Define the sympathetic nervous system, Science

Assignment Help:

Define the Sympathetic Nervous System

The sympathetic component of the autonomic nervous system is concerned with in- creasing the level of arousal and energy expenditure - primitive 'fight or flight' behaviour at times of stress. Alike the parasympathetic nervous system, the central integrating center for sympathetic activity is within the hypothalamus. This may be influenced by higher cortical centre. Efferent fibres descend from the hypothalamus within the intermediolateral columns of the spinal cord. As sympathetic fibres emerge from the central nervous system at spinal segments TI (thoracic) to L5 (lumbar), the sympathetic system is also known as the thoraco-lumbar outflow. Here 3 neurons are involved in covering impulses from the hypothalamus and medulla oblongata to effectors organs and tissues.

Neuron - 1: has its cell in the brain and its fibre extends to the spinal cord.

Neuron - 2: has its cell in lateral column of gray matter in the spinal cord.

Neuron - 3: has its cell in a ganglion (small mass of nerve tissue containing the cell bodies of the neuron) and terminates in the organ or tissue supplied.

 The preganglionic motor neurons of the sympathetic system arise in the spinal cord (lateral group column). They pass into sympathetic ganglia which are organized into two chains that run parallel to and on either side of the spinal cord. The neurotransmitter of the preganglionic sympathetic neurons is acetylcholine (ACh). It stimulates action potentials is the postganglionic neurons. The neurotransmitter released by the postganglionic neurons is noradrenaline (also called norepinephrine). The action of noradrenaline on a particular gland or muscle is excitatory in some cases, inhibitory in others.


Related Discussions:- Define the sympathetic nervous system

Disposal op carcass, DISPOSAL OP CARCASS : After the experiment with a...

DISPOSAL OP CARCASS : After the experiment with an animal is over, the dead animal, i.e. carcass should not be left in the laboratory. The dead animals start decaying and putr

Explain the filiform papillae, Explain the Filiform papillae These are ...

Explain the Filiform papillae These are long and slender and are the smallest of the three types of papillae. They are found to be most numerous on the edges and anterior two t

Food microbiology, discuss six major topics of microbiology

discuss six major topics of microbiology

Phase diagram for single component system, why don''t we have a crtical poi...

why don''t we have a crtical point on the solid liquid equilibrium line as we have on the liquid-vapour line...

Nursing responsibilities, what are the different types ofnursing responsibi...

what are the different types ofnursing responsibilities in lab test

DTA., Identification of curves

Identification of curves

Objectives of electricity and water in a laboratory, Objectives After c...

Objectives After completing this exercise you should be able to: 1. Locate the source and control points of gas/electricity/water supply in the lab you have visited, 2. D

Amoeba, what is Amoeba shaped like

what is Amoeba shaped like

Explain main factors that influence mass movement, Discuss main factors tha...

Discuss main factors that influence mass movements. Ans) Things as if climate and food availability will make a big dissimilarity if it is too cold, too dry then people will re

#space, if the moon is 240000 miles from earth how far is that in scientifi...

if the moon is 240000 miles from earth how far is that in scientific notation.

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