spinal cord Flashcards
where does the spinal cord end
L1-L2
where does the spinal cord end at birth
L3
what is the function of the spinal cord
- receive afferent fibres from sensory receptors of the trunk and limbs
- control movement of the trunk and limbs
- provide autonomic innervation for most of the viscera
what is the end of the spinal cord
a conical termination the conus medullaris.
what is the denticulate ligamment
a flat continuation of the pia mater taht teters the spinal cord to the arachnoid and the dura
what is the function of the two spinal cord enlargments
to accommodate a greater number of nerve cells and connections needed to process information rekated to the upper and lower limbs
where does cervical enlargement run
- Consists of spinal segments C4—T1;
where does the lumbar enlargement run
Consists of spinal segments L1—S3
what does the cervical enlargement innervate
corresponds to the upper limbs
Provides innervation via brachial plexus
what does the lumbar enlargement innervate
corresponds to the lower limbs
Provides innervation via lumbosacral plexus
how many nerve pairs attach to the spinal cord
31 pairs of spinal nerves
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
what is the cauda equina
collection of nerve roots at inferior end of vertebral canal
cervical spinal nerves exit ____ the respective vertebra
above
what is a ventral root
allow motor neurons to exit the spinal cord (efferent).
(anterior)
what is a dorsal root
allow sensory neurons to enter the spinal cord (afferent).
(posterior)
what are the two branches of a spinal nerve
- one composed of sensory fibres, enters the spinal cord via the dorsal root; its cell bodies lie in a spinal ganglion that is outside the spinal cord.
- The other branch, composed of motor fibres, leaves the spinal cord via the ventral root; its cell bodies lie in specific areas of the spinal cord itself.
what are the major neurotransmitters of parasympathetic postganglionic neurons
Acetylcholine and nitric oxide
what are Parasympathetic preganglionic neurons
neurons have their cell bodies in the central nervous system and make synapses in the ganglia close to or in the walls of the organs they supply.
the motor components of the parasympathetic nervous system run in which cranial nerves
nerves III, VII, IX, and X and in the sacral nerves.
where are the sympathetic nervous system’s outflows from
outflows are from the thoracic and upper lumbar spinal cord.
what is the function of the parasympathetic division
It exerts its effects on autonomically controlled organs of the head, thorax, abdomen, and pelvis
what is the denticulate ligament
a flat continuation of the pia mater that runs between the dorsal and ventral roots of the spinal cord
how does CSF protect the spinal cord
buffers CNS
lightens brain
removes toxic metabolites
transports hormones
what divides the spinal cord in half
by a posterior median sulcus and an anterior median fissure.
