Anp of spinal nerves for uitm puncak alam

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1. SPINAL CORD
AND SPINAL NERVE
FARRAH SHAFEERA @ ANN IBRAHIM
[email protected]
03-32584362
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2. SPINAL NERVES
n31 pairs; mixed nerves.
nCervical (C1-C8), thoracic (T1-T12), lumbar
(L1-L5), sacral (S1-S5) and coccygeal.
Connective tissue coverings of spinal nerves:
nEpineurium, perineurium and endoneurium:
nFascicles
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3. Spinal Nerves:
31 Pair
Cervical: 8
Thoracic: 12
Lumbar: 5
Sacral: 5
8 + 12 + 5 + 5 + 1 = 31
Coccygeal: 1
C1-C7 Emerge above the vertebra
for which they are named
C8 Emerges between C7 and T1
Thoracic, Lumbar, Sacral and
Coccygeal spinal nerves emerge
below the vertebra for which they are
named
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4. Spinal Nerves
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5. Spinal Nerves®Nerve Plexus
nDorsal and Ventral roots exit the spinal
cord and join together to make a spinal
nerve
nThe spinal nerve then splits into dorsal and
ventral rami (ramus)
qSome ventral rami give off branches to the
sympathetic ganglion
qThe other ventral rami mix and match to make
up nerve plexuses
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6. Ventral Rami
nThe Dorsal Root only contains sensory
neurons going toward the spinal cord
nThe Ventral Root only contains motor
neurons going out of the spinal cord
nVentral Rami contain BOTH sensory
and motor neurons
nAs the spinal nerves, rami and plexus are
crisscrossing, everything gets mixed
around.
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7. Spinal Cord
Dorsal
Ramus
(mixed)
Ventral
Ramus
(mixed)
Rami Communicantes
(White ramus + Gray Ramus)
Nerve Plexuses
Ventral Roots (Motor)
Spinal Nerve
(this is where sensory and motor mix)
Dorsal Roots (Sensory)
Sympathetic gangliaannshafeera@FSKUiTM

8. annshafeera@FSKUiTM

9. Spinal Nerves
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10. Distribution of Spinal Nerves
nSpinal nerves branch and their braches are called rami:
Posterior (dorsal) ramus
Anterior (ventral) ramus
nPlexuses: a network of axons
Anterior rami except T2-T12 form plexuses.
Axonfromtheanteriorramiofspinalnerveaxceptforthethoracic
nerveT2-T12donotgodirectlytothebodystructurestheysupply
INSTEADànetworkonbothleftandrightsidesofthebodybyjoining
withvariousnumberofaxonsfromanteriorramiofadjacentverves)
Cervicalp,brachialplexus,lumbarp,sacralp.)
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11. 1.Cervical Plexus
nFormed by the anterior
rami of C1-C5.
nPhrenic nerves-
important nerves from
the cervical plexuses.
nFormed by the anterior
rami of C1-C5.
nPhrenic nerves-
important nerves from
the cervical plexuses.
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12. nFormed by the anterior
rami of C5-C8 & T1.
nSupplies the shoulders
and upper limbs.
nRoots → trunks →
divisions → cords →
nerves.
n5 important nerves
arise from brachial is
2. Brachial plexus
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13. Brachial plexus continued
Important nerves that
arise from the brachial
plexuses are
nAxillary nerve
nMusculocutaneous
nerve
nRadial nerve
nMedian nerve
nUlnar nerve
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14. Injuries to the Brachial Plexus
nErb-Duchenne palsy
(waiter’s tip)-loss of
sensation along the
lateral side of the arm.
nWrist drop-inability to
extend the wrist and
fingers.
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15. 3. Lumbar Plexus
nFormed by the anterior
rami of L1-L4.
nSupplies the
anterolateral abdominal
wall, external genitals,
and part of the lower
limbs.
nFemoral nerves,
obturator nerves.
