Week 20 spinal cord Flashcards
What types of fibres innervate the bladder?
The external sphincter?
Bladder = visceral motor = sympathetic/parasympathetic
Sphincter = somatic motor = voluntary control
Discuss the functional anatomy of the spinal cord.
Motor divisions:
Somatic
Visceral which has sympathetic and parasympathetic
Sensory divisions:
Discriminative touch, conscious proprioception, and vibration,
Pain and temperature,
Unconscious proprioception to cerebellum.
Why would a T12 fracture affect lumbar segments of spinal nerves?
Because they travel inferiorly within the epidural space before exiting at their nerve root level. For example L1 and L2 roots exit the spinal cord close to T12 and travel downwards to the L1 and L2 vertebrae.
What is unique about the thoracic level of the spinal cord?
Lateral horn, small anterior horn.
In which portion of the spinal cord are ascending and descending tracts located?
White matter
In which portion of the spinal cord are posterior and anterior horns located and what is their function?
Gray matter.
Posterior = sensory.
Anterior = motor.
What types of fibres come from the lateral horn of the thoracic spinal cord?
Visceral motor/ sympathetic
Which arteries provide blood supply to the spinal cord?
Anterior spinal artery.
Posterior spinal arteries.
Segmental medullary arteries.
From which vessels does the anterior and posterior spinal arteries arise?
Vertebral arteries just proximal to basilar artery.
From which vessel do the segmental medullary arteries arise?
Aorta.
Fasciculus gracilis
Sensory tract (fine touch, conscious proprioception) from ipsilateral lower limb.
Fine touch, proprioception.
Fasciculus cuneatus
Sensory tract (fine touch, conscious proprioception) from ipsilateral upper limb.
Fine touch, proprioception.
Spinocerebellar tract
Nonconscious proprioception from limbs to cerebellum.
Does not decussate.
Lateral corticospinal tract
Motor to ipsilateral ventral horn - mostly limb musculature.
Skilled movement of the extremities.
Decussates in medulla.
Spinothalamic tract
Pain and temperature from contralateral side of body.
Only fibres projecting from the spinal cord to the thalamus.
Anterior corticospinal tract
Motor to ipsi and contralateral ventral horn - mostly axial musculature.
Postural adjustment.
Which CN provide parasympathetic fibres?
III, VII, IX, X
Where does sympathetic innervation arise?
T1-L2
What provides innervation to the detrusor mm of the bladder?
Parasympathetic: S2,3,4
What innervates the internal sphincter of the bladder in males?
Sympathetic: T12, L1
What innervates the external sphincter of the bladder?
Pudendal, somatic motor: S2,3,4
What area of the brain makes decisions about voiding the bladder?
Cortex.
What area of the brain does the cortex send voiding decisions to?
Pontine micturition centre in brain stem.
Pontine micturition centre
Coordinates voiding.
Activates the parasympathetics - detrusor contraction.
Inhibits sympathetics - relaxation of internal sphincter.
Inhibits somatics (pudendal nerve) - relaxation of external sphincter.