Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
Ask question how many years that our earth survived?#Minimum 100 words accepted#
Solar energy: The energy we get today from the fossil fuels like coal, is in reality sun's energy, trapped in them millions of years ago. Plants make their food and grow bec
What is Immunity? Amino acids are involved in giving immunity by maintaining the vulnerable surfaces of the body in such a way so as to resist infections. Most of the external
ethane covalent radius
Ultraviolet Radiations : The ultraviolet (UV) light has higher energy than visible light. Hydrogen lamps, deuterium lamps and other sources of ultra-violet are used for a variety
What are the ratios allowed for three year olds and Child Care Centers in Colorado and what is the citation of the rules that addresses ratios?
Explain Emphysema - Histotoxic Hypoxia Emphysema is a chronic respiratory disease where there is an over- inflation of the air sacs (alveoli) in the lungs, causing a decrease i
Non-renewable Resources: After learning about the renewable resources like water, forests etc., you would like to know what our non-renewable resources such as land, mineral,
Role of Communication in the Economic Development: This is as much as one-sixth of the world's population. In the year 1981,446 million Indians were illiterate, i.e., they co
Explain Cholesterol - Constituents of Bile Cholesterol: Cholesterol is an extremely important compound, a constituent of most cell membranes and the precursor of bile acids and
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd