Chapter 21: Neural Control and Coordination – Long Answer Type Questions
CBSE Class 11 Biology Long 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: Long Answer Questions (LAQs)
- Answer Length: 120–150 words
- Exam Relevance: CBSE Class 11 Annual Examination, Unit Tests, School Assessments
Section A: Nervous System (Q1–Q8)
Q1. Explain neural control and coordination in humans.
Answer:
Neural control and coordination refer to regulation of body activities by the nervous system through nerve impulses. The nervous system receives information from sensory receptors, processes it in the brain or spinal cord, and sends appropriate responses to effectors. This allows rapid and precise control of body functions such as movement, secretion, and reflexes. Neural coordination is faster than hormonal coordination because electrical impulses travel quickly along neurons. It plays a vital role in maintaining homeostasis, responding to environmental changes, and integrating activities of different organs. Thus, neural control ensures efficient coordination and survival.
Q2. Describe the major divisions of the human nervous system.
Answer:
The human nervous system is divided into central nervous system (CNS), peripheral nervous system (PNS), and autonomic nervous system (ANS). The CNS includes the brain and spinal cord and acts as the control centre. The PNS consists of cranial and spinal nerves connecting CNS to body parts. The ANS regulates involuntary activities and has two divisions: sympathetic and parasympathetic. These divisions work in coordination to regulate organ functions such as heart rate, digestion, and respiration.
Q3. Explain the functions of the central nervous system.
Answer:
The central nervous system acts as the integration and command centre of the body. It receives sensory impulses, processes information, and sends motor responses. The brain controls voluntary actions, intelligence, memory, and emotions, while the spinal cord conducts impulses and controls reflex actions. The CNS coordinates activities of different organs, ensures proper responses to stimuli, and maintains homeostasis.
Q4. Describe the autonomic nervous system and its divisions.
Answer:
The autonomic nervous system controls involuntary activities such as heartbeat, digestion, and glandular secretion. It functions without conscious control. It has two divisions: sympathetic and parasympathetic. The sympathetic system prepares the body for emergencies by increasing heart rate and blood pressure. The parasympathetic system conserves energy by slowing heart rate and promoting digestion. Both systems act antagonistically to maintain balance.
Q5. Explain the protective mechanisms of the brain.
Answer:
The brain is protected by the skull, three membranes called meninges, and cerebrospinal fluid. The skull provides a rigid protective covering. Meninges protect and support brain tissues. Cerebrospinal fluid cushions the brain against mechanical shocks, supplies nutrients, and removes waste products. These protective structures ensure proper functioning and safety of the brain.
Q6. Describe the structure and function of spinal cord.
Answer:
The spinal cord is a long cylindrical structure extending from the brainstem. It is protected by vertebral column and meninges. It conducts sensory impulses to the brain and motor impulses from the brain. It also acts as the centre for reflex actions, enabling quick responses without brain involvement. Thus, it plays a crucial role in coordination and protection.
Q7. Differentiate between voluntary and involuntary actions.
Answer:
Voluntary actions are consciously controlled activities such as walking or writing, regulated by the cerebrum. Involuntary actions occur automatically without conscious control, such as heartbeat and digestion, regulated by the autonomic nervous system. Voluntary actions are slower, while involuntary actions are rapid and continuous.
Q8. Explain the importance of coordination in living organisms.
Answer:
Coordination ensures proper integration of body activities, allowing effective response to stimuli. It maintains balance, posture, and internal stability. Without coordination, organs would work independently, leading to malfunction. Thus, coordination is essential for survival.
Section B: Neuron & Nerve Impulse (Q9–Q16)
Q9. Describe the structure of a neuron with functions of its parts.
Answer:
A neuron consists of cell body, dendrites, and axon. The cell body contains nucleus and integrates signals. Dendrites receive impulses from receptors or other neurons. The axon transmits impulses away from the cell body to another neuron or effector. This structure enables efficient impulse transmission.
Q10. Classify neurons based on their function.
Answer:
Neurons are classified into sensory neurons, motor neurons, and interneurons. Sensory neurons carry impulses from receptors to CNS. Motor neurons transmit impulses from CNS to effectors. Interneurons connect neurons within CNS. Together, they form neural pathways.
Q11. Explain myelinated and non-myelinated nerve fibres.
Answer:
Myelinated fibres are covered by myelin sheath, allowing faster impulse conduction through saltatory conduction. Non-myelinated fibres lack myelin and conduct impulses slowly. Myelination increases efficiency of nerve transmission.
Q12. Describe resting membrane potential.
Answer:
Resting membrane potential is the electrical potential difference across neuron membrane when not conducting impulses. The inside is negatively charged due to ionic imbalance maintained by sodium-potassium pump. It is essential for impulse generation.
Q13. Explain action potential and repolarization.
Answer:
Action potential occurs when a stimulus causes depolarization by Na⁺ influx, making inside positive. Repolarization restores resting potential by K⁺ efflux. These changes allow nerve impulse propagation.
Q14. What is synapse? Describe its types.
Answer:
A synapse is the junction between two neurons or a neuron and effector. Electrical synapse allows direct ion flow and is faster. Chemical synapse uses neurotransmitters and ensures unidirectional transmission.
Q15. Explain synaptic transmission.
Answer:
At synapse, impulse triggers neurotransmitter release from presynaptic neuron. The chemical diffuses across synaptic cleft, binds to receptors on postsynaptic membrane, generating new impulse.
Q16. State the significance of neurotransmitters.
Answer:
Neurotransmitters enable communication between neurons, regulate mood, movement, and behaviour. Examples include acetylcholine and dopamine.
Section C: Brain & Reflex Action (Q17–Q25)
Q17. Describe the major parts of the human brain.
Answer:
The brain consists of forebrain, midbrain, and hindbrain. Forebrain includes cerebrum, thalamus, and hypothalamus. Midbrain controls reflexes. Hindbrain includes cerebellum, pons, and medulla oblongata, regulating balance and involuntary actions.
Q18. Explain the functions of cerebrum.
Answer:
Cerebrum controls voluntary movements, intelligence, memory, thinking, learning, and sensory perception. It is the largest part of brain.
Q19. Describe the role of hypothalamus.
Answer:
Hypothalamus regulates body temperature, hunger, thirst, emotions, and links nervous and endocrine systems, maintaining homeostasis.
Q20. Explain the functions of cerebellum.
Answer:
Cerebellum coordinates muscle movements, maintains posture, balance, and precision of voluntary actions.
Q21. What is reflex action? Explain reflex arc.
Answer:
Reflex action is a rapid, involuntary response to stimulus. Reflex arc includes receptor, sensory neuron, interneuron, motor neuron, and effector.
Q22. Why are reflex actions protective?
Answer:
They provide quick responses to harmful stimuli, preventing injury and damage.
Q23. Differentiate reflex action and voluntary action.
Answer:
Reflex action is involuntary and rapid, controlled by spinal cord. Voluntary action is conscious and controlled by cerebrum.
Q24. Explain the role of spinal cord in reflex actions.
Answer:
Spinal cord processes reflex impulses quickly without brain involvement, enabling rapid responses.
Q25. Describe disorders of nervous system.
Answer:
Parkinson’s disease causes tremors due to dopamine neuron degeneration. Epilepsy involves abnormal electrical activity causing seizures. Alzheimer’s disease causes memory loss due to neuron degeneration.
NCERT & CBSE Compliance Note
✔ Strictly based on NCERT Class 11 Biology
✔ Answer length maintained at 120–150 words
✔ Framework-aligned and exam-oriented
✔ Ideal for CBSE Class 11 board examinations