--%>
Assignment Help - homework help

Motor activity of left side of body or right side of body

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

E

Expert

Verified

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

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

Motor fibers which descend from superior motor neurons to inferior motor neurons of spinal cord form the pyramidal tract. Injuries in this tract, for illustration, caused by the spinal sections or by central or spinal tumors might lead to the paraplegia and tetraplegia.

   Related Questions in Biology

  • Q : Description of carcinogens Provide a

    Provide a brief description of the term carcinogens?

    		•
  • Q : Degree of control - Taxonomy of

    This is a research process, which influence the validity and reliability of research findings Case studies, field studies, laboratory studies and other forms of studies have different levels of control. A case study describes what had happened in the past. The researc

    		•
  • Q : Systems approach Systems approach This

    Systems approach This school of recent origin having developed in late 1960's. it is an integrating approach which considers the management in its totally based on e

    		•
  • Q : Equity Theory of Work Motivation -

    This theory was formulated by J.S. Adams. It is based on the assumption that members of an organization experience strong expectations of justice, balance and fairness in treatment by the organization. When a person feels that he is being treated unfairly by the organization, these feelings can h

    		•
  • Q : Limitations of the contingency approach

    Limitations of the contingency approach In spite of the various contributes contingency approach has not been acknowledged as a unified theory of the management beca

    		•
  • Q : Describe Productivity Improvement

    Productivity Improvement: Productivity is affected by a diversity of factors, from the equipment employed to the attitude of the staff to the quality of materials. Enhancing productivity needs those factors such as these be addressed and mitigated and

    		•
  • Q : Structures participate in the human

    Name the structures which participate in the human auditory sensitivity?

    		•
  • Q : Spermatocyte I and spermatogonium

    Explain the difference between spermatocyte I and spermatogonium?

    		•
  • Q : Define the term bone matrix Define the

    Define the term bone matrix? Also describe its main components?

    		•
  • Q : Parasympathetic and sympathetic neural

    What do you mean by the antagonism between parasympathetic and the sympathetic neural actions?

    		•