chapter 8 nevouse system Flashcards
the primary coordinating and controlling system of the body
nervous system
the nervous system uses … to fulfill its function
electrochemical impulses
central nervous system include
brain, spinal cord, and the Body’s neural control center
Peripheral nervous system is located.. and consists of
outside the nervous system; nerves and sensory receptors.
sensory division
carries impulses from sensory receptors t the CNS.
Motor Division
carries impulses from CNS to effectors
Motor division had two divisions:
Somatic nervous system, and Autonomic nervous system.
Somatic nervous system
Voluntary control of skeletal muscle
Autonomic nervous system
Involuntary control of cardiac muscle, smooth muscle, and glands.
neurons
specialized to transmit neural impulse
nerurons are divided into their … units
structural and functional
the structure of a neuron hold the
cell body, dendrites, axon
the cell body holds the
nucleus and organelles
Dendrites are
numerous short highly branched that extend from the body of tthe cell, are also the primary site for recieving impulses.
Dendrites carry
impulses towards cell body and axon
Axon
are a long thin process that ends in axon terminals with synaptic knobs
The axon carrys impulses
away from cell body or dendrites
the Myelin sheath
insulates axon and increases speed of impulse transmission
Node of ranvier
space between cells that do not have a myelin sheath.
Structural classification of neurons
uni-polar, bi-polar,multi-polar
Bipolar neuron has two processes:
a dendrite and and axon
Bipolar neurons occur in the sensory portion of the
eyes, ears, and nose.
Multipolar neurons hav
several dendrites, a songle axon
multipolar neurons are found
in the brain and spinal cord
unipolar nurons
a single process extending from the cell body
unipolar neurons are
sensory
sensory neurons: carry impulses from
peripheral body part to the CNS
Sensory neurons detect
hoeostatic changes directly or via sensory receptors
interneurons are located
entirely in CNS and associate with other neurons
the interneurons …. and … impulses from CNS
process and interpret
interneurons activate
motor neurons
Motor neurons carry impuses
from CNs to effectors to produce an actine
Motor neurons cells bodies and dendrites are in
CNs
Motor neurons axons is located
in nerves of PNS
Neuroglia
suupport and protect neurons,
Neurolglia are
more numerous than neurons
Schwann cells form
myelin sheath by wrapping plasma membrane around axon
Outer layer of myelin sheath is
a neurolemma
Oligodendrocytes form
myelin sheath around CNs axons
oligodendrocytes do not
form neurolemma, so axon regeneration is not possible
Astocytes binds
neurons to blodd vessels
Astrocytes regulate
exchange of materials between blood and neurons
Astrocytes provide
structual support
Astrocytes stimulat
neurona growth
Astrocytes influence
synaptic transmission
Microglial cells
enguld and digest cellular debris and bacteria
Ependymal cells
line cavities in brian and spinal cord
Neurons have two uniqu functional characteristics
irritability and conductivity
Irritability
ability to respond to a stimulus by forming an impulse
conductivity
ability to transmit and impulse along a neuron to another cell.
Membrane is polarized due to
an unequal distribution of electrical charges on each side of the plasma membrane
excess of …. carged ions outside (… outside)
Positively… NA+
excess of ,,, charged ions on the inside of the neuron membrane(…,…,… and … proteins inside)
negatively (K+,POsub4 ^-2, SOsub4 ^-2 and protiens inside)
membrane potential changes when:
concentration of ions across the membrane changes, and permeability of membrane to ions changes.
graded potentials
incoming short distance signals
Action potentials
long-distance signals of axons
threshold stimulus is needed to
activate a neuron-> voltage difference “potential”
when activated by a stimulus
Na+ permeability increases
Na+ permibilty causes
posittive and negative ions to be equally abundant on both sides of the membrane
the membrane is the depolarized. this is
the nerve imulse or action potential
in Reolarization, which occurs after depolarizations
K+ diffuses outward to reestablish the resting potential
Next
Na+is then pumed out and K+ is pumped in to reestablished resting-state ion distribution
junction of an axon with another neuron or an effector cell
synapse
synapse structure
synaptic knob of presynaptic neuron, Postsynaptic structure (neuron or effector), synaptic cleft
neurotransmitter
enable communication between neurons and nuerons with other cells
one nueron relases only.. types of neurotransmitters
1 or 2
two basic types f neurotransmitters
Excitatory (EPSP) and inhibitory (IPSP) neurotransmitters
Meninges
three fibrous membranes
Pia matter
Thin innermost layer that adheres to CNS structure surface. contain blood vessels to nourish brain and spinal cord.
Archnoid
middle layer, thin and wbelike avascular. this does not penetrate smalller depressions like the pia. has subarachnoid space
subarachnoid space
space between pia mater and Arachnoid mater. filled with cerebrospinal fluid.
Dura mater
Tough, outermost layer that is attached to cranial bones. it forms protective tube in vertebral canal.
