Name________________________________Block_____Date______________________
Lisa Peck
(pp 222-224)
Nervous system the master controlling and communicating system of the body
3 functions: 1. sensory receptors to monitor changes occurring inside & outside body stimuli- changes sensory input- gathered information
2. processes and interprets the sensory input
integration- nervous system makes decisions about what should be done
3. effects a response by activating muscles or glands (effectors) via motor output
Regulating and Maintaining Homeostasis nervous system - fast-acting control via electrical impulses endocrine system- slow-acting control via hormones release into the blood
(p 223)
2 subdivisions: Central Nervous System
Peripheral Nervous System
1.
consists of: brain
spinal cord functions: integrating center.........interpret incoming sensory information
command center..........issue instructions based on past experience & current conditions
2.
consists of: nerves 2 types: cranial nerves carry impulses to and from the brain spinal nerves carry impulses to and from the spinal cord
ganglia - groups of nerve cell bodies
function: communication lines, linking all parts of the body

(pp 223-224) only deals with peripheral nervous system (PNS)
2
1. Sensory (Afferent) Division nerve fibers that carry impulses to the CNS from sensory receptors located throughout body sensory fibers types: 1. somatic sensory fibers- delivering impulses from the skin, skeletal
muscles, & joints
2. visceral sensory fibers- transmitting impulses from the visceral organs
2. Motor (Efferent) Division nerve fibers that carry impulses from the CNS to effector organs
ossicles and glands, bringing about a motor response
2 types: 1. somatic nervous system: conscious control of skeletal muscles
voluntary control skeletal muscles
2. autonomic nervous system (ANS) regulates activities that are automatic involuntary
cardiac muscle
smooth muscle
glands
2 nerve types that target same organ but yield opp. effects
exception: targeted only by sympathetic: some glands,
most blood vessels, most structures of the skin
2 types: 1.
sympathetic-” fight or flight” f ’ ns during extreme situations ex: increase heart rate
rapid breathing
cold, sweaty skin
dilated pupils
2.
parasympathetic- “resting & digesting”
most active when body at rest
causing normal digestion, voiding
feces & urine
goal: conserving energy

(pp 224-235) 3
2 types of cells : 1. neuroglia supporting cells
not able to conduct impulses
can undergo cell division
most brain tumors are gliomas- formed by glial cells
2. neurons nerve cells that transmit impulses
functional unit of nervous system
(pp 224-226) not able to conduct impulse glia (glial cells)- f ’ n: support, insulation, & protection ~90% cells in brain are glial cells
CNS : 4 types: astrocytes
microglia
ependymal
oligodendrocytes
PNS: 2 types
schwann cells
satellite cells
1. Astrocytes - star-shaped cells
account for over half of neural tissue
numerous projections have swollen ends that cling to neurons
f ’ n: 1. brace and anchor neurons to capillaries intermediary cell b/w neuron and capillary (aids in exchange)
protects neurons from harmful substances present in blood
2. control chemical environment in brain by picking up excess ions &
recapturing released neurotransmitters

2. Microglia- spiderlike phagocytes
dispose of debris (dead brain cells & bacteria) smallest of glial cells
3. Ependymal - line cavities of the brain & spinal cord
f ’ n- beating of cilia helps circulate cerebrospinal fluid
that fills cavities & forms protective cushion around CNS
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4. Oligodendrocytes - (CNS)
wrap their flat extensions around axons of many nerves
forms myelin sheath- fatty insulating covering protects and cushions nerves speeds up nerve transmission speed gives rise to white matter of brain fewer extensions than astrocytes
PNS: 2 types:
1. Schwann cells - cells of PNS that myelinate axons
2. satellite cells- protective & cushioning cells of PNS neurons

B. Neurons (pp 226-235)
1. Anatomy (of a generalized neuron)
5 cell body- metabolic center
contains typical cell organelles
(exception: no centrioles .....no mitosis -amitotic) axon - one per cell, process of neuron conduct impulses away from the cell body dendrites - many per cell, extension of neuron (often branched extensively)
conduct impulses toward cell body axon hillock - axon arises form this conelike
region of cell body axon terminals 100 ’ s to 1000 ’ s branches at terminal end of axon
contain vessicles of neurotransmitters collateral branch branch off of an axon

