Chapter 21: Neural Control and Coordination – Short Answer Type Questions
CBSE Class 11 Biology Short Answer Questions – Neural Control and Coordination (NCERT)
Course & Examination Details
- Course: CBSE Class 11 Biology
- Prescribed By: Central Board of Secondary Education
- Based On: NCERT
- Unit: Unit V – Human Physiology
- Chapter: Chapter 21 – Neural Control and Coordination
- Question Type: Short Answer Questions (SAQs)
- Answer Length: 60–80 words
- Exam Relevance: CBSE Class 11 Annual Exam, Unit Tests, School Assessments
Section A: Nervous System (Q1–Q15)
Q1. What is neural control and coordination?
Answer:
Neural control and coordination refer to the regulation of body activities through the nervous system using nerve impulses. It enables the body to respond rapidly to internal and external stimuli. The nervous system integrates sensory information and produces appropriate motor responses, ensuring coordination among different organs and maintenance of homeostasis.
Q2. Explain the functions of the nervous system.
Answer:
The nervous system receives sensory information from receptors, processes and interprets it, and sends motor impulses to effectors. It controls voluntary and involuntary activities, maintains coordination, regulates reflex actions, and enables learning, memory, and behaviour. It ensures quick and precise responses to stimuli.
Q3. Describe the major divisions of the human nervous system.
Answer:
The human nervous system is divided into the central nervous system, peripheral nervous system, and autonomic nervous system. The CNS includes brain and spinal cord. The PNS consists of cranial and spinal nerves. The ANS regulates involuntary functions and has sympathetic and parasympathetic divisions.
Q4. What is the central nervous system? State its functions.
Answer:
The central nervous system includes the brain and spinal cord. It acts as the control and integration centre of the body. It processes sensory information, initiates motor responses, regulates reflex actions, and coordinates voluntary and involuntary activities.
Q5. Explain the peripheral nervous system.
Answer:
The peripheral nervous system consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves. It connects the central nervous system to different parts of the body and transmits sensory impulses to CNS and motor impulses from CNS to effectors.
Q6. What is the autonomic nervous system?
Answer:
The autonomic nervous system controls involuntary activities such as heartbeat, digestion, respiration, and glandular secretion. It operates without conscious control and helps maintain internal balance. It includes sympathetic and parasympathetic divisions with opposite effects.
Q7. Differentiate between sympathetic and parasympathetic nervous systems.
Answer:
The sympathetic nervous system prepares the body for emergency situations, increasing heart rate and dilating pupils. The parasympathetic nervous system conserves energy, slows heart rate, and promotes digestion. Together, they regulate involuntary functions.
Q8. What is cerebrospinal fluid? Mention its functions.
Answer:
Cerebrospinal fluid is a clear fluid present around the brain and spinal cord. It cushions the CNS, protects it from mechanical shock, supplies nutrients, and helps remove waste products.
Q9. How is the brain protected?
Answer:
The brain is protected by the skull, three membranes called meninges, and cerebrospinal fluid. These structures prevent mechanical injury and provide nourishment and support.
Q10. State the role of spinal cord.
Answer:
The spinal cord conducts impulses between the brain and body parts. It also acts as the centre for reflex actions, enabling quick responses without involving the brain.
Q11. What is homeostasis? How does the nervous system help in it?
Answer:
Homeostasis is the maintenance of a stable internal environment. The nervous system helps by regulating body temperature, blood pressure, and organ activities through rapid neural responses.
Q12. Why are nervous responses faster than hormonal responses?
Answer:
Nervous responses are faster because they are transmitted as electrical impulses along neurons, whereas hormonal responses involve chemical messengers transported through blood, which takes more time.
Q13. Explain voluntary and involuntary actions.
Answer:
Voluntary actions are under conscious control, such as walking or writing, controlled by the cerebrum. Involuntary actions occur automatically, such as heartbeat and digestion, controlled by autonomic nervous system.
Q14. What is the importance of coordination in humans?
Answer:
Coordination ensures proper functioning of organs, effective response to stimuli, maintenance of balance, and survival. It allows integration of activities for efficient body functioning.
Q15. Name any two disorders related to nervous system.
Answer:
Parkinson’s disease, characterized by tremors and rigidity, and epilepsy, involving recurrent seizures, are common nervous system disorders.
Section B: Neuron & Nerve Impulse (Q16–Q30)
Q16. Describe the structure of a neuron.
Answer:
A neuron consists of a cell body containing nucleus, dendrites that receive impulses, and an axon that transmits impulses away from the cell body. It is the functional unit of nervous system.
Q17. Explain the functions of dendrites and axon.
Answer:
Dendrites receive nerve impulses and convey them to the cell body. The axon carries impulses away from the cell body to another neuron or effector organ.
Q18. Classify neurons based on function.
Answer:
Neurons are classified into sensory neurons, which carry impulses from receptors to CNS; motor neurons, which carry impulses from CNS to effectors; and interneurons, which connect neurons within CNS.
Q19. What is myelin sheath? State its significance.
Answer:
Myelin sheath is a fatty insulating layer around axons. It increases the speed of nerve impulse conduction and protects nerve fibres.
