Delhi Public School Notes

Control and Coordination

Class 10 Science | CBSE

Board Exam + Foundation Level Preparation

Chapter Overview

Living organisms are continuously surrounded by changes in their environment. These changes may be light, sound, smell, temperature, touch, gravity, water, pain, danger, food, or internal body changes. To survive, an organism must detect these changes, process the information, and respond correctly. This process is called control and coordination.

Control: The regulation of body activities according to internal and external conditions.
Coordination: The proper working together of different organs and organ systems to produce a suitable response.

What students will learn

How plants respond to stimuli without a nervous system.
Different types of plant movements such as tropic and nastic movements.
Role of phytohormones in plant growth and development.
Structure and function of the human nervous system.
Brain, spinal cord, reflex action, reflex arc, and synapse.
Endocrine glands, hormones, and their functions.
Coordination between the nervous system and hormonal system.

Why this chapter is important

This chapter is frequently asked in CBSE board exams. Questions usually come from plant hormones, tropic movements, reflex action, human brain, nervous system, endocrine glands, and hormone functions. Diagram-based questions from brain, neuron, and reflex arc are also very important.

Real-life relevance

We remove our hand immediately after touching a hot object because of reflex action.
Plants bend towards sunlight due to phototropism.
Adrenaline helps the body respond during fear, stress, or emergency.
Insulin controls blood sugar level.
Thyroxine controls metabolism and requires iodine for its synthesis.

Important Keywords

Keyword	Meaning
Stimulus	Any change in the environment that produces a response in an organism.
Response	The reaction of an organism to a stimulus.
Coordination	The working together of different organs to produce a proper response.
Neuron	The structural and functional unit of the nervous system.
Synapse	The small gap between two neurons through which nerve impulse passes chemically.
Reflex Action	A quick, automatic, involuntary response to a stimulus.
Reflex Arc	The pathway followed by nerve impulses during reflex action.
Hormone	A chemical messenger secreted by endocrine glands.
Endocrine Glands	Ductless glands that release hormones directly into the blood.
Phytohormones	Plant hormones that regulate growth, development, and responses in plants.
Tropic Movement	Directional movement of a plant part in response to a stimulus.
Nastic Movement	Non-directional movement of a plant part in response to a stimulus.

Control and Coordination in Plants

Plants do not have a nervous system, brain, muscles, or sense organs like animals. Still, they respond to different stimuli such as light, gravity, water, touch, and chemicals. Their responses are generally slow because they are controlled mainly by chemical substances called plant hormones or phytohormones.

NCERT Alert: Plants coordinate their behaviour against environmental changes by using hormones. Plant movements may be due to growth or due to changes in water content inside cells.

Types of Plant Responses

Type of Response	Meaning	Example
Growth-dependent movement	Movement caused by unequal growth in different parts of the plant.	Bending of shoot towards light.
Growth-independent movement	Movement caused by changes in water pressure or turgor inside cells.	Folding of Mimosa leaves on touching.

Phytohormones: Plant Hormones

Phytohormones are chemical substances produced in very small quantities in plants. They regulate growth, cell division, cell elongation, flowering, fruit ripening, seed dormancy, and responses to stimuli.

Major Plant Hormones and Their Functions

Plant Hormone	Main Functions	Important Example
Auxin	Promotes cell elongation, helps in phototropism and geotropism, promotes root formation, and maintains apical dominance.	Shoot bends towards light due to unequal distribution of auxin.
Gibberellins	Promote stem elongation, seed germination, flowering, and growth of fruits.	Used to increase length of grape stalks.
Cytokinins	Promote cell division, delay ageing of leaves, and help in growth of lateral buds.	Present in areas of active cell division such as fruits and seeds.
Abscisic Acid	Inhibits growth, promotes seed dormancy, causes closing of stomata during water stress, and helps plants tolerate drought.	Known as stress hormone of plants.
Ethylene	Helps in fruit ripening, ageing, and falling of leaves and fruits.	Used for artificial ripening of fruits.

