NERVOUS SYSTEM Flashcards
It processes and interprets the sensory input and
decides what should be done
integration
causes a response, or effect, by activating
muscles or glands (effectors)
motor output
brain and spinal cord.
occupy the dorsal body cavity.
Central nervous system
act as the integrating and command centers of the nervous
system.
interpret incoming sensory information and issue
instructions based on past experience and current conditions.
Central Nervous system
nerves and ganglia
— includes all parts of the nervous system outside the CNS.
— consists mainly of the nerves that extend from the spinal
cord and brain.
Peripheral Nervous system
carry impulses to and from the spinal cord.
Spinal Nerves
carry impulses to and from the brain.
Cranial Nerves
exits the CNS
— carries impulses from the CNS to effector organs, the
muscles and glands.
Motor Division (efferent division)
convey impulses to cns from sensory receptors
Sensory Division
— voluntary nervous system
— allows us to consciously (voluntarily), control our
skeletal muscles.
Somatic nervous system
involuntary nervous system
— regulates events that are involuntary (no conscious
control), activity of smooth muscle, cardiac muscle, and
glands.
Autonomic Nervous System
two parts of autonomic nervous system
sympathetic and parasympathetic.
keeps the CNS constantly informed of events going on both
inside and outside the body.
Sensory Division
delivering impulses from the skin,
skeletal muscles, and joints.
somatic sensory fibers
transmitting impulses from the
visceral organs.
Visceral sensory fibers
Afferent=
Soma =
Sensory =
to go forward
body
afferent
nervous tissue is made up of two principal types of cells
supportying cells & neurons
—supporting cells in the CNS are “lumped together”.
— “nerve glue”
— also called glial or glia.
Neuroglia
: abundant star-shaped cells that
form barrier between cappilaries and neurons
control the chem environment in brain
Astrocytes
spiderlike phagocytes
— monitor health of nearby neuron
— dispose debris, such as brain cells and bacteria
Microglia
neuroglia that wrap their flat extensions
(processes) tightly around CNS nerve fibers,
producing fatty insulating coverings called myelin
sheaths.
Oligodendrocytes
form the myelin sheaths around
nerve fibers in the PNS.
Schwann cells
act as protective, cushioning cells for
peripheral neuron cell bodies.
Satellite cells
neuroglia that line he central cavities of the
brain and spinal cord.
Ependymal cells
also called “nerve cells”
— are highly specialized to transmit messages
(nerve impulses) from one part of the body to
another.
Neurons
is the metabolic center of the neuron.
Cell body
intermediate filaments that are important in
maintaining cell shape) are particularly abundant
in the cell body.
Nissl bodies & neurofibrils
armlike processes, or fibers, vary in length from
microscopic to over 3 feet long, reaching from the
lumbar region of the spine to the great toe.
Processes
convey incoming messages (electrical signals)
toward the cell body.
DeNdrites
generate nerve impulses and typically conduct
them away from the cell body
Axons
protects and insulates the fibers and increases the
speed of nerve impulse transmission.
Myelin sheats
long nerve fibers that are covered with a whitish,
fatty material.
Myelin
each neuron has only one axon, which arises from
a conelike region of the cell body.
Axon Hillock
terminal end
— contain hundreds of tiny vesicles, or membranous
sacs.
Axon terminals
tiny gap that separates the next neuron or its
targets.
Synaptic cleft
functional junction, where an impulse is
transmitted from one neuron to another.
Synapse
The Schwann cell cytoplasm and exposed membrane
are referred to as the
Neurilemma
consist of dense collections of myelinated fibers
(tracts).
White matter
contains mostly unmyelinated fibers and cell
bodies.
Gray matter
gradually destroys
the myelin sheaths around CNS fibers by converting
them to hardened sheaths called scleroses.
Multiple sclerosis
Neurons carrying impulses from sensory receptors
(in the internal organs or the skin) to the CNS. ; keep us informed about what is happening insisde and outside the body
Sensory Neurons
activated by specific changes occurring nearby.
Receptors
simpler types of sensory receptors in the skin
Cutaneous sense organ
small collections of cell bodies.
— are found in a few sites outside the CNS in the PNS.
Ganglia
bundles of nerve fibers (neuron processes) running
through the CNS.
Tract
receptors in the muscles and tendons
— the least specialized of the cutaneous receptors.
Proprioceptors
several neuron
Multipolar neuron
neurons w 2 processes 1 axon 1 dendrite ; act as receptor cells in sensory processing
Bipolar neuron
have a single process emerging from the cell body.
— unique in that only the small branches at the end
of the peripheral process are dendrites.
Unipolar neurons
carries impulses from the CNS to the viscera
and/or muscles and glands.
Motor neurons
— connect the motor and sensory neurons in neural
pathways.
— their cell bodies are typically located in the CNS.
