NCERT Class 11 Biology Chapter 21 Notes Neural Control And Coordination- Download PDF Notes

NCERT Class 11 Biology Chapter 18 Notes Neural Control and Coordination is a must-know topic for board exams as well as competitive exams such as NEET. This chapter gives a clear idea of the human nervous system and how it plays an important role in coordinating body functions. Using NCERT Notes for Class 11 Biology, students can improve their knowledge of neural control and coordination so that they are well prepared for their exams. The important topics are the definition of the neural system, a summary of the human neural system, and the neuron as the structural and functional unit. In addition, it deals with the central nervous system (CNS), reflex action and reflex arc, and reception and processing of sense.

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This Story also Contains

1. Detailed Notes for Chapter 18: Neural Control and Coordination
2. Important Topics of Class 11 Biology Chapter 18
3. Most Important Questions Class 11 Biology Chapter 18
4. Approach to Solve Questions of Class 11 Biology Chapter 18
5. Chapter-Wise NCERT Class 11 Notes Biology

The chapter also contains key examples that are often exam questions, making it a good source for rapid revision. Students can download CBSE Notes in PDF for offline use, which helps them have effective study sessions. These notes cover all the key points, saving students time while preparing for their exams effectively. Having revision notes and NCERT Solutions for this chapter handy is beneficial to save you time.

Also, students can refer to:

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

• NCERT Exemplar for Class 11 Biology Chapter 18 Neural Control and Coordination.

Detailed Notes for Chapter 18: Neural Control and Coordination

The detailed notes of the chapter are given below:

Neural System

• The neural system gives an organized network for the rapid coordination of body functions.

• Coordination: Coordination among organs to support each other's functions.

• Made up of neurons that perceive, receive, and conduct stimuli.

Complexity grows:

1. Lower vertebrates: Uncomplicated neuron network.

2. Insects: Brain with ganglia and neural tissues.

3. Vertebrates: Advanced neural system.

Human Neural System

The human neural system is divided into two parts:

Subdivisions of PNS:

• Somatic Nervous System: Regulates voluntary muscles (e.g., skeletal muscles).

• Autonomic Nervous System (ANS): Regulates involuntary muscles (e.g., smooth muscles).

• Sympathetic Nervous System: "Fight or flight" response.

• Parasympathetic Nervous System: "Rest and digest" response.

Diagram: Structure of the Human Neural System

Neuron: Structural and Functional Unit

A neuron consists of three parts:

Types of Neurons:

• Multipolar: One axon, multiple dendrites (e.g., cerebral cortex).

• Bipolar: One axon, one dendrite (e.g., retina).

• Unipolar: Only axon present (found in embryos).

Axon Types:

The types of axons are:

Myelinated Axons:

• Covered with a myelin sheath formed by Schwann cells.

• Found in the spinal cord and cranial nerves.

• Gaps between myelin sheaths are called Nodes of Ranvier.

Unmyelinated Axons:

• No myelin sheath; found in autonomic and somatic systems.

Diagram: Structure of a Neuron

Generation and Conduction of Nerve Impulse

The stage and process of nerve impulse can be discussed In the table given below:

Diagram: Generation of Nerve Impulse

Central Neural System (CNS)

The CNS includes the brain and spinal cord.

Brain:

Protected by the skull and covered by three layers called cranial meninges:

1. Dura mater

2. Arachnoid

3. Pia mater

Divisions of the Brain:

The divisions of the brain are as follows

Forebrain

• Includes cerebrum, thalamus, and hypothalamus.

Functions:

• Cerebrum: Memory, sensory processing.

• Thalamus: Sensory relay center.

• Hypothalamus: Regulates temperature, hunger, and thirst.

Midbrain

• Connects forebrain to hindbrain.

• Contains corpora quadrigemina for visual/auditory reflexes.

Hindbrain

• Includes pons, cerebellum, and medulla oblongata.

Functions:

1. Pons: Relays signals between brain regions.

2. Cerebellum: Maintains posture/balance.

3. Medulla oblongata: Controls heart rate, breathing.

Diagram: Divisions of the Brain

Also read:

NCERT Books for Class 11

NCERT Syllabus for Class 11

Reflex Action and Reflex Arc

Reflex action is an involuntary response to a stimulus.

Components of a reflex arc:

1. Receptor

2. Sensory neuron

3. CNS (spinal cord)

4. Motor neuron

5. Effector

Diagram: Reflex Arc

Subject Wise NCERT Exemplar Solutions

• NCERT Exemplar Class 11 Solutions

• NCERT Exemplar Class 11 Maths

• NCERT Exemplar Class 11 Physics

• NCERT Exemplar Class 11 Chemistry

• NCERT Exemplar Class 11 Biology

Important Topics of Class 11 Biology Chapter 18

The important topics of the chapter are:

1. Neural System

2. Human Neural System

3. Neuron as Structural and Fundamental Unit of Neural System

4. Central Neural System

Most Important Questions Class 11 Biology Chapter 18

Below are a few solved questions:

Q1. What is the part of the internal ear responsible for hearing?

Answer:

The cochlea is an inner part of the ear which facilitates hearing.

Q2. What is the name of the wax gland present in the ear canal?

Answer:

The wax gland present in the ear canal is called the Sebaceous gland/ ceruminous gland.

Q3. What are the 3 layers of the human eyeball?

Answer:

The human eyeball has three layers- sclera, choroid, and retina. These three layers enclose lens, aqueous humor, and vitreous humor. Our paired eyes are located in sockets of the skull called orbits. The adult human eyeball is nearly a spherical structure. The eyeball is an elongated sphere about 2.5 cm in diameter.

Q4. Who controls the function of our visceral organs?

Answer:

The autonomic nervous system (option b) plays a crucial role in regulating involuntary functions such as heart rate, digestion, and respiratory rate. It is divided into the sympathetic and parasympathetic divisions, which work together to maintain homeostasis in the body.

Q5. What maintains the Resting membrane potential?

Answer:

The sodium-potassium pump and leak channels are examples of ion pumps and channels that preserve a cell's resting membrane potential. For every ATP molecule, this pump transports two potassium ions into the cell and three sodium ions out of it. The potassium ion concentration gradient produced by this action adds to the resting membrane potential. The electrical potential across a cell's plasma membrane when it is not activated is known as the resting membrane potential. Because more cations are released than are absorbed, the inside of the cell stays negatively charged in relation to the extracellular fluid.

Subject-Wise NCERT Solutions

• NCERT Solutions for Class 11 Mathematics

• NCERT Solutions for Class 11 Chemistry

• NCERT Solutions for Class 11 Physics

• NCERT Solutions for Class 11 Biology

Approach to Solve Questions of Class 11 Biology Chapter 18

The student should start by clearly understanding the structure and function of nerves, action potential, impulse transmission, and synaptic conduction. They should focus on important concepts like reflex action, the structure of the brain and spinal cord and the difference between the sympathetic and parasympathetic nervous systems. They should practice flow charts for processes such as pulse conduction and reflex arcs to answer accurately. While solving questions, they should use neat and labelled diagrams wherever possible.

Chapter-Wise NCERT Class 11 Notes Biology

The chapter wise notes are given below: