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NCERT Solutions for Class 11 Biology Chapter 18 Neural Control and Coordination

NCERT Solutions for Class 11 Biology Chapter 18 Neural Control and Coordination

Edited By Irshad Anwar | Updated on Jun 18, 2025 04:43 PM IST

Neural control and coordination are important for controlling body functions and giving a reaction to stimuli. The nervous system helps in receiving, processing, and passing on information by neurons, which makes the communication rapid. NCERT Solutions for Class 11 Biology Chapter 18 Neural Control and Coordination provide clear answers that allow the students to understand how the brain and nervous system control all voluntary and involuntary actions, including muscle movement, reflexes, and organ functions. Going through the NCERT Solutions gives students a clear idea of this chapter, with better retention of the concepts.

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This Story also Contains
  1. NCERT Solutions For Class 11 Biology Chapter 18 PDF Download
  2. Access Answers to NCERT Solutions for Class 11 Biology Chapter 18 (Exercise)
  3. Approach to Solve Questions of Class 11 Chapter 18
  4. Important Question from Chapter 18
  5. What Extra Should Students Study Beyond the NCERT for NEET?
  6. NCERT Solutions for Class 11 Biology - Chapter Wise
NCERT Solutions for Class 11 Biology Chapter 18 Neural Control and Coordination
NCERT Solutions for Class 11 Biology Chapter 18 Neural Control and Coordination

NCERT Solutions for Class 11 Biology Chapter 18 Neural Control and Coordination answers all your doubts. The chapter also describes the structure and functions of neurons, the human nervous system, and sensory organs, making it easier for you to learn how body coordination occurs. The structure of the human brain, including midbrain, forebrain, and hindbrain, is very well explained here in easy language, along with the well-labelled diagram provided by our subject experts. Students need to go through the NCERT Solutions Class 11 Biology of this chapter thoroughly and understand the mechanism of how coordination occurs in our body.

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NCERT Solutions For Class 11 Biology Chapter 18 PDF Download

Given below is the PDF of this chapter after going through these, you must be able to understand all the answers to the following questions:

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Access Answers to NCERT Solutions for Class 11 Biology Chapter 18 (Exercise)

The detailed solutions for in-text and exercise questions are provided below to make the concepts clear and to understand how the brain and nervous system work.

Q1. Briefly describe the structure of the brain.

Answer:

The brain is the main coordinating centre of the body. It is a part of the nervous system that controls and monitors every organ of the body.

It is well protected by cranial meninges, an outer layer called dura mater, a thin middle layer called arachnoid, and an inner layer called pia mater.

It is divided into three regions —

  1. Forebrain
  2. midbrain
  3. hindbrain

Forebrain: The largest part of the brain, responsible for thinking, memory, emotions, and controlling body temperature, hunger, and thirst. It includes the cerebrum (main thinking area), thalamus (sensory and motor coordination), and hypothalamus (controls body functions and emotions).

Midbrain: Connects the forebrain and hindbrain. It helps process visual and auditory information and controls some movements and reflexes.

Hindbrain: Controls basic life functions like breathing, heartbeat, and balance. It has three parts: the pons (connects parts of the brain), the cerebellum (balance and coordination), and the medulla oblongata (controls heart rate, breathing, and other automatic functions).

Q2. Compare the following:

(a) Central nervous system (CNS) and Peripheral nervous system (PNS)

Answer: The major difference between the Central nervous system (CNS) and the Peripheral nervous system (PNS) is discussed below in the table:

Central Neural System (CNS)Peripheral Neural System (PNS)
1. The CNS is made up of the brain and the spinal cord.1. PNS consists of cranial nerves and spinal nerves.
2. The brain is protected by the skull, and the spinal cord by the vertebral column.2. There are no protective structures for PNS.
3. CNS does not have any subdivisions.3. PNS is divided into the somatic nervous system and the autonomic nervous system.
4. CNS processes the information and controls the response to impulses.4. Nerves of the PNS carry impulses to the CNS and responses from the CNS to different organs of the body.
5. The group of neurons in the CNS is called nuclei.5. The group of neurons in the PNS is called ganglia.

Q2. Compare the following:

(b) Resting potential and action potential

Answer:

Resting PotentialAction Potential
1. It is the potential difference (difference in electric charge) across the membrane when the neuron is at the resting phase.1. It is the potential difference (difference in the electric charge) across the membrane when the neuron is stimulated or excited.
2. The outer side of the neuron is positively charged and the interior of the neuron is negatively charged.2. The outer side of the neuron is negatively charged, and the interior of the neuron is positively charged.
3. The plasma membrane of the neuron is more permeable to K+ ions.3. The plasma membrane of the neuron is more permeable to Na+ ions.
4. The sodium-potassium-ATPase pump is active and sends Na+ ions outside the neuron to maintain the resting potential.4. The sodium-potassium-ATPase pump functions in a reverse manner and sends Na+ ions into the neuron.


