Spinal Cord Flashcards
What is the spinal cord derived from?
ectoderm via the neural tube
What trimester is when the neural tube forms and what deficiency is it due to?
1st trimester due to folic acid deficiency
What layer of the neural tube turns into white matter of the spinal cord?
Marginal layer
What layer of the neural tube turns into dorsal (alar) and ventral (basal) plates?
Mantle layer
What do the alar plates differentiate into?
sensory neurons in the dorsal horn of grey matter
What do the basal plates differentiate into?
motor neurons in the ventral horn of grey matter
What is the dilated end of the spinal cord called?
conus medullaris
What level does the spinal cord end?
L1/L2
What level does the dural sac end?
S2
What is a part of the Pia mater and extends from the conus medullaris to the end of the dural sac at S2?
Filum terminale internum
What is a part of the Pia mater and is covered by a thin layer of the dura and extends from S2 to the coccyx as the coccygeal ligament?
Filum terminale externum
How many segments is the spinal cord divided into?
31 segments
What cells lie in-between myelinated axons?
Glial cells
What kind of sense do dorsal columns sense (DCML)?
vibration, 2pt touch, joint position sense
Where do fibers from the lower limb synapse?
nucleus gracilis
Where do fibers from the upper limb synapse?
Cuneate nucleus
Which tract of the anterolateral system carries pain and temperature?
lateral spinothalamic
Which tract of the anterolateral system carries crude touch and pressure?
Ventral spinothalamic
Which tract of the anterolateral system mediates autonomic responses to nociception?
Spinoreticular
Which tract of the anterolateral system activates eye movements in response to tactile stimuli?
Spinotectal
What descending tract’s function is voluntary movement of the muscles in the limbs?
Lateral corticospinal tract
What descending tract’s function is voluntary movement of the muscles in the head, neck, and trunk?
Ventral corticospinal tract
What descending tract’s function is in postural reflexes-neck muscles, extensors of back and legs?
vestibulospinal tract
What descending tract’s function excites proximal flexors and inhibits extensors mainly in the upper limb?
Rubrospinal tract
What descending tract’s function coordinates head and eye turning in response to light via superior colliculus?
Tectospinal tract
What descending tract’s function inhibits nociception by releasing serotonin and acts on the C fibers?
Raphespinal tract
What part of the grey matter is found only in the thoracic part of the spinal cord?
lateral horn
Which lamina is the thin layer which lies beneath the dorsolateral fasciculus?
Lamina I
Which lamina is made up of small neurons, contains high concentrations of Substance P, and is also known as Substantia Gelatinous of Rolando?
Lamina II
Which laminae’s main input is from fibers that carry mechanoreceptors and light touch and are referred to as Nucleus Proprius?
Lamina III and IV
Which lamina contains neurons that respond to both noxious and visceral afferent stimuli?
Lamina V
Which lamina is the deepest layer of the dorsal horn and receives mechanical signals from the skin and joints?
Lamina VI
Which lamina contains Clarke’s nucleus and the intermediolateral horn?
Lamina VII
Which laminae contain alpha and gamma motor neuron groups in the ventral horn?
Lamina VIII and IX
Which lamina is also known as the grey commissure surrounding the central canal of the spinal cord?
Lamina X