Exam Tip: In CBSE exams, auxin is the most important plant hormone. Learn its role in phototropism and geotropism very clearly.

How Auxin Helps in Phototropism

When light comes from one side of a plant shoot, auxin moves to the shaded side. Auxin causes cells on the shaded side to grow faster. As a result, the shaded side becomes longer and the shoot bends towards light.

Light from one side ↓ Auxin moves to shaded side ↓ Cells on shaded side elongate more ↓ Shoot bends towards light

Important Question: Why does a plant shoot bend towards light?

A plant shoot bends towards light because auxin accumulates on the shaded side of the shoot. Auxin causes more cell elongation on that side. Due to unequal growth, the shoot bends towards the light source.

Tropic Movements in Plants

Tropic movements are directional growth movements of plant parts in response to an external stimulus. If the plant part grows towards the stimulus, it is called positive tropism. If it grows away from the stimulus, it is called negative tropism.

Tropic Movement: A directional growth movement of a plant part in response to a stimulus.

Types of Tropic Movements

Type	Stimulus	Positive Response	Example
Phototropism	Light	Growth towards light	Shoot bends towards sunlight.
Geotropism	Gravity	Growth towards gravity	Roots grow downward.
Hydrotropism	Water	Growth towards water	Roots grow towards moisture.
Chemotropism	Chemicals	Growth towards chemical stimulus	Pollen tube grows towards ovule.
Thigmotropism	Touch	Growth around support	Tendrils coil around support.

Phototropism

Phototropism is the directional movement of a plant part in response to light. Shoots are generally positively phototropic because they grow towards light. Roots are usually negatively phototropic because they grow away from light.

Geotropism

Geotropism is the movement of plant parts in response to gravity. Roots are positively geotropic because they grow towards gravity. Shoots are negatively geotropic because they grow away from gravity.

Plant Part	Phototropism	Geotropism
Shoot	Positive phototropism	Negative geotropism
Root	Negative phototropism	Positive geotropism

Hydrotropism

Hydrotropism is the directional growth movement of plant roots towards water. This is very useful because roots help the plant absorb water and minerals from the soil.

Chemotropism

Chemotropism is the movement of a plant part in response to chemicals. The best example is the growth of pollen tube towards the ovule during fertilisation in flowers.

Thigmotropism

Thigmotropism is the directional growth response to touch. Tendrils of pea plants or grapevines coil around a support when they touch it. This helps weak-stemmed plants climb upwards.

Exam Tip: Always mention the stimulus when defining tropic movement. For example, phototropism is response to light, geotropism is response to gravity.

Nastic Movements in Plants

Nastic movements are non-directional movements of plant parts. In these movements, the direction of response does not depend on the direction of the stimulus. These movements are usually caused by changes in water content inside plant cells.

Nastic Movement: A non-directional movement of a plant part in response to a stimulus.

Example: Touch-Me-Not Plant

When we touch the leaves of the Mimosa pudica plant, the leaves fold quickly. This happens due to sudden loss of water from certain cells at the base of leaflets. The cells lose turgidity and the leaves droop.

Touch stimulus ↓ Electrical/chemical signal passes ↓ Water moves out from cells at leaf base ↓ Cells lose turgor pressure ↓ Leaves fold

Tropic Movement vs Nastic Movement

Basis	Tropic Movement	Nastic Movement
Direction	Directional	Non-directional
Depends on direction of stimulus?	Yes	No
Cause	Usually growth	Usually change in turgor pressure
Speed	Slow	Comparatively fast
Example	Shoot bending towards light	Mimosa leaves folding on touch

Control and Coordination in Animals

Animals need fast and accurate coordination because they move from place to place and face rapidly changing situations. For example, they need to catch food, escape danger, maintain posture, balance the body, and respond to pain. In animals, control and coordination are mainly achieved by:

Nervous system: Fast, electrical, short-lived response.
Endocrine system: Slower, chemical, longer-lasting response.

