CBSE Class 10 Science Chapter 7 Control and Coordination NCERT Solutions
This chapter, Control and Coordination, delves into the essential biological processes that allow living organisms to respond to their environment. The NCERT Solutions for Class 10 Science, Chapter 7, provide a comprehensive understanding of the nervous system, including the structure and function of neurons, the transmission of nerve impulses, and the concept of a synapse. It also explains the mechanism of reflex actions and the components of a reflex arc, detailing the roles of receptors, sensory neurons, the spinal cord, motor neurons, and effectors (muscles/glands). These solutions clarify how different types of receptors work and the pathways involved in coordinating responses. They are designed to help students grasp these complex topics effectively, aiding in their preparation for examinations by offering clear, step-by-step explanations and reinforcing key concepts.
Quick info
| Board | CBSE |
|---|---|
| Class | Class 10 |
| Subject | Science (Exemplar) |
| Session | 2026 |
| Language | English |
| Type | NCERT Solutions |
| Chapter | 7. Control and Coordination |
Chapter summary
Chapter 7, Control and Coordination, focuses on the nervous system's role in managing bodily functions and responses. The NCERT Solutions cover the fundamental units of the nervous system, neurons, and how electrical and chemical signals are transmitted. Key concepts explained include the structure of a synapse, the pathway of nerve impulses through a neuron, and the sequence of events in a reflex arc. The solutions also clarify the functions of various receptors like gustatory and olfactory receptors. This chapter's exercises are crucial for understanding how organisms coordinate their actions to react to stimuli.
Learning outcomes
- Understand the function of different types of receptors (gustatory, olfactory).
- Describe the pathway of electrical impulse transmission in a neuron.
- Explain the process of signal transmission across a synapse.
- Identify the components and sequence of a reflex arc.
- Define reflex action and differentiate between sensory and motor neurons.
- Recognize the conversion of electrical to chemical signals at the axonal end.
Topics covered
Paper topics
- Receptors (Gustatory, Olfactory)
- Neurons (Structure and Function)
- Nerve Impulse Transmission
- Synapse and Chemical Signaling
- Reflex Action
- Reflex Arc Components
- Coordination in Organisms
- Nervous System
Important topics
- Structure and function of a neuron
- Transmission of nerve impulses
- Mechanism of synapse
- Components and pathway of a reflex arc
- Role of receptors
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Questions and Solutions
Multiple Choice Questions
Explanation: Receptors are specialized cells or structures that detect specific stimuli. For instance, gustatory receptors, located in the taste buds on the tongue, are responsible for detecting tastes. Olfactory receptors, found in the nasal cavity, are responsible for detecting smells. Photoreceptors detect light, and auditory receptors detect sound. Therefore, option (a) accurately describes the functions of gustatory and olfactory receptors.
Explanation: A neuron receives stimuli through its dendrites. These stimuli are then transmitted as electrical impulses to the cell body (also called the soma or cyton). From the cell body, the impulse travels along the axon, which is a long projection of the neuron. Finally, the impulse reaches the axonal end (or axon terminal), where it can be transmitted to another neuron or an effector cell.
Explanation: A synapse is the junction between two neurons where information is transmitted. When an electrical impulse reaches the axonal end of the presynaptic neuron, it triggers the release of chemical messengers called neurotransmitters. These neurotransmitters diffuse across the synaptic gap and bind to receptors on the dendritic end of the postsynaptic neuron, converting the chemical signal back into an electrical signal in the next neuron.
Explanation: As an electrical impulse travels down the axon of a neuron, it reaches the axonal end (axon terminal). Here, the electrical signal stimulates the release of neurotransmitters, which are chemical messengers. These neurotransmitters are then released into the synaptic cleft to transmit the signal to the next neuron or target cell. This is the site where the electrical signal is transduced into a chemical signal.
