specialized in transmit messages (nerve impulses)
Neurons
Major regions of all neurons:
- cell body
- Processes
Nucleus and metabolic center of the cell
Cell body
Fiber that extend from the cell body
Processes
Metabolic center of the neuron
Cell body
Types of cell body:
- Nucleus
- Nissl bodies
- Neurofibrils
with large nucleolus
Nucleus
Rough endoplasmic reticulum
Nissl bodies
Intermediate filaments that maintain cell shape
Neurofibrils
are rapid, predictable, and involuntary responses to stimuli
Reflexes
Reflexes occur over neural pathways called?
Reflex arcs
Two types of reflexes:
- Somatic Reflexes
- Autonomic Reflexes
4 types of processes (fiber):
- Dendrites
- Axons
- Synaptic cleft
- Synapse
Conduct impulses toward the cell body
Dendrites
Conduct impulses away from the cell body
Axons
Gap between axon terminals and the next neuron
Synaptic cleft
Functional junction between nerves where a nerve impulse is transmitted
Synapse