Control and Coordination — Science Class 10 Notes (CBSE & HBSE)
Free NCERT Science notes for Control and Coordination (Class 10) on Siksha Sarovar, aligned to CBSE and Haryana Board (HBSE). This chapter is broken into 4 topics with clear explanations, formulas, solved examples and board-pattern practice — free to read, no sign-up required.
Board exam focus — Control and Coordination (CBSE & HBSE)
Focuses on how organisms respond to stimuli through nervous and chemical systems. CBSE emphasizes human brain and reflex action; HBSE focuses on hormones and plant movements.
Nervous System and Reflex Action
All living organisms respond to environmental changes (stimuli). In animals, this is controlled by nervous and muscular tissues.
1. The Neuron (Nerve Cell)
Structural and functional unit of the nervous system.
- Dendrite: Receives information.
- Cell Body: Processes the signal.
- Axon: Conducts electrical impulse (nerve impulse).
- Synapse: Gap between two neurons where electrical signals convert to chemical signals (neurotransmitters).
2. Reflex Action
An involuntary and rapid response to a stimulus (e.g., pulling back hand from a hot object).
- Reflex Arc: Stimulus → Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector (Muscle) → Response.
The Human Brain
The central information processing organ, protected by the skull (cranium) and cerebrospinal fluid.
Parts of the Brain:
- Forebrain (Cerebrum): Main thinking part. Responsible for memory, intelligence, hearing, smell, and sight.
- Midbrain: Controls involuntary actions and reflex movements of the head and neck.
- Hindbrain:
- Cerebellum: Maintains posture and balance; coordinates voluntary actions like walking.
- Medulla: Controls involuntary actions like blood pressure, salivation, and vomiting.
- Pons: Regulates respiration.
Coordination in Plants
Plants have neither a nervous system nor muscles. They respond using hormones (chemical coordination).
1. Immediate Response to Stimulus (Nastic Movement)
Does not involve growth. Example: Drooping of leaves in 'Touch-me-not' (Mimosa pudica) due to water movement.
2. Growth-Dependent Movements (Tropic Movements)
- Phototropism: Movement towards light (Shoot +ve, Root -ve).
- Geotropism: Movement towards gravity (Root +ve, Shoot -ve).
- Hydrotropism: Movement towards water.
- Chemotropism: Movement towards chemicals (e.g., pollen tube growth towards ovule).
Hormones in Plants and Animals
Plant Hormones (Phytohormones):
- Auxin: Promotes cell elongation and phototropism.
- Gibberellins: Help in the growth of the stem.
- Cytokinins: Promote cell division (high in fruits/seeds).
- Abscisic Acid (ABA): Inhibits growth; causes wilting of leaves (Stress hormone).
Animal Hormones (Endocrine System):
- Thyroxine (Thyroid): Regulates metabolism (needs Iodine).
- Growth Hormone (Pituitary): Regulates growth and development.
- Adrenaline (Adrenal): Prepare body for emergency (Fight or Flight).
- Insulin (Pancreas): Regulates blood sugar levels.
- Testosterone/Oestrogen: Regulate puberty and reproductive systems.
Frequently asked questions
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Do these notes follow CBSE and HBSE?
Yes. The Control and Coordination notes are NCERT-aligned and include guidance for both CBSE and Haryana Board (HBSE), with important questions and MCQs for revision.
What does the Control and Coordination chapter cover?
Concept explanations, key formulas and definitions, fully solved examples and board-pattern practice questions for Control and Coordination.