Nerve Anatomy synaptic cleft (synapse) separation b/w axon terminal and next neuron myelin covering of most long neurons (axon)
whitish, fatty substance
protects, insulates, speeds up neural transmission
CNS: oligodendrocytes- form myelin sheath
lacks neurolemma
f ’ n- protects and cushions nerve
increases speed of nerve transmission
located in CNS
PNS: schwann cell ’ s form myelin sheath covering of most long neurons
formed by wrapping of a Schwann cell schwann cell specialized supportive cells
wrap tightly around axon neurolemma- outermost part of schwann cell
aids in neuron regeneration nodes of Ranvier - gaps of myelin sheath b/ w Schwann cells loc. @ regular intervals action potential jumps from node to node- faster
6
CNS white matter- dense bundles of myelinated fibers (tracts) brain- inside spinal cord- surface gray matter unmyelinated fibers and cell bodies brain- surface spinal cord- inside
CNS PNS nuclei ganglia groups of cell bodies tracts nerves bundles of nerve fibers

Classification of Neurons functional classification according to direction of impulse is traveling relative to CNS
1. sensory neuron- nerve impulse travels towards CNS afferent
cell bodies outside CNS in ganglion
7 receptors- dendrite endings that are specialized activated by specific changes nearby (stimuli) taste, hearing, sight, equilibrium, smell cutaneous sense organs - pacinian & meissner corpuscles proprioceptors - loc. in muscles & tendons
detects amt. of stretch or tension
determines location, posture, and tone
muscle spindle
golgi tendon organs pain receptors- bare dendrite endings
least specialized cutaneous receptor
most numerous cutaneous receptor
2. motor neuron - nerve impulse travels away from CNS
efferent neuron
cell bodies inside CNS in nuclei
3. association neurons (interneurons) - connect motor and sensory neurons
cell bodies in CNS

Classification of Neurons structural classification based on number of processes extending from cell body multipolar several processes
all motor neurons
all association neurons
most common neuron type bipolar 2 process on cell body axon & dendrite
rare in adults (eg; eye & nose) unipolar - one process on cell body single process is very short process divides into 2
peripheral process- (distal) contains dendrites on end central process- (proximal) contains axon terminals axon- both peripheral & central
processes conducts impulses in both
directions (toward & away from cell body)
sensory neurons located in PNS ganglia are all unipolar
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3. Physiology nerve impulse generation (action potential) reflex arcs neural pathways involve both CNS & PNS reflexes - rapid, predictable and involuntary responses to stimuli once reflex begins...always goes in same direction
types: somatic reflexes - stimulate the skeletal muscles
eg: pull hand away from hot stove
autonomic reflexes- regulate the activity of smooth muscles, heart, & glands
eg: secretion of saliva, changes in pupil size, regulates: digestion, elimination, blood pressure, & sweating

(pp 235-249) 9

Functional Anatomy of the Brain (pp 235-241)
Brain- 3 parts
1. forebrain- cerebrum
diencephalon- thalamus
hypothalamus
2. midbrain- small superior part of brain stem
3. hindbrain- cerebellum
brain stem (part of it) - medulla oblongata
pons
10
2 parts: 1. cerebrum (cerebral hemispheres)
2. diencephalon
Cerebrum: largest part of brain
divided into left and right hemispherescerebral hemispheres separated by corpus callosum (internally)- large fiber tract connecting hemispheres longitudinal fissure (surface)
the spinal tracts cross over -------> left hemisphere deals w/ right side of body
right hemisphere deals w/ left side of body
surface is highly convoluted- increasing surface area (increases # of neurons) cortex- (exterior) gray matter
thin surface layer (1-4 mm thick)
Interior white matter, nerve tract relaying impulses to & from cerebral cortex gyrus (gyri)- elevated ridges on cerebral cortex sulcus (sulci) shallow grooves in cortex fissure deep sulcus in cortex
separate large areas of brain
sulci divide hemispheres into 4 lobes
frontal lobe
parietal lobe
occipital lobe
temporal lobe

Functional Anatomy of the Brain (pp 235-241) 11
cerebral cortex: 4 lobes
f ’ n - speech, memory, logical & emotional response, consciousness, interpretation of sensation, voluntary movement, problem solving frontal lobe
primary motor area - located anterior to central sulcus
initiates voluntary movement of skeletal muscles (motor language too) premotor area - located anterior to primary motor area
process input regarding body movement, modify movements
prefrontal area anterior frontal lobe
higher level thought, decision making, planning, impulsivity control
selective attention, personality, problem solving, behavior, emotions
Broca ’ s area inferior left frontal gyrus
controls facial neurons & speech production- articulation
(works in junction with Wernicke ’ s Area- language comprehension) parietal lobe somatic sensory area - located posterior to central sulcus
interprets input from sensory receptors (except specialized senses) aids in spacial orientation sensory pathways are crossed pathways (left sensory area receives input from right side of body) temporal lobe - auditory processing
olfactory area (located deep temporal)
memory: right lobe- visual memory (pictures, faces)
left lobe- verbal memory (words, names) occipital lobe- visual center , processes visual info and visual recognition of shapes & colors

12
“telencephalon”
located superior to brain stem & enclosed by cerebral hemispheres
3 parts - thalamus - relay station for sensory impulses passing upward to somatic sensory cortex
all sensory input passes thru thalamus to cortex (except olfaction) signals from cerebellum pass thru thalamus up to motor area of cortex
encloses 3rd ventricle (spaces filled w/ cerebrospinal fluid...aids in circulation)
hypothalamus -”seat” of autonomic nervous system
regulates homeostasis both nervous & endocrine f ’ ns source of 8 hormones
regulation of: body temp, water balance, blood chemistry, metabolism
heart rate,
death results if damaged
plays imp. part in limbic system- “emotional-visceral brain”
emotion, motivation
epithalamus - forms roof of 3rd ventricle choroid plexus knots of capillaries w/ in ea. ventricle forms CSF pineal body - endocrine gland
releases melatonin- regulates daily body rhythms
eg: day/ night cycle melatonin released @ night
Brain Stem - pathway for ascending & descending tracts, has gray areas- cranial nerves help control breathing, heart rate etc.
1. midbrain
2. pons
3. medulla oblongata
reticular formation extends length of brain stem (middle of hindbrain to midbrain) role in consciousness & awake/ sleep cycles damaged- coma

located upper part of brain stem very small portion of brain stem
13
evolutionarily: the oldest part of brain
only used for eye reflexes reticular formation collects input from higher brain centers & passes it on to motor neurons substantia nigra helps “smooth” out body movements damaged-Parkinson ’ s Disease ventral tegmental area (VTA) loaded w/ dopamine-releasing neurons that are activated
by nicotinic acetylcholine receptors & synapse deep w/ in
forebrain
VTA involved in pleasure: nicotine, amphetamines & cocaine
bind to and activate its dopamine-releasing neurons-
may account for their addictive qualities
consists of part of brain stem: 1. pons
2. medulla oblongata
3. cerebellum
pons rounded structure protruding below midbrain unconscious control of breathing (reflexive breathing)
reticular formation - area receives sensory input from forebrain & passes to thalamus
involved in sleep, arousal & vomiting
relay center b/w cerebral cortex ( impulses from eyes, ears, & touch receptors) & cerebellum medulla oblongata closest to spinal cord most inferior part of brain stem
f ’ n- regulation of heart beat, breathing, vasoconstriction (blood pressure),
reflex centers for vomiting, coughing, sneezing, swallowing, & hiccups important fiber tract area damaged- death
4th ventricle lies posterior to medulla oblongata
cerebellum - second largest part of brain 2 convoluted hemispheres
surface layer is gray matter and internal area is white matter
f ’ n- muscle coordination
maintain normal muscle tone & posture balance & equilibrium
Limbic System receives input from association areas in cortex & passes signals cerebrum
2 parts: hippocampus essential for formation of long term memories amygdala- center of emotions (eg fear)
send signals to hypothalamus& medulla wh/ can activate
“fight or flight”
receives signals form olfactory system....may account for
powerful effect that odor has on memory

14
Protection of the Central Nervous System (pp 241-244)
1. Bones of skull and vertebral column
2. Meninges dura mater- outermost arachnoid matter- middle pia matter - innermost

Protection of the Central Nervous System (pp 241-244) 15
2. Meninges 3 continuous sheets covering both spinal cord and brain dura mater- outermost, pressed against bony surface on interior of vertebrae & cranium arachnoid mater- middle layer, weblike, threadlike extensions pass thru subarachnoid
space & attach to pia mater pia mater - innermost layer, thin, attached to surface of spinal cord & brain
3. Cerebrospinal Fluid (CSF) fluid similar to blood plasma containing protein, vit. C, and ions
bathes cells of CNS protecting them from physical trauma
returns to blood thru veins drainging the brain
choroid plexus- capillaries that secrete CSF located hanging from roof of each ventricle ( 2 lateral, 3rd & 4th)
CSF location
4. Blood-Brain Barrier

C. Brain Dysfunctions (pp 244-247)
1. Traumatic Brain Injuries concussion- reversible damage contusions- nonreversible damage
2. Cerebrovascular Accidents (CVA)- stroke visual impairment paralysis aphasias
3. Alzheimer ’ s Disease
4. Huntington ’ s Disease
5. Parkinson ’ s Disease
6. Diagnosis (pp 262-263) electroencephalogram (EEG)
simple reflex tests
angiography
CT scans
PET scans
MRI & Functional MRI scans
16
D.
(247-249)
~17 inches from foramen magnum to L1 or L2
cauda equina- cord ends w/ spinal nerves @ L2
31 pairs of spinal nerves (dorsal & ventral roots)
Gray Matter of Spinal Cords & Spinal Roots gray matter in middle around central canal (H shape)
2 dorsal (post.) horns- contains interneurons connected to sensory neurons from dorsal root
2 ventral (ant.) horns- cell bodies of motor neurons whose axons leave via ventral root
White Matter of the Spinal Cord 3 regions
anterior column: ascending tracts only (incoming sensory)
lateral column: both ascending & descending
posterior column: both ascending & descending spinal nerve - fused dorsal & ventral roots (a mixed nerve- sensory & motor neurons)
dorsal root: entering sensory neurons
dorsal root ganglia- sensory nerve
cell bodies
ventral root: motor nerve axons

