BIOLOGICAL PRESENTATION

1. CONTROL AND COORDINATION
Nervous System

2. The changes in the environment to which living organisms
respond are called stimuli. Eg :- heat, cold, sound, smell, taste,
touch, pressure, gravity, water etc.
Living organisms respond to stimuli in the form of body
movements.
Coordination :-
For a proper response to a stimulus many organs in the body
should work together. The working together of various organs in
an organism to produce a proper response to a stimulus is called
coordination.
i) In animals control and co ordination is done by the nervous
system and endocrine system.
ii) In plants control and co ordination is done by chemical
substances called plant hormones or phytohormones.

3. Coordination in animals
In animals control and co ordination is done by
the –
Nervous system
ENDOCRINE SYSTEM

4. Nervous system of Human
Nervous
system
CNS PNS
Central nervous system includes
Brain and Spinal Cord .
Peripheral nervous system includes cranial
nerves and Spinal nerves .

5. NEURON
(Nerve Cell)
Neuron is the structural and functional
unit of nervous system .
Neuron has following parts.
1. Cyton- It is main cell body with
nucleus ,cell organelles and nissil’s
granules. From Cyton ,dendrites
and axon are arised.
2. Axon- Axon is the long process
,conducts nerve impulse. It is
coated by Myelin sheath. Uncoated
points are called as “Ranvier Node”.
Terminal points of axon are known a
“Teledendria”.

6. Synapse-The junction between two neurons or with
muscles is called synapse.

7. Human Brain
Brain is the most important part of
our nervous system.
It is present inside our skull and
protected by cranium.
It is covered by three membranes
called “Meninges” filled with a
fluid called cerebrospinal fluid .
These membranes protect the
brain from shocks.

8. Structure of Human Brain
Brain is divided into three
regions –
1.Fore brain
2.Mid brain
3.Hind Brain

9. Fore brain includes “Cerebrum &
Thalamus”.
Cerebrum – It is the biggest
part of the brain. It is divided
into two hemisphere. Each
hemisphere is divided into
four lobes –
Frontal – Muscular activity
Occipital - Visual reception
Temporal –Auditory reception.
Parietal - Touch ,smell ,
temperature and conscious
association.
Fore brain is the thinking
part of the brain .It controls
voluntary actions , touch ,
smell, hearing ,mental
activities learning ,Memory
and emotions.

10. Mid brain –It connects forebrain
and hind brain. It controls
reflexes involving eyes and ears .
Hind brain-It includes three parts-
Cerebellum- It is second big part
of brain.It controls muscular
movement, body posture and
equilibrium .
Pons- it controls respiratory
activities.
Medulla oblongata- It controls
involuntary activities like
coughing ,vomiting, sneezing,
blood pressure etc.

11. The spinal cord starts
from the brain (Medulla
Oblongata) and extends
through the vertebral
column. It has 31 pairs of
spinal nerves.
It carries messages to
and from the brain. It also
controls reflex actions.
Spinal cord has “Gray
matter” surrounded by
“White matter”. Sensory
and motor nerve are
arised from spinal cord.

12. Reflex action is a sudden,
unconcious and involuntary
response of the effectors to a
stimulus.
Ex :- We suddenly
withdraw our hand if we
suddenly touch a hot object.
In this reflex action, the
nerves in the skin (receptor)
detects the heat and passes
the message through the
sensory nerves to the spinal
cord. Then the information
passes through the motor
nerves to the muscles
(effector) of the hand and we
withdraw our hand.

13. The pathway of a reflex
action is called reflex arc.
In a reflex arc the
stimulus is received by
the receptors (sense
organs) and it passes
through the sensory
nerves to the spinal cord.
From the spinal cord the
information passes
through the motor nerves
to the effectors
(muscles/glands) for the
response.

14. Peripheral Nervous system
Somatic nervous system(SNS)
It is voluntary nervous system. It
is associated with the
voluntary control of body
movement . It includes cranial
nerves and spinal nerves.
Autonomic nervous system(ANS)
It is non-voluntary nervous
system. It is of two type-
(i) Sympathetic Nervous
system- This system makes
our body for action.
(ii) Para sympathetic nervous
system- This system brings
our body in resting
condition.