(a) Polarisation of the membrane of a nerve fibre

Answer:

Polarisation of the membrane of a nerve fibre:

When the nerve fibre is in the resting phase, it is said to be in the polarised state. In a polarised state, the membrane of the nerve fibre experiences a resting potential. The following steps take place during the process of polarisation of the membrane of a nerve fibre:

  • When a depolarised region of a nerve fibre starts becoming polarised initially, there are more K+ ions outside the nerve fibre and the axon membrane contains a large amount of Na+ ions.
  • As the region of the membrane starts attaining the polarised state, the membrane becomes more permeable to K+ ions and impermeable to Na+ ions and negatively charged proteins.
  • 3 Na+ ions are sent outside the axon and 2 K + ions are sent into the axon by a sodium-potassium pump by active transport.
  • The inner side of the membrane becomes electronegative (negatively charged) and the outer side becomes electropositive (positively charged) because of the movement of sodium and potassium ions. This makes the nerve fibre polarised.

Q3. Explain the following processes:

(b) Depolarisation of the membrane of a nerve fibre

Answer:

When the nerve fibre is stimulated, it is said to be in a depolarised state. In a depolarised state, the membrane of the nerve fibre experiences an action potential. The following steps take place during the process of depolarisation of the membrane of a nerve fibre:

  • In a polarised state, the axon has a higher concentration of K+ ions and outside the axon, the concentration of Na+ ions is more.
  • When the nerve fibre gets excited by the stimulus, the permeability of the membrane for Na+ ions and K+ ions is reversed.
  • The membrane becomes highly permeable for Na+ ions.
  • There is a rapid influx of Na+ ions into the axon.
  • This makes the inner side of the membrane positively charged and the outside of the membrane becomes negatively charged.
  • This results in depolarisation of the membrane of the nerve fibre and it experiences an action potential.

Q3. Explain the following processes:

(c) Transmission of a nerve impulse across a chemical synapse

Answer:

A synapse is the junction between two nerve cells (neurons).

  • In a chemical synapse, there is always a small gap called the synaptic cleft between the two neurons.
  • When a nerve impulse reaches the end of the first neuron (pre-synaptic neuron), calcium ions enter and cause tiny sacs (vesicles) to release a chemical called acetylcholine into the gap.
  • Acetylcholine crosses the gap and attaches to receptors on the next neuron (post-synaptic neuron).
  • This allows sodium to enter and potassium to leave the next neuron, creating a new nerve impulse.
  • The signal is then passed on to the next neuron.

(b) Brain

Answer:

Brain-

Human Brain


Q5. Write short notes on the following:

(a) Neural coordination

Answer:

Coordination helps different organs work together in living things. In humans, coordination happens in two ways: neural and chemical. Neural coordination uses special cells called neurons to send messages quickly.

  • Neurons connect receptors (which sense things) to effectors (which respond).

  • This system controls body actions, like moving muscles or activating glands.

  • It helps us remember, learn, think, and reason.

  • Neural coordination also manages vital functions like breathing, heartbeat, and digestion.

  • By linking all these processes, it keeps the body balanced and working well.

Q5. Write short notes on the following:

(b) Forebrain

Answer:

The forebrain has three main parts: the cerebrum, thalamus, and hypothalamus. The cerebrum is the biggest part and controls thinking, memory, and actions.

  • The cerebrum is split into two halves and joined by nerve fibres.

  • It has grey matter (outer layer) for thinking and white matter (inner part) for sending signals.

  • The limbic system, located within the cerebrum, is responsible for handling emotions and memory.

The thalamus passes messages between the body and brain and helps with emotions and senses.

  • It helps us feel things like heat, cold, and pain.

The hypothalamus keeps the body balanced.

  • It controls hunger, thirst, sleep, and temperature.

  • It also manages hormones and emotions.

Q5. Write short notes on the following:

(c) Midbrain

Answer:

The midbrain has two main parts: the cerebral peduncles and the corpora quadrigemina. The cerebral peduncles are thick nerve bundles that connect the cerebrum and cerebellum.

  • They help carry sensory and motor signals between the forebrain and hindbrain.

The corpora quadrigemina are two pairs of lobes on the back of the midbrain.

