Inability to move ,Neuro Q ??????? - jovana

[ArchivalUser]

okk...i will wait.

[ArchivalUser]

I am starting from the begining, so be patient and you will find the answer in the end..
Which is TRUE?

1. left somatosensory cortical lesion decrease left body somestesias
2. Left cortical lesions would cause left-side motor difficulties
3. Left auditory cortex lesions would cause left-ear deafness
4. Left cerebellar damage would cause left side motor difficulties


Because of the TOPOGRAFIC organization of a pathway:
1. weakness in the fingers on the right is often associated with weakness in the toes on the left
2. weakness in the fingers on the right is often associated with weakness in the toes on the right
3. weakness in the fingers is often associated with weakness in the wrist
4. weakness in the fingers is often associated with tingling in the fingers



A lesion leading to the inability to move the tongue and eye movement difficulties without causing other motor deficits most likely involve:
1. the spinal cord
2. the brainstem
3. the diencephalons
4. the telencephalon



A lesion yielding perfect vision and yet the inability to recognize your grandmother in the photograph most likely involves
1. the eye
2. the diencephalons
3. the telencephalon
4. the basal ganglia



The CNS is organize into œsystems œ.

1. Visual System
2. Somatosensory System
3. Somatic Motor System
4. Autonomic Nervous System (control the endocrine and exocrine glands, viscera and the smooth muscle)
5. Auditory System


There are 4 Major principles of organization of each system.

I. Each system is made up of many pathways
What is a pathway?
Serious of neurons connected to another into a functional unit.
Series of nuclei in the CNS that are interconnected by the axons projecting between nuclei.
Neurons each with its own axon connected to the next neuron by a synapse.

An example of multiple pathways within a system is the somatosensory pathway where the sub modality of pain is coded and transmitted on a separate pathway [spinothalamic (anterolatrel pathway], then the sub modality for the FINE DISCRIMINATIVE TOUCH (dorsal column/medial lemniscal pathway).
Because those pathways are physically separate lesion can sometime affect one without affecting another.
In Visual system two paraocellular and done magnocellular pathways code for color, form and motion separately.

Unlike the somatosensory, the visual pathways have AXONS that RUN TOGETHER. Thus in the visual system lesions affect those pathways together.

II.
EACH PATHWEY CONTAINS A SERIES OF NEURONS INTERCONNECTED AT SYNAPTIC RELAYS and IT IS AT THOSE RELAYS WHERE MODIFICATION OF SIGNAL TAKES PLACE.


Another words a pathway is NOT like A pipe WHRE WHAT FLOWS in at one end flows out unchanged at the other end.

A pathway is made up of a series of neurons with cell bodies clustered together-those clusters of cell bodies are called NUCLEI, AXONS are located in tracts that terminate and contact the next neuron at synapses the next nuclei. At those connections there is the capability for the signal to be modified

Two classes of neurons in the brain:

1) Projection neurons with long axons that go to the next nucleus
2) Local interneuron™s with short axons that have a
cell bodies and axon terminals within the same nucleus. So those two types of neurons both have their cell bodies in the nuclei of the brain, but they are different because of where their axons project to.


III.
EACH PATHWAY IS TOPGRAPHICALLY ORGANISED

That is the orderly array at the receptive surface and is maintained by an orderly progression of axon form nucleus to nucleus.
-That is why œHOMUNCULUS œis an orderly (although disproportionate) representation of the body™s surface in the somatosensory cortex (somatotropic organization)

- similarly the visual cortex is coded in an orderly manner on the retina and this order is maintained up true area 17 or primary visual cortex ( visiotropic or retinotropic organization )
- In the auditory system different tone are coded along different regions of the cochlea and this is maintained up to areas 41,42 (tonotropic organization )



IV. FINALLY MOST PATHWAYS CROSS THE MIDLINE

That is the left side of the brain receives INFO from and sends output to the RIGTH SIDE of the BODY.
Two notable EXCEPTIONS: CEREBELLUM that PRESERVE the SAME SID EOF THE BDY and the AUDITORY SYSTEM which has a large BILATERAL COMPONENT.




6 main regions of the CNS


1.Spinal cord :
Contain ascending or afferent pathways that bring sensory information to the brain
-contain descending pathways or efferent pathways that bring MOTOR commands from the brain to the neurons that play out these commands in the periphery
-contains many of the control stations for autonomic functions

THE BRAINSTEM:

2. The Medulla
3. The PONS (WITH ITS ROOF OF THE CEREBELLUM)
4. The Midbrain

The brainstem contains:
-the continuation of the pathway located in the spinal cord
-nuclei or clusters of cell bodies, any of which are the cranial nerve nuclei (which are like the afferent and efferent nuclei in the spinal cord EXCEPT those associated with the HEAD and NECK
-massive fibers systems connecting the cerebellum with the cord and brainstem nuclei.
-The reticular formation “a scattered array or cell bodies that control overall levels of brain activity and arousal
-The cerebellum-receive sensory and motor inputs, coordinates patterns of movement


5) The Diencephalon
-contains the thalamus (sensory and motor nuclei)
-contains the hypothalamus (autonomic motor system integration, feeding and drinking)


6 ). The Telencephalon (Cerebral Hemispheres)
-contain cortex (the top layers) for higher function of sensory perception, movement and higher cognitive functions
-contains the basal ganglia (movement)
-Contains the hippocampus “involve din memory storage
-Contains amygdale involved in emotion

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