NCERT Class 11 Biology Chapter 21 Notes Neural Control And Coordination- Download PDF Notes
Did you know that humans have a complex nervous system that controls all body actions and responses? The NCERT Class 11 Biology Chapter 18 Notes Neural Control and Coordination are written in clear language. It includes well-labeled diagrams, which make learning more effective. Neural Control and Coordination gives an idea of the human nervous system and how it plays an important role in coordinating body functions. These NCERT notes help in building a strong foundation for board and entrance exams like NEET.
This Story also Contains
- Download NCERT Notes for Class 11 Biology Chapter 18 PDF
- Neural Control and Coordination Class 11 Notes
- Chapter 18 Biology: Previous Year Questions and Answers
- Importance of Class 11 Biology Chapter 18 Notes
- Chapter-Wise NCERT Class 11 Notes Biology
The Neural Control and Coordination Class 11 Notes include the definition of the neural system and the neuron as the structural and functional unit. Students will understand how to write answers in an exam for better marks. In addition, the NCERT notes for class 11 Biology chapter 18 PDF also deal with the CNS, reflex action, and reception and processing of sense. The NCERT Notes for Class 11 help students understand complex topics in a simple way and improve exam performance.
Also, students can refer to:
Download NCERT Notes for Class 11 Biology Chapter 18 PDF
Students preparing for school exams and for NEET can download the PDF notes for quick revision. The notes explain the structure and functions of the nervous system in a simple and clear way. The NCERT notes for class 11 Biology chapter 18 PDF can be accessed both online and offline. The NCERT Notes for Class 11 Biology are useful for clear revision before exams and save a lot of time.
Neural Control and Coordination Class 11 Notes
The notes given below are a helpful resource for easy and quick revision. The Neural Control and Coordination chapter includes topics like the structure of neurons, reflex action, and coordination. Neural Control and Coordination Class 11 Notes also explain the brain and sense organs in a clear and simple way.
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:
Lower vertebrates: Uncomplicated neuron network.
Insects: Brain with ganglia and neural tissues.
Vertebrates: Advanced neural system.
Human Neural System
The human nervous system is divided into two parts:
System | Components |
The brain and spinal cord processes and controls information. | |
Nerves are connected to the CNS. Includes afferent (to CNS) and efferent (from CNS) nerve fibers. |
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:
Part | Description |
Cell Body | Contains cytoplasm, organelles, and Nissl’s granules (absent in axons). |
Dendrites | Short fibers branching from the cell body; they contain Nissl’s granules. |
Axon | Long fiber ending in synaptic knobs; may be myelinated or unmyelinated. |
Types of Neurons
The types of neurons based on structure are given below:
Multipolar: One axon, multiple dendrites (e.g., cerebral cortex).
Bipolar: One axon, one dendrite (e.g., retina).
Unipolar: Only one 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 a nerve impulse can be discussed in the table given below:
Stage | Process |
Resting State | - Membrane permeable to K+ but impermeable to Na+ |
- Sodium-potassium pump maintains ionic gradient (++ outside, −−inside). | |
- The potential difference across the membrane is called the resting potential. | |
Stimulus Response | - Membrane becomes permeable to Na+, reversing charges (−−outside, ++ inside). |
- This creates an action potential or nerve impulse. | |
- Impulse travels through repeated depolarization/repolarization cycles along the neuron. |
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:
Dura mater
Arachnoid
Pia mater
Divisions of the Brain:
The divisions of the brain are as follows
Diagram: Divisions of the Brain
Includes cerebrum, thalamus, and hypothalamus.
Functions:
Cerebrum: Memory, sensory processing.
Thalamus: Sensory relay center.
Hypothalamus: Regulates temperature, hunger, and thirst.
Structure of Forebrain:
Midbrain
Connects the forebrain to the hindbrain.
The Midbrain contains the orpora quadrigemina for visual/auditory reflexes.
Structure of the Midbrain:
Hindbrain
Hindbrain includes the pons, cerebellum, and medulla oblongata.
Functions:
Pons: Relays signals between brain regions.
