CBSE Class 10 Science — Control and Coordination

Human brain has various parts or regions that help in different actions, responses and coordination. From the following, identify the part responsible for precision of voluntary actions:

Directions: Question numbers 8 and 9 are Assertion and Reason based questions. Two statements are given, one labelled as Assertion (A) and the other is labelled as Reason (R). Select the correct answer from the codes given below. Assertion (A): Reflex actions do not involve thinking. Reason (R): Most reflex actions are controlled by the spinal cord.

(A) Observe the given figure and identify the labelled parts P, Q, R and S: [figure] OR (B) Which of the plant hormones are responsible for the following processes? (i) Promote cell division (ii) Inhibition of growth (iii) Detection of light (iv) Wilting of leaves

(a) State two differences between the act of chewing food and salivation on sight of food. OR (b) State two differences between pollination and fertilization.

(a) Mention the gland and the hormone secreted by it in scary situation in human beings. (b) Write two responses that enable the human body to be ready to deal with such situation.

The part of the brain which maintains the posture and balance of the body is:

Observe the given figures A and B. When chhui-mui (sensitive) plant is touched, its leaves fold. This is due to:

The plant hormone present in greater concentration in the areas of rapidly dividing cells is:

A pair of endocrine glands located in the human brain is:

The plant hormone whose concentration stimulates the cells to grow longer on the side of the shoot which is away from light is :

The plant hormones promoting rapid cell division in seeds and wilting of leaves respectively are

Assertion (A): In our actions of writing or talking, our nervous system communicates with the muscles. Reason (R): Cranial nerves and spinal nerves form the peripheral nervous system.

(a) How is brain protected in our body? (b) A doctor finds in one of his patients that he is not maintaining a proper posture and balance of his body. State the region of brain and also the part of brain which is responsible for it.

Name the parts of hind-brain of the human brain. Which part of the hind-brain controls involuntary actions such as blood pressure and salivation?

Plants have neither a nervous system nor muscles, even then they respond to stimuli. For example, the leaves of chhui-mui (touch-me-not) plant when touched begin to fold up and droop. (a) How is the information communicated in "touch-me-not" plants? (b) What enables the plant cells to bring out the observable response? (c) Differentiate the movement mentioned above from the movement of tendrils in a pea plant.

(a) Define hormone. (b) "Hormones should be secreted in precise quantities. We have a feedback mechanism through which this is done." With the help of an example justify the statement.

State two limitations of electrical impulses in multicellular organisms. Why is chemical communication better than electrical impulses as a means of communication between cells in multicellular organisms?

(A) (a) Analyse the given situations and interpret the possible reason for each: (i) Iodine deficiency in diet increases the possibility of a disease of swollen neck in a person. (ii) Some people in population may have very short heights (dwarfs). (iii) Thick facial hairs develop in boys at the age of 10-12 years. (b) Explain two reasons which necessitate the need of chemical communication in multicellular organisms. OR (B) (a) Differentiate between voluntary and involuntary action. (b) Define reflex action. With the help of a flow diagram, show the correct sequence of path of Nerve impulse from place of its origin.

A person while climbing up a rocky hill comes into a panic state and fear. His body starts reacting in a "flight-or-flight" condition to adjust to the dangerous and stressful situation. Based on the above facts, answer the questions that follow. (a) (i) Name the hormone secreted in the blood of the person in this situation. [2] OR (a) (ii) Name the source gland of the hormone secreted in this condition. [2] (b) State any two responses in the body of the person as a result of the secretion of this hormone. [1] (c) How does the action of the chemical signal in terms of hormones differ from the electrical impulses via nerve cells ? [1]

In life there are certain changes in the environment called 'stimuli' to which we respond appropriately. Touching a flame suddenly is a dangerous situation for us. One way is to think consciously about the possibility of burning and then moving the hand. But our body has been designed in such a way that we save ourself from such situations immediately. (i) Name the action by which we protect ourself in the situation mentioned above and define it. (ii) Write the role of (a) motor and (b) relay neuron. (iii) (A) What are the two types of nervous system in human body? Name the components of each of them. OR (iii) (B) Which part of the human brain is responsible for: (a) thinking (b) picking up a pencil (c) controlling blood pressure (d) controlling hunger

A plant growth inhibitor hormone which causes wilting of leaves is called:

The correct sequence of events when someone's hand touches a hot object unconsciously :

Select from the following a plant hormone which promotes cell division.

Sense organ in which olfactory receptors are present is :

Select out of the following a gland which does NOT occur as a pair in the human body :

Where are auxins synthesized? How do they promote phototropism?

Taking the example of any two animal hormones along with their gland of secretion, explain how these hormones help (i) in growth and development and (ii) regulate metabolism, in the body.

(a) List two constituents of Central Nervous System (CNS). How are these components protected from injuries? (b) Write two limitations of the use of electrical impulses.

(a) (i) Define a reflex arc. Why have reflex arcs evolved in animals? Trace the sequence of events which occur, when you suddenly touch a hot object. (ii) Name the part of nervous system which helps in communication between the central nervous system and other parts of the body. What are the two components of this system? OR (b) (i) Leaves of 'chhui-mui' plant begin to fold up and droop in response to a stimulus. Name the stimulus and write the cause for such a rapid movement. Is there any growth involved in the movement? (ii) Define geotropism in plants. What is meant by positive and negative geotropism? Give one example of each type.

(a) (i) Distinguish between hormonal co-ordination in plants and animals. (ii) Which part of the brain is responsible for - (1) intelligence (2) riding a bicycle (3) vomiting (4) controlling hunger (iii) How is brain and spinal-cord protected against mechanical injuries ? OR (b) (i) What are tropic movements ? Give an example of a plant hormone which (1) inhibits growth and (2) promotes cell division. (ii) Explain directional movement of a tendril in pea plant in response to touch. Name the hormone responsible for this movement.

