science holidays homework ppt submitted to; mrs. anita malhotra science teacher of dav8pkl

2. • “ It is the type of coordination present
between the cells or different organs
within the body of multicellular
organisms. In this kind of coordination
a group of cells releases specific
chemicals, which regulates the activities
of other cell of the body.”

3.  In animals Nervous
system & Hormonal
system plays an
important role in
control & co-
ordination.
 In plants control and
coordination is done by
chemical substances
called plant hormones
or phytohormones.

4. • Coordination in animals :- In animals control and
co ordination is done by the Nervous system and
Endocrine system.
• Nervous system- The nervous system is an organ
system containing a network of specialized cells
called neurons.
• Types of Nervous system-
• 1.Central Nervous system(CNS) – It includes –
Brain & Spinal cord.
• 2.Peripheral Nervous system( PNS)- It includes a.
Somatic nervous system(SNS)- it is also known as
voluntary nervous system & associated with the
voluntary control of body movements via skeletal
muscles.

5. Neurons
• Neurons(Nerves)- The structural & functional
unit of Nervous system called as Neurons.

6. Structure of Neurons
• It has a cell body called cyton containing a
nucleus and cytoplasm. It has several
branched structures called dendrites. It has a
long nerve fiber called axon which may
covered by Schwann cells & a protective
covering called Myelin sheath. Schwann cells
separated by a gap called as Nodes of Ranvier.
Neuron ends by bulb like structure at nerve
ending called as Synaptic Knob.

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

8. Nerve Impulse
• Nerve impulse -Messages
pass through the nerve
cell in the form of
chemical and electrical
signals called nerve
impulse. The dendrites
receive the information
and starts a chemical
reaction which produce
electrical impulse which
passes through the axon.

9. Reflex Action
• Reflex action  Reflex action is a sudden,
unconscious 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
(effectors) of the hand and we withdraw our
hand.

10. Reflex Arc
• REFLEX ARC- 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.

11. Role of Brain
• The brain plays no action as the reflex action
takes place at the level of spinal cord. But later
brain is informed by the spinal cord and then
later the thinking part of the action is done by
brain. But brain is not active during A reflex
action. Difference between Reflex action &
walking. Reflex action 1. It is inborn, involuntary (
automatic) & require for survival & protection.
Walking- 1.It is acquire by learning, under control
of brain(voluntary) & for various function

12. Human Brain 

13. Human Brain
• The brain is the main coordinating centre in the human body. It is
protected by the cranium. It is covered by three membranes called
meninges filled with a fluid called cerebrospinal fluid which protects
the brain from shocks. The brain has three main parts. They are fore
brain, mid brain and hind brain.
• i) Fore brain  consists of the cerebrum and Thalamus. It is the
thinking part of the brain and controls voluntary actions. It controls
touch, smell, hearing, taste, sight, mental activities like thinking,
learning, memory, emotions etc.
• ii) Mid brain  controls involuntary actions and reflex movements
of head, neck, eyes etc.
• iii) Hind brain  consists of cerebellum, pons and medulla.
Cerebellum controls body movements, balance and posture. Pons
controls respiration. Medulla controls heart beat, blood pressure,
swallowing, coughing, sneezing, vomitting etc.

14. Spinal Cord
• Spinal cord  The
spinal cord starts from
the brain 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.

15. Muscles are 3 types 
• Skeletal muscles (Voluntary muscles /Striated muscles)-
attached with bones & having alternate dark and light
bands.
• Smooth muscles (Involuntary muscles /Non striated
muscles) present in internal body organs.
• Cardiac muscles- present in heart Nerve impulse
reaches to muscle which resulted into muscular action.

16. ENDOCRINE GLANDS IN HUMAN
BEINGS

17. Endocrine Glands
• Endocrine glands in human beings  The
endocrine glands are also known as Ductless
gland. The endocrine glands produce chemical
substances called as Hormones, and it directly
diffuses into blood and reaches to target organ.
• The endocrine glands in our body are  pineal,
hypothalamus, pituitary, thyroid, parathyroid,
thymus, pancreas, adrenal, testes and ovary.

18. Glands In our Body
• Hypothalamus gland –it forms various
releasing or inhibiting hormones & regulate
the Pituitory glands for further function.
• Pituitory gland- It function in response of
hypothalamus & releases hormones. For ex.
GH-Growth hormones – It help for body
growth.

19. Hypothalamus, Pituitary, pineal Gland

20. Glands In our Body
• Thyroid glands- a pair of glands present in neck region, which forms
thyroxin hormone in response of TSH of pituitory.
• Thyroxin hormone - Thyroxin controls the metabolism of
carbohydrates, fats and proteins and helps in proper growth. If the
diet is deficient in iodine it causes deficiency of thyroxin leads to
cause the goiter in which enlargement of thyroid glands cause the
swelling of neck. The goiter disease are generally found in people
living in northern sub-himalayan areas where the diet are deficient
of iodine. Hence one must take the iodized salt. Excess secretion of
thyroxin cause exophthalmia (protrusion of eyes)
• Parathyroid glands- two pair of parathyroid glands which are close
to thyroid gland. It secretes the parathormone which require to
control the Calcium and phosphorous. It deficiency cause Cramps
and spasms Thymus gland- It is present near the heart & secretes
the hormone Thymosine. It is required for maturation of T-
lymphocytes which require for immunity.

21. Thyroid and Parathyroid glands

22. Glands In our Body
• Adrenal glands –> a pair of glands present over the Kidney, Adrenal
gland have two parts-
• Outer Adrenal cortex
• inner medulla.
• Adrenal cortex - stimulated by ACTH & forms 3 hormones namely -
Gluco-corticoids, Mineralo-corticoids, Androgens. . It requires for
Glucose metabolism, mineral balance, secondary sexual characters
respectively.
• Adrenal medulla- it produces two hormones – Adrenaline & Nor
adrenaline hormone – It is also known as Emergency hormone or
hormone of 3 F – Fight,Flight,Freight. It increase of heart beats,
blood pressure, rate of breathing , causes rapid contraction of rib
muscles etc to full fill the increasing demand of body. Nor
adrenaline hormone- It require for normal functioning of heart
beat, blood pressure, breathing rate etc.

23. Adrenal Glands

24. EFFORTS BY:
JASHANPREET
10TH C
DAV SR. SEC. PUBLIC
SCHOOL
SECTOR 8
PANCHKULA