chapter 11 Flashcards
made up of the brain and spinal cord, nerves and sensory receptors
Uses electrical and chemical signals to control functions of the body
Nervous System
sensory receptors detect internal or external stimuli
sensory function
the process of processing sensory info and making decisions for appropriate response
integrative function
after sensory information is integrated, nervous system can produce a motor response by activating effectors
Motor Functions
consists of brain and spinal cord
Central Nervous System
consists of all nervous tissue outside of the CNS
Peripheral Nervous System
12
Cranial Nerves
31
Spinal Nerves
clusters of cell bodies outside the brain and spinal cord
Ganglia
structure of the nervous system that monitors change in the external or internal environment
sensory Receptors
relays input from sensory receptors in the body to the CNS
Afferent
Conveys output from the CNS to the effectors ( muscles and glands)
efferent
conveys output from the CNS to the skeletal muscle- controls muscle movement
controls voluntary bodily functions
Somatic nervous system
controls output from CNS to smooth muscle, cardiac muscle, and glands
controls involuntary bodily functions
Autonomic nervous system
rest and digest
parasympathetic division
fight and flight
sympathetic division
network of neurons located in the walls of organs and the GI tract- help regulate digestive system
enteric plexuses
electrically excitable cells
connect all regions of the body to the brain and spinal cord
neurons
support, nourish and protect neurons
Neuroglia
cell body(soma)
dendrites
axon
Structure of neurons
contains typical organelles of a normal cell including mitochondria glogi apparatus and nucleus
cell body(soma)
rough ER
Nissl Bodies
consists of Neurofibrils composed of intermediate filaments
provides cell shape
Cytoskeleton
help move materials between cell body and axon
microtubules
short tampered extensions of the cell body
receives info from other neurons or from sensory receptors
dendrites
long, thin, projection, joins to cell body
propagates nerve impulses towards another neuron, a muscle fiber or gland
Axon
cone shaped area where axon arises
Axon Hillock
axon hillock narrows
initial segment
the combination of the axon hillock and the initial segment
where action potentials are generated
trigger zone
very end of the branching axon
axon terminal
tips of the axon terminal
synaptic end bulbs
the site of communication between two neurons or between a neuron and effector
synapse
the region of the axon ending at the synapse
presynaptic terminal
according to the number of processes extending from the cell body
structurally
according to the direction in which the nerve impulse is conveyed
functionally
several dendrites, one axon
neurons in the brain and spinal cord, motor neurons
Multipolar neurons
one dendrite, one axon
found in retina of eye, inner ear, olfactory area of the brain
bipolar neurons
dendrites and one axon are fused together to form a continuous process ; most function as sensory receptors that detect a sensory stimulus ; neurons are classified according to the direction in which the action potential is conveyed in relation to the CNS
Unipolar neurons
conduct action potential towards the CNS through cranial or spinal nerves
sensory or afferent neurons
conduct action potential away from the CNS towards effectors (muscles and glands)
motor or efferent neurons
conduct action potentials within the CNS from one neuron to another
interneurons
star shaped cell
regulate growth
largest and most numerous neuroglia
Astrocytes
form and maintain myelin sheath around CNS axons
Oligodendrocytes
multilayered lipid and protein covering that surrounds some axons
Myelin sheath
axons with a myelin sheath
Myelinated
insulates axons
increases speed of nerve impulse conduction
Myelin sheath
small cells
slender processes
remove cellular debris , phagocytize microbes and damage nervous tissue
Microglia
line cavities in the brain and spinal cord
produces and circulates cerebrospinal fluid
ependymal cells
fluid that flows in and around the brain and spinal cord - provides protection and nourishes spinal cord and brain
cerebrospinal fluid
surround axon in the PNS
form myelin sheath around axon in PNS
Schwann cells
surround neuron cell bodies in the ganglia
regulate exchange of materials between cell bodies and interstitial fluid
Satellite cells
demyelinated disease of axons in the CNS
attack its own myelin
Multiple Sclerosis
nerves lose myelin sheath
Demyelination
Chemotherapy
physical therapy
anti-inflammatory drugs
Treatment for MS
composed of myelinated axons
White matter
Neuron cell bodies dendrites unmyelinated axons neuroglia
gray matter
electrical signals produced by the nervous system
action potentials
randomly alternate between open and closed positions
Leak channels
open in response to the binding of a specific molecule to the receptor site
Ligand-gated channels
open and close in response to a change in membrane potential
Voltage gated ion channel
open/closes in response to mechanical stimulation ( vibration, touch, pressure, tissue stretching )
Mechanically gated ion channel
difference across the plasma membrane in an unstimulated cell
Resting membrane potential
the resting membrane potential in a neuron
-70mv
removes more positive ions from the cell then brings it into the cell= more negative inside the cell then out
sodium potassium pump
resting membrane potential fires the action potential
-55mv
occurs completely or not at all
action potential
rapid increase of positive charge inside a neuron
depolarization
voltage gated sodium into the cell increases, membrane depolarizes further
at -55mv
voltage gated sodium ions close
at +30mv
return of the membrane potential to the resting membrane potential
repolarization
voltage gated potassium ion channels open
at -30mv
voltage gated potassium channels remain open
hyperpolarization
potassium channels close
at -90mv
a period of time in which a neuron cannot regenerate another action potential
the refractory period
strong nerve impulse cannot initiate another AP
absolute refractory period
second nerve impulse can be initiated but only by a larger than normal stimulus
relative refractory period
used by unmyelinated axons
continuous conduction
used by myelinated axons
saltatory conduction
amount of myelination
temperature
axon diameter
affects speed of propagation
neuron that carries and action potential towards the synapse
presynaptic cell
receives a signal ( can be a muscle, gland or neuron)
Postsynaptic cell
ions flow from presynaptic cell to the postsynaptic cell through gap junctions
electrical synapse
an electrical signal is converted by the presynaptic cell to a chemical signal called a neurotransmitter
chemical synapse
will open up sodium or calcium channels causing depolarization in the postsynaptic cell action potential will be fired
excitatory
will cause hyperpolarization in the cell and no action potential will be fired
inhibitory
stimulates muscle contraction
acetylcholine
mood, happiness, muscle tone, smooth, controlled movement
dopamine
sleepiness, mood, temp regulation, appetite
serotonin
pain reduction, mood
endorphins
learning and memory
glutamate
calming affect helps with anxiety and fear
Gaba
antibodies breakdown ACH receptors
autoimmune disease
periods of mania and depression
bipolar disorder
experience depression during winter months
seasonal depression
the degeneration of the distal axon and myelin
Wallerian Degeneration
the rate new axons grow
1.5mm