Human Nervous System

The nervous system receives information from the surroundings, carries it to the brain or spinal cord, processes it, and sends instructions to muscles or glands for a response.

Stimulus → Receptor → Sensory Neuron → CNS → Motor Neuron → Effector → Response

Neuron: Structural and Functional Unit of Nervous System

A neuron is a specialised cell that carries messages in the form of electrical impulses. It has three main parts:

Part of Neuron	Function
Dendrites	Receive nerve impulses from receptors or other neurons.
Cell Body	Contains nucleus and cytoplasm; controls the activities of the neuron.
Axon	Carries nerve impulse away from the cell body.
Nerve Ending	Releases chemicals to pass the impulse to the next neuron or effector.

Dendrites → Cell Body → Axon → Nerve Ending

Synapse

A synapse is the tiny gap between the nerve ending of one neuron and the dendrite of the next neuron. Electrical impulses cannot directly jump across this gap. Therefore, chemicals called neurotransmitters are released at the nerve ending. These chemicals cross the synapse and start an electrical impulse in the next neuron.

NCERT Alert: At the synapse, electrical signals are converted into chemical signals and then again into electrical signals in the next neuron.

Central Nervous System

The central nervous system, or CNS, consists of the brain and spinal cord. It is the main control and processing centre of the body.

Brain

The brain is the highest coordinating centre in the body. It receives information from sense organs, interprets it, stores memory, controls voluntary actions, and regulates many involuntary actions.

Protection of Brain

The brain is protected by the skull.
It is covered by three membranes called meninges.
Cerebrospinal fluid protects the brain from shocks.

Parts of Brain and Their Functions

Part of Brain	Major Functions
Forebrain	Controls thinking, intelligence, memory, emotions, learning, speech, hearing, smell, sight, and voluntary actions. It also receives sensory impulses from different parts of the body.
Midbrain	Controls certain visual and auditory reflexes. It acts as a relay centre between forebrain and hindbrain.
Hindbrain	Includes cerebellum, pons, and medulla. It controls balance, posture, coordination of movement, breathing, heartbeat, blood pressure, swallowing, vomiting, and other involuntary actions.
Cerebellum	Maintains posture and balance of the body. Coordinates muscular movements such as walking, dancing, cycling, and picking objects.
Medulla Oblongata	Controls involuntary actions such as breathing, heartbeat, blood pressure, coughing, sneezing, and vomiting.

Exam Tip: For brain questions, remember: Forebrain = thinking and voluntary actions; Cerebellum = balance and posture; Medulla = involuntary actions.

Spinal Cord

The spinal cord is a long cylindrical structure that extends from the brain through the vertebral column. It acts as a communication pathway between the brain and the rest of the body. It also controls reflex actions.

Functions of Spinal Cord

Conducts nerve impulses from body parts to brain.
Conducts instructions from brain to body parts.
Acts as the centre for reflex actions.

Reflex Action and Reflex Arc

Reflex Action

Reflex action is a sudden, quick, automatic, and involuntary response to a stimulus. It protects the body from harm and reduces the time taken to respond.

Example: Pulling the hand away immediately after touching a hot object.

Why Reflex Action Is Important

In dangerous situations, waiting for the brain to analyse the stimulus may take extra time. Reflex action gives an immediate response through the spinal cord, which protects the body from injury.

Reflex Arc

The pathway followed by nerve impulses during reflex action is called a reflex arc.

Stimulus ↓ Receptor in skin ↓ Sensory neuron ↓ Spinal cord ↓ Motor neuron ↓ Effector muscle ↓ Response: Hand withdrawn

Components of Reflex Arc

Component	Function
Receptor	Detects stimulus such as heat, pain, or pressure.
Sensory Neuron	Carries impulse from receptor to spinal cord.
Spinal Cord	Processes impulse and sends response signal.
Motor Neuron	Carries impulse from spinal cord to effector.
Effector	Muscle or gland that produces the response.

