NCERT Solutions Class 10th Science
Chapter 6 Control and Coordination Extra Questions
The Previous Year Questions and Important Questions of Class 10th Science Chapter 6: Control and Coordination will help the students to bag a good score in the board exams so, on this page we have given the “Important Questions for Class 10th Science Chapter 6: Control and Coordination” so that you can solve different types of questions that are important for the board exams.
Class 10th Science Chapter 6: “Control and Coordination” Important Questions are given below:
Question 1.
Which is the largest and most prominent part of the brain?
Answer:
Cerebrum is the largest and most prominent part of the brain.
Question 2.
(a) Name one gustatory receptor and one olfactory receptor in human beings.
(b) Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.
Answer:
(a) Gustatory receptors are receptors for taste present in taste buds on tongue and olfactory receptors are the receptors for smell present in nasal chambers.
Question 3.
Write the main functions of the following:
(a) sensory neuron
(b) cranium
(c) vertebral column
(d) motor neuron.
Answer:
(a) Sensory neuron occurs in sense organs and receives stimuli through their dendrites. The sensory neurons transmit impulses towards the central nervous system (brain and spinal cord) with the help of their axons.
(b) Cranium: The bones of cranium or brain box protect the brain from mechanical injury.
(c) Vertebral column: Major function of the vertebral column is protection of the spinal cord and carries the weight of the upper body.
(d) Motor neuron: The dendrites of these neurons synapse with axons of interneurons in central nervous system. They transmit impulses from central nervous system towards effectors (muscles or glands). The latter respond to stimuli.
Question 4.
Why does the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron take place but not in the reverse direction? Explain.
Answer:
At the synapse, (functional junction between neurons) axon terminal comes in close proximity to the dendron terminal of next neuron. Axon terminal is expanded to form pre-synaptic knob and the other dendrite terminal forms post- synaptic depression.
In between the two, lies a narrow fluid filled space called synaptic cleft. As the nerve impulse reaches the pre-synaptic knob, the synaptic vesicles get stimulated to release neurotransmitter in the synaptic cleft. The neurotransmitter molecules diffuse across the gap to come in contact with post-synaptic membrane. In this way, nerve impulse passes across the minute gap to stimulate dendron of other neuron. The synapse acts as a one-way valve to conduct impulse in one direction only. This is so because chemical substance called neurotransmitter is secreted only on one side of the gap, i.e., on axon’s side. It carries impulse across the synapse and passes it to the dendron of the other neuron. In this way, impulses travel across the neurons only in one direction, i.e., from axon of one neuron to dendron of other neuron through a synapse.
Question 5.
“Reflex arcs continue to be more efficient for quick responses”. Justify this statement giving reason.
Answer:
Reflex action is an automatic and spontaneous response to a stimulus. The pathway taken by nerve impulses and responses in a reflex action is called a reflex arc. It consists of receptor, sensory nerve (afferent), spinal cord, motor nerve (efferent) and effector (muscles or glands). Reflex arc is evolved in animals because the thinking process of the brain is not fast enough. Reflex arc enables the body to give quick responses to harmful stimuli so that chances of damage to body are decreased. It also prevents overloading of brain, so prevents its fatigue. Many animals have very little or none of the complex neuron network needed for thinking. So, it is likely that reflex arc has evolved as an efficient way of functioning in the absence of true thought processes. However, even after complex neuron networks have came into existence, reflex arcs continue to be more efficient for quick responses.
Question 6.
(a) Define reflex arc.
(b) Trace the sequence of events which occur in our body when a bright light is focussed on your eyes.
Answer:
(a) The pathway taken by the nerve impulses in a reflex action, from receptor organ to spinal cord and back to effector organ of reflex action is called reflex arc. Receptor organ could be a sense organ such as eyes, skin, etc., and effector organ could be muscles, glands, etc.
(b) When a bright light is focussed on eye, receptor cell receives the stimulus and an impulse is generated. This impulse is passed on to sensory neuron, then it goes to brain, brain sends the impulse to the motor neuron which contracts the pupil. Sequence of events can be summarised as: Photoreceptors in eye → Sensory (Receptor) neuron → Brain → Motor (Effector) neuron → Eye muscle → Constriction of pupils
Question 7.
Mention three major regions of brain. Write one function of each.
Answer:
Brain is divided into three main regions forebrain, midbrain and hindbrain.
(i) Forebrain consists of cerebrum, olfactory lobes and diencephalon. Its main function is thinking and controlling various activities such as touch, smell, hearing, speech and sight.
(ii) Midbrain controls reflex movements of the head, neck and trunk in response to visual and auditory stimuli.
(iii) Hindbrain has three centres called pons, cerebellum and medulla. This part is responsible for regulating respiration, maintaining posture and balance of body and controlling involuntary actions such as heartbeat, breathing, swallowing, coughing, sneezing, vomiting, etc.
Question 8.
State one example of chemotropism.
Answer:
Growth of pollen tube towards the ovule due to chemical stimulus during the process of fertilisation in a flower is an example of chemotropism.
Question 9.
What is meant by tropic movements?
Answer:
Directional movements or orientations of specific part of a plant in response to external stimuli are called tropisms or tropic movements.
Question 10.
State the two types of movements seen in plants. Give one example of each type.
Answer:
Two types of movements seen in plants are:
(i) Nastic movements are movements independent of growth that are non-directional and occur due to turgor changes, e.g., closing of leaves in response to touch stimulus in ‘touch me not’ plant.
(ii) Tropic movements or tropism are movements due to growth, that are directional and very slow, e.g., movement of a part of the plant in response to light.
NCERT Solutions (Class 10th Science):
The Solutions for Class 10th Science are given here. Students can click on the links which are given below in the table for the specific chapter.
| Chapter 1: Chemical Reactions and Equations |
| Chapter 2: Acids, Bases and Salts |
| Chapter 3: Metals and Non-Metals |
| Chapter 4: Carbon and its Compounds |
| Chapter 5: Life Processes |
| Chapter 6: Control and Coordination |
| Chapter 7: How do Organisms Reproduce? |
| Chapter 8: Heredity |
| Chapter 9: Light – Reflection & Refraction |
| Chapter 10: The Human Eye and the Colourful World |
| Chapter 11: Electricity |
| Chapter 12: Magnetic Effects of Electric Current |
| Chapter 13: Our Environment |