Explanation: A reflex arc is the pathway followed by nerve impulses during a reflex action. It begins when receptors detect a stimulus. Sensory neurons then transmit this signal to the spinal cord (or brainstem). Within the spinal cord, the signal is processed, and a motor neuron carries the response signal from the spinal cord to an effector, which is typically a muscle or gland, causing a response.
(i) Sudden action in response to something in the environment is called reflex action
(ii) Sensory neurons carry signals from spinal cord to muscles
(iii) Motor neurons carry signals from receptors to spinal cord
(iv) The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc
Explanation: Statement (i) is true: A reflex action is an involuntary and rapid response to a stimulus. Statement (ii) is false: Sensory neurons carry signals from receptors to the spinal cord or brain, not from the spinal cord to muscles. Motor neurons carry signals from the spinal cord to muscles. Statement (iii) is false: Motor neurons carry signals from the spinal cord to muscles or glands, not from receptors to the spinal cord. Sensory neurons perform this function. Statement (iv) is true: The reflex arc is indeed the complete neural pathway involved in a reflex action, from the receptor to the effector.
Common mistakes
- Confusing the direction of nerve impulse travel in a neuron.
- Incorrectly identifying the roles of sensory and motor neurons.
- Misunderstanding the sequence of events in a reflex arc.
- Confusing the function of gustatory and olfactory receptors.
Revision tips
- Draw and label a neuron to visualize the path of nerve impulses.
- Create a flowchart for a reflex arc to remember the sequence of components.
- Use flashcards to memorize the functions of different receptors and parts of a neuron.
- Practice explaining the synapse and signal transmission to a friend.
Practice MCQs
Q1. Which type of receptor is responsible for detecting smells?
Explanation: Olfactory receptors are specialized cells located in the nasal cavity that detect airborne chemical molecules, enabling the sense of smell.
Q2. In a neuron, where does the electrical impulse typically begin its journey?
Explanation: The electrical impulse, or nerve impulse, is usually initiated when a stimulus is received by the dendrites of a neuron.
Q3. What is the primary role of the axonal end in signal transmission?
Explanation: At the axonal end, the electrical impulse triggers the release of chemical neurotransmitters into the synaptic gap, converting the signal.
Q4. Which of the following correctly sequences the path of a reflex arc?
Explanation: A reflex arc begins with receptors detecting a stimulus, followed by sensory neurons transmitting the signal to the spinal cord, then motor neurons carrying the response signal to the muscle (effector).
Q5. What is the correct term for the path signals take from a receptor to a muscle or gland?
Explanation: The reflex arc is the complete neural pathway that mediates a reflex action, starting from the receptor and ending at the effector (muscle or gland).
Frequently asked questions
What are the main functions of receptors in the nervous system?
Receptors are specialized cells or organs that detect specific stimuli from the external or internal environment. For example, gustatory receptors detect taste, and olfactory receptors detect smell.
How does an electrical impulse travel through a neuron?
An electrical impulse travels along a neuron starting from the dendrites, moving to the cell body (cyton), then through the axon, and finally reaching the axonal end.
What happens at a synapse?
At a synapse, the electrical signal arriving at the axonal end of one neuron is converted into a chemical signal (neurotransmitter), which then diffuses across the synaptic gap to stimulate the dendrites of the next neuron.
Can you explain what a reflex arc is?
A reflex arc is the neural pathway that controls a reflex action. It typically involves a receptor, a sensory neuron, an integration center (like the spinal cord), a motor neuron, and an effector (muscle or gland).
What is the difference between sensory and motor neurons in a reflex arc?
Sensory neurons carry signals from receptors towards the central nervous system (spinal cord or brain), while motor neurons carry signals from the central nervous system to effectors (muscles or glands) to produce a response.
Why is the conversion of electrical to chemical signals important at the axonal end?
This conversion is crucial because neurons are not directly connected. The chemical signal (neurotransmitter) released at the axonal end can cross the synaptic gap and activate the next neuron, allowing for continuous signal transmission.
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