Week 5 Flashcards
How is movement (skilled movement, posture, and spinal reflexes) organized?
Define voluntary movement
How is the nervous system organized?
Describe the gross anatomy of the spinal cord
Explain segmental organization of the spinal cord
List the spinal nerve innervation of skeletal muscles
Explain white and gray matter of the spinal cord
What are the regional differences of gray matter?
Cervical
- Oval shape
- Greatest amount of white matter - lots of tracts!
- Dorsal intermediate sulcus is present only in cervical region to T6
* Intermediate sulcus separates 2 tracts getting information from different areas of the body
- Big ventral horns C5-8 for brachial plexus
- In cervical region, spinal cord aligns with vertebrae
Thoracic
- Presence of lateral horn
- Small amount of gray matter, no plexus because it does not innervate and control any limbs
- Dorsal intermediate sulcus (T6 & above)
Lumbar
- Largest ventral horn: lumbosacral plexus
- Least amount of white matter (less motor tracts, more PNS)
* Tracts ascend, so you collect tracts as you ascend from the lumbar to the cervical regions of the spinal cord (the lumbar region only has lumbar and sacral tracts, while the cervical region has sacral, lumbar, thoracic, and cervical tracts)
- No dorsal intermediate sulcus
- Spinal cord ends (L1-L2 Intervertebral space)
- Cauda equina (long roots of the spinal nerves) present (L2 and below)
- Filum terminale (connective tissue that connects end of the SC to the coccyx)
Label
Label
What are the sensory tracts of white matter?
What are the motor tracts of white matter?
Describe primary, secondary, and third order neurons
What are the first order neurons of the spinal cord? Where do they go?
What are the second and third order neurons of the spinal cord? Where do they go?
Explain what the somatosensory areas are
How is the cerebrum organized?
Explain the signal route of discriminative touch and conscious proprioception
Label
What are the spinothalamic tracts?
Explain fast vs slow pain in the spinothalamic tracts
Which is fast?
A) fast
B) slow
Explain the primary, secondary, and third order neurons of the anterolateral system
What is the route of signal transmission in the anterolateral system?
What is the organization of the anterolateral system?
What is the route of signal transmission in slow nociceptive tracts?
Label
Where are the spinocerebellar tracts?
What are the spinocerebellar pathways?
Describe unconscious proprioception
Explain signal route of transmission for unconscious proprioception of posterior spinocerebellar tract from L/E and lower body
Explain signal route of transmission for unconscious proprioception of cuneocerebellar tract from U/E and upper body
Explain signal route of transmission for unconscious proprioception of anterior spinocerebellar tract from L/E and lower body
Label
Explain the descending pathways
Explain lateral and medial corticospinal tracts
What is the route of signal transmission in the corticospinal tract?
Label
Medial (anterior) CST
Label
What are the anatomical components of the corticospinal tract?
- Corona Radiata
- Internal Capsule
- Cerebral peduncle
- Pyramid
- Corticospinal fibers
Label
Explain the anatomy of CST
What is the CST organization of LMNs in the spinal cord?
- Cerebral Cortex Lesion (Uppermost X)
A lesion in the primary motor cortex disrupts signals before they travel down the corticospinal tract, causing contralateral motor deficits. This could lead to contralateral hemiparesis or hemiplegia, affecting voluntary movement and coordination on the opposite side of the body. - Midbrain Lesion (Middle X)
Damage at the midbrain level affects descending motor fibers before they cross in the medulla, resulting in contralateral weakness or paralysis. If surrounding structures are involved, this could lead to syndromes like Weber’s syndrome (which includes ipsilateral oculomotor palsy with contralateral hemiparesis). - Spinal Cord Lesion (Lowest X - After Decussation)
Since the corticospinal tract has already decussated at the medulla, damage in the spinal cord leads to ipsilateral motor deficits. This means muscle weakness, spasticity, or paralysis occurs on the same side as the lesion, affecting movement and reflex control below the injury level.
What is the function of spinal cord interneurons?
Modulate descending drives and integrate sensory inputs with motor output
Explain the stepping generator pattern of interneurons
Explain
Provide an example of withdraw reflex
