Download Spinal Cord PPT

Divisions of the Nervous System
Spinal Cord, Spinal
Nerves, & Reflexes Lab
Anatomy and Physiology I
Mary Catherine Flath, Ph.D.
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CENTRAL NERVOUS SYSTEM
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PERIPHERAL NERVOUS SYSTEM
(Brain & Spinal Cord; Interneurons)
(Cranial and Spinal Nerves
 SENSORY/AFFERENT NEURONS (INPUT)
 MOTOR/EFFERENT NEURONS (OUTPUT)
 SOMATIC (Effectors: skeletal muscle;
conscious)
 AUTONOMIC (Effectors: smooth muscle,
cardiac muscle, glands; unconscious)
 PARASYMPATHETIC (maintains
homeostasis; acetylcholine)
 SYMPATHETIC (Fight or Flight;
norepinephrine)
Copyright 2016 Dr. Mary Cat Flath
BONES OF THE VERTEBRAL COLUMN PROTECT THE SPINAL CORD
Spinal Cord Protection
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BONES
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MENINGES
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VERTEBRAL COLUMN
DURA MATER
ARACHNOID MATER
PIA MATER
CEREBROSPINAL FLUID
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Cervical Spine
Cervical Spine
The
Vertebral
Column:
Spine
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
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Spinal Cord Protection
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BONES
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VERTEBRAL COLUMN
MENINGES
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Meninges of the
Spinal Cord
DURA MATER
ARACHNOID MATER
PIA MATER
The dura mater of the spinal cord
is not directly attached to the bone
of the vertebrae
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CEREBROSPINAL FLUID
Copyright 2016 Dr. Mary Cat Flath
An epidural space is formed
 This space is filled with loose
connective tissue and fat
 Provides a second protective
cushion
Copyright 2016 Dr. Mary Cat Flath
Spinal Cord Protection
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BONES
MENINGES
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CEREBROSPINAL FLUID
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Within spinal cord in central canal
Around spinal cord in subarachnoid
space
We will learn circulation pathway for
cerebrospinal fluid later
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Divisions of the Nervous System

