Neuron and White Matter Essay

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Physiology Oct 1st Chapter 9: pgs (216-242). And Ch 10 (254-269). Do practice questions!

The Nervous System: CNS
*Always understand the learning objectives.

CNS- right in the center only brain & spinal cord and PNS- all the nerves

Anatomy of the CNS- glial cells (support). The 5 types of glial cells: astrocytes (blood brain barrier) ependymal cells (CSF production), microglia(phagocytosis), oligodendrocytes and schwann cells (PNS). Only Schwann cells can re-generate.

Astrocytes: only remember the blood brain barrier Migroglia- phagocytosis of bacteria and dead/ protect the neuron from all toxics that can be produced. Loss of myelln- slow action potentials

*Below each meninge, there is a space.

In terms of physical support of CNS, we also have the CSF. The production is like 125-150 ml

you DON’T need to know table 9.1, 9.2 9.3, 9.9*

3 structures of brainstem: midbrain pons medulla

The cerebral aqueduct of sylvius…

The CNS accounts for 2% of total body weigh but accounts for 20% of blood supply.
20% of oxygen
50% of glucose

Capillaries- cells that are lining the blood vessels; site of exchange b/w blood and fluid.

White matter vs gray matter in CNS: Ex: the rats Rat= neuron Gray matter- cell bodies of neurons & dendrites Tail= axon White matter= collection of axons It is white because of myelin due to lipid concentration. It’s the reason myelin is white.

White matter: 3 fibers: projection, association and commissural (connects 2 cerebral hemispheres)(ex: corpus callosum) Know what these 3 connect**
Spinal Cord
31 pairs
Dermatome-sensory region of the skin that is innervated by all the nerves
Ex- of the T3 and how if it were to be pulled off then they wouldn’t feel it. It is to help identify where the injury was located. The dermatome helps identify the location of the injury,

Spinal Cord and Spinal Nerves
Ventral: motor functions & dorsal: sensory functions
White matter
Ascending: sensory
Descending: motor
In spinal cord: the gray matter is on the inside and white matter on the outside. But in the brain it’s the opposite.

Know the subdivisions of brain: know the structures in figure 9.11

Motor coordination
Brainstem- know what each connects to.
10 of 12 cranial nerves emerge sleep wake cycles
Cerebral cortex
Gyri- ridges
Know the 4 lobes: frontal, parietal, temportal & occipital.
Important to identify the central sulcus- what is posterior to central sulcus is sensory and anterior is motor
Know figure 9.14
Wernick’s area: associates with language compression
You will suffer from Receptive aphasia: inability to understand any form of language. Can speak in a flowing manner but what they say makes no sense. Ex: stroke
Brocas area: language expression:
Expressive aphasia- inability to produce coherent speech, speech is “telegraphic” understanding of language is not affected’
Primary motor cortext- Precentral gyrus
Primary somatosensory- central gyrus
Brain lateralization: right brain vs. left brain

Basal nuclei- ex: parkinsons disease

Thalamus- everything gets processed here

Limbic system: normally more related to emotions

Involuntary Movement through reflex

Important: Skeletal Muslce