(pp 249-263)
contain only nerves (no glial cells)
Structure of a Nerve
nerve- bundle of neuron fibers (held tog. w/ connective tissue)
endoneurium- surrounds each never fiber
perineurium- binds groups of fibers into fasicles
epineurium- bind fascicles together
12 Pairs of Cranial Nerves
numbered in order from front to back
most are mixed nerves (3 sensory only)
I olfactory sensory 4 smell
II optic sensory 4 vision
III oculomotor motor fibers to eye muscles
IV trochlear motor fibers to eye muscles
V trigeminal sensory 4 face
motor fibers to chewing muscles
VI abducens motor fibers to eye muscles
VII facial sensory 4 taste
motor fibers to face
VIII vestibulocochlear sensory 4 hearing & balance
IX glossopharyngeal sensory 4 taste
motor fibers to pharynx
X vagus sensory & motor 4 pharynx,
larynx, & viscera
XI accessory motor nerve to neck &
upper back
XII hypoglossal motor fibers to tongue
17

31 Pairs of Spinal Nerves and Nerve Plexuses spinal nerves formed by combo of venrtral & dorsal roots of spinal cord spinal nerves named for region from which they arise spinal nerves divide after leave spinal cord
dorsal rami- serve skin & posterior trunk muscles
ventral rami- form plexus for the anterior plexuses ventral rami of spinal nerves form complex networks that serve motor & sensory
needs of limbs
4 plexus: cervical, brachial, lumbar, & sacral
18 classification of nerves by direction of impulse
mixed nerve- travels to & from CNS
inlcudes both sensory and motor nerve fibers
sensory nerve- carry impulse towards CNS (afferent)
motor nerve- carry impulse away from CNS (efferent)

Somatic NS Autonomic NS
Nerves one motor neuron preganglionic nerves
postganglionic nerves
Effector Organs skeletal muscle smooth muscle
cardiac muscle
glands
Neurotransmitters always use acetylcholine acetylcholine
epinephrine
norepinephrine
Autonomic Nervous System: involuntary control
2 divisions that serve same effector (smooth or cardiac muscle or a gland)
2 divisions bring about opposite effects, coutner balance ea. other
major difference 1) location of origin in CNS
parasympathetic- brain stem or S1-S4
sympathetic- T1-L2
2) location of ganglia
parasympathetic- ganglia near spinal cord
sympathetic- ganglia near effector organ

Autonomic Nervous System
Parasympathetic division (PaNS)
“housekeeping activities” conserves energy maintains daily necessary body functions
“D” division: digestion, defecation, and diuresis constricts pupils conserve E stimulates digestive (increase saliva) stimulates urinary organs (increase urine production) inhibit cardiovascular system (slow heart rate) inhibit respiratory systems ( constrict airways,
slow respirations)
20
Sympathetic division (SyNS)
“fight-or-flight” response to unusual stimulus takes over to increase activities
“E” division: exercise, excitement, emergency, & embarrassment pupils dialate stimulate respiratory organs (increase breathing rate & open airways) stimulate cardiovasculary system (increase heart rate) stimulate adrenal glands (release epinephrine and norepinephrine...stimulate liver) stimulated liver (convert glycogen into glucose....release into blood) inhibit digesitve system (decrease saliva...dry mouth) inhibit urinary system increase glucose use....generates heat and water...increase sweat, reddened skin polygraph- measures stress incurred when tell a lie. You know it is wrong to lie, when you do lie
your sympathetic NS kicks in and your adrenal glands cause heart rate to increase.
measures changes in heart rate

Developmental Aspects of the Nervous System (pp 263-266) 21 nervous system if formed during the first month of embryonic development any maternal infection can have extremely harmful effects the hypothalamus is one of the last areas of the brain to develop it controls body temperature: premature babies and infants can not maintain body temp there are no more neurons formed after birth, but growth and maturation continues for several years neurons will develop myelination during maturation- increases neuromuscular control the brain reaches maximum weight as a young adult
A. Embryonic Brain Development cerebral palsy anencephaly hydrocephalus spina bifida
B. Premature Infants temperature regulation via hypothalamus