Organisation of spinal cord Flashcards
what is the spinal cord?
The spinal cord is the connection between the brainstem and the spinal nerves.
It is protected by the bony vertebral canal.
The spinal cord is composed of white and grey matter. The white matter is made up of axons, covered in myelin, and the grey matter is composed of none myelinated components (cell bodies, synapses)
White matter is where info travels up and down
Grey matter is where the synapses process the info its receiving from the white matter
what do we mean by caudal vs rostral and when are these terms used
CAUDAL VS ROSTRAL used to refer to BRAIN
if used to spinal cord its same as a inferior superior..
Caudal= closer to back of brain/ ur head (towards tail)
Rostral= closer to front of brain/ forehead (towards beak)
the CNS (brain + spinal cord) is protected by 3 layers of meninges. what are they?
Meninges are protective layers:
* Dura mater (outside think of it as ‘durable’ as its on outside)
* Arachnoid mater
Pia mater
why is the epidural space clinically important (make sure u can point this out on diagram/cadaver)
Epidural is a type of anaesthetic that’s inserted in epidural space (just fat) so anaesthesia can diffuse across nerves and act on them
there’s no synapses in dorsal root ganglia its just a collection of _____ _____
there’s no synapses in dorsal root ganglia its just a collection of CELL BODIES
how many pairs of spinal nerves do we have. Name all of them
N.b. spinal nerves in cervical region are named according to the vertebrae below them, whereas the rest of those i.e. thoracic and down are named according to the vertebrae above them.
31 pairs of spinal nerves
* 8 cervical
* 12 thoracic
* 5 lumbar
* 5 sacral
* 1 coccygeal
just before the cauda equina (“horse tail”) the spinal cord tapers- this is called the CONUS MEDULARIS, from the bottom of the conus medularis there is a filament made of meninges and what is it called + what is its function?
just before the cauda equina the spinal cord tapers- this is called the CONUS MEDULARIS.
The filament from the bottom of the conus medualris is the FILUM TERMINALE comes out of the base of spinal cord and attaches to sacrum. It helps to anchor the spinal cord in place.
lumbar puncture is performed below which level of spinal cord
below the level of L3 to avoid damage to spinal cord. so its usually performed at L4/L5
where does the spinal cord receive its blood supply from
The spinal cord receives its blood supply from the anterior and posterior spinal arteries. These arteries are not enough to supply the whole cord, so they are reinforced by radiculospinal arteries which are derived from arteries of the body wall (to top of blood supply= radiculospinal arteries e.g. in thoracic region it wld be intercostal arteries topping up the blood supply to spinal cord)
Venous drainage is via 3 anterior and 2-3 posterior spinal veins
at which spinal cord level us there the most grey matter?
SACRAL very little white matter, predominantly grey matter as its the bottom of spinal cord so obvi this is where info received (synapses cell bodies)
where is the basilary artery found, and explain how it travels up to the brain
basilar artery found at base of the brain
Transverse foramen of cervical vertebrae, these ‘holes’ is where the vertebral artery travels through (branch of subclavian) it then enter skull through foramen magnum then the 2 branches join together to form BASILARY ARTERY
what is the function of the spinothalamic tract
the spinothalamic tract transmits the sensations of crude touch, pain + temperature from the spinal cord to the thalamus
What is decussation in the spinal cord? + why do neurons dessuccate
decussation= means crossing the midline i.e. when fibers cross from one side of a structure to the other. For example, motor fibers that travel in the corticospinal tract originate in the cerebral cortex and travel down to the body.
THEY need to desuccate cuz info from left side of body needs to go to the right side of brain + vice versa
what is the function of the dorsal column, aka the dorsal column medial lemniscus (DCML) pathway
the dorsal column medial lemniscus transmits the sensations of vibration, proprioception (ur position in space; sense of self-movement, force, and body position) + discriminative touch from the periphery to the brain via dorsal columns + medial lemniscus
what is the function of the spinocerebellar tract
spinocerebellar tract transmits the sensations of subconscious proprioception (ur position in space) from the spinal cord to the cerebellum
aka dorsal spinocerebellar tract (DSCT), also known as the posterior spinocerebellar tract or Flechsig tract, is a somatosensory part of the sensory nervous system that relays unconscious proprioceptive information from the lower limbs and trunk of the body to the cerebellum.