Common Mistake: Students often write that reflex action is controlled by the brain. In Class 10, the correct answer is that reflex action is mainly controlled by the spinal cord, although the brain receives information later.

Peripheral Nervous System

The peripheral nervous system, or PNS, consists of nerves that arise from the brain and spinal cord and spread throughout the body. It connects the central nervous system with organs, muscles, skin, and glands.

Types of Peripheral Nervous System

Type	Function
Somatic Nervous System	Controls voluntary actions such as walking, writing, speaking, and lifting objects.
Autonomic Nervous System	Controls involuntary actions such as heartbeat, digestion, breathing rate, and gland secretion.

Autonomic Nervous System

The autonomic nervous system controls activities that are not under our conscious control. It is divided into sympathetic and parasympathetic nervous systems.

System	Role	Example
Sympathetic Nervous System	Prepares the body for emergency or stress.	Increases heartbeat and breathing rate during fear.
Parasympathetic Nervous System	Brings the body back to normal resting condition.	Slows heartbeat after stress is over.

Memory Trick: Sympathetic = Stress system. Parasympathetic = Peace system.

Hormonal System in Animals

The endocrine system is made up of ductless glands that secrete hormones directly into the blood. Hormones are chemical messengers that regulate growth, development, metabolism, reproduction, and responses to stress.

Hormone: A chemical messenger secreted by an endocrine gland and carried by blood to a target organ.

Important Endocrine Glands, Hormones, and Functions

Gland	Hormone	Function
Pituitary Gland	Growth Hormone	Controls growth of bones and body. Deficiency causes dwarfism; excess causes gigantism.
Thyroid Gland	Thyroxine	Controls metabolism of carbohydrates, proteins, and fats. Requires iodine.
Pancreas	Insulin	Regulates blood sugar level by helping cells absorb glucose from blood.
Adrenal Gland	Adrenaline	Prepares body for emergency by increasing heartbeat, breathing rate, and blood flow to muscles.
Testes	Testosterone	Controls male secondary sexual characters and sperm production.
Ovaries	Oestrogen and Progesterone	Controls female secondary sexual characters, menstrual cycle, and pregnancy-related changes.

Adrenaline: Emergency Hormone

Adrenaline is secreted by adrenal glands during fear, anger, stress, or emergency. It prepares the body for a fight-or-flight response.

Effects of Adrenaline

Heartbeat increases.
Breathing rate increases.
Blood pressure increases.
More blood flows to muscles.
Glucose is released into blood for more energy.

Fear / Stress / Emergency ↓ Adrenal gland secretes adrenaline ↓ Heartbeat and breathing rate increase ↓ More blood and glucose reach muscles ↓ Body becomes ready for action

Insulin and Diabetes

Insulin is secreted by the pancreas. It helps in maintaining blood glucose level. If the pancreas does not produce enough insulin, blood sugar level increases. This condition is called diabetes.

Thyroxine and Iodine

Thyroxine is secreted by the thyroid gland. Iodine is necessary for the synthesis of thyroxine. Deficiency of iodine may cause goitre, in which the thyroid gland becomes enlarged.

NCERT Alert: Iodised salt is recommended because iodine is required for the production of thyroxine.

Coordination Between Nervous System and Hormonal System

The nervous system and endocrine system work together to maintain proper control and coordination in the body. The nervous system gives fast responses, while the endocrine system gives slower but longer-lasting responses.

Basis	Nervous System	Hormonal System
Nature of signal	Electrical impulse and chemical transmission at synapse	Chemical messengers called hormones
Speed	Very fast	Comparatively slow
Duration	Short-lived response	Long-lasting response
Pathway	Through neurons	Through blood
Target	Specific muscles or glands	Target organs having specific receptors
Example	Withdrawal of hand from hot object	Growth controlled by growth hormone

Feedback Mechanism

Hormone secretion is controlled by feedback mechanisms. If the level of a hormone or substance becomes too high, the gland reduces secretion. If the level becomes too low, the gland increases secretion.