CENTRAL NERVOUS SYSTEM

PERIPHERAL NERVOUS SYSTEM
(Brain & Spinal Cord; Interneurons)
(Cranial and Spinal Nerves
 SENSORY/AFFERENT NEURONS (INPUT)
 MOTOR/EFFERENT NEURONS (OUTPUT)
 SOMATIC (Effectors: skeletal muscle;
conscious)
 AUTONOMIC (Effectors: smooth muscle,
cardiac muscle, glands; unconscious)
 PARASYMPATHETIC (maintains
homeostasis; acetylcholine)
 SYMPATHETIC (Fight or Flight;
norepinephrine)
Copyright 2016 Dr. Mary Cat Flath
Spinal Cord Structure
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Begins at foramen magnum
Ends between L1 and L2 at point called
the conus medullaris
31 segments named for vertebrae
 8 cervical
 12 thoracic
 5 lumbar
 5 sacral
 1 coccygeal
Copyright 2016 Dr. Mary Cat Flath
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Spinal Cord Structure
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About thickness of thumb
Enlarged cervical and lumbar regions
31 pairs of spinal nerves (PNS) arise
from each of the 31 segments
Spinal nerves below L2 form Cauda
Equina
Distal remnant of pia mater terminates
as filum terminale
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
SPINAL CORD CROSS-SECTION
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
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Spinal Cord Model
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Copyright 2016 Dr. Mary Cat Flath
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(cross-section)
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Copyright 2016 Dr. Mary Cat Flath
Key to Spinal Cord Model
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1. Posterior White
Column
2. Lateral White
Column
3. Anterior White
Column
5. Posterior Gray Horn
6. Lateral Gray Horn
7. Anterior Gray Horn
8. Gray Commissure
9. Central Canal
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10. Posterior Median
Sulcus
14. Anterior Median
Fissure
23. Dorsal Root
24. Dorsal Root
Ganglion
25. Ventral Root
26. Spinal Nerve
(mixed)
28. Ventral Ramus
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Key to Spinal Cord Photo
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Copyright 2016 Dr. Mary Cat Flath
1. Posterior White
Column
2. Lateral White
Column
3. Anterior White
Column
4. Posterior Gray Horn
5. Lateral Gray Horn
6. Anterior Gray Horn
7. Gray Commissure
8. Central Canal
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9. Posterior Median
Sulcus
10. Anterior Median
Fissure
11. Dorsal Root
Ganglion
12. Dorsal Root
13. Ventral Root
14. Spinal Nerve
(mixed)/Ventral
Ramus
Copyright 2016 Dr. Mary Cat Flath
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Structures on either side
of the Spinal Cord (PNS)
1___________________
2___________________
3___________________
4___________________
5___________________
6___________________
7___________________
8___________________
9___________________
10__________________
11__________________
12__________________
13__________________
14__________________
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Spinal nerves are formed from the
fusion of a
 Dorsal root
 Cell bodies (of sensory
neurons) form enlarged Dorsal
Root Ganglion
 Ventral root
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Spinal Cord Functions
Tracts of the Spinal Cord
• conduit for nerve impulses to & from brain
•White Matter houses Nerve Tracts
• Ascending Tracts
• Sensory impulses are carried in Posterior
White Columns
• Descending Tracts
• Motor impulses are carried in Anterior
White Columns
• center for spinal reflexes
• Gray Matter
11-8
Copyright 2016 Dr. Mary Cat Flath
Spinal Cord Model
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1
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tracts conduct sensory
impulses to the brain
•Posterior White Columns
• Descending tracts conduct motor
impulses from the brain to motor
neurons reaching muscles and
glands
•Anterior White Columns
Copyright 2016 Dr. Mary Cat Flath
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Key to Spinal Cord Model
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Copyright 2016 Dr. Mary Cat Flath
11-13
(cross-section)
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• Ascending
1. Posterior White
Column
2. Lateral White
Column
3. Anterior White
Column
5. Posterior Gray Horn
6. Lateral Gray Horn
7. Anterior Gray Horn
8. Gray Commissure
9. Central Canal
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10. Posterior Median
Sulcus
14. Anterior Median
Fissure
23. Dorsal Root
24. Dorsal Root
Ganglion
25. Ventral Root
26. Spinal Nerve
(mixed)
28. Ventral Ramus
Copyright 2016 Dr. Mary Cat Flath
5
Spinal Cord Functions
• conduit for nerve impulses to & from brain
•White Matter houses Nerve Tracts
• Ascending Tracts
• Sensory impulses are carried in Posterior
White Columns
• Descending Tracts
• Motor impulses are carried in Anterior
White Columns
• center for spinal reflexes
• Gray Matter
Copyright 2016 Dr. Mary Cat Flath
11-8
Copyright 2016 Dr. Mary Cat Flath
Reflex Arcs – Simplest demonstration
of nerve pathways
Reflexes – automatic, subconscious responses to stimuli
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Withdrawal Reflex
Knee-jerk Reflex
• helps maintain posture
Copyright 2016 Dr. Mary Cat Flath
11-9
• protective
11-10
Copyright 2016 Dr. Mary Cat Flath
11-11
6
Take a few minutes
And test your
Patellar reflex &
Pupillary reflex.
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Divisions of the Nervous System

