Human movement and sensation - L20 Flashcards
Where does the spinal cord begin?
It begins at the base of the skull, at a place called the foramen magnum (big hole)
Where does the spinal cord end?
At Lumbar 1 (Big process)
Where is the spinal cord found?
Runs through the spinal canal
What covers the spinal cord around the spinal canal
The sacs made of meninges (meningeal sac)
What is between the bone and the meningeal sac?
Fat that acts as a cushion
What part of the vertebrae are at the back and front?
Back - spinous process
Front - Body
Where does the meningeal sac and spinal canal extend to?
To the coccygeal vertebrae as the spinal nerves grow till there
What is in the meningeal sac?
Gel like fluid called the Cerebrospinal fluid (CSF)
Why are there two structures to support the spinal cord at the end?
The end is wavy and we don’t want the spinal cord to move around so there is the Conus Medularis and the Filum Terminale
Conus Medularis
*Cone shaped non-neuronal tissue that is the attatchment point for Filum Terminale
Filum Terminale
*Terminal Filament
*From Conus Medularis to end of spinal cavity and meningeal sac
*Stabilises and anchors the spinal cord
*Fibrous, non-neuronal tissue
How many segments of the spinal cord?
31
C- 8 pairs of spinal nerves
T - 12 pairs
L - 5 pairs
S - 5 pairs
C - 1 pair
What are spinal nerves?
Exit points from the vertebra
Where does C1 spinal nerves exit?
Between the skull and C1 vertebra
What is special about C8 spinal nerve?
It doesn’t have an associated vertebra, exits above? C7
What is different about the top lumbar spinal nerves
Some originate from the T vertebrae region and the spinal nerves have to grow all the way from the spinal cord to their corresponding vertebrae to exit.
How are spinal nerves named?
By the vertebrae they exit below
What is the collection of long nerves at the end of the spinal cord?
Cauda Equina
What is at the posterior of the spinal cord?
The posterior median sulcus
What is at the anterior of the spinal cord?
The anterior median fissure
Butterfly structure?
Grey matter made of cell bodies, found in the SC and the cerebral cortex, forms the dorsal, lateral and ventral horns
Stuff around butterfly?
White matter, made of myelinated axons, appears white due to the myelin being made of fat
*forms the dorsal, ventral and lateral COLUMNS.
Dorsal part of spinal cord has:
Dorsal nerve root that connects to the dorsal root ganglion and extends to form the spinal nerve
Sensory i.e afferent region from PNS to CNS
Anterior part of spinal cord has:
Motor i.e efferent region from CNA to PNS
Ventral nerve root
Where are the somatic motor efferent neurons?
Lower motor neurons, in the ventral horn
Where are the autonomic efferent neurons and somatic visceral neurons?
In the lateral horn
What happens if theres damage to the ventral horn?
Paralysis of the muscles as motor neurons can’t carry out info to muscles
Flow of afferent info into brain
*Cell bodies of sensory neurons are in dorsal root ganglion
* Input zone in body associates with receptors for sensory stimulus
* Output zone enters the spinal cord through
What kind of neurons are sensory neurons?
Unipolar neurons with a singular process which then splits into one input and one output zone
If there was damage to dorsal side?
No incoming info of the things around us, loss of sensation
What are spinal nerve info pathways?
Two ways like a motorway i.e both efferent and afferent i.e the spinal nerve splits
What does the dorsal ramus do?
Afferent and Efferent info from and to back
Ventral ramus
Afferent and Efferent info from and to the front
Rami communicans
Has to do w sympathetic nervous system
*only present at thoracolumbar level T1 - L2
*short axon to sympathetic chain ganglia on either side of vertebral column
What are axons covered with?
Endoneurium
Preganglionic nerve of PNS
Myelinated and unmyelinated for postganglionic
Buncles of axons
Fasicle w perineurium
Bundles of fasicles
nerve covered with epineurium
Bundles of axons in the CNS
Called tracts
Where are the rami communicans present
Present in spinal nerves T1-L2, Axons of autonomic symp nerves