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16. 5. Sacral Plexus
nFormed by the anterior rami
of L4-L5 and S1-S4.
nSupplies the buttocks,
perineum, and lower limbs.
nGives rise to the largest
nerve in the body-the
sciatic nerve.
nSN= It begins in the lower
back and runs through the
buttock and down the lower
limb. It is the longest and
widest single nerve in the
human body.
nThe sciatic supplies nearly
the whole of the skin of the
leg, the muscles of the back
of the thigh, and those of
the leg and foot.annshafeera@FSKUiTM

17. Distribution of Nerves from the Lumbar and
Sacral Plexuses
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18. 6. Coccygeal Plexus
nFormed by the
anterior rami of S4-
S5 and the
coccygeal nerves.
nSupplies a small
area of skin in the
coccygeal region.
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19. Reflex
nA reflex is an automatic, sudden, involuntary
response to a stimulus.
nWhen the integration takes place in the spinal
cord, the reflex is a spinal reflex.
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20. Reflex Arc
nThe pathway followed by nerve impulses that
produce a reflex is a reflex arc.
nA reflex arc includes:
a. sensory receptor
b. sensory neuron
c. integrating center
d. motor neuron
e. effector
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21. 1SENSORY RECEPTOR
(responds to a stimulus
by producing a generator
or receptor potential)
1SENSORY NEURON
(axon conducts impulses from
receptor to integrating center)
SENSORY RECEPTOR
(responds to a stimulus
by producing a generator
or receptor potential)
2 1SENSORY NEURON
(axon conducts impulses from
receptor to integrating center)
SENSORY RECEPTOR
(responds to a stimulus
by producing a generator
or receptor potential)
INTEGRATING CENTER
(one or more regions within the CNS
that relay impulses from sensory to
motor neurons)
Interneuron
2
3
1SENSORY NEURON
(axon conducts impulses from
receptor to integrating center)
SENSORY RECEPTOR
(responds to a stimulus
by producing a generator
or receptor potential)
INTEGRATING CENTER
(one or more regions within the CNS
that relay impulses from sensory to
motor neurons)MOTOR NEURON
(axon conducts impulses from
integrating center to effector)
Interneuron
2
3
4
1SENSORY NEURON
(axon conducts impulses from
receptor to integrating center)
SENSORY RECEPTOR
(responds to a stimulus
by producing a generator
or receptor potential)
INTEGRATING CENTER
(one or more regions within the CNS
that relay impulses from sensory to
motor neurons)MOTOR NEURON
(axon conducts impulses from
integrating center to effector)
EFFECTOR
(muscle or gland that
responds to motor
nerve impulses)
Interneuron
2
3
4 5
Reflex Arc
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22. The Stretch Reflex
nCauses contraction of a skeletal muscle in
response to stretching of the muscle.
nMonosynaptic reflex.
nPatellar or knee-jerk reflex:Stretching of a
muscle →activation of muscle spindles
→sensory neuron →spinal cord→motor
neuron → muscle contraction.
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23. Stretch Reflex
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24. 1Stretching stimulates
SENSORY RECEPTOR
(muscle spindle)
Antagonisticmuscles relax
1Stretching stimulates
SENSORY RECEPTOR
(muscle spindle)
SENSORYNEURONexcited
To brain
SpinalNerve
+
+
21Stretching stimulates
SENSORY RECEPTOR
(muscle spindle)
SENSORYNEURONexcited
Within INTEGRATINGCENTER (spinal cord),sensory neuron activatesmotor neuron
Inhibitoryinterneuron
To brain
SpinalNerve
+
–
+
2
3
1Stretching stimulates
SENSORY RECEPTOR
(muscle spindle)
SENSORYNEURONexcited
MOTORNEURONexcited
Antagonisticmuscles relax
Motor neuron toantagonistic musclesis inhibited
Within INTEGRATINGCENTER (spinal cord),sensory neuron activatesmotor neuron
Inhibitoryinterneuron
To brain
SpinalNerve
+
–
+
+
2
3
4
1Stretching stimulates
SENSORY RECEPTOR
(muscle spindle)
SENSORYNEURONexcited
MOTORNEURONexcited
EFFECTOR(same muscle)contracts andrelieves thestretching
Antagonisticmuscles relax
Motor neuron toantagonistic musclesis inhibited
Within INTEGRATINGCENTER (spinal cord),sensory neuron activatesmotor neuron
Inhibitoryinterneuron
To brain
SpinalNerve
+
–
+
+
2
3
4
5
annshafeera@FSKUiTM

25. The Tendon Reflex
nPolysynaptic reflex.