CENTRAL NERVOUS SYSTEM

PERIPHERAL NERVOUS SYSTEM
(Brain & Spinal Cord; Interneurons)
(Cranial and Spinal Nerves
 SENSORY/AFFERENT NEURONS (INPUT)
 MOTOR/EFFERENT NEURONS (OUTPUT)
 SOMATIC (Effectors: skeletal muscle;
conscious)
 AUTONOMIC (Effectors: smooth muscle,
cardiac muscle, glands; unconscious)
 PARASYMPATHETIC (maintains
homeostasis; acetylcholine)
 SYMPATHETIC (Fight or Flight;
norepinephrine)
Copyright 2016 Dr. Mary Cat Flath
Peripheral Nervous System
Definition of a nerve:
A bundle of myelinated axons in the
PNS
•Cranial nerves arising from the brain
• 12 pairs
• Spinal nerves arising from the spinal cord
• 31 pairs
• All mixed
11-42
Copyright 2016 Dr. Mary Cat Flath
Spinal Nerves
Mixed nerves
• 31 pairs
• 8 cervical (C1 to C8)
•
• 12 thoracic (T1 to T12)
• 5 lumbar (L1 to L5)
• 5 sacral (S1 to S5)
• 1 coccygeal (Co)
Copyright 2016 Dr. Mary Cat Flath
11-54
Copyright 2016 Dr. Mary Cat Flath
7
Spinal Cord Model
Spinal Nerve Structure
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2
Dorsal root
• axons of sensory neurons from the dorsal root
ganglion
Dorsal root ganglion
• cell bodies of sensory neurons
Ventral root
• axons of motor neurons whose cell bodies are in
spinal cord
Spinal nerve
• union of ventral root and dorsal root
Copyright 2016 Dr. Mary Cat Flath
11-55
23 24
26/28
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3
5
(cross-section)
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14
Copyright 2016 Dr. Mary Cat Flath
Nerve Plexus
Nerve plexus – complex networks formed by anterior
branches (i.e. ventral rami) of spinal nerves; fibers of
various spinal nerves are sorted and recombined
Cervical Plexus
C1-C4
Brachial Plexus
C5-T1
Lumbosacral Plexus
T12-S5
Copyright 2016 Dr. Mary Cat Flath
Photo from NHC A&P Help I
http://science.nhmccd.edu/biol/ap
1lab.htm
Copyright 2016 Dr. Mary Cat Flath
11-57
Copyright 2016 Dr. Mary Cat Flath
Divisions of the Nervous System

CENTRAL NERVOUS SYSTEM

PERIPHERAL NERVOUS SYSTEM
(Brain & Spinal Cord; Interneurons)
(Cranial and Spinal Nerves
 SENSORY/AFFERENT NEURONS (INPUT)
 MOTOR/EFFERENT NEURONS (OUTPUT)
 SOMATIC (Effectors: skeletal muscle;
conscious)
 AUTONOMIC (Effectors: smooth muscle,
cardiac muscle, glands; unconscious)
 PARASYMPATHETIC (maintains
homeostasis; acetylcholine)
 SYMPATHETIC (Fight or Flight;
norepinephrine)
Copyright 2016 Dr. Mary Cat Flath
8
Name the structure
10
1
Let’s take practice quiz.
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23 24
26/28
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3
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6
25
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14
Copyright 2016 Dr. Mary Cat Flath
Key to Spinal Cord Model








1. Posterior White
Column
2. Lateral White
Column
3. Anterior White
Column
5. Posterior Gray Horn
6. Lateral Gray Horn
7. Anterior Gray Horn
8. Gray Commissure
9. Central Canal
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





10. Posterior Median
Sulcus
14. Anterior Median
Fissure
23. Dorsal Root
24. Dorsal Root
Ganglion
25. Ventral Root
26. Spinal Nerve
(mixed)
28. Ventral Ramus
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
9
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
How many
bones per
region?
How many
spinal
nerves per
region?
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Spinal Nerves
mixed nerves
• 31 pairs
• 8 cervical (C1 to C8)
•
• 12 thoracic (T1 to T12)
• 5 lumbar (L1 to L5)
• 5 sacral (S1 to S5)
• 1 coccygeal (Co)
Copyright 2016 Dr. Mary Cat Flath
11-54
Copyright 2016 Dr. Mary Cat Flath
10
Photo from NHC A&P Help I
http://science.nhmccd.edu/biol
/ap1lab.htm
Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
Photo from NHC A&P Help I
http://science.nhmccd.edu/biol/ap
1lab.htm
Name the components of a
reflex arc.
Copyright 2016 Dr. Mary Cat Flath
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Copyright 2016 Dr. Mary Cat Flath
Copyright 2016 Dr. Mary Cat Flath
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Key to Spinal Cord Photo
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
1. Posterior White
Column
2. Lateral White
Column
3. Anterior White
Column
4. Posterior Gray Horn
5. Lateral Gray Horn
6. Anterior Gray Horn
7. Gray Commissure
8. Central Canal
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9. Posterior Median
Sulcus
10. Anterior Median
Fissure
11. Dorsal Root
Ganglion
12. Dorsal Root
13. Ventral Root
14. Spinal Nerve
(mixed)/Ventral
Ramus
Good luck studying for
next week’s quiz!
Copyright 2016 Dr. Mary Cat Flath
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