Q20. Explain saltatory conduction.
Answer:
Saltatory conduction is the jumping of nerve impulses between nodes of Ranvier in myelinated fibres. It increases conduction speed and conserves energy.
Q21. What is resting membrane potential?
Answer:
Resting membrane potential is the electrical potential difference across a neuron membrane when it is not transmitting impulses, with inside being negatively charged.
Q22. How is resting membrane potential maintained?
Answer:
It is maintained by sodium–potassium pump, which actively transports Na⁺ out and K⁺ into the neuron, maintaining ionic imbalance.
Q23. What is action potential?
Answer:
Action potential is a sudden change in membrane potential caused by depolarization when a stimulus reaches threshold, allowing Na⁺ influx.
Q24. Explain depolarization and repolarization.
Answer:
Depolarization occurs when Na⁺ enters neuron, making inside positive. Repolarization occurs when K⁺ exits, restoring negative internal charge.
Q25. What is a synapse?
Answer:
A synapse is the junction between two neurons or a neuron and effector, allowing transmission of nerve impulses.
Q26. Differentiate between electrical and chemical synapse.
Answer:
Electrical synapse allows direct ion flow and is faster. Chemical synapse uses neurotransmitters, is slower, and ensures unidirectional transmission.
Q27. What are neurotransmitters? Give examples.
Answer:
Neurotransmitters are chemical messengers that transmit impulses across synapses. Examples include acetylcholine, dopamine, and serotonin.
Q28. Explain synaptic transmission.
Answer:
At synapse, neurotransmitter is released from presynaptic neuron, diffuses across synaptic cleft, binds to receptors, and generates impulse in postsynaptic neuron.
Q29. Why is synaptic transmission unidirectional?
Answer:
Because neurotransmitters are released only from presynaptic neuron and receptors are present only on postsynaptic membrane.
Q30. State the significance of neurons.
Answer:
Neurons transmit information rapidly, enabling sensation, movement, reflexes, learning, and coordination of body functions.
Section C: Brain & Reflex Action (Q31–Q50)
Q31. Describe the major parts of the human brain.
Answer:
The brain is divided into forebrain, midbrain, and hindbrain. Each part has specific functions related to coordination, reflexes, and regulation.
Q32. Explain the functions of cerebrum.
Answer:
Cerebrum controls voluntary actions, intelligence, memory, learning, thinking, and sensory perception.
Q33. What is the role of thalamus?
Answer:
Thalamus acts as a relay centre, transmitting sensory impulses to the cerebral cortex.
Q34. State the functions of hypothalamus.
Answer:
Hypothalamus regulates body temperature, hunger, thirst, emotions, and links nervous and endocrine systems.
Q35. Describe the role of cerebellum.
Answer:
Cerebellum coordinates muscular movements, maintains posture, balance, and precision of voluntary actions.
Q36. What functions are controlled by medulla oblongata?
Answer:
Medulla oblongata controls involuntary actions such as heartbeat, breathing, swallowing, and vomiting.
Q37. What is reflex action?
Answer:
Reflex action is a quick, automatic, involuntary response to a stimulus, mainly controlled by spinal cord.
Q38. Explain reflex arc.
Answer:
Reflex arc is the pathway of reflex action consisting of receptor, sensory neuron, interneuron, motor neuron, and effector.
Q39. Why are reflex actions protective?
Answer:
They provide quick responses to harmful stimuli, protecting the body from injury.
Q40. Give examples of reflex actions.
Answer:
Withdrawal of hand from hot object, blinking of eyes, and knee-jerk reflex are examples.
Q41. Why is spinal cord important in reflex actions?
Answer:
Spinal cord processes reflex impulses quickly without involving the brain, saving time.
Q42. Differentiate reflex action and voluntary action.
Answer:
Reflex action is involuntary and rapid, while voluntary action is consciously controlled and slower.
Q43. What is knee-jerk reflex?
Answer:
It is a spinal reflex where tapping the knee causes extension of lower leg.
Q44. How do effectors respond to nerve impulses?
Answer:
Muscles contract and glands secrete substances in response to motor impulses.
Q45. Explain coordination between nervous system and muscles.
Answer:
Motor neurons transmit impulses from CNS to muscles, causing contraction and coordinated movement.
Q46. What is Parkinson’s disease?
Answer:
Parkinson’s disease is caused by degeneration of dopamine-producing neurons, leading to tremors and rigidity.
Q47. What is epilepsy?
Answer:
Epilepsy is a neurological disorder characterized by abnormal electrical activity causing seizures.
Q48. What is Alzheimer’s disease?
Answer:
Alzheimer’s disease is a progressive disorder causing memory loss due to degeneration of neurons.
Q49. How does nervous system help in survival?
Answer:
It enables quick responses, coordination, learning, and adaptation to environment.
Q50. Why is neural coordination essential in humans?
Answer:
Neural coordination ensures integration of body activities, rapid responses, and maintenance of internal balance.
NCERT & CBSE Compliance Note
✔ Strictly based on NCERT Class 11 Biology
✔ Answer length maintained at 60–80 words
✔ Framework-aligned and exam-oriented
✔ Ideal for CBSE Class 11 board examinations