Control and Coordination – Short Answer Type Questions
Class 10
CBSE Board Examinations
NCERT-aligned • Short Q&A for quick revision
Presented in systematic order for CBSE board:
Syllabus-aligned
Short-answer format
Topic-wise grouping
Nervous System — Basics (Q1–Q12)
Structure and function of the nervous system
1. What is the basic structural unit of the nervous system?
The neuron (nerve cell) is the basic structural and functional unit of the nervous system.
2. Name the three main parts of a neuron.
Cell body (soma), dendrites, and axon.
3. What is a synapse?
A synapse is the junction between two neurons where information is transmitted chemically or electrically.
4. What is the role of myelin sheath?
Myelin sheath insulates the axon and speeds up nerve impulse conduction.
5. Define nerve impulse.
A nerve impulse is an electrochemical signal that travels along a neuron to carry information.
6. What are sensory and motor neurons?
Sensory neurons carry signals from receptors to the CNS; motor neurons carry signals from the CNS to effectors (muscles/glands).
7. What is the Central Nervous System (CNS)?
CNS consists of the brain and spinal cord; it processes information and coordinates responses.
8. What is the Peripheral Nervous System (PNS)?
PNS includes all nerves outside the CNS that connect the CNS to organs, limbs, and sensory receptors.
9. What is the role of the cerebrum?
The cerebrum controls voluntary actions, intelligence, memory, learning, and sensory perception.
10. Where is the medulla oblongata and what does it control?
Medulla oblongata is part of the brainstem and controls involuntary actions like heartbeat and breathing.
11. What is the function of the spinal cord?
The spinal cord relays messages between the brain and body and coordinates reflex actions.
12. Distinguish between voluntary and involuntary actions (one line).
Voluntary actions are consciously controlled by the brain; involuntary actions occur without conscious control.
Neuron & Impulse (Q13–Q16)
How impulses originate and travel
13. What initiates a nerve impulse?
A stimulus that changes the membrane potential of a neuron initiates a nerve impulse.
14. What is resting potential?
Resting potential is the voltage difference across a neuron's membrane when it is not transmitting a signal (typically about –70 mV).
15. What is an action potential?
An action potential is a rapid change in membrane potential that travels along the axon as a nerve impulse.
16. How do neurons communicate at a synapse?
Neurotransmitters released from the presynaptic neuron cross the synaptic gap and bind to receptors on the postsynaptic neuron.
Reflex Actions (Q17–Q20)
Quick, automatic responses — reflex arc
17. What is a reflex action?
A reflex action is an automatic, rapid response to a stimulus that does not involve conscious thought.
18. Name the components of a reflex arc.
Receptor → sensory neuron → spinal cord (relay neuron) → motor neuron → effector.
19. Give one example of a reflex action.
The knee-jerk (patellar) reflex is an example; withdrawing a hand from a hot object is another.
20. Why are reflexes important?
Reflexes protect the body from harm and help maintain posture and balance.
Endocrine System & Hormones (Q21–Q32)
Glands, hormones and their functions
21. What is the endocrine system?
The endocrine system is a network of glands that release hormones into the bloodstream to regulate body functions.
22. What are hormones?
Hormones are chemical messengers produced by endocrine glands that travel through blood to target organs.
23. Name two major endocrine glands in humans.
Pituitary gland and thyroid gland (others include adrenal, pancreas, testes/ovaries).
24. What is the role of the pituitary gland?
Pituitary gland is called the 'master gland' because it secretes hormones that control other endocrine glands and many body functions.
25. Function of insulin and where it is produced?
Insulin, produced by the pancreas, lowers blood glucose by promoting its uptake and storage as glycogen.
26. What does glucagon do?
Glucagon (pancreas) raises blood glucose by stimulating glycogen breakdown in the liver.
27. What is thyroxine and its role?
Thyroxine (from thyroid gland) regulates metabolic rate, growth, and development.
28. Name one hormone from adrenal gland and its function.
Adrenaline (epinephrine) increases heart rate, breathing rate, and prepares the body for 'fight or flight'.
29. How do endocrine and nervous systems differ (one line)?
Nervous system uses fast electrical signals for short-term responses; endocrine uses hormones for slower, long-term regulation.
30. What is feedback regulation in hormones?
Feedback regulation (often negative feedback) is when hormone levels control their own production to maintain balance.
31. Which gland controls secondary sexual characteristics?
Sex hormones from ovaries and testes (regulated by pituitary hormones) control secondary sexual characteristics.
32. What happens in diabetes mellitus (basic)?
In diabetes, insulin production or action is defective, causing high blood glucose levels and related complications.
Control & Coordination in Plants (Q33–Q42)
Plant hormones, tropisms and movements
33. Do plants have a nervous system?
No, plants do not have a nervous system; they use hormones and movement responses to coordinate functions.
34. What are plant hormones (phytohormones)?
Plant hormones are chemical substances that control growth, development, and responses to stimuli.
35. Name four major plant hormones.
Auxin, gibberellin, ethylene, and abscisic acid (ABA).
36. What is phototropism?
Phototropism is growth movement of plant parts towards (positive) or away (negative) from light.
37. How does auxin help in phototropism?
Auxin accumulates on the shaded side of a stem, promoting cell elongation there and causing the stem to bend toward light.
38. What is geotropism (gravitropism)?
Geotropism is growth response to gravity: roots show positive geotropism (grow down), shoots show negative geotropism (grow up).
39. Define nastic movement and example.
Nastic movements are non-directional responses to stimuli (e.g., closing of Mimosa leaves on touch).
40. What effect does ethylene have on plants?
Ethylene promotes fruit ripening and leaf fall (abscission).
41. Role of abscisic acid (ABA)?
ABA promotes dormancy and helps plants tolerate stress by closing stomata and inhibiting growth.
42. How do plants respond to water scarcity?
Plants close stomata (ABA-mediated), reduce growth, and may enter dormancy to conserve water.
Comparisons & Quick Facts (Q43–Q50)
Useful short comparison points and definitions
43. Difference between neuron and nerve (one line)?
A neuron is a single nerve cell; a nerve is a bundle of many axons (fibres) bound together.
44. What is a hormone receptor?
A hormone receptor is a specific protein on or in target cells that binds a hormone and mediates its effect.
45. One function of pituitary follicle stimulating hormone (FSH).
FSH stimulates development of ovarian follicles in females and spermatogenesis in males.
46. What is homeostasis (one line)?
Homeostasis is the maintenance of a stable internal environment despite external changes.
47. Why are plant hormones effective at low concentrations?
Plant hormones act at very low concentrations because target cells have high sensitivity and specific signalling pathways.
48. How does insulin affect protein and fat metabolism?
Insulin promotes protein synthesis and fat storage by stimulating amino acid uptake and lipogenesis.
49. What is meant by 'fight or flight' response?
It is the body's acute stress response (mediated by adrenaline) preparing for defense or escape by increasing energy availability.
50. Give one exam tip for answering short Qs from this chapter.
Write concise definitions and include a key example (e.g., reflex arc components or a plant tropism) to score full marks.