The nervous system controls and regulates all body activities. It has three main properties: sensitivity, conductivity, and responsiveness. The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). The CNS includes the brain and spinal cord, while the PNS connects the CNS to the body and is composed of nerves. The PNS can be further divided into the somatic and autonomic nervous systems.
2. Introduction:-
• Nervous system is the chief controlling and coordinating system of the
body.
• It control and regulates all activities of the body, whether voluntary or
involuntary.
• This is based on the special properties:-
1. Sensitivity
2. Conductivity
3. responsiveness
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3. General Functions of the
Nervous System
Sensory:-
• The sensory impulses are transmitted by the sensory (afferent) nerves from
periphery ( skin, mucous membranes, muscles, tendons, joints, and special
sense organs) to the central nervous system (CNS).
Motor:-
• The motor impulses are transmitted by the motor (efferent) nerves from
the central nervous system to the periphery (muscle and glands)
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4. Classification of Nervous system
Central nervous system (CNS)
• com p o sed of:-
1. Brain
2. Spinal cord
Peripheral Nervous System
Spinal nerves
• 12 pai
rs of
cranial
nerves.
• 31 pai
rs of
spinal
nerves.
A utonomic N.S. S o m atic N.S.
Sympathetic Parasympathetic
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5. Central nervous system
• The central nervous system
(CNS) is composed of the
brain and spinal cord.
• These neurons cannot
regenerate if damaged.
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6. Peripheral nervous system
• (PNS) is made up of peripheral
nerves that connect the CNS to
the rest of the body.
• These neurons can regenerate if
damaged.
• 12 pairs of cranial nerves.
• 31 pairs of spinal nerves.
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7. Peripheral nervous system…
PNS can be subdivided
into 2 divisions:
(1) Somatic
• Cranial & spinal nerves
connecting CNS to skin
& skeletal muscles
• Oversees conscious
activities
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8. Peripheral nervous system…
(2) Autonomic
• Cranial & spinal nerves connecting CNS to
heart, stomach, intestines, glands.
• It controls unconscious activities.
ANS divided into 2 part:-
1. Sympathetic:- Acts in emergency
2. Parasympathetic:-Counter acts the sympathetic ns
after the emergency.
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12. Cell type of Nervous System
• Nervous Tissue is composed of
two major cell types: neurons
and neuroglial cells.
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13. Neurons
• Neurons are made up of a cell body,
dendrites, and axons.
• Dendrites receive information.
• Axons send information.
• Larger axons are enclosed by sheaths of
myelin produced by Schwann cells.
• Narrow gaps in the myelin sheath
between Schwann cells are called nodes of
Ranvier.
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14. Neuroglial cells
• Provide physical
support, insulation
(myelin), and nutrients
for neurons.
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15. Structural Classification of Neurons
(1) Multipolar
• Many processes arising from cell body
• Brain or spinal cord
(2) Bipolar
• 2 processes (1 from each end of cell
body)
• Ear, eyes, nose
(3) Unipolar
• Single process extends from cell body
• Outside of brain & spinal cord
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16. Functional Classification of Neurons
Sensory Neurons – (afferent) have specialized receptor ends that sense stimuli and
then carry impulses from peripheral body parts to brain or spinal cord. Can be
unipolar or bipolar.
Interneurons – lie entirely within the brain or spinal cord; direct incoming sensory
impulses to appropriate parts for processing and interpreting.
Motor Neurons – (efferent) carry impulses out of the brain or spinal cord to
effectors (muscles, glands).
Interneurons and motor neurons are multipolar.
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