B.Pharmacy 1st semester Uploaded by Ms.Sapna in Pharmacology MMCP,Mullana,MM(DU) Mullana,Ambala-133207 (Haryana). In this ppt we have discussed the various functions of nervous system. Nervous system divided into two parts the central nervous system & the peripheral nervous system. Reflex action is a sudden and involuntary response to stimuli. It helps organisms to quickly adapt to an adverse circumstance that could have the potential to cause bodily harm or even death. Pulling our hands away immediately after touching a hot or cold object is a classic example of a reflex action. Reflex actions happen through the reflex arc, which is a neural pathway that controls the reflexes. The receptor here is the sense organ that senses danger.

1. REFLEX ACTION &
AUTONOMIC NERVOUS
SYSTEM
PRESENTED BY : Ms. SAPNA
MMCP
ASSISTANT PROFESSOR
PHARMACOLOGY

2.  Reflex - Rapid, involuntary Motor
Response to Stimulus
 Reflexes may:
– Inborn (Intrinsic) or Learned (Acquired)
– Involve only Peripheral Nerves & Spinal Cord
– Involve Higher Brain Centers as Well

3.  5 Components of Reflex Arc
– Receptor – Site of Stimulus
– Sensory Neuron – Transmits Afferent Impulse to
CNS
– Integration Center – Monosynaptic or Polysynaptic
Region within CNS
– Motor Neuron – Conducts Efferent Impulses from
Integration Center to Effector
– Effector – Muscle Fiber or Gland that Responds to
Efferent Impulse

6. ReflexArc

8.  Superficial reflexes ---
plantar,abdominal,corneal.conjuctival,cremastric
 Deep reflexes---- biceps,triceps,knee,ankle jerks
 Spinal
 Cranial

9.  Segmental
 Intersegmental
 suprasegmental

10.  Monosyneptic--- strech reflex
 Di-syneptic---- Golgi tendon Reflex
 Polysyneptic---- withdrawal reflex

11.  For Skeletal Muscles to Perform Normally:
– Golgi Tendon Organs (Proprioceptors)
 Constantly Inform Brain as to State of Muscle
– Muscle Spindles
 Stretch Reflexes
 Maintain Healthy Muscle Tone

12. Autonomic Nervous System

13. Definition
The portion of the nervous
system that controls most
visceral functions of the body is
called the autonomic nervous
system (ANS).
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14. Definition
Or it is the motor nervous
system that controls glands,
cardiac muscle, and smooth
muscle.
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15. • The ANS is part of the peripheral nervous system
and it controls many organs and
muscles within the body.
•In most situations, we are unaware of the workings of
the ANS because it functions in an involuntary,
reflexive manner.
•For example, we do not notice when blood vessels
change size or when our heart beats
faster.
•However, some people can be trained to control
some functions of the ANS such as
heart rate or blood pressure.

17. The primary target organs of the
ANS
The viscera of the thoracic and
abdominal cavities and
some structures of the body
wall, including cutaneous blood
vessels, sweat glands, and
piloerector muscles.
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18. Control
Autonomic literally
means “self-governed.”.
The ANS usually carries out its
actions involuntarily, without our
conscious intent or awareness, in
contrast to the voluntary nature of
the somatic motor system.
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19. Visceral effectors
Visceral effectors do not depend
on the ANS to function, but only
to adjust their activity to the
body’s changing needs.
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20. Visceral effectors
The heart, for example, goes on
beating even if all autonomic
nerves to it are severed, but the
ANS modulates (adjusts) the
heart rate in conditions of rest
or exercise.
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21. Visceral effectors
If the somatic nerves to a
skeletal muscle are severed, the
muscle exhibits flaccid
paralysis—it no longer
functions.
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22. Visceral effectors
But if the autonomic nerves to
cardiac or smooth muscle are
severed, the muscle exhibits
exaggerated responses
(denervation hypersensitivity).
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24. striking characteristics of the ANS
The rapidity and intensity.
For instance,
Within 3 to 5 seconds it can increase the heart rate
to twice normal.
Within 10 to 15 seconds the arterial pressure can
be doubled.
The arterial pressure can be decreased low
enough within 10 to 15 seconds to cause fainting.
Sweating can begin within seconds, and the
urinary bladder may empty involuntarily, also within
seconds.
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25. Autonomic System
• Two divisions:
– sympathetic
– Parasympatheitic
• Control involuntary functions
– heartbeat
– blood pressure
– respiration
– perspiration
– digestion
• Can be influenced by thought and
emotion

28. Sympathetic N.S. Parasympathetic N.S.
Like the accelerator of
your car
Mobilized the body for
action
Preganglionic: short, synapse
within the lateral & collateral
ganglia
Postganglionic: long
Has a wide distributions
Like the brakes in your car
Slows the body down to
keep its rhythm
Enables the body to
conserve and store energy
Preganglionic: long, synapse
within the terminal ganglia
Postganglionic: short
Has a restricted distributions

29. THANK YOU