Download unit 2 – nervous system / senses - Greater Atlanta Christian Schools

UNIT 2 – NERVOUS SYSTEM / SENSES
Chapter 8 – Nervous System
I. DIVISIONS OF NERVOUS SYSTEM
A. CENTRAL NERVOUS SYSTEM
1. BRAIN
2. SPINAL CORD
B. PERIPHERAL NERVOUS SYSTEM
1. AFFERENT (SENSORY) SYSTEM
2. EFFERENT (MOTOR) SYSTEM
a. SOMATIC MOTOR

CONTROL SKELETAL MUSC.
b. AUTONOMIC N.S.

PARASYMPATHETIC – STIMULATES ACTIVITIES THAT ARE NORMALLY ASSOCIATED WITH THE BODY
AT REST (DIGESTION, ETC..)
SYMPATHETIC – PREPARES THE BODY FOR PHYSICAL ACTIVITY
Enteric Nervous System


II. BRAIN
A. CEREBRUM – CONSCIOUS THOUGHT, PROBLEM SOLVING, MEMORY AND CRITICAL THINKING
1.
2.
FRONTAL LOBE – INITIATES VOL. MOTOR FXNS, MOTIVATION, MOOD, AGRESSION AND
PROCESSES SMELL
PARIETAL LOBE – RECEPTION / PROCESS SENSORY INFO. : TOUCH, PAIN, TEMP., BALANCE, TASTE
3.
TEMPORAL LOBE – MEMORY, PROCESS OLFACTORY / AUDITORY INFO., ABSTRACT THOUGHT AND
JUDGEMENT
4.
OCCIPITAL LOBE – PRIMARY VISION CENTER
B. CEREBELLUM – BALANCE, MAINTENANCE OF MUSCLE TONE, COORDINATION OF FINE MOTOR SKILLS
1.
COMPARATOR – COMPARES INTENDED MOVEMENTS OF CEREBRAL CORTEX WITH ACTUAL
POSITION OF BODY PART
2.
2ND NATURE FUNCTIONS – “LEARNS” FROM CEREBRAL CORTEX AND LATER AUTOMATICALLY
CONTROLS COMPLICATED MOVEMENTS
C. DIENCEPHALON


1.
THALAMUS – INFLUENCES MOOD, AND SENSES UNLOCALIZED / UNCOMFORTABLE PAIN
2.
EPITHALAMUS – VISCERAL / EMOTIONAL RESPONSES TO ODOR
* PINEAL BODY – INVOLVED IN PUBERTY ONSET
3. HYPOTHALAMUS – HOMEOSTATIC FXNS: BODY TEMP., HUNGER AND THIRST
EXTREME EMOTIONS: FEAR, RAGE, RELAXATION
CONTROLS PITUITARY GLAND (MEDIATOR BTW NERV. SYSTEM AND ENDOCRINE SYSTEM
D. BRAINSTEM – RELAY STATION BTW CEREBRUM AND SPINAL CORD / CEREBELLUM

1. MEDULLA OBLONGATA
CV, RESP. REGULATION (HR, BL. VESS. DIA., BREATHING, COUGHING, SNEEZING)

UPPER DIG. REGULATION – VOMITING, SWALLOWING
2.


3. MIDBRAIN
SUPERIOR COLLICULI – VISUAL REFLEXES
INFERIOR COLLICULI – AUDITORY RELAY CENTER
4.
RETICULAR FORMATION – REGULATES SLEEP (R.F. INHIBITED) / WAKE (R.F. STIMULATED) CYCLE

5. BASAL GANGLIA
PLANS / COORDINATES MOTOR ACTIVITY ( i.e. POSTURE) BY INHIBITING MUSCLE ACTIVITY (VIA
DOPAMINE)
EXAMPLES OF DAMAGE : CEREBRAL PALSY, PARKINSON’S DISEASE



6. LIMBIC SYSTEM
RESPONDS TO SMELL BY INTITIATING RESPONSES NECESSARY FOR SURVIVAL
INFLUENCES MOOD, EMOTIONS AND MOTIVATION
EXAMPLES OF DAMAGE: VIROCIOUS APPETITE, PERVERSE SEXUAL ACTIVITY, INCREASED DOCILITY