Walking in a straight line and riding a bicycle are the activities which are possible due to a part of the brain. Choose the correct location and name of this part from the given table : Table: | | Part of the Brain | Name | |---|---|---| | (a) | Fore brain | Cerebrum | | (b) | Mid brain | Hypothalamus | | (c) | Hind brain | Cerebellum | | (d) | Hind brain | Medulla |

The part in which gustatory receptors are present in our body is:

Select from the following the correct statement about tropic movement in plants:

In plants the role of cytokinin is :

(a) List two differences between the movement of leaves of a sensitive plant and the movement of a shoot towards light. OR (b) What happens at synapse between two neurons? State briefly.

(A) Name the part of brain which is responsible for the following actions: (i) Maintaining posture and balance (ii) Beating of heart (iii) Thinking (iv) Blood pressure OR (B) Where are auxins synthesized in a plant ? Which organ of the plant shows : (i) Positive phototropism (ii) Negative geotropism (iii) Positive hydrotropism

(a) Write the role of insulin in regulating blood sugar levels in human body. Mention the disease caused due to it. (b) How is the timing and the amount of release of insulin in the blood regulated?

Write the name and function of parts (i) and (ii) in the diagram of a neuron given below.

(a) (i) List three points of difference between nervous and hormonal mechanisms for control and coordination in animals. (ii) How are auxins related with the bending of plant shoot towards unidirectional light? Explain. OR (b) (i) Name the disorder which a person is likely to suffer from due to the following: (I) Over-secretion of growth hormone (II) Deficiency of oestrogen in females (III) Less secretion of thyroxine Also name the gland that secretes each of the hormones mentioned above. (ii) How is the timing and amount of hormone released regulated? Explain with the help of an example.

(b) State the function of thyroxine in human body.

Question numbers 4(a) - 4(d) are based on the table and related information in the passage given below. Thyroid Stimulating Hormone (TSH) stimulates thyroid gland to produce thyroxine. Study the table given below. Table: TSH levels during pregnancy Stage of pregnancy | Normal (mU/L) | Low (mU/L) | High (mU/L) First trimester | 0.2 – 2.5 | < 0.2 | 2.5 – 10 Second trimester | 0.3 – 3.0 | < 0.3 | 3.01 – 4.5 Third trimester | 0.8 – 5.2 | < 0.8 | > 5.3 It is important to monitor TSH levels during pregnancy. High TSH levels and hypothyroidism can especially affect chances of miscarriage. Therefore, proper medication in consultation with a doctor is required to regulate/control the proper functioning of the thyroid gland. 4(a) Give the full form of TSH. 4(b) State the main function of TSH. 4(c) Why do TSH levels in pregnant women need to be monitored? 4(d) A pregnant woman has TSH level of $8.95 \text{ mU/L}$. What care is needed for her?

(c) What is hyperthyroidism?

Questions numbers 4(a) to 4(d) are based on table given below. Study the table in which the levels of Thyroid Stimulating Hormone (TSH) in women are given and answer the questions that follow on the basis of understanding of the following paragraph and the related studied concepts. | Age Range | Normal (mU/L) | Low (mU/L) | | :--- | :--- | :--- | | 18 – 29 years | 0.4 – 2.34 mU/L | < 0.4 mU/L | | 30 – 49 years | 0.4 – 4.0 mU/L | < 0.4 mU/L | | 50 – 79 years | 0.46 – 4.68 mU/L | < 0.46 mU/L | Women are at greater risk for developing abnormal TSH levels during menstruation, while giving birth and after going through menopause. Around $5\%$ of women in the United States have some kind of thyroid problem compared to $3\%$ of men. Despite claims that high TSH increases your risk for heart disease, a 2013 study found no link between high TSH and heart diseases. But a 2017 study showed that older women are especially at risk for developing thyroid cancer if they have high TSH levels along with thyroid nodules. (a) A 35 year old woman has TSH level 6.03 mU/L. What change should she bring in her diet to control this level? (b) When do women face a greater risk of abnormal TSH level? (c) State the consequence of low TSH level. (d) Name the mineral that is responsible for synthesis of hormone secreted by thyroid gland.

(d) How can we control hypothyroidism?

(a) Where is thyroid gland situated in our body?

OR Why is chemical communication better than electrical impulses as a means of communication between cells in a multi-cellular organism?

A cheetah, on seeing a prey, moves towards him at a very high speed. What causes the movement of his muscles? How does the chemistry of cellular components of muscles change during this event?

A squirrel is in a scary situation. Its body has to prepare for either fighting or running away. State the immediate changes that take place in its body so that the squirrel is able to either fight or run?

Define geotropism. Draw a labelled diagram of a plant showing geotropic movements of its parts.

Trace the sequence of events which occur when a bright light is focused on your eyes.

What are plant hormones? Name the plant hormones responsible for the following: (i) Growth of stem (ii) Promotion of cell division (iii) Inhibition of growth (iv) Elongation of cells

(a) Name one gustatory receptor and one olfactory receptor present in human beings. (b) Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.

Name the hormones secreted by the following endocrine glands and specify one function of each: (a) Thyroid (b) Pituitary (c) Pancreas

Name the two components of peripheral nervous system.

Mention three characteristic features of hormonal secretions in human beings.

(a) Write three main functions of the nervous system. (b) In the absence of muscle cells, how do plant cells show movement?

How is the spinal cord protected in the human body?

What are hormones? Name the hormone secreted by thyroid and state its function.