Lecture 2 - Spinal Cord & Brainstem Flashcards
Myelination limits plasticity. Why is this important?
Molecules on the myelin make it harder for the synapse to change.
What is the role of astrocytes?
Act as blood/brain barrier because blood cannot come into contact with the brain – shuttle stuff from the blood to neurons
Rostral
Towards front of head
Caudal
Towards tail
Dorsal
Up (on the backside)
Ventral
Down (towards belly)
Horizontal or axial
Slice front of head to back (bagel)
Coronal
Slice from ear to ear (loaf of bread)
Sagittal
Slice from in-between eyes and nose (hot dog)
4 roles of cerebrospinal fluid (CSF)
Protection
Buoyancy
Nutrition
Waste removal
In spinal cord gray matter is where
In the inside (middle)
In spinal cord white matter is where
On the outside (white matter includes the axons)
In the spinal cord how can you orient ventral vs dorsal
Ventral gray matter wider than dorsal
In spinal cord where are secondary sensory neurons
Dorsal horn gray matter
In spinal cord where are the motor neurons
Ventral horn gray matter
Sensory input from the body _____ to the brain
Ascends
Motor output from the brain ___ to the body
Descends
Why is it clinically relevant that the spinal cord only goes halfway down our back?
CSF but no nerves once the spinal cord ends so it doctors can administer anesthesia or epidurals in this region
Sections of spinal cord from top to bottom
Cervical
Thoracic
Lumbar
Sacral
Coccygeal
Why might someone feel pain in their arm when they have a heart attack?
The same dermatome or part of the spinal cord innervates these regions
Biggest to smallest size of spinal cord sections
Cervical (ovular)
Thoracic (small oval)
Lumbar (circular)
Sacral (small circle)
Why is there more white matter at the cervical level?
All of the axons from all over the body are in the same place so there is a lot of white matter at the top
Why isn’t there much gray matter at the thoracic level?
Poor sensitive acuity in the back – not a lot to innervate
In the spinal cord the white matter are what
Axons
Where you need more neural control what do you see more of?
Gray matter
What’s in the brainstem?
- Ascending and descending pathways to/from body and brain
- Nuclei important for sleep, hear rate, breathing, neurotransmitter production
- Cranial nerves
3 parts of brainstem
Midbrain
Pons
Medulla
Ventral brainstem
Pyramid bumps on medulla in the middle
Dorsal brainstem
Superior colliculi
Inferior colliculi
Cerebellar peduncles
Gracile nucleus
Cuneate nucleus
What marks that you are in the midbrain
Inferior colliculi
Cuneate nucleus is towards what side of the gracile nucleus
Lateral (towards the outside)
Dorsal columns ascending tract
Sends information about fine-grained touch and position sense (proprioception) from body to brain
Dorsal columns primary neurons – where is cell body
In dorsal root ganglion
Dorsal columns primary neurons – where do they synapse
Synapse in dorsal column nucleus (medulla)
Dorsal columns primary neurons – synapse in gracile nucleus for information on which body region
Lower body
Dorsal columns primary neurons – synapse in cuneate nucleus for information on which body region
Upper body
Dorsal columns secondary neurons – axon crosses over and ascends as what
Medial lemniscus
Dorsal columns secondary neurons – where is cell body
In gracile or cuneate nucleus
Dorsal columns secondary neurons – where do they synapse
Crosses over to synapse in thalamus
Dorsal columns tertiary neurons – cell body is where
Ventral posterior lateral nucleus of the thalamus
Dorsal columns tertiary neurons – axon where
In internal capsule/corona radiata
Dorsal columns tertiary neurons – synapse where
Primary somatosensory cortex
Where is the dorsal column system in the spinal cord
Cervical
In the upper medulla what switches
In images, the right side will carry info from left side of the body
Where is the dorsal column system in the cortex?
Primary somatosensory cortex
Dorsal column primary neurons – axon where
Posterior spinal cord
Corticospinal tract descending tract
Sends info about conscious motor control from brain to body
Corticospinal tract primary neurons – cell body where
In motor cortex
Corticospinal tract primary neurons – synapse where
Ventral horn
Corticospinal tract secondary neurons – cell body where
In spinal cord
Corticospinal tract secondary neurons – synapse where
On muscle
Where do primary neurons decussate (dorsal tract)
In the medulla
Primary motor cortex is where in reference to the sensory cortex
Anterior (rostral) to sensory cortex
Axon of primary neuron travels first where then where
Corona radiate
Internal capsule
Axon of the primary neuron is where in the midbrain
Cerebral peduncles
Axon of the primary neuron is where in the pons
Ventral part
Axon of the primary neuron is where in the upper and lower medulla
Pyramids
Axon of the primary neuron crosses where (corticospinal tract)
In the lowest medulla
Axon of the primary neuron is where in the corticospinal tract
Lateral corticospinal tract
