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The Nervous System
 Control and coordinate the body parts and
processes.
 It receives sensory stimuli from internal and
external environments.
 It responds in a coordinated manner.
Two Division Of The Nervous System
The central nervous system (CNS)
 Made up of the brain and spinal cord.
 The control center of the body.
 Receives and transmits messages
to all body parts.
The peripheral Nervous System
 Made up of cranial and spinal
nerves.
 Take messages to and from
CNS.
Autonomic Nervous System (ANS)

regulates the functions of our internal organs
such as the heart, stomach and intestines.

The ANS is part of the peripheral nervous system.
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
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also controls some of the muscles within the
body.
We are often unaware of the ANS because it
functions involuntary and reflexively.
For example, we do not notice when blood
vessels change size or when our heart beats
faster.
Cerebrum
Main Parts of The Brain

The bulk of the brain

Responsible for voluntary actions.

Control speech, thinking, emotions and
personality.

Coordinates messages to and from the brain.
Cerebellum

Controls muscular coordination, balance,
posture and muscle tone.
Medulla Oblongata
Control involuntary activities of internal organs
such as heart beat, breathing, peristalsis,
temperature regulation.
Hypothalamus

Forms the floor and sides of the brain.
Control:

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Blood pressure
Heart rate
Peristaltic gut movements
Pituitary Glands

Water content

Body temperature

Produce antidiuretic
hormone (ADH)
Nerve and Neurone
Nerve
 A bundle of many nerve fibres connecting the
central nervous system with parts of the body.
Neurone
 A nerve cell, specialized for the rapid transfer
of electrical impulses.

It send messages in
one detection.
Types of neurones
Sensory Neurones
 Collect information from the body parts and
transmit it towards the brain and spinal cord
(CNS).
Voluntary Action


Types of Actions
Actions which are under the person’s
control.
The person decides to carry out the
action.
Involuntary Action
 An action that is not under the person’s control.



It happens automatically, without
the person thinking about it.
The simplest type of involuntary
action is a reflex action.
This is an automatic response, over which you
have no conscious control.
Spinal Reflex Action




This gives us a quick response to
stimulus.
Impulses pass from sense organ to
the spinal cord and straight back to
the effectors muscles.
This quickly moves the body parts away.
This serves to protect the part of the body near the
dangerous external stimulus.


When You touches Something Hot
When hand touches hot plate temperature and
pain receptors in skin are stimulated.
Sensory neurons then conduct impulse along the
arm, to spinal cord.


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The sensory neurons enter the dorsal dorsal root
of spinal cord.
Impulses passes across spinal cord to relay
neurons.
After making a quick decision, relay then send
impulse to motor neurons.


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Motor neurons leave spinal cord at the ventral
root.
Motor neurons take impulse to the effectors
muscle of arm, telling them to contract .
Arm is then removed from hot plate.
Knee- Jerk Reflex
 There is no relay neurone.


The stimulus passes directly from sensory to
motor neurone.
A doctor perform this to check that your nervous
system actions are working properly.
Conditioned Reflex
Some reactions have to be learned
first.
 After that they can be done without
conscious thought.

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The child learning to walk and riding a
bicycle are examples.
At first they are voluntary movements.
Later they are performed without conscious
thought.
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They are called condition reflexes because they
have to be acquired through learning.
Once learned they are controlled by part of the
brain which is not concerned with conscious
thoughts.
Endocrine System


System of coordination and
communication in the body.
Uses hormones secreted by
endocrine glands.
Hormone


A chemical substance produced
by gland and carried by the
blood.
This affect one or more body
organs.
Types of Glands
Endocrine Glands


Secrete and release hormones directly into the
bloodstream.
Example the pituitary gland , secretes ADH into
the blood.