  • The superior colliculi control visual reflexes, like moving your head and eyes towards something you see.

  • The inferior colliculi manage auditory reflexes, helping you turn your head towards sounds.

Q5 . Write short notes on the following:

(d) Hindbrain

Answer:

The hindbrain has three main parts: the cerebellum, pons Varolii, and medulla oblongata. The cerebellum is at the back of the brain.

  • It has an outer grey matter layer and an inner white matter layer.

  • It helps coordinate muscle movements and keeps the body balanced.

The pons Varolii sits above the medulla oblongata.

  • It is made of white nerve fibres and links the two sides of the cerebellum.

  • It also controls breathing.

The medulla oblongata is at the lower part of the brain, connecting to the spinal cord.

  • It carries signals between the brain and spinal cord.

  • It controls vital functions like heartbeat and breathing, so damage to it can be life-threatening.

Q5. Write short notes on the following:

(e) Synapse

Answer:

Synapse:

  • A synapse is formed by the membranes of the presynaptic neuron and the postsynaptic neuron.
  • A synapse may or may not be separated by a gap, which is called the synaptic cleft.
  • There are two kinds of synapses-electrical synapses and chemical synapses.

Q6. Give a brief account of the Mechanism of synaptic transmission.

Answer:

The mechanism of synaptic transmission at the electrical synapse:

  • In this case, the pre-synaptic and post-synaptic membranes are in proximity.
  • Impulse in the form of an electric current directly flows from the presynaptic neuron to the postsynaptic neuron.
  • Transmission is faster than the chemical synapse.

The mechanism of synaptic transmission at the chemical synapse:

  • The pre-synaptic and post-synaptic neurons are separated by the synaptic cleft.
  • When an impulse arrives at the axon terminal, the calcium ions present in the synaptic cleft enter the synaptic knobs present at the axon terminals of the pre-synaptic neuron.
  • The synaptic vesicles present in the synaptic knobs present in the pre-synaptic neuron move towards the plasma membrane and fuse with it.
  • The vesicles release the neurotransmitter acetylcholine in the synaptic cleft. (Empty synaptic vesicles return to the cytoplasm of the presynaptic neuron where they are refilled.)
  • The molecules of acetylcholine bind to the protein receptors present on the plasma membrane of the postsynaptic neurons.
  • This binding opens the channels, and sodium ions enter the post-synaptic neuron, while potassium ions leave the post-synaptic membrane.
  • This generates an action potential in the membrane of the post-synaptic neuron, and hence, the impulse is transmitted to the post-synaptic neuron.

Q7. Explain the Role of Na+ in the generation of an action potential.

Answer:

Sodium ions diffuse from the outside to the intracellular fluid because of the electrochemical gradient. The potassium ions move out, and the membrane becomes negatively charged from the outside and positively charged from the inside. This sudden change in the membrane potential is called the action potential, and the membrane is said to be depolarised.

Q8. Differentiate between:

(a) Myelinated and non-myelinated axons

Answer: The major difference is discussed below:

Myelinated AxonsNon-myelinated Axons
1. Myelin sheath is present.1. Myelin sheath is absent.
2. Nodes of Ranvier are present.2. Nodes of Ranvier are absent.
It is found in the grey matter of the brain, spinal cord, and autonomic nervous system.3. It is found in the white matter of the brain, spinal cord and autonomic nervous system.
4. The conduction of nerve impulses is from node to node.4. The conduction of nerve impulses is smooth.
5. The speed of conduction of the impulse is 50 times faster than in non-myelinated axons.5. The speed of conduction of the impulse is slow.


Q8. Differentiate between:
(b) Dendrites and axons

Answer:

DendritesAxons
1. They are short processes.1. Axons are long processes.
2. Dendrites carry impulses towards the cell body of the neuron.2. Axons carry impulses away from the cell body of the neuron.
3. Dendrites are always branched.3. Axons may or may not be branched.
4. Nissl's granules are present in the neuroplasm.4. Nissl's granules are absent in the neuroplasm.

Q8. Differentiate between:

(c) Thalamus and Hypothalamus

Answer: The major difference is discussed below:

ThalamusHypothalamus
1. It is made of only grey matter.1. It is made of white and grey matter.
2. The thalamus does not secrete any hormones.2. The hypothalamus secretes certain hormones which control the activity of the pituitary gland.
3. It is situated superior to the midbrain.3. It is situated at the base of the thalamus.
4. It contains the centres of sensations such as heat, cold and pain.4. It contains the centres which control body temperature, blood pressure and homeostasis.