Example: Blood Sugar Regulation

Blood glucose level rises ↓ Pancreas secretes insulin ↓ Cells absorb more glucose ↓ Blood glucose level decreases ↓ Insulin secretion reduces

Exam Tip: For questions on insulin, always mention pancreas, blood glucose, and diabetes.

NCERT Line-by-Line Important Points

Living organisms must use systems of control and coordination to respond to environmental changes.
In animals, control and coordination are provided by nervous and muscular tissues.
Neurons transmit information in the form of electrical impulses.
A synapse is the gap between two neurons where chemicals help in transmission of impulse.
The brain and spinal cord form the central nervous system.
The brain is protected by the skull, membranes, and cerebrospinal fluid.
The spinal cord is responsible for reflex actions.
Reflex action is a quick and automatic response to a stimulus.
Plants do not have nervous or muscular tissue but still show movements.
Plant movements may be growth-dependent or growth-independent.
Auxin helps in cell elongation and bending of shoots towards light.
Hormones are chemical messengers secreted by endocrine glands.
Adrenaline prepares the body for emergency situations.
Insulin helps in controlling blood sugar level.
Iodine is necessary for the synthesis of thyroxine.

Important Diagrams and Flowcharts

1. Reflex Arc

Stimulus → Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector → Response

2. Neuron

Dendrites → Cell Body with Nucleus → Axon → Nerve Endings

3. Human Brain: Main Functional Areas

Brain ├── Forebrain: Thinking, memory, voluntary actions ├── Midbrain: Visual and auditory reflexes └── Hindbrain ├── Cerebellum: Balance and posture ├── Pons: Relay of signals └── Medulla: Breathing, heartbeat, blood pressure

4. Plant Movement Flowchart

Plant Movements ├── Tropic Movements │ ├── Phototropism │ ├── Geotropism │ ├── Hydrotropism │ ├── Chemotropism │ └── Thigmotropism └── Nastic Movements └── Folding of Mimosa leaves on touch

Important Formulae / Equations

This chapter does not contain chemical equations or numerical formulae like chemistry and physics chapters. However, the following process equations are important for board answers:

Stimulus → Receptor → Coordinator → Effector → Response

Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector

Endocrine Gland → Hormone → Blood → Target Organ → Response

Board Exam Important Questions with Answers

Very Short Answer Questions

Q1. What is a stimulus?

A stimulus is any change in the environment that produces a response in an organism.

Q2. Name the plant hormone responsible for cell elongation.

Auxin.

Q3. Which gland secretes insulin?

Pancreas secretes insulin.

Q4. Which part of the brain controls balance and posture?

Cerebellum controls balance and posture.

Q5. What is the functional unit of nervous system?

Neuron is the functional unit of nervous system.

Short Answer Questions

Q1. Differentiate between tropic and nastic movements.

Tropic movements are directional growth movements and depend on the direction of stimulus, such as bending of shoot towards light. Nastic movements are non-directional and do not depend on the direction of stimulus, such as folding of Mimosa leaves on touch.

Q2. Why are hormones called chemical messengers?

Hormones are called chemical messengers because they are chemical substances secreted by endocrine glands. They travel through blood and carry messages to specific target organs.

Q3. Explain the role of adrenaline in the body.

Adrenaline is secreted by adrenal glands during fear, stress, anger, or emergency. It increases heartbeat, breathing rate, blood pressure, and blood supply to muscles. It prepares the body for quick action.

Q4. What is synapse? Why is it important?

Synapse is the tiny gap between two neurons. It is important because nerve impulses pass from one neuron to another through chemicals released at the synapse.

Long Answer Questions

Q1. Explain reflex action with the help of reflex arc.

