-
Spinal Cord
Position
- Foramen Magnum L1 – L2
- SkullL 1-2
- -Spinal Cord growth stops at 4years old
- -Vertebral column grows until full height reached
- - About 18 inches long
- -End of cord = conus medullaris
-
Spinal Cord
General
- 1.Cauda Equina (“horse’s tail”)
- -Spinal nerves are pulled with growing vertebrae.
- -Exit sacral foramina.
- 2. Filum Terminale tethers conusmedullaris to the sacral vertebrae, via coccygealligament.a.
- -Prevents superior movement.
- 3. Laterally, denticulate ligament anchors cord
- -Composed of Pia Mater attached to Arachnoid
- -Prevents lateral movement
-
Lumbar Puncture
- 1. Done between L3 & L4, or L4 & L5.
- 2. Reduce chance of spinal cord injury because it is BELOW tip of cord.
- 3. Sample of CSF taken from Sub-arachnoid space
-
Epidural
- 1. Catheter inserted intoepidural space.
- 2. Left in place with continuous infused analgesic.
- 3. Long-term pain relief
-
Spinal Cord
- carries SENSORY impulses up towards brain,
- and MOTOR impulses down from the brain (TRACTS).
Motor/Efferent (Descending)
Sensory/Afferent(Ascending) --
Can act as an integration center!
-
Reflex Arc
1. Sensory input received
2. Signal travels down a sensory neuron
3. Info integrated by interneuron (NOT BRAIN)
4. Motor signal sent out by motor neuron
5. Motor signal travels to EFFECTOR and appropriate reaction occurs
-
spinal Cord
Gray Matter
- 1. Central in the spinal cord.
- 2. Contains Mostly cell bodies & unmyelinatedinterneurons.
- 3. Central Canal (CSF) surrounded by gray commissure.a. Neuron crossover site.
- 3. Arranged in 3 Horns
- a. Posterior (Dorsal) Horn
- b. Anterior (Ventral) Horn
- c. Lateral Horn
-
D.A.V.E
- Arranged in 3 Horns
- a. Posterior (Dorsal) Horn
- - Somatic & VisceralSensory fibers
- b. Lateral Horn
- - Visceral motor
- c. Anterior (Ventral) Horn
- - Somatic motor cell bodies
- Grey commisures
- - axons of interneurons
-
Spinal Cord
White Matter
- 1. Peripheral in the spinal cord.
- 2. Contains Myelinated & unmyelinated axon.
- 3. Arranged in 3 Columns (Funiculi)
- a. Lateral Column
- b. Anterior Column
- c. Posterior Column
- 4. Each column contains “Tracts”:
- a. Axons that share structural or functional similarities.
- b. Tracts may travel in 3 directions…
-
Spinal Nerves
- 1. Branch from spinal cord.
- 2. 31 pairs.
- 3. Carries BOTH sensory & motor neurons
- 4. Formed through fusion of ventral & dorsal ROOTS.
- 5. Innervates (connect with) muscles, skin, and glands of neck & body
- 6. Nerve splits to form:
- a. Dorsal Ramus
- 1) Innervating back!
- 2) T1-L2, only
- b. Ventral Ramus
- 1) Innervating sides & front!
- 2) Includes all plexuses!
-
Lumbar vs. Sacral Plexus
- • Lumbar leads anterior
- • Sacral leads posterior
-
Spinal Nerves
Nerve Plexuses (4)
- a. Nerve Network.
- b. All from ventral rami.
- c. Thoracic nerves don’t form plexus
-
Spinal Nerves
Dermatomes
- a. The area of the body that is monitored by a specific sensory nerve.
- b. Map of Somatic Sensory Innervation.
- c. Doctors use this to determine damage to nerves.
-
Receptor Types
- 1. Mechanoreceptor
- a. Detect mechanical or physical change.
- b. Touch, vibration, pressure, stretch.
c. PROPRIOCEPTOR• detect position of body in space.
-
Receptor Types
Thermoreceptor
Detects heat or cold within range.
-
Receptor Types
Chemoreceptor
a. Detects chemical change.
b. Molecules dissolved in fluid
.c. Taste, smell, etc
-
Receptor Types
Photoreceptors
Detect photons (light).
-
Receptor Types
Nociceptors.
Detects tissue damage and pain.
|
|