nControl muscle tension by causing muscle relaxation
when muscle tension is great.
nA tendon(or sinew) is a tough band of fibrous
connective tissuethat usually connects muscleto bone
and is capable of withstanding tension
n↑ Tension applied to the tendon → tendon organ
stimulation → nerve impulse → spinal cord →motor
neuron causes muscle relaxation and relieves tension.
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26. Tendon Reflex
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27. 1
Increased tensionstimulatesSENSORYRECEPTOR (tendon)
1
Spinalnerve
SENSORYNEURONexcited
To brain
Increased tensionstimulatesSENSORYRECEPTOR (tendon)
2 ++
1
Within INTEGRATINGCENTER (spinal cord),sensory neuron activatesinhibitory interneuron
Excitatoryinterneuron
Spinalnerve
Inhibitoryinterneuron
SENSORYNEURONexcited
+
To brain
Increased tensionstimulatesSENSORYRECEPTOR (tendon)
++2
3
–
+1
–
Within INTEGRATINGCENTER (spinal cord),sensory neuron activatesinhibitory interneuron
Excitatoryinterneuron
Antagonisticmusclescontract
Spinalnerve
MOTOR NEURONinhibited
Inhibitoryinterneuron
SENSORYNEURONexcited
+
To brain
Increased tensionstimulatesSENSORYRECEPTOR (tendon)
Motor neuron toantagonisticmuscles is excited
+
+
+
+2
3
4
1
–
EFFECTOR(muscle attachedto same tendon)relaxes andrelieves excess
tension
Within INTEGRATINGCENTER (spinal cord),sensory neuron activatesinhibitory interneuron
Excitatoryinterneuron
Antagonisticmusclescontract
Spinalnerve
MOTOR NEURONinhibited
Inhibitoryinterneuron
SENSORYNEURONexcited
+
To brain
Increased tensionstimulatesSENSORYRECEPTOR (tendon)
Motor neuron toantagonisticmuscles is excited
+
+
+2
3
45
+
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28. Flexor (Withdrawal) Reflex
nPolysynaptic reflex
nStepping on a tack (stimulus) → nerve
impulse → activation of the interneuron →
activation of the motor neuron →muscle
contraction →withdrawal of the leg.
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29. Flexor (Withdrawal) Reflex
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30. 1Stepping on tack stimulatesSENSORY RECEPTOR (dendritesof pain-sensitive neuron)
1
+
Stepping on tack stimulatesSENSORY RECEPTOR (dendritesof pain-sensitive neuron)
SENSORYNEURONexcited
+
2
1
+
Stepping on tack stimulatesSENSORY RECEPTOR (dendritesof pain-sensitive neuron)
SENSORYNEURONexcited
Within INTEGRATING CENTER(spinal cord), sensory neuronactivates interneurons in several
spinal cord segments
Ascendinginterneuron
Interneuron
Descendinginterneuron
Spinalnerve
+
+
+
+
+
+
2
3
1
+
Stepping on tack stimulatesSENSORY RECEPTOR (dendritesof pain-sensitive neuron)
SENSORYNEURONexcited
MOTORNEURONSexcited
MOTORNEURONexcited
Within INTEGRATING CENTER(spinal cord), sensory neuronactivates interneurons in several
spinal cord segments
Ascendinginterneuron
Interneuron
Descendinginterneuron
Spinalnerve
+
+
+
+
+
+
+
+
+
2
3
4
4
1
+
Stepping on tack stimulatesSENSORY RECEPTOR (dendritesof pain-sensitive neuron)
SENSORYNEURONexcited
MOTORNEURONSexcited
MOTORNEURONexcited
EFFECTORS(flexor muscles)contract and
withdraw leg
Within INTEGRATING CENTER(spinal cord), sensory neuronactivates interneurons in several
spinal cord segments
Ascendinginterneuron
Interneuron
Descendinginterneuron
Spinalnerve
+
+
+
+
+
+
+
+
+
2
3
4
5
4
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31. Crossed Extensor Reflex
nAn example of this is when a person steps on a nail, the leg
that is stepping on the nail pulls away, while the other leg
takes the weight of the wholebody
nThe crossed extensor reflex is contralateral, meaning the reflex
occurs on the opposite side of the body from the stimulus.
