NERVOUS SYSTEM Flashcards
quiz
Nervous System Functions
- Receiving sensory input
- Integrating information
- Controlling muscles and glands
- Maintaining homeostasis
- Establishing and maintaining mental activity
Main Divisions of NS
* brain and spinal cord
CENTRAL NS
Main Division of NS
* All the nervous tissue outside the CNS
PERIPHERAL NS (PNS)
- Conducts action potentials from sensory receptors
to the CNS
Sensory division
- Conducts action potentials to effector organs, such
as muscles and glands
Motor Division
- Transmits action potentials from the CNS to skeletal
muscles.
Somatic Nervous System
- Transmits action potentials from the CNS to cardiac
Autonomic Nervous System
- A special nervous system found only in the digestive
tract.
Enteric NERVOUS system
receive stimuli, conduct action potentials, and
transmit signals to other neurons or effector organs.
NEURONS
supportive cells of the CNS and PNS, meaning these
cells do not conduct action potentials. Instead, carry out different functions that enhance
neuron function and maintain normal conditions
within nervous tissue.
Glial Cells
A neuron (nerve cell) has a: – which contains a single nucleus
CELL BODY
A neuron has a : – which is a cytoplasmic extension from
the cell body, that usually receives information from
other neurons and transmits the information to the
cell body
DENDRITE
a NEURON HAS A : which is a single long cell process that leaves
the cell body at the axon hillock and conducts
sensory signals to the CNS and motor signals away
from the CNS
axon
neurons have many dendrites and a
single axon.
Most of the neurons within the CNS and nearly
all motor neurons are ___________________
multipolar
neurons have two processes: one
dendrite and one axon.
are located in some sensory
organs, such as in the retina of the eye and in
the nasal cavity.
Bipolar
neurons have a single process
extending from the cell body, which divides into
two processes as short distance from the cell
body.
pseudo-unipolar
are the supportive cells of the CNS and
PNS.
Glial CELLS
serve as the major supporting cells in
the CNS.
aSTROCYTES
cells line the cavities in the brain
that contains cerebrospinal fluid.
EPENDYMAL
Astrocytes can stimulate or inhibit the signaling
activity of nearby neurons and form the _____________
BLOOD-BRAIN BARRIER
cells act in an immune function in the
CNS by removing bacteria and cell debris.
MICROGLIAL
provide myelin to neurons in
the CNS.
OLIGODENDROCYTES
cells provide myelin to neurons in the
PNS.
SCHWANN
are specialized layers that wrap
around the axons of some neurons, those
neurons are termed, myelinated.
MYELIN SHEATHS
are formed by oligodendrocytes in
the CNS and Schwann cells in the PNS.
sheaths
is an excellent insulator that prevents
almost all ion movement across the cell
membrane.
Myelin
Gaps in the myelin sheath,
nodes of ranvier
can occur at the nodes of
Ranvier.
ION MOVEMENT
is a disease of the myelin
sheath that causes loss of muscle function.
MULTIPLE SCLEROSIS
lack the myelin sheaths.
Unmyelinated axons
varies in color due to the
abundance or absence of myelinated axons.
Nervous tissue exists as gray matter and white
matter.
NERVOUS TISSUE
matter consists of groups of neuron cell
bodies and their dendrites, where there is very
little myelin.
gray
matter consists of bundles of parallel
axons with their myelin sheaths, which are
whitish in color.
WHITE
always open
leak channels
are generally closed until opened by specific signals
gated channels
are conducted slowly in
unmyelinated axons and more rapidly in
myelinated axons.
action potentials
This type of action potential conduction
saltatory conduction
do not normally remain in the
synaptic cleft indefinitely, thus their effects are short
duration.
Neurotransmitter
An enzyme called _________________ breaks down the
acetylcholine.
acetylcholinesterase
is either actively transported back into
the presynaptic terminal or broken down by enzymes.
Norepinephrine
pathway is a simple pathway in
which two or more neurons synapse with the
same postsynaptic neuron.
converging pathway
pathway is a simple pathway in which
an axon from one neuron divides and synapses
with more than one other postsynaptic neuron.
DIVERGE PATHWAY
