unit 7 Flashcards
cns
-brain and spinal cord
-command center
-closed system
-interprets incoming info and issues outgoing instructions
pns
-cranial and spinal nerves (anything outside of cns)
-open system with fewer supporting cells
-communication lines; carries impulses
sensory division
afferent; nerve fibers carrying info to cns; somatic and visceral organs
motor division
efferent; nerve fibers carrying info away from cns;
somatic
skeletal muscles, skin, and joints
voluntary
just skeletal muscles
autonomic
involuntary; cardiac and smooth muscle glands; into parasympathetic and sympathetic
neurons
actual nerve cell that sends and receives messages
neuroglia
supporting cells; never lose ability to divide; support, insulate, and protect neuron; do not conduct nerve signals
general structure of neuron
cell body and processes
cell body
nucleus (decision maker-control center)
processes
bring in or send away messages; fibers that extend away from cell body (dendrites and axon)
myelin sheath
-white fatty protein covering axon
-schwann cells wrap like jelly roll
-protect and insulate nerve fibers and speed up nerve transmission
gray matter
unmyelinated fibers and cell bodies
white matter
myelinated fibers (tracts) - axons; corpus callosum - association fiber tracts and projection fiber tracts
interneurons
connect sensory and motor neurons
types of general sensory receptors
multipolar, bipolar, unipolar
multipolar neurons
extensions; motor and interneurons; most common
bipolar neurons
one axon and one dendrite; sense organs; rare
unipolar neurons
sensory in pns ganglia; impulses both away and toward
reflex arc
reflexes occur over neural pathways
reflexes
involuntary; somatic and autonomic
2 neuron reflex arc
patella and knee reflex
3 neuron reflex arc
(5 elements of reflex arc) receptor, sensory neuron, interneuron, motor neuron, and effector; flexor (withdrawal) reflex
cerebral hemispheres
large halves or brain; gyrus, sulcus, and longitudinal fissure; cortex (gray matter), white matter, basal nuclei (deep pockets of gray matter)
diencephalon
thalamus, hypothalamus, and epithalamus
brain stem
midbrain, pons, medulla oblongata
cerebellum
controls balance and coordination; gray and white matter
dura mater
outermost layer; 2 layers
arachnoid
middle layer; subarachnoid space for cerebrospinal fluid
pia mater
internal most layer
cerebrospinal fluid
continually made by choroid plexuses; special capillaries
blood-brain barrier
allows water, glucose, and amino acids to pass through capillary walls
concussion
slight brain injury; little permanent brain damage
brain contusion (skull smashed)
marked nervous tissue destruction occurs; coma
intracranial hemorrhage
death; direct blood contact
cerebral edema
death; swelling in or around brain
CVA
stroke; blocked brain circulation and kills tissue
TIA
temporary restricted blood flow; numbness
alzheimers
dementia
parkinsons
basal nuclei problem; posture and movement
huntingtons
genetic disease - basal nuclei - cerebral cortex; wild movements and spastic; lack of focus, fatigue, and irritability
general organization of spinal cord
cauda equina, gray matter (cell bodies), white matter (myelinated fiber tracts)
general structure of nerve
endoneurium, perineurium, and epineurium
parasympathetic division
acetylcholine; brain stem; rest and digest: digestion, defecation, and diuresis (urination); heart rate slows
sympathetic division
epinephrine; spine; fight or flight: exercise, excitement, emergency, embarrassment; digestive process slows
spina bifida
vertebrae forms incompletely; dimple to functionless spinal cord; can’t control bowel movements or bladder and lower limbs are paralyzed
anencephaly
birth defect where cerebrum fails to develop; can’t see, hear, or process sensory info
cerebral palsy
temporary lack of oxygen; voluntary muscles are poorly controlled and spastic; seizures, intellectually disabled, and impaired hearing or vision
senility
gradual decline of oxygen from aging process; forgetfulness, irritability, difficulty concentrating and thinking clearly and confusion
brain functions
sensory input, motor output, and integration
microglia
cns; phagocytosis
ependymal
cns; circulate spinal fluid
oligodendrocytes
cns; wrap around nerve fibers to insulate them
Schwann cells
pns; form myelin sheath to wrap around nerve fibers; more rapid transmission of nerve signals