Reflex action is a quick, automatic, and involuntary response to a stimulus. For example, when we touch a hot object, we immediately withdraw our hand. The pathway followed by the nerve impulse is called reflex arc. The receptor in the skin detects heat. The sensory neuron carries the impulse to the spinal cord. The spinal cord processes the information and sends an impulse through the motor neuron to the muscles. The muscles contract and the hand is withdrawn. This response is controlled mainly by the spinal cord, so it is very fast.

Q2. Describe the major parts of the human brain and their functions.

The brain has three major parts: forebrain, midbrain, and hindbrain. The forebrain controls thinking, memory, intelligence, emotions, sensory perception, and voluntary actions. The midbrain controls certain visual and auditory reflexes. The hindbrain consists of cerebellum, pons, and medulla. The cerebellum maintains balance, posture, and coordination of muscular movement. The medulla controls involuntary actions such as breathing, heartbeat, blood pressure, coughing, sneezing, and vomiting.

Q3. Explain the functions of major plant hormones.

Auxin promotes cell elongation and helps in phototropism and geotropism. Gibberellins promote stem elongation, seed germination, and flowering. Cytokinins promote cell division and delay ageing of leaves. Abscisic acid inhibits growth, promotes seed dormancy, and helps plants tolerate stress by closing stomata. Ethylene helps in fruit ripening and ageing of plant parts.

Assertion-Reason Questions

Q1. Assertion: Reflex actions are very fast.
Reason: Reflex actions are controlled mainly by the spinal cord.

Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Q2. Assertion: Iodine is necessary in our diet.
Reason: Iodine is required for the synthesis of thyroxine hormone.

Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Case Study Based Question

Case Study: A student placed a potted plant near a window. After a few days, the shoot was observed bending towards the window. The student also noticed that the roots continued to grow downward in the soil.

Questions:

Name the movement shown by the shoot.
Name the hormone responsible for bending of shoot.
Why do roots grow downward?
Is the shoot positively or negatively phototropic?

The movement shown by the shoot is phototropism.
Auxin is responsible for bending of the shoot.
Roots grow downward due to positive geotropism.
The shoot is positively phototropic.

Competency-Based Questions

Q1. A person suddenly sees a speeding vehicle coming towards him. His heartbeat increases and he runs away quickly. Which hormone is involved and why?

Adrenaline is involved. It is secreted during emergency situations and increases heartbeat, breathing rate, and blood supply to muscles so that the body can respond quickly.

Q2. A patient has high blood sugar level. Which hormone may be deficient and which gland secretes it?

The hormone insulin may be deficient. It is secreted by the pancreas.

NCERT-Based Questions and Answers

Q1. What is the difference between a reflex action and walking?

Reflex action is automatic, quick, and involuntary. It is controlled mainly by the spinal cord. Walking is a voluntary action controlled by the brain and involves conscious coordination of muscles.

Q2. What happens at the synapse between two neurons?

At the synapse, the electrical impulse reaching the nerve ending causes the release of chemical substances. These chemicals cross the gap and start a new electrical impulse in the next neuron.

Q3. Which part of the brain maintains posture and balance?

The cerebellum maintains posture and balance of the body.

Q4. How do auxins promote the growth of a tendril around a support?

When a tendril touches a support, auxin moves to the side away from the support. Cells on that side grow faster, causing the tendril to bend and coil around the support.

Q5. Why is the use of iodised salt advisable?

Iodised salt is advisable because iodine is required by the thyroid gland to produce thyroxine hormone. Thyroxine regulates metabolism. Lack of iodine can cause goitre.

Q6. How does chemical coordination take place in animals?

Chemical coordination takes place through hormones secreted by endocrine glands. Hormones are released directly into the blood and carried to target organs where they produce specific responses.

Common Mistakes Students Make

Mistake 1: Writing that plants do not respond because they lack nerves.
Correction: Plants respond using hormones and growth movements.