Interneurons
2 MAJOR FUNCTIONAL PROPERTIES OF NEURONS
IRRITABILITY & CONDUCTIVITY
the ability to respond to a
stimulus by producing a nerve impulse.
Irritability
ability to transmit the impulse
to other neurons, muscles, or glands.
Conductivity
are rapid, predictable, and involuntary responses to stimuli.
Reflexes
reflexes that occur over neural pathways.
Reflex arcs
— stimulate the skeletal muscles.
— involuntary reflexes even though skeletal muscle normally is
under voluntary control.
Somatic reflexes
regulate the activity of smooth muscles, the heart, and
glands.
— Secretion of saliva and changes in the size of eye pupils.
— regulate such body functions as digestion, elimination, blood
pressure, and sweating.
Autonomic reflexes
withdrawal, reflex is a three-neuron reflex arc in which the limb is
withdrawn from a painful stimulus.
The flexor
—most superior part of the brain.
—covers and obscures most of the brain stem.
Cerebrum
responsible for: speech
memory
logical responses
consciousness
sensation interpretation
voluntary movement
; PARIETAL LOBE
Cerebral cortex
allows you to recognize pain, differences in temp / light touch
allow to consciously move our skeletal muscles ; face, mouth & hands
primary somatic sensory area
Primary motor area
entire surface of the cerebrum exhibits
elevated ridges of tissue
Gyri
cerebral hemispheres are
separated by a single deep fissure,
Longitudinal fissure
an interbrain atop the brain,
consists of the thalamus, hypothalamus, and
epithalamus.
Diencephalon
relays sensory impulses to
the sensory cortex, where neurons localize and
interpret sensations, involved in memory
thalamus
Provides “instructions” to cerebral motor cortex and
subcortical motor centers, resulting in smooth,
coordinated skeletal muscle movements
Responsible for proper balance and posture
Cerebellum
a crucial autonomic center responsible for
regulating body temperature, water balance, and
metabolism.
Hypothalamus
the center for emotions like thirst, appetite, sex,
pain, and pleasure.
— regulates the pituitary gland, producing two
hormones.
HYPOTHALAMUS
forms the roof of the third ventricle,
includes the pineal gland and the choroid plexus.
Epithalamus
a large
fiber tract that allows the cerebral hemispheres to
communicate, connecting areas within a hemisphere and
lower CNS centers.
Corpus callosum
a tiny canal that travels through
the midbrain,
Cerebral aqueduct
regulate voluntary motor activities by modifying
instructions sent to skeletal muscles by the primary
motor cortex, with a tight band of projection fibers.
Basal nuclei
Mediates emotional response; involved in memory
processing
Limbic system
forms the outermost covering of the
brain
meningeal layer
typically diagnosed by examining cerebrospinal fluid
from the subarachnoid space surrounding the spinal
cord.
Meningitis
Contains visual and auditory reflex centers
Midbrain
Cooperates with the medullary centers to control
respiratory rate and depth
Pons
Contains nuclei controlling heart rate, blood vessel
diameter, respiratory rate, vomiting, etc. ; most inferior
Medulla oblongata
a fluid formed from blood, forms a protective
cushion around the brain and spinal cord, preventing
damage from trauma.
Cerebrospinal FLUID
-Head trauma can cause bleeding from ruptured
vessels or cerebral edema
— causing neurological deterioration.
Cranial hemorrhage
are the second leading cause of
death and disability worldwide.
— occur when blood circulation to a brain area is
blocked, leading to vital brain tissue dying.
BRAIN INJURIES (CVA’S)
keeps neurons separated from blood borne substances. metabolic wastes like
urea, toxins, proteins, and drugs are prevented from
entering brain tissue.
Blood brain Barrier
resembling a
butterfly, contains neurons with specific functions,
gray matter of spinal cord
consists of
myelinated fiber tracts, some running to higher centers,
some from the brain, and some conducting impulses.
White matter of spinal cord
a delicate connective tissue sheath.;
coarser connective tissue wrapping.
Endoneurium & perineurium
neurons of the cranial region send their axons
out in cranial nerves to serve the head and neck
organs.
Parasympathetic dvision / craniosacral division
ALLOWS US TO UNWIND AND CONSERVE ENERGY
parasymphathetic division
mobilizes the body during extreme situations (such as
fear, exercise, or rage)
Symphatetic division
— Its activity is evident when we are excited or find
ourselves in emergency or threatening situations.
Example: being freightenedy a stranger at night.
Sympathetic division / thoracolumbular
sometimes called the “rest-and-digest” system.
— is most active when the body is at rest and not
threatened in any way.
parasympathetic division
specialized cortical area involve in speaking
Brocas area
area: intellectual reasoiniing & social behaviour
Anterior association area
are: role in recognizing patterns and faces
Posterior association area
reticular activating system
role in conciousness/ sleep cycle
provides 2 way conduction of the brain stem
spinal chord
collection of spinal nerves
cauda equina
serve motor and sensory needs of the limbs
plexuses