Q8. Differentiate between:

(d) Cerebrum and Cerebellum

Answer: The major difference is discussed below:

CerebrumCerebellum
1. It is the largest part of the brain.1. It is the second-largest part of the brain.
2. It is part of the forebrain.2. It is part of the hindbrain.
3. The cerebrum is divided into two cerebral hemispheres.3. The cerebellum is divided into three lobes: the central vermis and the two lateral cerebellar hemispheres.
4. It is the site of memory and intelligence.4. It is the site of body equilibrium and posture.

Q9. Answer the following:

(a) Which part of the human brain is the most developed?

Answer:

The cerebrum is the most developed.

Q9. Answer the following:

(b) Which part of our central neural system acts as a master clock?

Answer:

The hypothalamus of the central nervous system acts as a master clock.

Q10. Distinguish between:

(a) afferent neurons and efferent neurons

Answer: The major difference is discussed below:

Afferent NeuronsEfferent Neurons
1. They conduct sensory impulses from the receptors to the central nervous system.
1. They conduct motor impulses from the central nervous system to the effector organs, such as muscles.
2. They are present in the sense organs.
2. They are present in the brain and the spinal cord.
3. They are sensory neurons.
3. They are motor neurons.

Q10. Distinguish between:

(b) Impulse conduction in a myelinated nerve fibre and an unmyelinated nerve fibre

Answer: The major difference is discussed below:

Impulse Conduction in a Myelinated Nerve FibreImpulse Conduction in Non-Myelinated Nerve Fibre
1. Impulse travels from node to node.1. Impulse travels along the length of the entire nerve fibre.
2. The speed of conduction is 50 times faster than that of a non-myelinated nerve fibre.2. The speed of conduction is slower.
3. Energy expenditure during impulse transmission is less.3. Energy expenditure during impulse transmission is higher.

Q10. Distinguish between:

(c) cranial nerves and spinal nerves.

Answer: The major difference is discussed below:

Cranial NervesSpinal Nerves
1. There are 12 pairs of cranial nerves.1. There are 31 pairs of spinal nerves.
2. They arise from the brain and extend to the other parts of the body.2. They arise from the spinal cord and extend to other parts of the body.
3. They may be sensory, motor, or mixed.3. They are mixed nerves.

NCERT Solutions for Class 11: Subject-wise

Approach to Solve Questions of Class 11 Chapter 18

Provided below are some easy and effective strategies to help you solve questions from this topic with a better understanding and accuracy.

  1. For the first step, it's important to understand key terms like neurons, synapses, reflex arc, and neurotransmitters.
  2. By going through the textbook line by line, students can understand a lot of concepts.
  3. After understanding, use the NCERT Solutions to review how questions have been given in exams and gain confidence to answer them.
  4. It's necessary to make and practice diagrams of the brain, spinal cord, and reflex arc, as they are frequently asked in exams.
  5. Flowcharts for nerve impulse transmission and coordination can also be prepared for quick revision and to deepen the knowledge of this concept.
  6. Solving MCQs and previous year questions is crucial to do the self-assessment, and also to build speed and accuracy.

Important Question from Chapter 18

Understanding how our body senses, processes, and responds to stimuli is key to understanding this chapter. The question below focuses on the most critical concepts that often appear in exams and require a clear vision.

Question 1: Match List I with List II :


List I
List II
APonsI

Provides additional space for neurons and regulates posture and balance.

BHypothalamusIIControls respiration and gastric secretions.
CMedullaIIIConnects different regions of the brain.
DCerebellumIVNeurosecretory cells

Choose the correct answer from the options given below :

1. A-II, B-III, C-I, D-IV

2. A-III, B-IV, C-II, D-I

3, A-I, B-III, C-II, D-IV

4. A-II, B-I, C-III, D-IV

Answer:

  • A. Pons → III. Connects different regions of the brain: The pons facilitates signal transmission and connections between various brain regions.

  • B. Hypothalamus → IV. Neurosecretory cells: The hypothalamus contains cells that produce hormones and regulate vital bodily processes like appetite and body temperature.

  • C. Medulla → II. Controls respiration and gastric secretions: The medulla aids in digesting and regulates breathing.

  • D. Cerebellum → I. Provides additional space for Neurons, and regulates posture and balance: The cerebellum helps with balance and movement, and gives space for brain cells to work.

Hence, the correct answer is option 2)A-III, B-IV, C-II, D-I.

Also, check the NCERT Books and NCERT Syllabus here:

What Extra Should Students Study Beyond the NCERT for NEET?

