Chapter 13 A&P Flashcards
What are the 3 main functions of the spinal cord?
- Process reflexes
- Integrate EPSPs and IPSPs
- Conduct sensory impulses to the brain and motor impulses to effectors
Motor=
Movement
What is the spinal cord protected by? (3)
- Bone (vertebrae)
- Connective tissue (meninges)
- Fluid (cerebrospinal fluid AKA CSF fluid)
What is CSF Fluid?
Cerebrospinal fluid
What is it called when all the vertebra are stacked?
Vertebral Column
The 3 types of meninges:
- Dura Mater
- Arachnoid Mater
- Pia Mater
Which meninge is a thick, strong layer of dense irregular tissue?
Dura mater. (think durable)
Which meninge is a meshwork webbing?
Arachnoid mater (think of the first part of “arachnophobia” Spiders = Webbing)
Which meninge is a thin, delicate tissue?
Pia mater
What are the spaces and meninges from out to in?
Hint: Every Dog Slurps Apple Sauce Playfully
Epidural space
Dura mater
Subdural space
Arachnoid mater
Subarachnoid space
Pia mater
The 3 spaces in the protection of the spinal cord? Out to in
Epidural space, Subdural space, Subarachnoid space
The 3 meninges from out to in:
Dura mater, arachnoid mater, pia mater
In which space does the CFS flow?
Subarachnoid space
What are denticulate ligaments?
Paired extensions of spinal pia mater to help anchor the spinal cord
FYI
What are nerve plexuses?
Interweaving nerves
What are the spinal cord subdivisions?
Cervical, Thoracic, Lumbar, and Sacral
At what vertebrae does the spinal cord end?
L1 or L2
What is at the end of the spinal cord?
Conus Medullaris
What is cauda equina Latin for?
Horse’s Tail
What is the cauda equina?
Extension of nerve root
What is the filum terminale?
Thin strand of pia mater that helps to anchor conus medullaris to coccyx.
FYI: Conus medullaris, Cauda equina, filum terminale
What are the three layers of the nerve?
outer to inner
Epineurium- outer layer
Perineurium- middle layer around fascicle
Endoneurium- inner layer around each axon
What are “mixed” nerves?
Nerves that contain both sensory and motor axons
How many spinal nerve pairs do you have?
31 pairs
How many cervical nerves do you have?
8 (C1-C8)
How many thoracic nerves do you have?
12 (T1-T12)
How many lumbar nerves do you have?
5 (L1-L5)
How many sacral nerves do you have?
5 (S1-S5)
How many coccygeal nerves do you have?
1 (Co1)
Why is gray matter gray?
It is unmyelinated
What shape does gray matter resemble?
An “H”
T or F: White matter is external to the gray matter.
True
Which matter uses “horns”?
Gray matter
Which matter uses “columns”?
White matter
What is white matter composed of?
Myelinated axons tracts going to and from the brain
FYI: Gray and white matter drawn diagram
FYI: Transverse section of lumbar spinal cord
What is the anterior root known as?
Ventral root
What kind of axons does the anterior/ventral root contain?
Only motor axons
What is another name for posterior root?
Dorsal root
What kind of axons does the posterior/dorsal root contain?
Only sensory axons
How do spinal nerves become mixed nerves?
The anterior and posterior root unite within the intervertebral foramen to become the spinal nerves.
FYI
FYI: Very important to know!!
FYI: Drawn diagram of sensory and motor root
What kind of pathways are ascending?
Sensory. Signals from sensory receptors ascending to the brain.
What kind of pathways are descending pathways?
Motor. Signals from brain to muscles or glands.
What does decussate mean?
A cross over from one side of the body to the other side.
Relationship to opposite side:
(90%)
Contralateral
Relationship to same side:
Ipsilateral
What are dermatomes?
A specific segment of skin supplied by a single spinal nerve
What are 3 things that dermatomes help with?
- Divides skin into segments (dermatome map)
- Can indicate potential damage to one or more spinal nerves
- Involved in referred visceral pain
FYI: Dermatome map
What does the chickenpox virus invade?
Dorsal root ganglion and remains latent until adulthood
What causes rash and blisters along the dermatome with burning and tingling pain?
Shingles
What is nerve plexus?
Network of interweaving spinal nerves
Main plexuses:
Cervical
Brachial
Lumbar
Sacral
FYI: Cervical Plexus
FYI: Brachial Plexus
What does axillary refer to?
Armpit
FYI: Lumbar Plexus
FYI: Sacral Plexus
Sciatic nerve is the sciatic nerve UNTIL IT…
Splits
What are reflexes?
Rapid, pre-programmed, involuntary reactions of muscles or glands
What do reflexes help maintain?
Homeostasis
What are the 5 steps of the reflex arc?
- Sensory receptor
- Sensory neuron
- Integrating center
- Motor neuron
- Effectors
What does the motor neuron transmit?
A nerve signal to an effector
FYI: Reflex arc
What does a hypoactive reflex mean?
Reflex is diminished or absent.
May indicate damage to segment of spinal cord, neuromuscular junction, or muscle disease.
What does a hyperactive reflex mean?
Abnormally strong response.
May indicate damage in brain or spinal cord.
What is Clonus?
Rhythmic oscillations between flexion and extension.
- May especially indicate damage.
What are 4 types of traumatic injuries to the spinal cord?
Monoplegia- loss of function to one limb.
Paraplegia- loss of function to legs/lower body.
Hemiplegia- loss of function of one side of the body. (right or left)
Quadriplegia- loss of function of all four limbs.
What is a lumbar puncture?
Spinal tap
What is a lumbar puncture for?
Used to analyze CSF to determine infection or disorder of CNS.
What levels are lumbar puncture done at?
L3 - L4 or L4 - L5
Remember that the spinal cord ends at L1-L2
What does EPSP stand for?
Excitatory Postsynaptic Potential
What does IPSP stand for?
Inhibitory Postsynaptic Potential
