The Spinal Cord (Theme A) Flashcards
Which several of the following structures are parts of the white matter of the spinal cord (when viewed in cross section)?
- Central sulcus
- Temporal lobe
- Central canal
- Ventral horn
- Ventral white commissure
- Dorsal horn
- Dorsal Funiculus
- Lateral Funiculus
- Dorsal Funiculus
- Ventral white commissure
- Lateral Funiculus
The width of the human spinal cord and the ratio of grey & white matter varies depending on the ______ level at which a section is taken
Rostro-caudal
At ____ levels, there is much more white matter than grey matter.
Cervical
At _______ levels, the spinal cord is narrower than in ______ regions.
At THORACIC levels, the spinal cord is narrower than in CERVICAL & LUMBAR regions
In sacral regions, the ratio of grey matter to white matter is very skewed towards ______.
Grey matter
Thick parts of the spinal cord, appearing as swellings at cervical and lumbar / sacral regions are associated with the innervation of the ________.
Limbs
If you step onto a drawing pin, you experience pain. That sensation is transmitted to the spinal cord via the dorsal or the ventral root of the spinal cord?
The dorsal root (as it is sensory information)
A patient is experiencing pain down the back of their right thigh. This appears to be caused by pressure on a nerve exiting the vertebral column.
What nerve is this likely to be?
R lumbar nerve 1
R thoracic nerve 10
R sacral nerve 2
R sacral nerve 7
R cervical nerve 5
R lumbar nerve 8
R sacral nerve 2
How many pairs of spinal nerves are there in total?
31
How many pairs of cervical spinal nerves are there?
8
How many pairs of thoracic spinal nerves are there?
12
How many pairs of lumbar spinal nerves are there?
5
How many pairs of sacral spinal nerves are there?
5
How many pairs of coccyx spinal nerves are there?
1 pair
What does the Dorsal Root Ganglion (DRG) of a spinal nerve contain?
Sensory neurone cell bodies
The dorsal root of the spinal nerve is responsible for what?
Sensory information going IN to the spinal cord
(Contains the central branch of the sensory neurone)
The ventral root of a spinal nerve is responsible for what?
Motor information going OUT of the spinal cord
Contains motor neurone axons
Give 4 examples of external stimuli
Pain
Touch
Heat / cold
Pressure
What is proprioception?
‘Position’ sense - the awareness of the relative positions & orientations of different body parts
(A type of internal stimulus)
What are Dermatomes?
Specific regions of the skin that are innervated by a single spinal nerve
(Each SENSORY area of skin corresponds to a specific spinal nerve)
Where do Dermatomes originate from?
The dermatomyotome of somites. They develop based on the segmentation of the somites during development.
In a spinal cord cross-section - what is the layout of the white & grey matter?
The white matter is on the outside, the grey matter is on the inside
Compare the cells in the dorsal horn of the spinal cord to the ventral horn of the spinal cord
Smaller cells in the dorsal horn & larger (motor neurone) cells in the ventral horn
Grey matter in the SC can be split into laminae (layers). These are referred to as…
Rexed’s laminae
(Often numbered with roman numerals, from dorsal -> ventral)
Are the ascending & descending tracts of the SC part of the white or grey matter?
White matter
Describe the direction of the axons in the ascending and descending tracts of the SC
Ascending tracts - axons going UP the spinal cord
Descending tracts - axons going DOWN the spinal cord
Give 3 names of ascending tracts in the spinal cord
- Dorsal columns (aka. Dorsal / posterior funiculus)
- Spinocerebellar tracts
- Spinothalamic tracts
What do the spinocerebellar tracts do?
Transmit proprioceptive information from the SC to the cerebellum
What are the 2 main spinocerebellar tracts?
Dorsal & ventral
What is the cerebellum responsible for?
Coordinating voluntary movements, maintaining posture, regulating balance
What do the spinothalamic tracts do?
Carry sensory information (related to pain, temp, touch) from the periphery to the thalamus
The spinothalamic tracts are part of which system?
The anterolateral system
What are the 2 (adjacent) pathways of the spinothalamic tract, and what information do they carry?
- Anterior spinothalamic tract - carries sensory input about crude touch
- Lateral spinothalamic tract - carries information about pain & temperature
What are the 3 types of sensory fibres associated with the spinothalamic tract?
- Type III fibres
- Unmyelinated c-fibres
- Myelinated A-delta fibres
