Nervous System Flashcards
Brain
Spinal cord
Central nervous system
Nervous tissue outside CNS
Peripheral Nervous System
conducts action
potentials from sensory receptors to the CNS
Sensory (afferent) division
conducts action
potentials from the CNS to effector organs, such
as muscles and glands
Motor (efferent) division
transmits action potentials from
the CNS to skeletal muscles
Somatic NS
transmits action potentials
from the CNS to cardiac muscle, smooth
muscle, and glands.
Autonomic NS
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contains a
single nucleus
nucleus of the neuron is
the source of information
for gene expression
Cell body
receive information from
other neurons or from
sensory receptors and
transmit the information
toward the neuron cell
body
Dendrites
Axon single long cell
process extending from
the neuron cell body
conduct action potentials
Neurons
area where
the axon leaves the
neuron cell body
Axon hillock
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What are the types of neurons?
Multipolar – most motor and CNS neurons
To receive input from many different source
Bipolar – special senses
Pseudo-unipolar – most sensory neurons
The difference between multipolar neuron, bipolar neuron, and pseudo-unipolar neuron
A multipolar neuron has many dendrites and an axon, the bipolar neuron has a dendrite an an axon while pseudo-unipolar neuron have an axon but no dendrite
major
supporting cell
Astrocytes
separates blood from
the brain’s
extracellular fluid
Blood brain barrier page 22
line the
fluid-filled cavities
(ventricles and canals)
within the CNS
Ependymal cells
immune cells of the CNS
help protect the brain by removing bacteria and
cell debris
Microglia
specialized layers that wrap around the axons of
some neurons
Myelin Sheaths
Axons with these myelin sheaths are called
myelinated axons
gaps are called
nodes of ranvier
consists of groups of neuron cell
bodies and their dendrites, where there is very
little myelin
Gray matter
Parallel axons with myelin sheath
White matter Page 30
are closed until opened by
specific signals.
Gated channels
Describe the difference between Chemically gated channels and voltage-gated channels
Chemically gated channels are opened by
neurotransmitters or other chemicals
Voltage-gated channels are opened by a change
in membrane potential
rapid sequence of changes in the voltage
across a membrane
Action Potential
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Resting membrane potential
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Depolarization
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Repolarization
Threshold is reached = action potential
Threshold is not reached =
action potential
is not reached = no action potential
action
potential propagation across
unmyelinated axons
Continuous conduction
in
myelinated axons, action
potentials “jump” from one
node of Ranvier to the next
along the length of the axon
Saltatory Conduction
junction where the
axon of one neuron
interacts with
another neuron or
with cells of an
effector organ,
such as a muscle
or gland
Synapse
end of the axon
forms a
presynaptic
terminal
The membrane of
the dendrite or
effector cell is the
postsynaptic
membrane
space separating the
presynaptic and
postsynaptic
membranes is the
synaptic cleft
Chemical substances
called
neurotransmitters
neurotransmitters are
stored in
synaptic
vesicles in the
presynaptic terminal.
involuntary reaction in response to a stimulus
applied to the periphery and transmitted to the
CNS
Reflexes
basic functional unit of the
nervous system because it is the smallest,
simplest pathway capable of receiving a
stimulus and yielding a response
Reflex arc
arise along the spinal cord from the union of
the dorsal roots and ventral roots
Spinal nerves
contain axons of both sensory and somatic
motor neurons and thus are called
mixed nerves
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Spinal nerves _______ do not join a plexus
because they directly control the muscles and
skin in the chest and abdomen
T2 through T11
Three major plexus
Cervical plexus – neck, upper shoulders
Phrenic nerve – diaphragm
Brachial plexus – upper limbs
Lumbosacral plexus – lower limbs and pelvic
region
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How many nerves we have?
12 cranial nerves
31 spinal nerves
Which part of the brainstem, located at its most inferior portion and continuous with the spinal cord, regulates vital functions such as heart rate, blood vessel diameter, breathing, swallowing, and coordination?
Medulla oblongata
functional bridge between the cerebrum and
cerebellum
breathing, swallowing, balance, chewing and
salivation
Pons
smallest region of the
brainstem
Midbrain
major
relay centers for the
auditory nerve pathways
Inferior colliculi
visual
reflexes and receive
touch and auditory input
Superior colliculi
involved in maintaining
balance and muscle tone
and in coordinating fine
motor movement.
Cerebellum
part of the brain
between the
brainstem and the
cerebrum
Diencephalon
largest part of the diencephalon.
processes and sends sensory information to the
appropriate areas of the cerebral cortex for
interpretation
Thalamus
body homeostasis
linking the nervous system to the endocrine system
via the pituitary gland
control of body temperature, hunger, and thirst.
Sensations such as sexual pleasure, rage, fear, and
relaxation after a meal
Hypothalamus
small area superior and
posterior to the thalamus
Hypothalamus
regulating the body’s circadian
rhythms
Releases melatonin
Pineal gland
largest part of the
brain
Cerebrum
Gyri – folds
Sulci - grooves
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control of
voluntary motor
functions, motivation,
aggression, mood, and
olfactory (smell)
reception
Frontal lobe
principal
center for receiving and
consciously perceiving
most sensory
information, such as
touch, pain,
temperature, and
balance
Parietal lobe
involved in olfactory
(smell) and auditory
(hearing) sensations
and plays an
important role in
memory
Temporal lobe
receiving and
perceiving visual
input
occipital lobe
Describe what is autonomic nervous system
Sympathetic
fight-or-flight
prepares the body for physical activity
Parasympathetic
rest-and-digest
stimulates involuntary activities of the body at
rest
action potentials
initiated in this region control voluntary
movements of skeletal muscles
Primary motor cortex
where motor functions are
organized before they are actually initiated in
the primary motor cortex
Premotor area
motivation and foresight to
plan and initiate movements
Prefrontal area
surround and protect the brain and spinal cord
Meninges
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