To prepare well for NEET, it’s good to go a little beyond NCERT. Some questions need a deeper understanding that comes from extra study.

NCERT Solutions for Class 11 Biology - Chapter Wise

Below are the Chapter-wise solutions for easy access and quick revision:

Frequently Asked Questions (FAQs)

1. What are the benefits of NCERT solutions for class 11 biology chapter 18 neural control and coordination?

The benefits of NCERT solutions of Class 11 Biology chapter 18 are listed below: 

  • NCERT is the base of your learning.  
  • You will get all the answers to neural control and coordination ncert and neural control and coordination ncert pdf will help you to score good marks in the exam.  
  • NCERT solutions for chapter 21 biology class 11 will also help you with competitive exams like NEET.  
  • Solution of NCERT neural control and coordination will also boost your knowledge.  
  • NCERT solutions given in neural control and coordination class 11 ncert pdf will also help you in your 12th board exam. 
  • To score well in the examination, follow the NCERT syllabus and solve the exercise given in the NCERT Book. To practice more problems, students must refer to NCERT Exemplar.
2. What are the important topics of NCERT solutions for class 11 biology chapter 18?

These are the important topics of NCERT  solutions for class 11 biology chapter 18:

  • Neural System  
  • Human Neural System  
  • Neuron as Structural and Functional Unit of Neural System  
  • Generation and Conduction of Nerve Impulse  
  • Transmission of Impulses  
  • Central Neural System  
  • Reflex Action and Reflex Arc  
  • Sensory Reception and Processing  
  • Eye  
  • The Ear 
3. What are the major parts of our brain?
  1.   Forebrain,  
  2.   Midbrain  
  3.   Hindbrain 
4. What are the difference between the dendrites and axon according to biology class 11 chapter 18?


Dendrites  Axons 
 1. They are short processes.  1. Axons are long processes. 
 2. Dendrites carry impulses towards the cell body of the neuron.  2. Axons carry impulses away from the cell body of the neuron. 
 3. Dendrites are always branched.  3. Axons may or may not be branched. 
 4. Nissl's granules are present in the neuroplasm.  4. Nissl's granules are absent in the neuroplasm. 
5. What are synapses, and what role do they play in neural coordination?

Synapses are points of interconnection between two neurons where impulses are communicated. They are important in neural coordination because they enable the transfer of communication between neurons in the form of chemical or electrical signals. This facilitates the efficient functioning of the nervous system by enabling the regulation of response and reflexes.

6. How does the structure of a neuron help in its function?

The anatomy of a neuron is optimized for its job of conducting nerve impulses. Dendrites gather information from other neurons, the cell body analyzes the data, and the axon conducts the impulse to the next neuron or target cell. The myelin sheath, which covers the axon, accelerates the transmission of the impulse, making for effective communication within the nervous system.

7. How do sensory, motor, and interneurons function in the nervous system?

Sensory neurons receive stimuli from the environment and send signals to the central nervous system (CNS). Interneurons, which are in the CNS, process and analyze these signals, making connections between sensory and motor neurons. Motor neurons send commands from the CNS to muscles or glands, which results in a response. This coordination enables the body to respond appropriately to stimuli. All of these neurons work together to facilitate perception, reflexes, and voluntary movements.

8. How does the autonomic nervous system regulate body functions?

The autonomic nervous system (ANS) controls involuntary bodily functions such as heartbeat, digestion, and breathing. It has the sympathetic and parasympathetic branches, which function in opposition to each other to ensure balance. The sympathetic division readies the body for emergencies or stress, whereas the parasympathetic division induces relaxation and conservation of energy. They work together to provide homeostasis and normal organ function.

9. What is the role of neurotransmitters in neural transmission?

Neurotransmitters are chemical messengers that carry signals across synapses between neurons. They are released by the presynaptic neuron and attach to receptors on the postsynaptic neuron, initiating a response. Excitatory neurotransmitters facilitate signal transmission, and inhibitory ones decrease neural activity. This process maintains nerve cell communication and governs different body functions.

10. How do myelinated and non-myelinated nerve fibers differ in function?

Myelinated nerve fibres possess a fatty sheath (myelin) covering the axon, with a possibility of quicker conduction of nerve impulses via saltatory conduction. The fibres that do not have a sheath are non-myelinated and transmit impulses more slowly and continuously. Myelinated fibres exist in the peripheral and central nervous systems, which provide quick responses. Non-myelinated fibres are in the autonomic nervous system, regulating involuntary functions. The disparity in speed of conduction influences reaction times and coordination.

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