Nervous System

Created Jan 25, 2013
by brittanyshaw
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nervous system
coordinates stimuli betweem the internal and external environment PROPERTIES irritability-...
structural organization of the nervous system
CNS- brain and spinal cord PNS- cranial nerves and spinal nerves that link the brain and the...
PNS afferent system
transmits information from sensory receptors to the CNS
PNS efferent system
 transmits information from the CNS to muscles and glands
division of the PNS somatic
voluntary division - requires nerve stimulus. attached to skeletal concerned with the external...
autonomic
involuntary division - controls all internal involuntary responses in the smooth muscle, cardiac...
visceral
internal, central organs
Autonomic Nervous System
- involuntary - consists of visceral efferent fibers - conducts impulses to smooth muscle,...
sympathetic 
- mobilizes energy during stressful situations - times of emergency, "fight or flight" -...
parasympathetic
- responds to everything back to normal - slow HR - constrict pupils back to normal - constrict...
cells of the nervous system
- neuron is the functional unit of the nervous system - has a single nucleus, but no centrioles...
axon coverings
- enveloped by a sheath of schwann, also called a neurilemma, which is produced by schwann...
larger axons
- have an inner sheath of myelin, which functions as an electrical insulator and speeds conduction...
axons in CNS 
lack a neurilemma sheath - unmyelinated fibers withoug a neurilemma occur in the gray substance...
sensory 
- afferent neuron conduct impulses from the receptors in the skin sense organs, or internal...
motor neurons
- efferent neuron neurons relay impulses from the CNS to the effectors
interneurons
- associated neurons are found entirely within the CNS
neuroglia
commonly called glia, supporting cells of CNS
astrocytes
- star shaped cells - vascular feet - requires glucose, ATP. connect
oligodendrocytes
similar to schwann cells found in the PNS - form myelin sheaths that are wrapped around axons...
microglia
cells have a phagocytic role
ependmal cells
line the cerebral cavities, form cerebrospinal fluid
Nucleus
A collection of neuron cell bodies located inside the CNS
Ganglion
Collection of neuron cell bodies located outside the CNS
Nerve
Collection of nerve cell processes located outside the CNS fibers are held together and supported...
Endoneurium
Surround each individual nerve fiber
Perineurium
Surround a group if fibers in a fasicle
Epineurium
Surround each group if fascicles 
Mixed nerves
Most peripheral nerves are mixed they contain both unmyelinated and myelinated afferent and...
Tract
Collection of nerve fibers inside the brain or spinal cord that have a common origin and destination
Commissure
Band of nerve fibers that joins corresponding opposite sides of the brain or spinal cord
Synapses
Synaptic space between the axon of the presynaptic neuron and post synaptic dendrites - highly...
Alkalosis
Above pH 7.4 increases neuronal activity
Acidosis
Below 7.4  depresses neuronal discharge 
Anoxia
Depresses neuronal excitability
Drug effects
Increase or decrease neuronal excitability caffeine increase passage of impulse general anesthesia...
Acetylcholine
Generally excitatory, inhibitory to some visceral effectors, skeletal muscle - a chemical
Norepinephrine 
Excitatory or inhibatiry found in visceral and cardiac neuromuscular junctions coccaine and...
Epinephrine 
Excitatory or inhibitory  found in pathway concerned with behavior and mood
Dopamine
Excitatory  foubd in pathway that regulate emotional responses, decreases levels in Parkinson's...
