CNS sensory Flashcards
Describe the structure of the spinal cord from inside to outside:
Central canal
Gray matter
White matter
Roots (dorsal and ventral)
Spinal nerve
What is role of the gray matter in the spinal cord?
It’s where information can be processed
What is the role of the white matter in the spinal cord?
it’s where axons travel through the spinal cord
How does the structure of grey and white matter vary in the spinal cord as compared to the brain?
Unlike the brain, the white matter is on the outside layer of the spinal cord with gray matter inside of it
What is the role of the central canal in the spinal cord?
It’s where CSF travels
What are the two main segments of the grey matter in the spinal cord? Describe their functions.
There is the dorsal horn and the ventral horn. The dorsal horn receives sensory inputs, while the ventral horn sends out signals.
What is the difference between the dorsal root and the ventral root of the spinal tract?
The ventral roots carry axons from motor neurons in the CNS. The dorsal roots are the way through which afferents send their axons into the dorsal horn.
What is the other way that information gets in and out of the CNS aside from the spinal cord?
It can travel through one of the 12 cranial nerves
Where are cranial nerves located?
They all go into and out of the brain stem except for two: the olfactory nerve and the optic nerve.
Describe the development of the nervous system in week 1.
during week one, it’s simply a blastocyte that starts to have some structure
Describe the development of the nervous system in week 2.
On week two, the blastocytes start to develop cavities which will become different parts of the body.
Describe the development of the nervous system in week 3.
On week three, we can see the appearance of an embryonic disk
The top of the embryonic disk is called […]
the neural plate
Describe the structure of the neural tube as of week 3 of development. Include the embryonic disk.
The neural plate (top layer of the disk) will become the neural groove and finally close to creating a tube, part of the CNS and PNS. This happens with the ectoderm layer. In between that one and the mesoderm, we have the appearance of the neural crest which will be part of the PNS.
Describe how the neural tube develops during week 4
There a vesicles that start forming: the forebrain, the midbrain and the hindbrain followed by a tube
The neural crest cells formed during week […] become […]
3, PNS
Describe how the different segments of the neural tube develop into different parts of the CNS.
Forebrain: central hemispheres and thalamus
Midbrain: Midbrain
Hindbrain: Cerebellum, pons and medulla
Tube: spinal cord
Cavity: ventricles and central canal
What is the function of the ventricles in the brain?
It’s where the CSF can circulate
How much cerebral spinal fluid do the ventricles contain?
150 ml
Name the 3 major types of ventricles.
Lateral ventricles
Third ventricle
Fourth ventricle
How is the cerebrospinal fluid formed?
It’s produced by the choroid plexus in the four ventricles (mostly lateral as they are bigger).
What is the rate of production of CSF per day?
500 ml/day
Name the 3 functions of the CSF.
- Supports and cushions the CNS
- Provide nourishment to the brain
- Remove metabolic waste through absorption at the arachnoid villi
What is the composition of the CSF?
It’s a sterile, colorless and acellular fluid that contains glucose