🧠 Class 10 Biology — Control and Coordination FULL EXAM NOTES
CBSE Board Level Detailed Explanation + Expected Questions with Answers + PYQs + Diagrams + NCERT Keywords
📖 INTRODUCTION
All living organisms continuously react to changes occurring around them. These changes are called stimuli.
To respond properly, the body needs a system that:
- Receives information
- Processes information
- Produces response
This system is called Control and Coordination.
🌟 WHAT IS CONTROL?
The process of regulating different body activities.
🌟 WHAT IS COORDINATION?
The process by which different organs work together efficiently.
🌟 EXAMPLES
| Stimulus | Response |
|---|---|
| Hot object | Pulling hand back |
| Bright light | Closing eyes |
| Smell of food | Salivation |
🧠 CONTROL AND COORDINATION IN ANIMALS
Animals coordinate through:
- Nervous system
- Endocrine system
🧠 NERVOUS SYSTEM
The nervous system controls body activities by electrical impulses.
🌟 FUNCTIONS OF NERVOUS SYSTEM
- Receives stimuli
- Transfers messages
- Produces response
- Controls voluntary and involuntary actions
- Helps in memory and thinking
🌟 STIMULUS
Any change in surroundings that causes a response.
Examples:
- Heat
- Cold
- Light
- Pain
🌟 RECEPTORS
Special cells that detect stimuli.
TYPES OF RECEPTORS
| Receptor | Stimulus |
|---|---|
| Photoreceptor | Light |
| Phonoreceptor | Sound |
| Olfactory receptor | Smell |
| Gustatory receptor | Taste |
🧠 NEURON
Structural and functional unit of nervous system.
🌟 STRUCTURE OF NEURON
A neuron has:
- Dendrites
- Cell body (Cyton)
- Axon
🧠 Neuron Diagram
🌟 FUNCTIONS OF NEURON PARTS
| Part | Function |
|---|---|
| Dendrite | Receives impulse |
| Cell body | Processes information |
| Axon | Transfers impulse |
🌟 NERVE IMPULSE
Electrical signal transmitted through neuron.
🌟 SYNAPSE
Tiny gap between two neurons.
Function:
Transfers impulse using chemicals called neurotransmitters.
IMPORTANT NCERT POINT ⭐
Impulse travels: Dendrite → Cell body → Axon
🌟 TYPES OF NEURONS
| Type | Function |
|---|---|
| Sensory neuron | Carries impulse from receptor to CNS |
| Motor neuron | Carries impulse from CNS to muscles |
| Relay neuron | Connects neurons |
🧠 CENTRAL NERVOUS SYSTEM (CNS)
Consists of:
- Brain
- Spinal cord
🧠 HUMAN BRAIN
Control center of body.
🧠 Human Brain Diagram
🌟 PROTECTION OF BRAIN
- Skull protects brain
- Cerebrospinal fluid acts as shock absorber
🌟 PARTS OF BRAIN
- Forebrain
- Midbrain
- Hindbrain
🌟 FOREBRAIN ⭐ VERY IMPORTANT
Largest part of brain.
FUNCTIONS OF FOREBRAIN
- Thinking
- Intelligence
- Memory
- Voluntary actions
- Decision making
- Smell detection
🌟 CEREBRUM
Main part of forebrain.
Controls:
- Thinking
- Learning
- Emotions
- Sensory information
🌟 MIDBRAIN
Controls reflex movements of:
- Head
- Neck
- Eyes
🌟 HINDBRAIN
Consists of:
- Cerebellum
- Pons
- Medulla oblongata
🌟 CEREBELLUM
Controls:
- Balance
- Posture
- Precision
🌟 PONS
Controls breathing rate.
🌟 MEDULLA OBLONGATA ⭐
Controls involuntary actions.
INVOLUNTARY ACTIONS
Actions that occur automatically.
Examples:
- Heartbeat
- Breathing
- Digestion
🌟 VOLUNTARY ACTIONS
Actions controlled by will.
Examples:
- Walking
- Writing
- Speaking
⚡ REFLEX ACTION
Immediate automatic response to a stimulus.
🌟 EXAMPLES
- Pulling hand from hot object
- Sneezing
- Blinking
🌟 WHY REFLEX ACTION IS FAST?
Because spinal cord controls it directly without involving brain immediately.
⚡ Reflex Arc Diagram
🌟 PATH OF REFLEX ARC
Stimulus → Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector
🌟 IMPORTANCE OF REFLEX ACTION
- Saves body from injury
- Produces rapid response
🌟 EXAM LEVEL QUESTION ⭐
Q. Differentiate between reflex action and voluntary action.
| Reflex Action | Voluntary Action |
|---|---|
| Automatic | Under control |
| Fast | Comparatively slow |
| Controlled by spinal cord | Controlled by brain |
| Example: Sneezing | Example: Writing |
🧪 ENDOCRINE SYSTEM
System of glands secreting hormones.
