Topic 4: The Spinal Cord Flashcards
The ______ ____ links the brain and the rest of the body.
Spinal Cord
The spinal cord extends from the _______ ______ to vertebrae L1-2.
Foramen magnum
The ______ _________ is the cone-shaped end of the spinal cord.
conus medullaris
The lumbar and sacral spinal nerves exit from the conus medullaris to form the _____ ______.
cauda equina (“horse’s tail”).
T/F: The cauda equina is part of the PNS.
True
The spinal cord segments for S1-S5 are level with T__-L_ vertebrae.
T12-L1 vertebra
In a Spinal Tap, a needle is inserted between two lumbar vertebrae below the _____ ________. A sample of CSF is removed from the subarachnoid space, the area between the arachnoid membrane and the pia mater.
conus medullaris
__________ (“without sensation”) is a state of controlled, temporary loss of sensation that is induced for medical purposes.
Anesthesia
A spinal cord segment is the area of the spinal cord from which a pair of ______ and ______ roots attach. Within the cord itself there are no distinct boundaries between these segments.
Dorsal and ventral roots
The anterior and posterior nerve roots combine on each side to form the spinal nerves as they exit the vertebral canal through the _________ _______.
Intervertebral foramina
The ______ root carries afferent information.
The ______ root carries efferent signals from the SC to muscles and viscera.
The dorsal (posterior) root carries afferent information. The ventral (anterior) root carries efferent signals from the SC to muscles and viscera.
A _________ is an area of skin supplied by peripheral nerve fibers (axons) originating from a single dorsal root ganglion (DRG) .
Dermatome
Because sensory information from the body is relayed to the CNS through the dorsal roots, the axons originating from the DRG cells are classified as _______ ______ ________, and the dorsal root’s neurons are the first order (1°) sensory neuron.
Primary sensory afferents
T/F: The amount of grey and white matter is the same at each SC level.
False: The amount of grey and white matter varies at different SC levels.
The ____ matter consists of the cell bodies of neurons, neuroglia, “mostly” unmyelinated axons, and the dendrites of interneurons and motor neurons.
Gray
Unipolar axons entering the dorsal horn usually synapse with hundreds of ___________.
Interneurons
All sympathetic nervous system outflow is via the T_-L_ cell bodies in the lateral horn. The Sympathetic NS is therefore referred to as the thoracolumbar division of the ANS.
T1-L2
The Parasympathetic NS is also known as the _____ _____ division of the ANS.
Cranial sacral
Most sensory tract names begin with “spino-, indicating they begin in the spinal cord. Their name will end with the part of the brain where the tract leads. For example, the spinothalamic tract travels from the spinal cord to the ______.
thalamus
Tracts whose names end in “-spinal” are _____.
Motor
_____ ______ is a condition where the space in the vertebral canal narrows. It narrows because of degenerative changes in the vertebrae. These changes cause excessive bone growth (osteophytes), ligament hypertrophy, or loss of spinal disc height.
Spinal stenosis
People with spinal stenosis find a ____ _______ position while walking or sitting down helps decompress the area and relieve the pain.
Bent forward
In severe cases _________ is an option to immediately relieve the pressure off the nerves.
laminectomy
A person’s level of injury is defined as the ________ level of full sensation and function.
Lowest
T/F: A C3 spinal cord injury means that everything below C3 is affected.
True
C4 injury: _________ complete paralysis below the neck
Tetraplegia (quadriplegia)
C_ injury: partial paralysis of hands and arms as well as lower body.
C6
T6 injury:__________ ; results in paralysis below the chest
Paraplegia
L_ injury: results in paralysis below the waist
L1
The _______ horn contains the cell bodies of lower motor neurons. LMN axons leave the spinal cord.
Ventral
LMNs that leave the ___ innervate mm. of the body (e.g. biceps brachii).
LMNs of the motor cranial nerves (those that leave the _________) usually innervate the mm. of the head (e.g., masseter via CN V).
LMNs that leave the SC innervate mm. of the body (e.g. biceps brachii).
LMNs of the motor cranial nerves (those that leave the brainstem) usually innervate the mm. of the head (e.g., masseter via CN V).
__________ tracts from the brain synapse with lower motor neurons cell bodies in the ventral horn.
Descending