II.
PONS – COORDINATES WITH MED. OBL.
FUNCTIONAL AREAS OF THE CEREBRAL CORTEX (FIG. 8 – 20; 210)
A. PRIMARY SENSORY AREAS – PORTIONS WHERE STIMULI ARE PERCEIVED
B. ASSOCIATION AREAS – PORTIONS IN WHICH SENSATIONS ARE RECOGNIZED OR ANALYZED
C. PREFRONTAL AREA – WHERE MOTIVATION AND EMOTIONAL RESPONSES ORIGINATE
D. PREMOTOR AREA – WHERE MOTOR ACTIVITIES ARE ORGANIZED BEFORE INITIATED
E. PRIMARY MOTOR CORTEX – WHERE MOTOR ACTIVITIES ARE INITIATED BEFORE SENT TO
THE CEREBELLUM
**NOTE DIFFERENT PRIMARY SENSORY AREAS:
1. PRIMARY SOMESTHETIC CORTEX – PAIN, PRESSURE & TEMP. (PARIETAL)
2. VISUAL CORTEX (OCCIPITAL)
3. PRIMARY AUDITORY CORTEX (TEMPORAL)
4. TASTE AREA (PARIETAL)
**NOTE DIFFERENT ASSOCIATION AREAS:
1. VISUAL
2. AUDITORY
3. SOMESTHETIC
F.
III.
SPEECH AREAS
1.
SENSORY SPEECH (WERNICKE’S AREA) - WHERE “SOMETHING” IS UNDERSTOOD BEFORE SPEAKING
2.
MOTOR SPEECH AREA (BROCA’S AREA) – WHERE WORDS ARE FORMED BEFORE SPEAKING
CRANIAL NERVES ( SENSORY, MOTOR, PARASYMPATHETIC)
**TABLE 8-3; 223 – KNOW NAME OR NUMBER
I – OLFACTORY
S
SMELL
II – OPTIC
S
VISION
III – OCULOMOTOR
M
P
VOL. MVMT OF EYE (4 EYE MUSC.)
ACCOMODATION (PUPIL CONSTRICTION; LENS
THICKENING)
IV.
IV – TROCHLEAR
M
VOL. MVMT OF EYE (1 EYE. MUSC.)
V – TRIGEMINAL
S
M
FACE / TEETH
MASTICATION (CHEWING)
VI – ABDUCENS
M
VOL. MVMT OF EYE (1 MUSC.)
VII – FACIAL
S
M
P
TASTE
FACIAL EXPRESSION
SALIVA / TEARS
VIII – VESTIBULOCOCHLEAR S
HEARING / BALANCE
IX – GLOSSOPHARYNGEAL
S
M
P
TASTE / TOUCH OF TONGUE
SWALLOWING
SALIVA
X – VAGUS
S
M
P
THROAT AREA / VISCERA
SPEECH
VISCERA OF THORAX / ABDOMEN
XI – ACCESSORY
M
NECK / BACK MUSCLES (2 EACH)
XII – HYPOGLOSSAL
M
TONGUE MVMT
SPINAL NERVES

CLASSIFICATION / ORGANIZATION
1.
2.
3.
4.
5.
V.
C1 – C8
T1 – T12
L1 – L5
S1 – S5
Cx
AUTONOMIC N.S.
1.
PARASYMPATHETIC – CONTROLS BODY FXNS WHEN AT REST
- ^ DIGESTION / FECES FORMATION, URINATION
- v HR, RESPIRATION, BP
- EXCLUSIVELY CONTROLS ACCOMODATION
2.
SYMPATHETIC – PREPARES BODY FXNS FOR ACTIVITY; PRIMARILY FROM T / L SPINAL N.
- OPPOSITE OF ABOVE + ^ GLUCOSE RELEASE
- EXCLUSIVELY CONTROLS BLOOD VESSEL DILATION & PERSPIRATION
VI.
VII.
TRACING NERVE IMPULSES THROUGH THE NERVOUS SYSTEM

