All details related to the topic Controls and coordination for class 10 and Class 12.

1. CONTROL
AND
COORDINATI
ON

2. Some important terms
•Stimulus- any external or internal factor that
causes a living organism to react is called a
stimulus. (Pl: stimuli)
•Response- the specific reaction shown by a
living organism towards a stimulus
•Impulse- a electrical wave of excitation or
irritation that travels across a neuron and carries
specific messages.

3. Some important terms
•Receptors- group of organs that
receive sensory impulses and convey
them to the brain
•Effectors- group of organs that show
responses to a specific stimulus

4. Neuron-
• The fundamental structural and functional unit of the nervous
system that carries impulses across the body.

5. Structure of a neuron
A neuron is made up of two main parts;
a) Cyton
b) Axon
Cyton – also called cell body, this part of neuron
contains a large prominent nucleus in the center.
The cell membrane is branched into several cytoplasmic
branches called dendrites.
Dendrites receive the impulses.

6. Structure of a neuron
The cytoplasm is called neuroplasm.
Inside the neuroplasm are scattered several stainable
granules called Nissl granules.
B) Axon – The long cytoplasmic projection of the neuron that
extends from the cell body.
An axon is covered by an insulating membrane called
Neurolemna.
Axons carry the impulse they receive from the cyton. They usually
terminate into another neuron or an organ or gland or muscle.

7. Structure of a neuron
In some neuron there is an additional envelop inside the
neurolemna called the Myelin sheath which help in
faster conduction of the impulse.
Such neurons are called myelinated neurons and are
mostly present in cerebral medulla.
Impulse always travels from Cyton to Axon.

8. Types of Neurons
• Sensory neurons- Those neurons that carry impulses from the
receptors (sense organs)to the brain. These impulses are sensory in
nature.
• Motor neurons- Those neurons that carry impulses from the brain
to the effectors . These impulses are motor in nature.
• Associated neurons- They are also called mixed neurons as they
carry impulses both to and from the brain.

9. Types of Neurons
Sensory
Motor
Interneuron

10. Nerves
A bundle of neurons with a common envelop around the
axons called nerve membrane.
A nerve provides a common
pathway for the
electrochemical
nerve impulses that are
transmitted along each of the
axons

11. Types of Nerves
• Sensory nerves- Those nerves that carry impulses from the
receptors (sense organs)to the brain. These impulses are sensory in
nature.
• Motor nerves- Those nerves that carry impulses from the brain to
the effectors . These impulses are motor in nature.
• Mixed nerves- They are also called mixed nerves as they carry
impulses both to and from the brain. They are also called spinal
nerves.

12. NERVO
US
SYSTEM

13. Classification of the Human
Nervous System
The human Nervous System is classified into three
major divisions-
The Central Nervous System
The Peripheral Nervous System
The Autonomous Nervous System

14. Central Nervous System
 The CNS constitutes the main division of the Nervous system in
Human Beings.
 It comprises of two main organs concerned with control and
coordination-
A) The Brain
B) The Spinal Cord.

15. THE BRAIN

16. The Brain
• Location: Head region
• Protection: a) Body protection made up of immobile bones that
make up the skull. The skull is also called the Cranium.
b) Membranous protection in the form of three membranes called
the meninges. These three layers are called – Dura mater, Arachnoid
mater and Pia mater.
The cerebro-spinal fluid in between the three layers, protects the
brain further from

17. Meninges of the Brain

18. Parts of the Brain
Fore- Brain
The fore brain makes up the largest part of the brain.
The forebrain consists of
the cerebrum,
thalamus,
and hypothalamus (part of the limbic system)

19. Fore Brain
• Olfactory lobes:
Two small lobe like
structures situated in the
lower part of the anterior
brain.
Controls the sense of
smell

20. Fore Brain
The cerebrum is the largest, most prominent part of the
human brain. The longitudinal fissure partitions the
cerebrum into right and left hemispheres, which are
each separated into four lobes:
 Frontal
 Parietal
 Temporal
 Occipital
 The cerebrum consists of the cerebral cortex (outer
gray matter) and white matter.
 The cerebral cortex is configured into convolutions
(folds) that maximize surface area
 The interior white matter consists of myelinated
axons of neurons that link several regions of the brain

21. Lobes of the Cerebrum
 Frontal Lobe- associated
with reasoning, planning,
parts of speech, movement,
emotions, and problem
solving
 Parietal Lobe- associated
with movement,
orientation, recognition,
perception of stimuli
 Occipital Lobe- associated
with visual processing
 Temporal Lobe- associated
with perception and
recognition of auditory
stimuli, memory, and
speech

22. Fore Brain
Thalamus is between the cerebral cortex
and the midbrain, both in terms of its
location and its neurological connections.
Its function includes relaying sensation
and special sense signals to the cerebral
cortex, relaying motor signals from the
cerebral cortex, and the regulation of
consciousness, sleep and alertness.

23. Fore Brain
Hypothalamus
The hypothalamus is a portion of the brain that contains a number
of small nuclei with a variety of functions. One of the most
important functions of the hypothalamus is to link the
nervous system to the endocrine system via the pituitary gland
(hypophysis). The hypothalamus, is located below the thalamus,
just above the brain stem
The hypothalamus is responsible for certain metabolic processes and
other activities of the Autonomic Nervous System. It synthesizes
and secretes neurohormones

24. Mid Brain
• It consist of Crura cerebri
and corpora
Quadregemina.

25. Hind Brain
 Hind brain is made
up of three parts:
a) Cerebellum
b) Pons
c) Medulla oblongata

26. Cerebellum
 The hind part of brain. It is divided into cerebellar cortex and
cerebellar medulla.
 Cerebellar cortex has longitudinal fissures and not folds. While the
medulla looks like a branched tree.
 Cerebellum consists of 12% of the brain.
Functions:
a) It controls muscular co-ordination
b) It regulates body balance.

27. Medulla Oblongata
•The medulla contains the
cardiac, respiratory,
vomiting and vasomotor
centers and deals with
autonomic functions, such
as breathing, heart rate
and blood pressure

28. Pons Verolli
 The pons is a structure located on
the brain stem.
 The pons relays sensory
information between the
cerebellum and cerebrum, aids in
relaying other messages in the
brain, controls arousal, and
regulates respiration.

29. SPINAL
CORD

30. Spinal Cord- Structure
 The spinal cord is an extension
of the brain stem.
 It runs mid-dorsally through the
body and innervates the body.
 The Sectional view of the spinal
cord shows the outer white
matter and inner grey matter.
 The inter-neurons are present in
the gray matter and help in
reflexes.
 Spinal cord is protected by a set
of 33 bones called vertebral
column and the three
meninges.

31. Spinal Cord- Structure
•A central canal is filled with the cerebro-
spinal fluid.
•31 pairs of spinal nerves emerge out from
either sides of the spinal cord.
•Spinal nerves are mixed nerves as they
have the sensory as well as the motor
neurons in them.

32. Functions of the spinal cord
•Spinal cord conducts impulses
from the receptors to the brain as
well as from the brain to the
effectors.
•Spinal cord controls reflexes.

33. Reflexes
• A reflex is an involuntary, rapid response towards a stimulus with
the active participation of the brain. Reflexes are protective
responses against harmful stimuli.
For ex: If we touch a hot plate we recoil our hand immediately to
prevent it from getting burnt. This immediate and unconscious
response is called reflex
• Reflexes can be inborn or acquired.

34. Reflex Arc
 The path travelled by an
impulse during a reflex
response is called a reflex arc.
 A reflex arc begins from the
receptors passes through the
sensory neuron, passes via the
interneuron to the motor
neuron and then to the
effectors.

35. PERIPHE
RAL
NERVOU
S
SYSTEM

36. PNS
• The peripheral nervous system is composed of sensory neurons and
the neurons that connect them to the nerve cord, spinal cord and
brain, which make up the central nervous system. In response to
stimuli, sensory neurons generate and propagate signals to the
central nervous system which then processes and conducts signals
back to the muscles and glands.
• It is made up of 12 Pairs of Cranial Nerves and 31 pairs of spinal
nerves.

37. AUTONOMIC
NERVOUS SYSTEM

38. Plant Hormones
1. Auxin
This is the best known plant hormone and have many effects on the plant
growth. Experiments on plant hormones were initially performed by Charles
Darwin and his son Francis Darwin. They worked on the seedlings of the
canary grass and were amazed to observe that the direction of the growth of
the coleoptile (a sheath which protects the stem tip (plumule) of a
germinating grass seed) was influenced only when its tip was exposed to
light and not the base where the actual growth was taking place. They also
observed that when the coleoptile was illuminated from one side, it bent
towards the light but if the tips were chopped or covered with metal foil,
bending response would not occur. After watching this, Darwin concluded
that certain kind of 'influence' is generated at the tip which is then transmitted
to the base where the growth takes place. However he couldn't identify the
influence.

39. Functions of Auxin:
1. Cell enlargement: Auxin causes cell enlargement by solubilisation of
carbohydrates, loosening of cell wall micro-fibrils, synthesis of new wall material and
increase in respiration.
2. Prevention of lodging: Lower inter-nodes of the stem of cereals are long and
weak. AS a result the plant bends down or droops. Application of NAAM prevents
lodging.
3. Apical dominance: In many plants, apical bud suppresses the growth of lateral
buds. This condition is known as apical dominance. A plant with strong apical
dominance has little or no branching like in sunflower.
2. Gibberellin
These largely effects the shoots of the plants and have little or no effect on the
roots. It came under observation when some Japanese farmer noticed some
abnormally tall and thin seedlings on the rice field which never bore seeds. This
disease was called the foolish seedling disease or bakanae. E. Kurosawa found
that Gibberella fujikuroi is the causative organism of this disease which is a
fungus. Later on, Yabuta and Sumuki isolated Gibberellic acid which was
responsible for the rapid growth from the fungus.

40. Functions of Gibberellins:
1. In bolting: In rosette forming plants, inter-node growth is poor but large leaves
appear to rise arise in tufts. The inter-nodes suddenly elongate and the stem
becomes normal just before flowering. This is called bolting.
2. Parthenocarpy: Gibberellins have been found to be effective in inducing
parthenocarpy in tomatoes, apple etc.
3. Breaking of dormancy: These can effectively break the dormacy of potato tuber,
winter buds and seeds of many trees.
3.Cytokinin
Callus formation from inter-nodal segments of tobacco can proliferate only if
auxin is supplied with extract of vascular tissue, yeast extract, coconut milk or
DNA. This was observed by Skoog. Later, Miller showed that yeast extract
contains some growth regulators. This growth regulator was isolated from the
herring sperm DNA and yeast cells and was called as kinetin (6-
furfurylaminopurine). Letham named it as cytokinin.

41. Functions of cytokinin:
1. Cell division: These are found in a higher amount where rapid division is going
on.
2. Morphogenesis: Cytokinins promotes cell division and in the presence of auxin,
it promote cell division even in the meristematic tissues. In tissue culture, mitotic
division are accelerated when both auxin and cytokinin are present. The ratio of
high cytokinin and low auxin promote shoot buds in tissue culture.
3. Apical dominance: Cytokinin and auxin acts antagonistically in the control of
apical dominance.
4. Ethylene
It is the only gaseous growth hormone. It is produced by almost all the organs but
maximum production occurs in ripening fruits and senescent leaves. High
concentration of auxin leads to the formation of ethylene.
Functions of ethylene:
1. It helps in ripening of fruits.
2. Inhibition of stem elongation and stimulation of transverse growth by causing
increase in the girth of the plant and promotes horizontal growth.

42. 5. Abscisic Acid
It was discovered by Addicott and Wareing separately. They named it abscisin II
and dormin respectively. In 1967 it was decided to call it as abscisic acid (ABA). It
is major inhibitor of growth in plants and is antagonistic to all the three growth
promoters, especially GA. These are mainly produced in mature leaves but it is
also called synthesized in stems, fruits and seeds and then transported to other
parts through vascular tissues.
Function of abscisic acid
1. It hastens the formation of abscission layer and senescence.
2. Transpiration: It helps in closing of stomata by causing potassium ions to leave
the guard cells during periods of water shortage or drought and hence is also
known as stress hormone.
3. It promotes bud dormancy in seeds during winters.
4. Seed dormancy: It induces seeds dormancy hence is named dormin. Thus it
helps the seed to withstand desiccation and other unfavorable factors.
5. It inhibits cambial activity.

43. Animal Hormones
• Adrenaline gland or adrenal
These are a pair of glands situated on upper side of each kidney.It is termed
as emergency hormone.In normal situation these hormones are secreted in
small amount,however when a person faces stress,danger,they are secreted in
large amount.
Function
1)They increase the heart beat to supply more oxygen to muscles.
2)It helps the body to control blood sugar.
3)It regulates blood pressure
4)It controls increase in breathing rate due to contraction of diaphragm and rib
muscles.
Thyroid Gland
It is the largest endocrine gland.It is bilobed,situated in neck region.It secretes
hormone thyroxine.
Iodine is essential for the synthesis of thyroxine.
Function
1)They regulate carbohydrates,fats,proteins metabolism in the body.
2)It regulates the rate of rate of oxidation.
3)It regulate the production of energy.

44. Pituitary Gland
It is present just below the brain.It is small,red- grey pea shaped gland.
Improper secretion of growth hormone can cause:
1)Dwarfism:Deficiency of growth hormone.
2)Gigantism:Excess secretion of growth hormone.
Testes
In males,a pair of testes are present.They secrete male sex hormone
testosterone.
Ovaries
A pair of ovaries lie in the abdomen in females.They secrete female sex
hormone – estrogen and progesterone.
Pancreas
It lies below the stomach.It secretes pancreatic juices.It secretes 2
hormones namely
1)Insulin:It lowers the blood sugar or glucose level.
Deficiency of insulin hormone cause a disease called Diabetes.In this
disease patient excretes sugar in urine,feels excessive thirst and also does
excessive urination.

45. 2)Glucagon:Its function is to increase the concentration of glucose in the
bloodstream.It causes the liver to convert stored glycogen into glucose,which is
released in the bloodstream.

46. Thankyou