nContraction of muscles that extend joints in the opposite limb in
response to a painful stimulus.
nStepping on a tack (stimulus) → nerve impulse →activation of
several interneurons → activation of the motor neurons → muscle
contraction causing flexion of the leg stepping on a tack & extension
on the opposite side.
nPolysynaptic reflex.
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32. Crossed Extensor Reflex
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33. 1
Withdrawal of right leg
(flexor reflex)
Stepping on a tack
stimulates SENSORY
RECEPTOR (dendrites of
pain-sensitive neuron) in
rightfoot
1
SENSORY
NEURON
excited
Withdrawal of right leg
(flexor reflex)
Stepping on a tack
stimulates SENSORY
RECEPTOR (dendrites of
pain-sensitive neuron) in
rightfoot
2
+
1
+
Ascending
interneurons
SENSORY
NEURON
excited
Spinal
nerve
Within INTEGRATING CENTER
(spinal cord), sensory neuron
activates several interneurons
Descending
interneurons
Withdrawal of right leg
(flexor reflex)
Stepping on a tack
stimulates SENSORY
RECEPTOR (dendrites of
pain-sensitive neuron) in
rightfoot
+
++
2
3
+
++
++
++
Interneurons
from other side
1
+
Ascending
interneurons
SENSORY
NEURON
excited
Spinal
nerve
Within INTEGRATING CENTER
(spinal cord), sensory neuron
activates several interneurons
MOTOR
NEURONS
excited
Descending
interneurons
Withdrawal of right leg
(flexor reflex)
Stepping on a tack
stimulates SENSORY
RECEPTOR (dendrites of
pain-sensitive neuron) in
rightfoot Extension of left leg
(crossed extensor reflex)
MOTOR
NEURONS
excited
+
++
2
3
4
4
+
++
++
++
+
+
+
Interneurons
from other side
1
+
Ascending
interneuronsEFFECTORS
(extensor muscles)
contract, and extend
leftleg
SENSORY
NEURON
excited
Spinal
nerve
Within INTEGRATING CENTER
(spinal cord), sensory neuron
activates several interneurons
MOTOR
NEURONS
excited
Descending
interneurons
Withdrawal of right leg
(flexor reflex)
Flexor muscles
contract and with-
drawrightleg
Stepping on a tack
stimulates SENSORY
RECEPTOR (dendrites of
pain-sensitive neuron) in
rightfoot Extension of left leg
(crossed extensor reflex)
MOTOR
NEURONS
excited
+
++
2
3
4
4
5
+
++
++
++
+
+
+
Interneurons
from other side
+
+
+
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34. nMedian nerve palsy-numbness, tingling and
pain in the palm and fingers.
nUlnar nerve palsy-inability to abduct or
adduct fingers
nWinged scapula-the arm cannot be abducted
beyond the horizontal position.
Copyright 2009, John Wiley & Sons, Inc.annshafeera@FSKUiTM