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.
short notes of cholestrol
Explain Major Histocornpatability Complex (MHC) Major histocompatability complex is also known as the Human Leukocyte Antigen (HLA). MHC molecules are important components of t
Which substance is NOT likely to have been formed by glaciers: dike
How are babys produced
Explain Cytoplasmic Vacuoles Figure illustrates the structure of vacuoles. These are the voids in the cytoplasm which store small molecules such as water, ions, sucrose and am
Atmosphere: Atmosphere is an envelope of the most useful gases that cover the planet earth. It makes our planet unique and enables life to prosper. If the earth did not have a
Define the both macronutrientand micronutrient. An element necessary in large amounts (usually > 50 mg/kg in the plant) for the growth of plant is called a macronutrient and in
Explain the term Liming - Decreasing Soil Acidity Acid soils can be managed in two ways, viz. either by growing crops suitable for particular soil pH or by treating the soils w
Explain Cough reflex Actions - Respiratory Process Cough reflex causes cough due to irritation of some receptors in tracheo-bronchial tree. It is a protective reflex. The irrit
Ask question #Minimum 100 words accept231
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd