Knowledge Point Classes

Ram kushvaha 7678309456 , 9971848246

Class – X
Science Notes (Control and Coordination)

Control and Co-ordination in Animals: Nervous system and endocrine system.

In animals, the nervous system and hormonal system are responsible for control and
co¬ordination.

Receptors: Receptors are the specialized tips of the nerve fibres that collect the information to be
conducted by the nerves.
Receptors are in the sense organs of the animals.
These are classified as follows :

 Phono-receptors: These are present in inner ear.

Functions: The main functions are hearing and balance of the body.
 Photo-receptors: These are present in the eye.
Function: These are responsible for visual stimulus.
 Thermo-receptors: These are present in skin.
Functions: These receptors are responsible for pain, touch and heat stimuli.
These receptors are also known as thermoreceptors.
 Olfactory-receptors: These are present in nose.
Functions: These receptors receive smell.
 Gustatory-receptors: These are present in the tongue.
Functions: These helps in taste detection.
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

Nervous System: The nervous system is composed of specialized tissues, called nervous tissue.
The nerve cell or neuron is the functional unit of the nervous system. It is the nervous system
which is mainly responsible for control and coordination in complex animals.

Functions of the nervous system

 Nervous system receives information from the environment.

 To receive the information from the various body.
 To act according to through muscles and glands.

A neuron is the structural and functional unit of the nervous system.

Neuron: Neuron is a highly specialized cell which is responsible for the transmission of nerve
impulses. The neuron consists of the following parts
(i) Cyton or cell body: The cell body or cyton is somewhat star-shaped, with many hair like
structures protruding out of the margin. These hair-like structures are called dendrites. Dendrites
receive the nerve impulses.

(ii) Axon: This is the tail of the neuron. It ends in several hair-like structures, called axon
terminals. The axon terminals relay nerve impulses.
(iii) Myelin sheath: There is an insulator cover around the axon. This is called myelin sheath. The
myelin sheath insulates the axon against nerve impulse from the surroundings.

Types of neuron

 Sensory neuron: These neurons receive signals from a sense organ.

 Motor neuron: These neurons send signals to a muscle or a gland.
 Association or relay neuron: These neurons relay the signals between sensory neuron and
motor neuron.

Synapse: The point contact between the terminal branches of axon of one neuron with the
dendrite of another neuron is called synapse.
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

Neuromuscular Junction (NMJ): NMJ is the point where a muscle fibre comes in contact with a
motor neuron carrying nerve impulse from the control nervous system.

Transmission of nerve impulse: Nerve impulses travel in the following manner from one neutron to the
next :
Dendrites → cell body → axon → nerve endings at the tip of axon → synapse → dendrite of next neuron.
Chemical released from axon tip of one neuron, cross the synapse or neuromuscular junction to reach the
next cell.

Human Nervous System: The nervous system in humans can be divided into three main parts
1. Central Nervous System: The central nervous system is composed of the brain and the spinal
cord. The brain controls all the functions in the human body. The spinal cord works as the relay
channel for signals between the brain and the peripheral nervous system.

2. Peripheral Nervous System: The peripheral nervous system is composed of the cranial

nerves and spinal nerves. There are 12 pairs of cranial nerves. The cranial nerves come our of the
brain and go to the organs in the head region. There are 31 pairs of spinal nerves. The spinal
nerves come out of the spinal cord and go to the organs which are below the head region.

3. Autonomous Nervous System: The autonomous nervous system is composed of a chain of

nerve ganglion which runs along the spinal cord. It controls all the involuntary actions in the human
body. The autonomous nervous system can be divided into two parts :

 Sympathetic nervous system.

 Parasympathetic nervous system.

Sympathetic Nervous System: This part of the autonomous nervous system heightens the
activity of an organ as per the need. For example, during running, there is an increased demand
for oxygen by the body. This is fulfilled by an increased breathing rate and increased heart rate.
The sympathetic nervous system works to increase the breathing rate the heart rate, in this case.

Parasympathetic Nervous System: This part of the autonomous nervous system slows the down
the activity of an organ and thus has a calming effect. During sleep, the breathing rate slows down
and so does the heart rate. This is facilitated by the parasympathetic nervous system. It can be
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

said that the parasympathetic nervous system helps in the conservation of energy.

Human Brain: Human brain is a highly complex organ, which is mainly composed of nervous
tissue. The tissues are highly folded to accommodate a large surface area in less space. The brain
is covered by a three-layered system of membranes, called meninges. Cerebrospinal fluid is filled
between the meninges. The CSF providers cushion the brain against mechanical shocks.
Furthermore, protection. The human brain can be divided into three regions, viz. forebrain,
midbrain and hindbrain.
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

Parts of Human Brain :

 Fore-brain: It is composed of the cerebrum.

 Mid-brain: It is composed of the hypothalamus.
 Hind-brain: It is composed of the cerebellum, pons, medulla, oblongata.

Some main structures of the human brain are explained below :

Cerebrum: The cerebrum is the largest part in the human brains. It is divided into two
hemispheres called cerebral hemispheres.

Functions of cerebrum

 The cerebrum controls voluntary motor actions.

 It is the site of sensory perceptions, like tactile and auditory perceptions.
 It is the seat of learning and memory.

Hypothalamus: The hypothalamus lies at the base of the cerebrum. It controls sleep and wake
cycle (circadian rhythm) of the body. It also controls the urges for eating and drinking.

Cerebellum: Cerebellum lies below the cerebrum and at the back of the whole structure. It
coordinates the motor functions. When you are riding your bicycle, the perfect coordination
between your pedalling and steering control is achieved by the cerebellum.

 It controls posture and balance.

 It controls the precision of voluntary action.

Medulla: Medulla forms the brain stem, along with the pons. It lies at the base of the brain and
continues into the spinal cord. The medulla controls various involuntary functions, like hear beat
respiration, etc.
It controls involuntary actions.
Example: Blood pressure, salivation, vomiting.

Pons: It relays impulses between the lower cerebellum and spinal cord, and higher parts of the
brain like the cerebrum and midbrain, also regulates respiration.

Spinal cord: Spinal cord controls the reflex actions and conducts massages between different
parts of the body and brain.
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

Reflex Action: Reflex action is a special case of involuntary movement involuntary organs. When
a voluntary organ is in the vicinity of sudden danger, it is immediately pulled away from the danger
to save itself. For example, when your hand touches a very hot electric iron, you move away your
hand in a jerk. All of this happens in flash and your hand is saved from the imminent injury. This is
an example of reflex action.

Reflex Arc: The path through which nerves signals, involved in a reflex action, travel is called the
reflex arc. The following flow chart shows the flow of signal in a reflex arc.
Receptor → Sensory neuron → Relay neuron → Motor neuron → Effector (muscle)
The receptor is the organ which comes in the danger zone. The sensory neurons pick signals from
the receptor and send them to the relay neuron. The relay neuron is present in the spinal cord.
The spinal cord sends signals to the effector via the motor neuron. The effector comes in action,
moves the receptor away from the danger.

The reflex arc passes at the level of the spinal cord and the signals involved in reflex action do not
travel up to the brain. This is important because sending signals to the brain would involve more
time.
Although every action is ultimately controlled by the brain, the reflex action is mainly controlled at
the level of spinal cord.

Protection of brain and spinal cord

Brain is protected by a fluid filled balloon which acts as shocks absorber and enclosed in cranium
(Brain box)
Spinal chord is enclosed in vertebral column.

Muscular Movements and Nervous Control: Muscle tissues have special filaments, called actin
and myosin. When a muscle receives a nerve signal, a series of events is triggered in the muscle.
Calcium ions enter the muscle cells. It result in actin and myosin filaments sliding towards each
other and that is how a muscle contracts. Contraction in a muscle brings movement in the related
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

organ.

Endocrine System: The endocrine system is composed of several endocrine glands. A ductless

gland is called endocrine gland. Endocrine gland secretes its product directly into the bloodstream.
Hormones are produced in the endocrine glands. Hormone is mainly composed of protein.
Hormones assist the nervous system in control and co-ordination. Nervous do not react to every
nook and corner of the body and hence hormones are needed to affect control and coordination in
those parts. Moreover, unlike nervous control, hormonal control is somewhat slower.

Hormones: These are the chemical messengers secreted in very small amounts by specialised
tissues called ductless glands. They act on target tissues/organs usually away from their source.
Endocrine System helps in control and coordination through chemical compounds called
hormones.
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

Endocrine Gland: A ductless gland that secretes hormones directly into the bloodstream.

Endocrine  Gland
Location Hormones Produced Functions

GH stimulates growth.
Growth hormone (GH).
TSH stimulates the
Pituitary gland (also Thyroid stimulating
At the base of the functioning of the thyroid
known as the master hormone (TSH). Follicle
brain gland.
gland) stimulating hormone
FSH stimulates the
(FSH)
follicles during ovulation.

Controls general

Thyroid Gland Neck Thyroxine metabolism and growth

in the body.

Adrenal gland Above kidneys Adrenalin Prepares the body for

 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

emergency situations

and hence is also called

‘Fight and flight’

hormone.

Controls blood sugar

Pancreas Near stomach Insulin
level

Sperm production,

development of

Testis (male) In Scrotum Testosterone secondary sexual

characters during

puberty.

Egg production,

development of

Ovary (female) Near uterus Oestrogen secondary sexual

characters during

puberty.

Iodised salt is necessary because: Iodine mineral is essential part of thyronine hormone so it is
important that we must consume iodised salt as in turn it is essential for thyroid gland as it controls
carbohydrate, proteins and fat metabolism for best balance of growth deficiency of iodine might
cause disease called goitre.

Diabetes: Cause : It is due to deficiency of insulin hormone secreted by pancreas that is

responsible to lower/control the blood sugar levels.
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

Treatment : Patients have to internally administer injections of insulin hormone which helps in
regulating blood-sugar level.

In case of flight or fight reaction to an emergency situation, Adrenal glands → release adrenaline
into blood → which acts on heart and other tissues → causes faster heart beat → more oxygen to
muscles → reduced blood supply to digestive system and skin → diversion of blood to skeletal
muscles → increase in breathing rate.

Feedback mechanism: A type of self-regulating mechanism in which the level of one substance in
body influences the level of another.

Control and Co-ordination in Plants: Movements in plants and plant harmones.

Co-ordination in Plants: Unlike animals, plants do not have a nervous system. Plants use chemical
means for control and co-ordination. Many plant hormones are responsible for various kinds of
movements in plants. Movements in plants can be divided into two main types :

1. Tropic movement
2. Nastic movement

1. Tropic Movement: The movements which are in a particular direction in relation to the stimulus
are called tropic movements. Tropic movements happen as a result of growth of a plant part in a
particular direction. There are four types of tropic movements.
(i) Geotropic movement: The growth in a plant part in response to the gravity is called geotropic
movement. Roots usually show positive geotropic movement, i.e. they grow in the direction of the
gravity. Stems usually show negative geotropic movement.

(ii) Phototropic Movement: The growth in a plant part in response to light is called phototropic
movement. Stems usually show positive phototropic movement, while roots usually show negative
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

phototropic movement. If a plant is kept in a container in which no sunlight reaches and a hole in
the container allows some sunlight; the stem finally grows in the direction of the sunlight. This
happens because of a higher rate of cell division in the part of stem which is away from the
sunlight. As a result, the stem bends towards the light. The heightened rate of cell division is
attained by increased secretion of the plant hormone auxin in the which is away from sunlight.

