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33 terms

Nervous Tissue

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General Functions of the nervous system
Communication/Homeostasis
Sensation
Integration
Reaction
What are the two major parts of the nervous system?
The central nervous system (CNS) and the peripheral nervous system (PNS)
Major anatomical components of the CNS
Brain and spinal cord
What are most cell bodies in the CNS?
Interneurons and motor neurons
Major anatomical components of the PNS
Everything else; nerves (cranial and spinal)
What nerves make up the ganglia?
Sensory and autonomic nerves
What is the major aspect of the CNS?
Integrative and control centers
What is the main function of the PNS?
Communication lines between the CNS and the rest of the body
Sensory (afferent) division
Somatic and visceral sensory nerve fibers; Conducts impulses from receptors to the CNS
Motor (efferent) division
Motor nerve fibers; Conducts impulses from the CNS to effectors (muscles and glands)
Viscerosensory (visceral sensory nerve fibers)
"viscus"= organ; sensation from internal organs; part of the sensory division
Somatosensory (somatic sensory nerve fibers)
"soma"=body; sensation from skin sent down; part of the sensory division
Somatic Nervous System
Somatic motor=voluntary; conducts impulses from the CNS to the skeletal muscles; part of the motor (efferent) division
Autonomic Nervous System
Visceral motor (involuntary); conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands.
Sympathetic Division
Part of the Autonomic Nervous System; mobilizes body systems during activity; "fight or flight"; innervates skeletal muscle
Parasympathetic Division
Part of the Autonomic Nervous System; conserves energy; promotes house functions during rest; "rest and relax"
What are the basic properties of neurons?
Excitability,Conductivity, and Secretion
Excitability
Respond to stimuli (mechanical, chemical, and electrical)
Conductivity
Quickly transmits electrical signals over long distances
Secretion
Releases a neurotransmitter to affect another cell
Sensory/afferent
Neurons conduct signals from receptors TO CNS
Interneurons
Association neurons; are confined to the CNS; integrate neurons
Motor/efferent
Neurons conduct signals FROM the CNS to effectors
Effectors
muscles and glands; they respond to the stimulus
Sensation, Integration, and Reaction
Each neuron is capable of performing theses basic functions of the nervous system.
Cell body/soma
Nucleus is located here along with the organelles
Neurofibrils
Bundles of actin filaments that support the cell
Nissl bodies
Concentrations of rough ER (needed for protein synthesis); responsible for making proteins needed by the cell.
Dendrites
Where other cells' axons usually make contact; mostly sensory neurons come into the dendrite and sent to the cell body; "processes"
Axon
One axon/neuron coming from the cell body, but then has multiple shooting off; carries info AWAY from the cell body; a SINGLE process that transmits an action potential.
Initial segment
Most sensitive to electrical charges in membrane potential; first part of the cell to depolarize; first part of an axon.
Axon collaterals
Branches that allow one neuron to communicate with multiple targets
Axon terminals
where axons terminates on their targets (neuron/target groups)