The nervous system is unique in the vast complexity of
thought processes and control actions it can perform. It receives literally
millions of bits of information from the different sensory organs and integrates
all these to determine the responses to be made by the body. Together with the
endocrine system; it control important aspects of the body function and
maintain homeostasis. For descriptive purpose, the parts of nervous system
could be classed as follows
thought processes and control actions it can perform. It receives literally
millions of bits of information from the different sensory organs and integrates
all these to determine the responses to be made by the body. Together with the
endocrine system; it control important aspects of the body function and
maintain homeostasis. For descriptive purpose, the parts of nervous system
could be classed as follows
1.
The central nervous system (CNS) consisting of
the brain and spinal cord.
The central nervous system (CNS) consisting of
the brain and spinal cord.
2.
The peripheral nervous system (PNS) consisting
of all the nerves outside the brain and spinal cord. The PNS comprises 12 pairs of cranial nerves
and 31 pairs of Spinal nerves. It is useful to consider the functional parts
within the PNS.
The peripheral nervous system (PNS) consisting
of all the nerves outside the brain and spinal cord. The PNS comprises 12 pairs of cranial nerves
and 31 pairs of Spinal nerves. It is useful to consider the functional parts
within the PNS.
Sensory division (Afferent)
and motor division (efferent)
and motor division (efferent)
The third part is called
the mixed. The motor division is in turn sub-classed into ANS (autonomic
nervous system) functioning for the innervations of smooth and cardiac muscles
(involuntary Muscles). The second part is somatic nervous system which
innervate the voluntary muscles (skeletal muscles).
the mixed. The motor division is in turn sub-classed into ANS (autonomic
nervous system) functioning for the innervations of smooth and cardiac muscles
(involuntary Muscles). The second part is somatic nervous system which
innervate the voluntary muscles (skeletal muscles).
The Autonomic Nervous system
The autonomic nervous system is also known as the
involuntary part of the Nervous system controls the function of the body which
are carried out automatically i.e. it is not under the will for the purpose of
description and convenience it is
divided into two parts viz: Sympathetic and parasympathetic nervous system.
involuntary part of the Nervous system controls the function of the body which
are carried out automatically i.e. it is not under the will for the purpose of
description and convenience it is
divided into two parts viz: Sympathetic and parasympathetic nervous system.
Sympathetic and
parasympathetic nervous system (Thoracolumber outflow) has 3 neurons conveying
impulses from the origin in the hypothalamus and the medulla oblongata to the
effectors organs and tissues. The parasympathetic nervous system (Craniosacral
outflow) has two neurons involved in the transmission of impulses from their
source to the effector’s organs.
parasympathetic nervous system (Thoracolumber outflow) has 3 neurons conveying
impulses from the origin in the hypothalamus and the medulla oblongata to the
effectors organs and tissues. The parasympathetic nervous system (Craniosacral
outflow) has two neurons involved in the transmission of impulses from their
source to the effector’s organs.
Functions
Sympathetic
*Similar effect to hormones
* prepare the body to deal with excitement
* prepares the body to deal with stressful situations.
* Mobilizes the body for “fight or flight situations
Parasympathetic
·
Slows down body processes except the digestion
and absorption of food
Slows down body processes except the digestion
and absorption of food
·
It is a pace maker, allowing restoration
processes quietly and peacefully
It is a pace maker, allowing restoration
processes quietly and peacefully