(iii) Hydrotropic Movement: When roots grow in the soil, they usually grow towards the nearest
source of water. This shows a positive hydrotropic movement.

(iv) Thigmotropism Movement: The growth in a plant part in response to touch is called

thigmotropism movement. Such movements are seen in tendrils of climbers. The tendril grows in a
way so as it can coil around a support. The differential rate of cell division in different parts of the
tendril happens due to action of auxin.

2. Nastic Movement: The movement which do not depend on the direction from the stimulus acts
are called nastic movement. For example, when someone touches the leaves of mimosa, the
leaves droop. The drooping is independent of the direction from which the leaves are touched.
Such movements usually happen because of changing water balance in the cells. When leaves of
mimosa are touched, the cells in the leaves lose- water and become flaccid, resulting in drooping
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

of leaves.

Plant hormones: Plant hormones are chemical which help to co-ordinate growth, development
and responses to the environment.
Type of plant hormones: Main plant hormones are

 Auxin: (Synthesized at shoot and root tip).

Function:
 Helps in growth,
 Fruit growth
 Responsible to geo and photo tropism
Phototropism: more growth of cells towards the light.

 Gibberellin: Helps in the growth of the stem.

 Cytokinins: Promotes cell division , help in opening of stomata, delay the ageing of leaves.
 Abscisic acid: Inhibits growth, cause wilting of leaves. (Stress hormone) , closing the stomata
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

Control and Coordination in Plants

 Stimuli: The change in the environment to which an organism responds.

 Co-ordination: Working together of various organs of an organism in a systematic manner
to produce a proper response.
 Phyto-hormones: These are plant hormones.
 Auxin: It is a plant hormone which promotes cell enlargement and growth in plants.
 Gibberellins: A plant hormone which promotes cell differentiation and breaking dormancy of
seeds and buds.
 Cytokinin: A plant hormone which promotes cell division and the opening of stomata.
 Abscisic Acid: It helps in inhibiting the growth of the plant and promotes wilting and falling
of leaves and food.
 Tropism: A growth movement of a plant which determines direction with the stimulus.
 Nastism: A growth movement of a plant which does not determine direction with a stimulus.
 Phototropism: Movement of plants towards a light.
 Geotropism: Movement of plants towards the gravity of earth.
 Chemotropism: Movement of plants towards chemicals.
 Hydrotropism: Movement of plants towards the water.
 Thigmotropism: Movement of plants towards a response to the touch of an object.

Control and Coordination in Animals

 Stimuli: The change in the environment to which the organism responds.

 Co-ordination: Working together of various organs of an organism in a systematic manner
to produce a proper response.
 Neuron: Functional unit of the nervous system.
 Synapse: A microscopic gap between a pair of adjacent neurons.
 Receptor: A cell in a sense organ which is sensitive to stimuli.
 Motor nerves: It carries the message from the brain to body parts for action.
 Sensory nerves: It carries the message from body to brain.
 Olfactory receptor: It detects smell by the nose.
 Gustatory receptor: It detects taste by a tongue.
 Thermoreceptor: It detects heat and cold by a skin.
 Photoreceptor: It detects light by eye.
 Reflex action: Sudden movement or response to the stimulus which occurs in a very short
duration of time and does not involve any will or thinking of the brain.
 Brain: An organ present in the skull which controls and regulates the activity of the whole
body and is known as president of the body.
 Cerebrum: Main thinking part of brain present in the forebrain area which controls all
voluntary actions.
 Cerebellum: It is present in the hindbrain area and helps in maintaining posture and balance
of the body.
 Knowledge Point Classes
Ram kushvaha 7678309456 , 9971848246
Class – X
Science Notes (Control and Coordination)

 Medulla: It is present in the hindbrain area and helps in controlling voluntary actions of the
brain.
 Spinal cord: It is a cylindrical structure of nerve fibres enclosed in the vertebral column
which helps in the conduction of nerve impulses to and from the brain.