Lecture 7 Flashcards
What fibres does the spinal cord receive from peripheral receptors?
Primary afferent fibres
What are two functions of the spinal cord?
Sends motor axons to skeletal muscle
Provides communications between brain and periphery
Where do the anterior and posterior roots of the spinal cord pass through?
Subarachnoid space
When the posterior root passes through the appropriate intervertebral foramina, what happens?
It enlarges by the posterior root ganglion
What produces posterior and anterior rami?
Fusion of the roots
Where is the spinal cord continuous with the medulla?
Site just before the foramen magnum
What is the termination of the spinal cord called?
Conus medularis
What is the continuation of the thin cord of the conus medularis?
Filum terminale
What level does the spinal cord end?
L1
What level does the dural sac end?
S2
The spinal cord is suspended in the canal by a ribbon of tissue called?
Denticulate ligament
What is the denticulate ligament made of?
Pia and arachnoid tissue
Where does the dorsal and ventral roots come together to form the spinal nerve?
Intervertebral canal
What is the spinal cord made of?
Outer layer of white matter and inner layer of grey matter in the shape of a ‘H’
Where does the central canal open into rostrally?
4th Ventricle
Where is grey matter greatest in the spine?
Cervical and lumbar enlargements
Where is white matter greatest?
Cervical level
What is the white matter made up of?
Dorsal, lateral and ventral fasciculi
What is the grey matter divided into?
Left/right dorsal horns
Left/right ventral horns
At T1 to L2 there is a smaller horn called?
Lateral horn
What does the lateral horn made from?
Preganglionic sympathetic neurons
What is rexed laminae?
Ten cell lamina in grey matter of the spinal cord
Overlying lamina I is what?
The tract of Lissauer
Afferents entering the spinal cord divide into?
Ascending and descending branches
Where do the ascending and descending branches travel in?
Tract of Lissauer before penetrating the grey matter
What are the three major longitudinal arteries?
One anterior and two posterior
What arteries are derived from vertebral, deep cervical and lumbar arteries?
Segmental arteries
What arteries travel along the dorsal and ventral roots?
Radicular arteries
Where do longitudinal veins drain to?
Cerebellar veins and cranial sinuses
Where do segmental veins drain to?
Vertebral plexuses
What is the space between the dura and bone in the spinal canal?
Epidural space
What is contained in the epidural space?
Adipose tissue and the anterior and posterior epidural venus plexuses
What does the spinothalamic tract carry?
Pain, temperature and deep pressure
What tract controls precision and speed of skilled movements?
Corticospinal tract
What tract forms visible ridges referred to as pyramids on the anterior surface of the medulla?
Corticospinal tract
Where do 85% of fibres cross in the caudal medulla?
Decussation of the pyramids
What tract has excitatory control of tone of limb flexor muscles?
Rubrospinal tract
What tract has fibres originate in red nucleus of midbrain?
Rubrospinal tract
What is the small tract with input mostly to cervical segments?
Tectospinal Tract
Where do fibres originate in the tectospinal tract?
Superior colliculus
What region of the midbrain has the superior colliculus?
Tectum
What tract has excitatory input to antigravity extensor muscles?
Lateral Vestibulospinal Tract
Where do the fibres originate in the lateral Vestibulospinal tract?
Ipsilateral vestibular nuclei of pons and medulla
The motor systems outside the pyramidal tract are referred to as?
Extrapyramidal system
