Chapter Unit 6 Flashcards
Axon
Part of the neuron that conducts impulses away from the cell body; each cell has one
Affectors
Cells functioning in reception of stimuli; receiving end of sensory nerves
Autonomic Nervous System
Automatically regulates the action of the glands, the smooth muscles of the hollow organs, and the heart, often without one being aware of it.
Cell Body
Part of the neuron that acts as a sending and receiving center, carries on metabolism, and stores energy
Central Nervous System
Consists of nerve tissues that form the brain and spinal cord; controls voluntary acts
Cerebral cortex
Outer layer of gray matter of the cerebrum
Cerebrospinal fluid (CSF)
Watery fluid protecting the brain and spinal cord
Dendrite
Part of the neuron that carries impulses to the cell body
Effectors
Nerve endings that carry out actions
Electroencephalogram (EEG)
A tracing of the electrical activity of an individuals brain
Fissure
A deep groove or furrow in an organ such as the brain
Ganglion
Mass of nerve tissue; principally nerve cell bodies, outside the central nervous system
Gray matter
Nerve tissue of a grayish color consisting primarily of non myelinated nerve fibers; contains large numbers of cell bodies of neurons
Hemisphere
Either half of the cerebrum or cerebellum
Lobe
A fairly well defined part of the organ such as the brain separated by boundaries
Meninges
The tough, 3 layered membrane protecting the spinal cord and the brain
Myelinated
Covered with myelin
Myelin Sheath
Noncellular, fatty covering of a nerve fiber
Myoneural Junction
Ending of a nerve at a muscle
Nerve
bundle of nerve fibers, blood vessles, and connective tissue outside the central nervous system
Nerve Fibers
Threadlike projections of cytoplasm from the cell body of a neuron; axon and dendrites
Nervous System
system of the body dealing with the brain, spinal cord, and nerves which coordinates body activity
neurogila
supporting structure for nerve tissue consisting of blood vessles, connective tissue, and specialized cells found only in the brain and spinal cord
neurology
study of the nervous system
neuron
basic nerve cell
periphreal nervous system
provides input sensory receptors to the central nervous system and output from the central nervous system to effectors
Plexus
a network of nerves
Regeneration
repair, regrowth, or restoration of a part
stimulus
any agent or influence that produces a response or increase in activity or living protoplasm
sulcus
a slight groove, furrow, or depression in an organ, especially of the brain
synapse
junction of an axon and one or more dendrites which transmits nerve impulses in one direction only
ventricle
one of the cavities of the brain
White Matter
nerve tissue consisting of myelinated nerve fibers
3 functions of the nervous system
A. receive internal/external stimuli through sensory organs
B. Transmits messages to/from brain, interprets messages, stores info. and coordinates response (if needed)
C. Respond to Internal/External stimuli through motor organs
Parts of Typical Neuron and their Functions
(Part A) Cell Body
- Acts as a sending and receiving center
- Carries on metabolism
- Stores energy
Parts of Typical Neuron and their Functions
B. Dendrites
- Carries impulses to cell body
- usually shorter and more numerous that axon
- a neuron may have one or more dendrite
Parts of Typical Neuron and their Functions
- Axon
- Conducts impulses away from cell body
- A neuron never has more than 1 axon
- May be long as a meter
Sensory Neurons Description and function
- AKA Afferent or Receptor
- receives messages from all parts of body and transmits them to CNS
- Controlled by Thalamus- the “sensory” integrating center located below the cerebral hemisphere
Connective Neurons Description and Function
- AKA Central or internuncial
- Conducts messages or impulses from sensory or motor neurons.
- Found only in central nervous system
Motor Neurons Description and Function
- AKA efferent
- Transmits messages from the CNS to all parts of body
- located in muscles or glands
- controlled by frontal lobe of brain
when a neuron receives a signal, it _____ an impulse on to the _____ ______ across the _______ between axon and dendrite
- sends
- next
- neuron
- synapse
___ or more neurons arranged in a _____ _______ to conduct impulses from one _____ to another
- two
- chain
- function
- place
impulses pass only in ___ _________ from receptor dendrite to cell body to ____ to _______ and so on
- one
- direction
- axon
- dendrite
when a nerve impulse is blocked, the blocking usually takes place in the _______
-synapse
Components of Reflex Arc
1 Affector 2 Sensory Neuron 3 Central Neuron 4 Motor Neuron 5 Effector
Characteristic of nerve fiber
- elongated process of neuron, usually axon, concerned with conduction of impulses
- nerve fibers form major part of white matter, spinal cord, all nerves
- most nerves fibers in peripheral nerves are myelinated
Axis Cylider
central core of jelly-like material
myelin sheath
fatty covering which provides insulation and speed impulse conductions
neurilemma
thin membrane which nuclei called schwann cells completely covering the nerve fiber, regenerates fiber nerves
mechanism of regeneration of periphreal nerves
- part of the fiber separated from the cell body disintegrates
- neurilemma starts to regenerate at the sight of injury
- remaining stump of the axon attached to the cell body is able to grow in repaired tubes
Central nervous system contains the
Brain and Spinal Cord
Periphreal Nervous system contains
Cranial Nerves
Spinal Nerves
Autonomic Nerves
Cranial Nerves functions and contains
- 12 Pairs
- carries impulses to/from the brain
Spinal Nerves Function and contains
- 31 pairs
- Carry messages to/from the spinal cord
Autonomic Nerves Functions and Contains
- Can be referred to as Autonomic Nervous System (ANS)
- lie on either side of the spinal cord
- has two sub-divisions
- sympathetic
- parasympathetic - has to do largely with activities which go more or less automaticlly
- controlled by hypothalamus
Constituents found in the spinal canal
- spinal cord
- CSF
- Meninges
- Adipose tissue
- Blood vessels
Characteristics of the spinal cord
- small about 18in in adults
- lies within spinal canal surrounding by the vertebrae
- acts as great conduction pathway of impulses between periphreal nerves and brain
- cross section of the spinal cord reveals an inner H-shaped area of grey matter surrounded by white matter
_____ ______ emerge from the cord by two short roots, the _____ root and _______ root
- Spinal
- Nerves
- Dorsal
- Ventral
cord extends from the _______ to the lower border of first lumbar vertebra or top of second lumbar ______, where it begins to taper into a “______ _____” of fibers that finally end in the ___________ area
- medulla
- vertebra
- horse
- tail
- coccygeal
in the embryo, the spinal cord occupies the ______ spinal column extending down into the tail portion of the vertebral column, however bone tissue grows ____ rapidly than nerve tissue so by adulthood the cord only reaches to the level of first or second lumbar vertebra
- entire
- more
spinal ___________ are given between third and fourth and fourth and fifth lumbar vertebra
anesthesia
Components of CSF
- Water
- Glucose
- Sodium Chloride
- Proteins
- waste products (Urea)
Purpose of CSF
To circulate around the brain and spinal cord to maintain even pressure for cushion and shock absorber
Layers of Meninges
- Dura Mater
- Arachnoid
- Pia Mater
Dura Mater Layers and Function
- Outer Layer
2. Provides Protection
Arachnoid Layer and Function
- Middle Layer
2. Resembles a cobweb with CSF filling the subnarachnoid space under it
Pia Mater Layer and Function
- Inner layer
2. is a thin vascular layer containing blood vessels which bring oxygen and carry away waste products