SENSORY NERVE  CNS  EFFERENT (MOTOR / PARASYMPATHETIC) NERVE

USE CRANIAL SENSORY NERVES, DIFFERENT PARTS OF CEREBRAL CORTEX, CEREBELLUM, BRAINSTEM
OR DIENCEPHALON, AND CRANIAL & / OR SPINAL EFFERENT NERVES
NEURONS
A. STRUCTURE
1.
2.
3.
CELL BODY – CENTRAL PORTION; CONTAINS NUCLEUS
DENDRITES – RECEIVES NERVE IMPULSES AND TRANSMITS THEM TO CELL BODY
AXON – TRANSMITS NERVE IMPULSES AWAY FROM CELL BODY AND TO TARGET CELL / TISSUE
B. TYPES
1.
2.
MYELINATED – W/ MYELIN (INSULATOR); QUICKER IMPULSE TRANSMISSION VIA SALTATORY
CONDUCTION
UNMYELINATED – W/O MYELIN; IMPULSE MUST TRAVEL ENTIRE DISTANCE OF NERVE
C. ACTION POTENTIAL
1. resting membrane potential – describes an unstimulated neuron
-“polarized” b/c of electrical charge difference that
exists on each side of the cell membrane
- inside cell: -ve ; high amt. of K+
- outside cell: +ve; high amt of Na+
- cell membrane permeability  K+ > Na+
- Na+/ K+ exchange pump  maintains RMP
3. Stimulated Neuron (action potential)
a. nerve (electrical) impulse stimulates neuron; Na+ channels open and Na+ floods inside of
neuron  Depolarization
b. charge difference reverses (inside  +ve; outside  -ve) from depolarization; this causes Na+
channels to close and K+ channels open  Repolarization
**this causes the charge difference to return to normal
c. an increase in K+ diffusion causes hyperpolarization and this causes K+ channels to close
d. Na+ / K+ exchange pump returns the ions to their proper places  RMP
**Threshold
**All – or – None Response
D. Nerve Impulse crossing the Synapse – keys words underlined
1. Action Potential causes synaptic vesicles in Presynaptic knob to fuse with Presynaptic membrane
and neurotransmitters are released into the synaptic cleft via exocytosis
2. Neurotransmitters travel across synaptic cleft and bind with receptor molecules on postsynaptic
membrane
**depending on the neurotransmitters, this may stimulate or inhibit action potential of target cell / neuron
**most common neurotransmitters – Acetylcholine, Norepinephrine, Dopamine
CH. 9 – SENSES
I.
MAJOR GROUPS OF SENSES
A. SPECIAL – TASTE, SMELL, HEARING, BALANCE AND VISION
B. GENERAL – TOUCH, PAIN, TEMPERATURE, VIBRATION, ITCH AND PROPRIOCEPTION

II.
STIMULI – MILLIONS COMING IN, BUT ONLY THE ONES THAT REACH THE CEREBRAL CORTEX IS
PERCEIVED
GENERAL SENSES / RECEPTORS
A. MECHANORECEPTORS – STIMULATED BY BEING BENT; HEARING, TOUCH, AND BALANCE
B. CHEMORECEPTORS – STIMULATED BY PRESENCE OF CHEMICALS; SMELL AND TASTE
C. PHOTORECEPTORS – STIMULATED BY LIGHT; VISION
D. THERMORECEPTORS – STIMULATED BY VARYING TEMP. (COLD AND HOT)
E. NOCICEPTORS – DETECT / REACT TO PAIN
III.
PAIN
A. SHARP, FAST CONDUCTING PAIN v. DULL, SLOW CONDUCTING PAIN
 WHICH WOULD MORE LIKELY HAVE MYELINATED / UNMYELINATED NEURONS
B. LOCAL ANESTHESIA v. GENERAL ANESTHESIA
1.
2.
LOCAL – SUPPRESSES SPECIFIC NERVE
GENERAL – SUPPRESSES RETICULAR FORMATION
C. GATE CONTROL THEORY – PROVIDING EXTRA STIMULI TO AN AREA OF PAIN

THE EXTRA STIMULI IS THOUGHT TO HELP BLOCK SOME OF THE PAIN IMPULSES TO THE BRAINS
D. REFERRED PAIN – WHEN A DEEP, VISCERAL PAIN IS FELT AT A SUPERFICIAL LOCATION DUE TO
CONVERGING / DIVERGING NEURONAL CIRCUITS.

IV.
BRAINS RECEIVES THE PAIN FROM INTERNAL ORGAN / TISSUE AND THAT NERVE COMBINES WITH A
SUPERFICIAL NERVE AS IT APPROACHES THE SPINAL CORD, - BUT WHEN THE BRAIN SENDS THE
IMPULSE BACK TO THE SOURCE, THEN THE PAIN IS FELT IN THE MOST SUPERFICIAL LOCATION.
EYE / VISION
A. LIGHT / ACTION POTENTIAL PATHWAY
1.


