EXAM 4: Chapter 12 The Nervous System I: Nervous Tissuec単語カード | Quizlet

central nervous system (CNS)

consists of the brain and spinal cord

peripheral nervous system (PNS)

consists of nerves and ganglia, which are all the nervous tissues structures external to the CNS

afferent (sensory) division and efferent (motor) division

What does the peripheral nervous system (PNS) divide into?

afferent (sensory) division

sensory impulses are carried from sensory receptors through the PNS TOWARDS the CNS

efferent (motor) division

motor impulses are carried AWAY FROM THE CNS, through the PNS, to the EFFECTORS (muscles and glands)

somatic nervous system and autonomic nervous system

What does the efferent (motor) division further divide into?

somatic nervous system (SNS)

voluntary control over skeletal muscle contraction

autonomic nervous system (ANS)

automatic control, involving regulation of smooth muscles, cardiac muscles and glandular activity

(involuntary)

somatic

outer body

visceral

inner body

general

widespread

special

localized

branchial innervation

refers to the motor innervation of the pharyngeal (branchial) muscle

proprioception

refers to a series of senses that monitor the degree of stretch in muscles, tendons, and joint capsules

sensing the position and movement of our body parts

neurons

long lived, non-dividing cells

has a cell body, axons and dendrites

nissl bodies (chromatophilic substance)

Rough endoplasmic reticulum (RER) and free ribosomes in neurons

in the CNS except for those found in ganglia of the PNS

Where are all neuron cell bodies found?

axon hillock

specialized region of an axon, which connects the initial segment of the axon to the cell body

axoplasm

cytoplasm of axon, which contains numerous organelles

collaterals

side branches of the axon

terminal arborization

a series of fine, terminal extensions, which branch from the tip of the axon and end at synaptic terminals

terminal bouton

the area where one neuron synapses on another

axolemma

plasma membrane of axon

ganglia

clusters of cell bodies in the PNS

nerves

bundles of axons in the PNS

dendrites

branched receptive sites that conduct signals from other neurons TOWARD the neuron cell body

axon

neuron structure that generates and conducts nerve impulses AWAY FROM the neuron cell body

synapse

a functional junction between neurons (or between a neuron and another cell) at neuroeffecter junctions

- site of intercellular communication

- occurs on dendrites, cell body, or along axon)

vesicular synapse

chemical synapse that involves neurotransmitters

nonvesicular synapses

electrical synapse that involves direct contact between cells

1. sensory neurons

2. motor neurons

3. interneurons

What are the 3 functional groups that neurons can be categorized in?

sensory (afferent) neurons

conduct impulses TOWARD THE CNS

motor (efferent) neurons

conduct impulses AWAY FROM THE CNS

Interneurons (association neurons)

neurons that lie in the CNS between sensory and motor neurons

neuroglia or glial cells

supporting cells of the nervous system

- astrocytes

- microglia

- ependymal cells

- oligodendrocytes

What are the neuroglia/glial cells of the CNS?

astrocytes

largest and most numerous type of glial cells

- controls interstitial environment

- repairs damaged neural tissue

- creates 3D framework for CNS

- guides neuron development

- maintain BLOOD-BRAIN barrier

microglia

phagocytic cells of the CNS (engulf cellular debris, waste products, and pathogens)

immune defense

ependymal cells

cuboidal to columnar epithelial cells that line the central canal and ventricles of the brain

creates and secretes CSF

oligodendrocytes

glial cells that maintains cellular organization in the gray matter AND PRODUCES MYELIN to completely sheath areas of white matter (myelinated axons)

- schwann cells (neurolemmocytes)

- satellite cells

What are the neuroglia/glial cells of the PNS

schwann cells (neurolemmocytes)

myelin-forming cells that cover all peripheral axons, whether myelinated or unmyelinated

satellite cells

enclose neuron cell bodies in the peripheral ganglia;

- regulate the exchange of nutrients and waste products between the neuron cell body and the extracellular fluid

speeds impulse conduction

What is the function of myelin?

myelin sheath

a coat of supporting-cell membranes wrapped in layers around the axon

Nodes of Ranvier (Neurofibral Nodes)

gaps in the myelin sheath

peripheral nerves, or simply nerve

a bundle of axons wrapped in connective tissue in the PNS

epineurium

surrounds the whole nerve

perineurium

surrounds each fascicle of axons

endoneurium

surrounds each axon

divergence of neurons

convergence of neurons

serial processing neurons

parallel processing neurons

Reverberation neurons

neural circuit - homeostasis; balance; biofeedback

Exteroceptors

provide information about the external environment

Interoceptors

monitor internal organ activity

Exitability

ability of plasmalemma to conduct electrical impulses

action potential

an electrical impulse that develops after the plasmalemma is stimulated to its threshold

nerve impulse

an action potential traveling along an axon

- presence/absence of myelin sheath

- diameter of axon

The rate of impulse conduction depends on what properties of the axon?

reflex

an immediate involuntary response to a specific stimulus

can be either somatic or visceral

reflex arc

a neural "writing" of a single reflex