🌟 HORMONES
Chemical messengers secreted by endocrine glands.
CHARACTERISTICS OF HORMONES
- Secreted in small quantity
- Act on target organ
- Travel through blood
- Slow but long-lasting effect
🌟 IMPORTANT ENDOCRINE GLANDS
| Gland | Hormone | Function |
|---|---|---|
| Pituitary | Growth hormone | Body growth |
| Thyroid | Thyroxine | Metabolism |
| Pancreas | Insulin | Blood sugar control |
| Adrenal | Adrenaline | Emergency response |
| Testes | Testosterone | Male characters |
| Ovary | Estrogen | Female characters |
🧠 Endocrine Glands Diagram
🌟 PITUITARY GLAND ⭐
Called “Master gland” because it controls other glands.
🌟 THYROID GLAND
Produces thyroxine hormone.
🌟 FUNCTION OF THYROXINE
Controls metabolism of carbohydrates, fats and proteins.
🌟 IODINE DEFICIENCY
Causes goitre.
🌟 GOITRE
Swelling of neck due to enlarged thyroid gland.
🌟 INSULIN
Controls glucose level in blood.
🌟 DIABETES
Disease caused due to insulin deficiency.
🌟 ADRENALINE ⭐
Emergency hormone.
EFFECTS OF ADRENALINE
- Faster heartbeat
- Faster breathing
- Increased blood pressure
- More energy supply
🌟 PUBERTY
Stage when body becomes reproductively mature.
🌟 SECONDARY SEXUAL CHARACTERS
Boys:
- Beard growth
- Deep voice
Girls:
- Breast development
- Wider hips
🌱 CONTROL AND COORDINATION IN PLANTS
Plants do not have nervous system but respond through hormones.
🌟 PLANT HORMONES
| Hormone | Function |
|---|---|
| Auxin | Cell elongation |
| Gibberellin | Stem growth |
| Cytokinin | Cell division |
| Abscisic acid | Wilting |
| Ethylene | Fruit ripening |
🌟 MOVEMENTS IN PLANTS
- Tropic movement
- Nastic movement
🌟 TROPIC MOVEMENT
Growth movement depending on direction of stimulus.
TYPES OF TROPISM
| Type | Stimulus |
|---|---|
| Phototropism | Light |
| Geotropism | Gravity |
| Hydrotropism | Water |
| Thigmotropism | Touch |
🌱 Tropism Diagram
🌟 PHOTOTROPISM
Shoot bends toward light due to auxin.
🌟 GEOTROPISM
Roots grow downward due to gravity.
🌟 HYDROTROPISM
Roots grow toward water.
🌟 THIGMOTROPISM
Growth response to touch.
Example:
Tendrils coil around support.
🌟 NASTIC MOVEMENT
Movement independent of direction of stimulus.
Example:
Touch-me-not plant folds leaves.
🔥 MOST IMPORTANT BOARD QUESTIONS WITH ANSWERS
Q1. What is reflex action? Explain reflex arc.
Answer:
Reflex action is a quick automatic response to a stimulus without conscious thinking.
The pathway followed by nerve impulse during reflex action is called reflex arc.
Path:
Stimulus → Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector
Reflex action protects body from injury and provides rapid response.
Q2. Why is pituitary gland called master gland?
Answer:
Pituitary gland is called master gland because it controls and regulates activities of other endocrine glands by secreting hormones.
Q3. Differentiate between nervous control and hormonal control.
| Nervous Control | Hormonal Control |
|---|---|
| Fast action | Slow action |
| Electrical impulses | Chemical messengers |
| Short-lasting effect | Long-lasting effect |
Q4. Explain functions of cerebellum.
Answer:
Cerebellum maintains:
- Body balance
- Posture
- Coordination of muscles
- Precision in movement
Q5. What are hormones?
Answer:
Hormones are chemical messengers secreted by endocrine glands in small quantities and transported through blood to target organs.
Q6. Explain phototropism.
Answer:
The movement of plant parts toward light is called phototropism.
Shoots bend toward light due to unequal distribution of auxin hormone.
🔥 NCERT IMPORTANT LINES
- Brain is protected by skull.
- Reflex action involves spinal cord.
- Hormones are chemical messengers.
- Auxin promotes growth.
- Adrenaline prepares body for emergency.
✍️ MOST IMPORTANT DIAGRAMS
- Neuron
- Human brain
- Reflex arc
- Endocrine glands
- Tropic movement
🎯 EXPECTED QUESTIONS FOR 2026 BOARD
- Explain reflex action with diagram.
- Draw neuron and explain functions.
- Why is pituitary called master gland?
- Explain phototropism.
- Difference between voluntary and involuntary action.
- Explain functions of cerebellum.
- What are hormones?
- Explain nervous system in humans.