LIGHT PATHWAY
a. CORNEA
b. ANTERIOR CHAMBER** (AREA BTW. CORNEA AND PUPIL)
c. PUPIL / IRIS
d. POSTERIOR CHAMBER** (AREA BTW. PUPIL AND LENS)
**FILLED WITH AQUEOUS HUMOR
e. LENS
f. POSTERIOR COMPARTMENT / VITREOUS HUMOR
g. RETINA – CONTAINS PHOTORECEPTORS
CONES – DETECT COLOR
RODS – DETECT LIGHT INTENSITY
2.


ACTION POTENTIAL PATHWAY
a. OPTIC NERVE
b. OPTIC CHIASMA
c. SUP. COLLICULI / THALAMUS
d. VISUAL CORTEX
OPTIC DISK – “BLIND SPOT” ; AREA WHERE RETINA CONNECTS WITH OPTIC NERVE; CONTAINS NO
PHOTORECEPTORS
FOVEA CENTRALIS – AREA ON RETINA WHERE THERE IS THE GREATEST [CONES] AND HAVE
SHARPEST, CLEAREST VISION
B. LIGHT REFRACTION
 DONE BY 4 STRUCTURES / FLUIDS IN EYE
1. CORNEA – GREATEST AMOUNT OF REFRACTION
2. VITREOUS / AQUEOUS HUMOR
3. LENS – FOCUSES LIGHT ON RETINA BY CHANGING SHAPE


MYOPIA – NEARSIGHTEDNESS; LIGHT FOCUSED “IN FRONT” OF RETINA; LENS TOO CONVEX
HYPEROPIA – FARSIGHTEDNESS; LIGHT FOCUSED “ BEHIND” RETINA ; LENS TOO CONCAVE

ACCOMMODATION – FOCUSING ON CLOSE OBJECTS
 LENS THICKENS DUE TO CILIARY MUSC. CONTRACTING / SUSP. LIGAMENTS RELAXING

DISTANCE FOCUSING
 LENS BECOMES THIN DUE TO RELAXATION OF CILIARY MUSC. / TIGHTENING OF LIGAMENTS
C. CONTROL OF LIGHT
V.
1.
HIGH LIGHT INTENSITY – PUPIL CONSTRICTS B/C CIRCULAR MUSC. IN IRIS CONTRACT
 PARASYMPATHETIC NERVE IMPULSE
2.
LOW LIGHT INTENSITY – PUPIL ENLARGES B/C RADIAL MUSC. IN IRIS CONTRACT
 SYMPATHETIC NERVE IMPULSE
EAR / HEARING AND BALANCE
A. HEARING – DETECTED BY THE COCHLEA

SOUND / ACTION POTENTIAL PATHWAY
1. AURICLE (OUTER EAR)
2. EXTERNAL AUDITORY MEATUS – “ EAR CANAL”
3. TYPMANIC MEMBRANE – “EARDRUM”
4. MALLEUS – “HAMMER”
5. INCUS – “ANVIL”
6. STAPES – “STIRRUP”
7. OVAL WINDOW
8. COCHLEA

COCHLEA – FILLED WITH GEL-LIKE FLUID THAT VIBRATES SENSORY HAIRS WHEN STIMULATED BY
VIBRATIONS OF SOUND ROUND WINDOW (LOCATED INFERIOR TO OVAL WINDOW) ALLOWS THE
VIBRATION OF THE FLUID TO OCCUR
9.
10.
11.
12.
SENSORY HAIRS
COCHLEAR NERVE
VESTIBULOCOCHLEAR NERVE
AUDITORY CORTEX
B. BALANCE – CONDUCTED BY VESTIBULAR NERVE
1.

BONY GRAINS SUSPENDED IN GEL – LIKE MASS IN VESTIBULE RESPOND TO GRAVITY AND BEND
SENSORY HAIRS TOWARD GRAVITY
2.

STATIC EQUILIBRIUM – DETECTED BY VESTIBULE  EVALUATES THE POSITIONOF THE HEAD
RELATIVE TO GRAVITY
KINETIC EQUILIBRIUM – DETECTED BY SEMICIRCULAR CANALS  EVALUATES THE CHANGE OF
RATE AT WHICH THE HEAD MOVES (WHAT CAUSES YOU TO BECOME DIZZY WHEN YOU SPIN)
TURNING THE HEAD CAUSES THE SEMICIRC. CANALS TO MOVE (AND THE SENSORY HAIRS IN THE
SEMICIRC. CANALS), BUT THE GEL – LIKE FLUID IN THE CANALS TAKES LONGER TO MOVE AND THIS
CAUSES THE SENSORY HAIRS TO BEND IN THE OPPOSITE WAY IN WHICH THE HEAD MOVES