Describe the basic working of cerebral hemisphere, Biology

Assignment Help:

Q. How is it structurally explained that the motor activity of the left side of the body is controlled by the right cerebral hemisphere and the motor activity of the right side of the body is controlled by the left cerebral hemisphere?

In the cerebral hemispheres there are neurons that centrally control and command muscle movements. These neurons are called superior motor neurons and they are located in a special gyrus of both frontal lobes called as motor gyrus or precentral gyrus. The superior motor neurons send axons that transmit impulses to the inferior motor neurons of the spinal cord for trunk, neck and limb movements and to the motor nuclei of the cranial nerves for eyes, face and mouth movements).

The fibers cross to the other side in specific areas of those axon paths about 2/3 of the fibers that go down the spinal cord cross at the medullar level forming a structure known as pyramidal decussation. The other (1/3) of fibers descends in the same side of their original cerebral hemisphere and cross only inside the spinal cord at the level where their associated motor spinal root exit and the fibers that command the inferior motor neurons of the cranial nerves cross to the other side just before the connection with the nuclei of these nerves.

The motor fibers that descend from the superior motor neurons to the inferior motor neurons of the spinal cord form the pyramidal tract. Injuries in this tract, for instance, caused by spinal sections or by spinal or central tumors may lead to tetraplegia and paraplegia.


Related Discussions:- Describe the basic working of cerebral hemisphere

Poultry and duck diseases-avian leucosis complex (alc), Avian leucosis comp...

Avian leucosis complex (ALC) The disease in poultry is caused by an RNA virus classified under avian type C Retrovirus group under the family Retroviridae. Epidemiology:

What is fehling's test - reduction tests, What is Fehling's test - Reductio...

What is Fehling's test - Reduction Tests? This test is answered by all reducing sugars which possess a free aldehyde or ketone group. All monosaccharides possess a free aldehyd

Formation of gemmules, Formation of Gemmules Throughout the formation...

Formation of Gemmules Throughout the formation of gemmules, masses of food - laden amoebocytes called archaeocytes feed on other cells and lay down in within them. They get s

Define guidelines of school children and adolescents, Define Guidelines of ...

Define Guidelines of School Children and Adolescents? 1) Do not skip breakfast. At least have milk, fruit and cereal. Some children prefer to flavour the milk with cereal or pr

Food-borne clostridium, Food-borne Clostridium Clostridium botulinum a...

Food-borne Clostridium Clostridium botulinum and Cl. perfringens, the two members of the group have been implicated in food-borne illnesses. C. botulinum causes classical food

Mollusca, An account of characters of mollusca

An account of characters of mollusca

What is the cell theory, Cell theory is a theory that asserts that the cell...

Cell theory is a theory that asserts that the cell is the ingredient unit of the living beings. Before the discovery of the cell, it was not examined that the living beings were

Explain the primary function of blood, Explain the primary function of bloo...

Explain the primary function of blood? The primary function of the blood to transport oxygen from the lungs to body tissues for interior respiration. The blood helps in maintai

What is mucic acid test and its principle, What is Mucic Acid Test and its ...

What is Mucic Acid Test and its principle? This is a specific test for galactose and is given by galactose as well as lactose, which is made up of galactose and glucose. Pr

Explain the metabolic aberrations of underweight, Explain the Metabolic Abe...

Explain the Metabolic Aberrations of Underweight? When energy intake falls below the minimal requirements, the body responds with an orderly physiologic adaptation involving th

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd