a brief description on division of nervous system,SOMATIC NERVOUS SYSTEM and working, SENSORY DIVISION and MOTOR DIVISION, SENSORY RECEPTORS, CATEGORIZATION OF SENSORY RECEPTORS, TYPES OF NERVES, SPINAL NERVES, CRANIAL NERVES, REFLEX ARCS, AUTONOMIC NERVOUS SYSTEM and it's properties and division, PARASYMPATHETIC NERVOUS SYSTEM, SYMPATHETIC NERVOUS SYSTEM

1. NERVOUS
SYSTEM
Function of somatic and autonomic nervous system

2. NERVOUS SYSTEM
DEFINITION
‘ The network of nerve
cell and fiber which transmit
nerve impulses b/w parts of
body. ’

3. DIVISION OF NERVOUS SYSTEM

4. SOMATIC NERVOUS SYSTEM
VOLUNTARY NERVOUS SYSTEM.
DEFINITION
“part of peripheral nervous system
associated with the voluntary
control of body movement via
skeletal muscles.”

5. WORKING
When stimulated, sensory receptors
send impulses to sensory neurons.
 Sensory neurons then send impulses
to the central nervous system.
 For example, walking by flowers will
stimulate chemoreceptors and
photoreceptors.

6. SENSORY DIVISION
SNS consists of somatic nervous system
consists of afferent nerves or
sensory nerves, and efferent nerves or
motor nerves.
The somatic nervous system controls all
voluntary muscular systems within the
body, and also mediates involuntary reflex
arcs.

7. SENSORY RECEPTORS
SENSORY RECEPTORS are cells that send info. about changes in
external as well as
internal environment
These changes
are called STIMULI

8. CATEGORIZATION OF SENSORY
RECEPTORS

10. TYPES OF NERVES

11. SPINAL NERVES
 31 pairs and 62 spinal nerves.
 Each spinal nerve has a VENTRAL ROOT and a
ROOT.
 VENTRAL ROOT :
has motor fibers , efferent fibers
transmit message from CNS to effectors
cell body found in the spinal cord gray matter
 DORSOL ROOT :
sensory fibers , afferent fibers
carry information from sensory receptor to CNS

12. CRANIAL NERVES
 12 pairs of cranial nerves and 24 total cranial
nerves
 Transmit information on the senses of sight ,
smell , balance , taste and hearing from the
special sensory receptors
 Also transmit information from general sensory
receptors in the body , largely from the head .
 Information is received and processed by the
CNS and then the response travels via the
cranial nerves to the skeletal muscle to control
movements in face and throat e.g. smiling and
swallowing .

14. REFLEX ARCS
 Although the somatic nervous
system is generally considered to be
under conscious control, some
actions of the system occur
automatically.
 For example, if you accidentally step
on a tack with your bare foot, your
leg may recoil before you are even
aware of the pain.
 This rapid response (a reflex) is
caused by impulses that travel a
pathway known as a reflex arc.

15. REFLEX ARCS
Sensory receptors react to the sensation of the tack and send an impulse to sensory
neurons.
Sensory neurons relay the information to the spinal cord.
An interneuron in the spinal cord processes the information and forms a
response.
A motor neuron carries impulses to its effector, a muscle that it stimulates.
The muscle contracts and your leg moves.
1
2
3
4
5

17. AUTONOMIC NERVOUS
SYSTEM The autonomic nervous system regulates activities that are involuntary, or not
under conscious control.
 The autonomic nervous system consists of two parts, the sympathetic nervous
system and the parasympathetic nervous system.
 In general, the sympathetic and parasympathetic systems have opposite effects on
each organ.
 Consists of only motor nerves.
 Within the brain, the autonomic nervous system is regulated by the
hypothalamus. Autonomic functions include control of respiration , cardiac
regulation (the cardiac control center), vasomotor activity (the vasomotor
center), and certain reflex actions such
as coughing, sneezing, swallowing and vomiting.

22.  Sometimes called the rest and digest system.
 The parasympathetic system conserves energy as it slows the
heart rate, increases intestinal and gland activity, and relaxes
sphincter muscles in the gastrointestinal tract.
 The parasympathetic nervous system consists of cells with
bodies in one of two locations: the brainstem (Cranial Nerves
III, VII, IX, X) or the sacral spinal cord (S2, S3, S4). These are the
preganglionic neurons, which synapse with postganglionic
neurons

23. REST
RELAX
RUMINATE

24.  The sympathetic nervous system activates what is often termed the fight or
flight response.
 the sympathetic nervous system can accelerate heart rate, widen bronchial
passages, decrease motility of the large intestine, constrict blood vessels,
increase peristalsis in the esophagus, cause pupillary dilation, piloerection
(goose bumps) and perspiration (sweating), and raise blood pressure
 Sympathetic neurons are frequently considered part of the peripheral nervous
system (PNS), although there are many that lie within the central nervous
system (CNS).
 Sympathetic nerves originate inside the vertebral column, toward the middle of
the spinal cord in the intermediolateral cell column (or lateral horn), beginning
at the first thoracic segment of the spinal cord and are thought to extend to the
second or third lumbar segments.