CH. 14 - INTEGRATION OF NERVOUS SYSTEM FUNCTIONS
I. SENSES
A. SPECIAL - later, Ch. 15
B. GENERAL: SOMATIC & VISCERAL (Fig. 14.1 & Tab. 14.1, p. 472 & 473)
C. SENSATION/PERCEPTION - awareness of stimuli
1. STEPS (read p. 473)
a. STIMULUS
b. RECEPTOR
c. PROPAGATION/CONDUCTION/TRANSMISSION
d. TRANSLATION/INTERPRETATION
e. PROCESSEDèAWARENESSè SENSATION PROJECTED
TO site of stimulus
2. ACCOMMODATION or ADAPTATION
a. ê sensitivity to continued stimuli
b. wearing clothes, ring on finger, glasses, etc.
D. RECEPTOR TYPES – GENERAL – named by STIMULUS type
1. MECHANORECEPTOR - touch, pressure, proprioception
2. THERMORECEPTOR - warm, cool
3. NOCICEPTOR - pain/irritation
a. Mechanical, chemical, thermal
E. 8 TYPES OF SENSORY RECEPTORS (Tab 14.2, p. 474) *KNOW!
3 GROUPS – by LOCATION:
- Exteroreceptors – skin
- Visceroreceptors – guts
- Proprioceptors – joints, tendons
1. FREE - skin, viscera & tendons
a. Pain, tickle & itch, movement & temp.
b. Temp: i. Cold é A.P. as you go from 350è120 C
ii. Warm é A.P. as you go from 250è470 C
iii. PAIN if <120 or >470 C
2. MERKEL’S DISKS - light touch/pressure
3. HAIR FOLLICLE - light touch/bending of hair
4. PACINIAN CORPUSCLE - onion shaped
- Deep pressure, vibration & proprioception
5. MEISSNER’S CORPUSCLE - 2-point discrimination
6. RUFFINI’S END-ORGANS
a. Continuous touch/pressure
b. Stretch/depression of the skin
7. GOLGI TENDON ORGANS - muscle contractions
a. Proprioception w/movement
b. In tendons
8. MUSCLE SPINDLE - muscle tone
a. stretch in muscle
“FREE MEN HELP PAN MISS RUFF’S GOLD MINE”
II. SENSORY NERVE TRACTS = ASCENDING SPINAL PATHWAYS - sensory input (p. 477)
A. ANTEROLATERAL SYSTEM (Fig. 14.8, p. 484)
1. SPINOTHALAMIC - Pain & temp., pressure, light touch, tickle & itch
2. SPINORETICULAR – Pain, awaken by pain
3. SPINOMESENCEPHALIC – SPINOTECTAL – visual/touch & pain reflexes
3. 3 neurons:
-1o Receptor è dorsal root è dorsal gray horn
-2o Decussates, ascends è thalamus
-3o Thalamus è cortex
B. DORSAL COLUMN-MEDIAL LEMNISCAL (Fig. 14.9, p. 480)
1. FASCICULUS CUNEATUS - above mid-thorax
2. FASCICULUS GRACILIS - below mid-thorax
3. Proprioception, vibration, 2-point discrimination
4. 3 neurons:
-1o Sensor è ascends to medulla
-2o Decussates è medial lemniscus è thalamus
-3o Thalamus è cortex
C. OTHERS:
1. SPINOCEREBELLAR - Proprioception to cerebellum (Fig. 14.10, p. 480)
2. SPINO-OLIVARY - Proprioception relating to balance
D. PRIMARY SOMATIC SENSORY AREAS/CORTEX (Fig. 14.11, p. 481)
1. Posterior to central sulcus
2. Input from general senses - pressure, pain & temp. (Fig. 14.12, p. 484)
E. ASSOCIATION AREAS - Adjacent to sensory areas (Fig. 14.11, p. 481)
1. Sorting & integration of input from sensory areas
2. Input compared w/past experience/memory & emotions
III. CONTROL OF SKELETAL MUSCLES (Fig 14.11, p. 481 & Fig. 14.13, p. 485)
A. PRIMARY MOTOR AREA/CORTEX - Anterior to central sulcus
1. PREFRONTAL AREA - Foresight, motivation & aggression, AP initiated
2. PREMOTOR AREA - complex, skilled & learned movements staged
3. PRIMARY MOTOR CORTEX - AP out to control voluntary muscle movements
B. DESCENDING - motor output (Fig. 14.14, p. 487; Tab. 14.4, p. 486 - 487)
- UPPER neurons: -Cortex/cerebellumèspinal cord
-Modulate lower neurons
- LOWER neurons: C.N.S. gray matter (anterior horn)èmuscle
1. DIRECT/PYRAMIDAL - tract through pyramids on medulla oblong.
(Fig. 14.16, p. 488) - CONSCIOUS movements & muscle tone
- DECUSSATE in brainstem or spinal cord
a. CORTICOSPINAL - innervates all but head, especially hands
b. CORTICOBULBAR - innervates head
2. INDIRECT/EXTRAPYRAMIDAL - miss pyramids (Fig. 14.17, p. 489)
- UNCONSCIOUS movements
- DECUSSATE in brainstem
a. RUBROSPINAL – movement coordination
b. VESTIBULOSPINAL - postural muscles
c. RETICULOSPINAL - gross trunk & limb movements
- control of heart & respiration
d. TECTOSPINAL - head & neck response to visual & auditory reflexes
C. FINE TUNING (Fig. 14.15, p. 488)
1. BASAL NUCLEI
2. CEREBELLUM (Fig. 14.18, p. 491)
IV. OTHER BRAIN FUNCTIONS
A. SPEECH - left cortex (Fig. 14.20, p. 495)
1. WERNICKE AREA - sensory speech è ARCUATE FASCICULUS è
a. Comprehension & formulation (pathway to Broca area)
2. BROCA AREA - motor speech
a. Input from Wernicke, output to Premotor area è Primary motor area
è Primary motor cortex è muscles of speech è word spoken!
B. BRAIN WAVES - via EEG (Fig. 14.21, p. 497)
1. ALPHA - low frequency, resting
2. BETA - hi frequency, intense mental activity
3. THETA - é in children, frustration in adults
4. DELTA - é in infants, deep sleep, brain disorders in adults
C. MEMORY (Fig. 14.22, p. 498)
1. WORKING/SENSORY –few secs è 1min, transient RMP changes
a. look up phone number & dial
2. SHORT-TERM - minutesèdays
a. perhaps due to é in synaptic transmissions
3. LONG-TERM – permanent; HIPPOCAMPUS & AMYGDALA
a. change in shape of neuron using CALMODULIN
b. change in synapses/pathways
c. 2 types:
i. EXPLICIT/DECLARATIVE - facts, dates, names & places
-in TEMPORAL lobe-HIPPOCAMPUS & AMYGDALOID
ii. IMPLICIT/PROCEDURAL - skill development: piano playing
- in CEREBELLUM