Mistake 2: Confusing phototropism with photosynthesis.
Correction: Phototropism is movement towards light. Photosynthesis is food preparation using light.

Mistake 3: Writing that reflex action is controlled by the brain.
Correction: Reflex action is mainly controlled by the spinal cord.

Mistake 4: Confusing endocrine glands with exocrine glands.
Correction: Endocrine glands are ductless and release hormones directly into blood.

Mistake 5: Writing insulin is secreted by liver.
Correction: Insulin is secreted by pancreas.

Memory Tricks

Topic	Memory Trick
Brain functions	Forebrain = Feel + Think; Cerebellum = Balance; Medulla = Involuntary actions.
Plant hormones	AGCAE: Auxin, Gibberellin, Cytokinin, Abscisic acid, Ethylene.
Reflex arc	RSSME: Receptor, Sensory neuron, Spinal cord, Motor neuron, Effector.
Autonomic nervous system	Sympathetic = Stress; Parasympathetic = Peace.
Thyroxine	Thyroxine needs iodine; iodine deficiency causes goitre.

Quick Revision Sheet

Must-Know Definitions

Stimulus: Change that causes a response.
Neuron: Functional unit of nervous system.
Synapse: Gap between two neurons.
Reflex Action: Quick, automatic, involuntary response.
Hormone: Chemical messenger secreted by endocrine glands.
Tropic Movement: Directional growth movement.
Nastic Movement: Non-directional movement.

Most Important Examples

Phototropism: Shoot bends towards light.
Geotropism: Roots grow downward.
Hydrotropism: Roots grow towards water.
Thigmotropism: Tendrils coil around support.
Nastic movement: Mimosa leaves fold on touch.

Important Hormones

Auxin: Cell elongation.
Gibberellin: Stem growth.
Cytokinin: Cell division.
Abscisic Acid: Growth inhibition.
Ethylene: Fruit ripening.
Insulin: Blood sugar control.
Adrenaline: Emergency response.
Thyroxine: Metabolism.

Important Flowcharts

Reflex Arc: Stimulus → Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector → Response

Hormonal Coordination: Endocrine Gland → Hormone → Blood → Target Organ → Response

Final Practice Section with Answers

Q1. Name two systems responsible for control and coordination in animals.

Nervous system and endocrine system.

Q2. Why are plant movements generally slower than animal movements?

Plant movements are generally slower because plants do not have nervous and muscular systems. Their movements are mainly controlled by hormones and growth changes.

Q3. Give one example each of positive and negative geotropism.

Roots show positive geotropism because they grow towards gravity. Shoots show negative geotropism because they grow away from gravity.

Q4. What is the role of pancreas in control and coordination?

Pancreas secretes insulin, which helps in regulating blood glucose level.

Q5. Mention three effects of adrenaline.

Adrenaline increases heartbeat, increases breathing rate, and increases blood supply to muscles.

Q6. Why is reflex action considered protective?

Reflex action is protective because it produces an immediate response to harmful stimuli, such as removing the hand from a hot object before serious injury occurs.

Q7. Differentiate between nervous coordination and hormonal coordination.

Nervous coordination is fast, uses electrical impulses, and gives short-lived responses. Hormonal coordination is slower, uses chemical messengers, and gives longer-lasting responses.

Q8. What is the function of cerebellum?

Cerebellum maintains posture, balance, and coordination of voluntary muscular movements.

Q9. Why does the shoot bend towards light?

Auxin accumulates on the shaded side of the shoot. Cells on that side elongate more, causing the shoot to bend towards light.

Q10. What is feedback mechanism in hormone secretion?

Feedback mechanism is a regulatory process in which the level of a hormone or substance controls further secretion of the hormone. For example, when blood glucose rises, insulin is secreted. When glucose level falls, insulin secretion reduces.

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Class 10 CBSE important notes for Control and Coordination Exam 2026