satellite cells
pns; protect and cushion neuron cell bodies (axon)
dendrites
toward body
axon
away from body to axon terminal (end with gap)
synaptic cleft
gap between terminals and neuron
synapse
functional junction between nerves where a nerve impulse is transmitted; where two neurons meet but don’t touch
nodes of ranvier
gaps in myelin sheath along the
axon
tracts
bundles of nerve fibers in CNS; commissures
nerves
bundles of nerve fibers in PNS
ganglia
collections of cell bodies outside CNS and inside PNS
nuclei
clusters of cell bodies in CNS
free nerve endings
pain and temp receptors
meissners corpuscle
touch receptors
lamellar corpuscle
deep pressure receptors (pushing down of something)
Golgi tendon organ (proprioceptors)
lifting heavy weights
muscle spinder (proprioceptors)
lifting heavy things and needs to release before straining
5 basic elements of reflex arcs
-sensory receptor (touch)
-sensory neuron (entering spine)
-integration center (cns-attaching to motor neuron)
-motor neuron (sending to effector organ)
-effector organ (muscle movement)
cerebral cortex
-primary somatic area in parietal lobe
-visual (occipital)
-auditory and olfactory (temporal)
-primary motor (frontal)
-brocas area (speech)
association fiber tracts
connect areas within a hemisphere
projection fiber tracts
connect the cerebrum with lower CNS centers
corpus callosum
connects hemispheres
thalamus
distributes sensory receptors
hypothalamus
regulates body temp, water balance, and metabolism
epithalamus
forms melatonin by pineal body
medulla oblongata
heart rate, blood pressure, breathing, swallowing, and vomiting
reticular formation
gray matter along brain stem
ventricles
make cerebrospinal fluid; a space
order of ventricles
lateral - 3rd - aqueduct - 4th
4 plexuses
cervical, brachial, lumbar, sacral
plexus
networks of nerves serving motor and
sensory needs of the limbs
cervical plexus
phrenic nerve for breathing
brachial plexus
arm
lumbar plexus
front of leg
sacral plexus
back of leg
premature babies have trouble with what
regulating body temperature because the hypothalamus is the last to develop
axon hillock
where axon arises from cell body
multiple sclerosis (MS)
nerve damage disrupts communication between the brain and the body; vision loss, pain, fatigue, and impaired coordination
polarized
The cell plasma membrane at rest is described as inactive; positive on outside and negative on inside
resting membrane potential (RMP)
the electrical potential inside the cell relative to the adjacent extracellular space
depolarization
The inward rush of sodium ions changes the polarity at that site; negative on outside and positive on inside
graded potential
localized depolarization; exists
where the inside of the membrane is more positive and the outside is less positive
action potential (nerve impulse)
if the stimulus is strong enough and sodium influx great enough, local depolarization activates the neuron to conduct an action potential
repolarization
restoring the inside of the membrane to a negative charge and the outer surface to a positive charge; when the neuron returns to its resting state - must do this before sending out another nerve signal
propagation of action potential
All-or-none response means once it begins the nerve impulse will be propagated along the axon and will not stop until it reaches the axon terminal
saltatory conduction
the way an electrical impulse skips from node to node down the full length of an axon
synaptic transmission
the biological process by which a neuron communicates with a target cell across a synapse
pyramidal (corticospinal) tract
provides voluntary control of muscular movements
motor homunculus
a topographic representation of the body parts and its correspondents along the precentral gyrus of the frontal lobe
reticular activating system (RAS)
regulating arousal and sleep−wake transitions
meningitis
an inflammation (swelling) of the protective membranes covering the brain and spinal cord
hydrocephalus
an abnormal buildup of fluid in the ventricles (cavities) deep within the brain
cauda equina
a collection of spinal nerves at the inferior end of the cord; Provides a two-way conduction pathway to and
from the brain; 31 pairs of spinal nerves
neurotransmitter
chemical travels from axon of one neuron to dendrite on the next neuron