Cerebellum: Maintains posture/balance.
Medulla oblongata: Controls heart rate, breathing.
Structure of Hindbrain:
Reflex Action and Reflex Arc
Reflex action is an involuntary response to a stimulus.
Components of a reflex arc:
Receptor
Sensory neuron
CNS (spinal cord)
Motor neuron
Effector
Diagram: Reflex Arc
Also, Read
Chapter 18 Biology: Previous Year Questions and Answers
Some previous year questions given below help students get familiar with the exam format and test their level of preparation. For conceptual clarity, students can use the NCERT Class 11 Biology Chapter 18 Notes Neural Control and Coordination.
Question 1: Which of the following is not involved in the Knee reflex?
Option 1. Muscle spindle
Option 2. Motor neuron
Option 3. Brain
Option 4. Inter neurons
Answer:
An automatic response channel that does not directly engage the brain is known as the reflex arc. It consists of parts, including motor neurons, which send signals to muscles for contraction, interneurons, which let sensory and motor neurons in the spinal cord communicate, and muscle spindles, which sense changes in muscle length.
Hence, the correct answer is Option (3) Brain
Question 2: Resting membrane potential is maintained by
Option 1. Hormones
Option 2. Neurotransmitters
Option 3. Ion pumps
Option 4. None of the above
Answer:
The sodium-potassium pump and leak channels are examples of ion pumps and channels that preserve a cell's resting membrane potential:
Potassium-sodium pump
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.
Hence, the correct answer is option (3): Ion pumps.
Question 3: The Potential difference across the resting membrane is negatively charged. This is due to the differential distribution of the following ions.
Option 1. Na+ and K+ ions
Option 2. CO32-and Cl- ions
Option 3. Ca2+ and Mg2+ ions
Option 4. Ca2+ and Cl- ions
Answer:
The potential difference across the resting membrane is negatively charged. This is due to the differential distribution of Na+ and K+ ions. The electrical charge differential across a cell membrane caused by the combined forces of ions and their permeability is known as the membrane potential. It is essential for both cellular communication and general bodily processes.
Hence, the correct answer is Option (1) Na+ and K+ ions.
Also Read:
Importance of Class 11 Biology Chapter 18 Notes
Studying with well-prepared notes helps learners focus on the core topics and understand concepts clearly. They also make revision easier and save time during exam preparation.
Class 11 Biology Chapter 18 Notes help in quick last-minute revision.
Gives students clarity of difficult concepts like the nervous system, reflex action, etc.
These organised notes reduce exam stress.
The Class 11 Biology Chapter 18 Notes are a reliable source as they follow the latest syllabus.
Improves the retention and memorisation of the concepts.
Chapter-Wise NCERT Class 11 Notes Biology
The chapter-wise notes are given below, by which students can easily access all the chapters and start practicing to score well in the exam.
Frequently Asked Questions (FAQs)
Q: What is neural control and coordination in Class 11 Biology?
A:
Neural control refers to the nervous system’s regulation of body activities through electrical impulses, while coordination ensures organs work together harmoniously as explained in the NCERT Class 11 Biology Chapter 18 Notes Neural Control and Coordination. For example, withdrawing a hand from fire involves rapid neural signaling
Q: What is the difference between CNS and PNS?
A:
CNS processes information (brain/spinal cord), while PNS transmits signals between CNS and body parts via afferent (to CNS) and efferent (from CNS) nerves. For a detailed comparison, students can refer to the NCERT Class 11 Biology Chapter 18 Notes on Neural Control and Coordination.
Q: What are the components of the human nervous system?
A:
The components are the Central Nervous System (CNS) and Peripheral Nervous System (PNS). CNS includes the brain and spinal cord, while PNS consists of nerves connecting CNS to organs.
Q: How do neurons transmit nerve impulses?
A:
Neurons transmit electrical signals (action potentials) via depolarization. At synapses, neurotransmitters carry signals to the next neuron.
Q: What are the functions of the brain in neural control?
A:
The brain processes sensory input, controls voluntary movements and homeostasis, and regulates emotions, memory, and endocrine functions.
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