Spinal Cord Flashcards
Where does the spinal cord end?
L1/L2
Where does the spinal cord start?
Medulla
The brain and spinal cord make up the?
Central nervous system
How many pairs of spinal nerves are in the typical human?
31
12 cranial
What is responsible for controlling the involuntary systems including smooth muscles, glands and internal organs?
Autonomic nervous system
What are the cell types of the nervous system?
Neuroglia, Schwann, neurons=PNS
Oligodendrocytes=CNS
The structural and functional unit of the nervous system?
Neuron
Layer of lipid and protein that sheaths some axons thereby increasing the velocity of impulse transmission from neuron to neuron?
Myelin
Collection of nerve fibers that connects the CNS with somatic muscles and structures in the body?
Peripheral nerves
Origin and termination of the spinal cord?
Medulla/L1/L2
Efferent fiber (motor) cell bodies are found in what?
Ventral horns/anterior horns
Which level of the spinal cord has the most gray matter?
Lumbar
Outermost meningeal layer?
Dura mater
The subarachnoid space contains what?
Cerebral spinal fluid
What anchors the spinal cord to the posterior coccyx?
Filium terminale
What anchors the spinal cord to the dural sac?
Denticulate ligament
Where do cervical spinal nerves exit the intervertebral formina?
Above the named segment
What surrounds a fascicle in a peripheral nerve that protects the nerve against foreign substances?
Perineurium
What accommodates the Cauda Equina?
Lumbar cistern
Do spinal nerves contain both sensory and motor fibers?
Yes
What carries impulses away from the cell? Myelinated or unmyellinated?
Axons
What is the point at which one neuron communicates with another?
Synapse
Gray matter is where in the CNS? White matter is where?
Nucleus, tract (axon, nerve fibers)
PNS has what that are a collection of nerve cell bodies?
Ganglion
Motor?
Efferent–>ventral root to spinal cord
Sensory?
Afferent–>dorsal root (away from the spinal cord)
The CNS
Nucleus is gray matter, collection of neuron cell bodies
Tract is white matter, collection of nerve fibers, connects nuclei
The PNS
Ganglion is a collection of nerve cell bodies, outside of CNS
peripheral nerve is collection of nerve fibers, connect CNS with peripheral structures
SPINAL OR CRANIAL NERVES
Spinal nerves how many?
31
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
What do spinal nerves do?
Carries dorsal (afferent, sensory) and ventral (efferent, motor) from one spinal segment
Dorsal and ventral roots run in subarachnoid space covered in pia mater
What is epineurium?
Encloses bundle of fascicles
Fat, blood vessels, lymphatics
What is Perineurium?
Dense tissue around a fascicle, protection action foreign substances
What is endoneurium?
Delicate sheath surrounding neurolemma and cells
What is the lumbar cistern?
Enlargement of subarachnoid space to accomodate Cauda Equina
What are dermatomes and myotomes?
Areas of skin innervated by a single spinal nerve
Muscle receiving innervation from a single spinal level
What vertebral arteries run from the brain stem to conus medullaris and supply superior cord?
Anterior spinal artery (from vertebral artery) and 2 posterior spinal arteries (from vertebral artery)
What arteries supply most of the cord?
Segmental medullary and radicular arteries
What veins supply the spinal cord?
3 anterior spinal veins, 3 posterior spinal veins
Thoracic region what kind of matter?
Mostly white, lateral horn
Cervical region what kind of matter?
A lot of white because all sensory information goes through this area
Lumbar region what kind of matter?
A lot of gray because of big motions of the limbs
What does the dural sac do?
Dura mater forms a protective covering on top of the spinal cord
Where is the spinal cord thicker?
Cervical and lumbosacral enlargements
Cervical=brachial plexus
Lumbosacral=lumbosacral plexus
What continues after the spinal cord ends?
Fibers
Spinal ganglia consist of?
Dorsal and ventral roots, splits into posterior ramus (sensory and motor) and anterior ramus (sensory and motor)
The somatic nervous system
Voluntary
Skeletal muscle
Sensation=pain pressure touch proprioception
The autonomic nervous system
Involuntary
Smooth muscle
Glands
Internal organs
Glial cells (neuroglia)
Non-excitable cells, cells support insulate, and nourish neurons
Schwann cells
Major glial cell in PNS
Produces myelin protein for myelinated axons
Equilateral to oligodendrocytes in CNS
What is a neuron?
Structural and functional unit of the nervous system, rapid communication
A neuron has what parts and what do they do?
Cell body
Dendrites carry impulses to the cell body
Axons carry impulses away from the cell body and can be myelinated or unmyelinated
Neurotransmitter so facilitate what?
Synapses Acetylcholine Norepinephrine Dopamine GABA
What is the dura mater?
Outermost layer, thick and fibrous, forms spinal dural sac
What is the arachnoid mater?
Middle layer, delicate, encloses CSF (cushion for the cord)
What is the pia mater?
The innermost layer, most delicate, covers spinal nerve roots, continues as filum terminale
What are denticulate ligaments?
Sheets of pia mater that anchor the cord to the dural sac, separates anterior (ventral) and posterior (dorsal) nerve roots–>longitudinal to the cord