Serotonin
Inhibitory inhibits excessive discharge of neurons
Gamma
Aminobutyric acid (GABA) inhibitory, inhibits excessive discharge of neurons
Endorphins and enkephalins 
Inhibitory, inhibit release of sensory pain neurotransmitters opiates mimic the effect
CNS- brain
human brain comprises of 2% of the total body weight consumes 25% of its oxygen and receives...
forebrain
telenephalon, cerebral hemispheres, basal ganglia; diencephalon-thalmus and hypothalmus
midbrain
cerebral peduncles and corpora quadrigemmina
hindbrain
medulla oblongata, pons and cerebullum
central sulcu
divide brain into frontal, temporal, parietal, occipital
corpus callosum
myelinated fibers joins the cerebral hemispheres
fissures sulci
deep grooves shallow grooves
longitudinal fissure
divides the cerebrum into left and right hemisphere
occipital lobe
primary visual area
auditory area
receives nerve impulses concerned with hearing
primary olfactory area
temporal lobe is concerned with the sense of smell
primary taste (gustatory)
involoved in the preception of taste
frontal lobe
higher thinking, artisitc, creativity, intuition, problem solving can live without 
somatic
positional relationship of body parts
long and short association tracts
interconnect neurons within the same hemisphere
commissure fibers 
connect one hemisphere to the corresponding area of the other hemisphere
projection fibers
ascending and descending pathways coming and going from neurons located in other parts of the...
descending tracts ascending tracts
motor, cross over at the level of the medulla, down the cord then out sensory, cross over...
medulla
center of crossing over of motor tracts
cerebral hemisphere
main part of the brain
diencephalon
"between brain" lies between the cerebrum and the midbrain and is hidden by the...
thalamus
2 oval masses relay station 
hypothalamus
most important autonomic nervous system control center part of the forebrain= cerebrum "primitive...
brain stem
includes the midbrain, pons, medulla oblongata
midbrain
contains the corpora quadrigemina, visual and auditory reflex center, the "righting reflex"...
hindbrain
consists of 3 parts, the pons, the medulla oblongata, the cerebellum
pons
pneumotaxic aponeustic (control rhythm) a prominent swelling of the brainstem serves as a...
medulla oblongata
located inferior to the pons and superior to the spinal cord inferior end: located at the...
cerebellum
"little brain" composed of 2 hemispheres and a central constricted part called the...
spinal cord
oval shaped cylinder, 17-18 inches in adult inner core is composed of gray matter shaped like...
functions of spinal cord
serves as a center for the reflex arc serves as pathway for ascending (sensory) tracts (sensory...
reflex receptors (sensory) efferent (motor)
involuntary response to a stimulus dorsal side ventral side
reflex arc
a place in which incoming sensory impulses become outgoing motor impulses
ascending tracts descending tracts
conduct sensory impulses from afferent neurons upward to the brain conduct impulses from...
meninges
membranes covering of the brain and spinal cord connective tissue
cerebral spinal fluid
will be found in the sub arachnoid space
dura mater
2 layers closely connected except when they separate to form sinuses for venous blood
arachnoid
delicate fibrous membrane (cobwebby in appearance) cob web design allows for blood vessels...
pia matter
very delicate layer filled with blood vessels
epidural/extradural space
between the dura mater and the vertebrae epidural space only exists in injuries in the cranial...
subdural subarachnoid
between the dura mater and the arachnoid between the arachnoid and the pia matter. contains...
cerebrospinal fluid
"water helmet" a clear watery fluid, formed by filtration of blood found in subarachnoid...
ventricles spinal cord ends meninges continue down to sacrum
spaces in the brain between L1-L2 ends at L5, cerebrospinal fluid ends at L5
functions of cerebrospinal fluid
acts as a shock absorber pathway of exchange of nutrient material and waste between the blood...
spinal puncture
performed betwen the 3-4 lumbar vertebrae with no danger to the cord
PNS
consists of spinal nerves, cranial nerves, and the autonomic nervous system
spinal nerves
31 pair, names for the regions of the vertebral column from which they arise 8 pairs- cervical...
phrenic 
nerve which causes movement to diaphram between 3 and 4
cranial nerves
12 pair emerge from the brain
ANS
involuntary branch of PNS visceral efferent system sends motor impulses 2 neuron relay system
sympathetic 
times of emergency, "fight or flight" intervate HR increase pulse dialates bronchi/pupils does...
parasympathetic
responds everything back to normal neurotransmitter: acetylcholine slow HR constrict pupils/bronchi normal...


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