Solutions of Control and Coordination Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 115 Class 10 Biology
1. Name the two systems of control and coordination in higher animals.
Answer
→ Nervous system and endocrine system are the two systems of control and coordination in higher animals like human.
2. What are the two parts of the vertebrate nervous system?
Answer
→ Central nervous system and peripheral nervous system are the two parts of the vertebrate nervous system.
3. If we happen to touch a hot object unknowingly, we immediately pull back our hand. What is this type of action known as?
Answer
→ A reflex action occurs when the body responds to a stimulus without the involvement of the brain. Rapid pull out of hands from touching a hot surface and batting of eyelids are examples of reflex actions.
4. Name the three components of a neuron (or nerve cell).
Answer
→ A neuron, also known as nerve cell, is mainly consists of three components, namely cell body or soma, dendrites and axon.
5A. What are the short fibres of a neuron known as?
Answer
→ Dendrites are the short fibres of a neuron. They transmit impulses from synapses to cell body.
5B. What is the long fibre of a neuron known as?
Answer
→ Axon is the long fibre of a neuron. It carries the impulse away from the cell body.
6. Name the most important part of the human brain.
Answer
→ Cerebrum is the largest and uppermost portion of the human brain.
7. Which part of the brain maintains posture and balance of the body?
Answer
→ The cerebellum is the area of brain that controls motor movement coordination, balance, equilibrium and muscle tone.
8. State one function each of cerebellum and pons.
Answer
→ Function of cerebellum: It controls motor movement coordination, balance, equilibrium and muscle tone.
Function of pons: It regulates the breathing process. It also takes part in sensations such as hearing, taste and balance.
9. Name one hormone secreted by the pituitary gland.
Answer
→ Growth hormone (GH), also known as somatotropin, is secreted by anterior lobe of the pituitary gland.
10. Where are hormones made in the human body?
Answer
→ Hormones are the chemical messengers produced by glands in the endocrine system.
11. What is the name of the system of glands which produces hormones?
Answer
→ Hormones are the chemical messengers produced by glands in the endocrine system.
12. Which gland secretes the growth hormone?
Answer
→ Growth hormone (GH), also known as somatotropin, is secreted by anterior lobe of the pituitary gland.
13. Name the hormones secreted by (a) testes, and (b) ovaries.
Answer
→ (a) Testosterone hormone, also known as male sex hormone, is secreted by testes.
(b) Oestrogen and progesterone hormones are released by ovaries.
14. What are the scientific names for the following receptors in animals?
(a) receptors for light
(b) receptors for heat
(c) receptors for sound
(d) receptors for smell
(e) receptors for taste
Answer
→ (a) The scientific name for light receptor is photoreceptor.
(b) The scientific name for heat receptor is thermoreceptor.
(c) The scientific name for sound receptor is phonoreceptor.
(d) The scientific name for smell receptor is olfactory receptor.
(d) The scientific name for taste receptor is gustatory receptor.
15. Name the disease caused by the deficiency of insulin hormone in the body.
Answer
→ Diabetes mellitus, also known as hyperglycemia, is caused by the deficiency of insulin hormone in the body.
16. Name the disease caused by the deficiency of thyroxine hormone in the body.
Answer
→ Goitre, an enlargement of the thyroid gland, is caused by the deficiency of thyroxine hormone in the body.
17. Which halogen element is necessary for the making of thyroxine hormone by the thyroid gland?
Answer
→ Iodine is necessary for the making of thyroxine hormone by the thyroid gland which prevents goiter formation.
18. Why are some patients of diabetes treated by giving injections of insulin?
Answer
→ Some patients of diabetes treated by giving injections of insulin because it decreases the blood sugar level in the body.
19. What is the name of in-built 'arrangement' in our body which controls the timing and amount of hormones released by various endocrine glands in the body?
Answer
→ Feedback mechanism is a method of controlling the hormone production.
20. Name one gland each:
(a) which acts only as an endocrine gland.
(b) which acts only as an exocrine gland.
(c) which acts both as an endocrine gland as well as an exocrine gland.
Answer
→ (a) Thyroid is large, ductless gland present in the neck. It acts as an endocrine gland.
(b) Salivary glands present in and around the mouth and neck acts as an exocrine gland.
(c) Pancreas, an organ located in the abdomen, acts both as an endocrine gland as well as an exocrine gland.
21. What part does the diet play in helping us to have a healthy thyroid gland?
Answer
→ Diet provides iodine which makes keeps the thyroid gland healthy by making thyroxine hormone and also prevents goitre.
22. If sugar is detected in the urine of a person, name the disease he is suffering from.
Answer
→ In the diabetes (hyperglycemia) disease, the sugar level gets increased in the body.
23. Name two parts of the body which contain receptors of chemical stimuli.
Answer
→ Nose contains olfactory receptor whereas tongue has gustatory receptor.
24. Which part of the eye contains cells which are sensitive to light?
Answer
→ Eye retina contains cells which are sensitive to light.
25. What are the two main communications systems in an animal's body?
Answer
→ Endocrine system and Nervous system are the two main communications systems in an animal's body.
26. Which one term in each of the following includes the other three?
(a) thyroid, ductless gland, thymus, pituitary, ovary
(b) adrenalin, insulin, hormone, thyroxine, estrogen
Answer
→ (a) Thyroid, thymus, pituitary and ovary these all are ductless glands.
(b) Adrenalin, insulin, thyroxine and estrogen these all are hormones.
27. Which parts of the body form the central nervous system?
Answer
→ Spinal cord and brain form the central nervous system (CNS).
28. Give three examples of reflex actions.
Answer
→ Knee jerk reflex is an example of reflex action. The other examples include coughing and sneezing.
29. Why do you need iodine in your diet?
Answer
→ Iodine is required to synthesize of thyroxine hormone in the body hence necessary in our diet.
30. State whether coughing is a voluntary action or reflex action.
Answer
→ Coughing is an important defensive reflex that occurs through the stimulation of a complex reflex arc.
31. Fill in the following blanks with suitable words:
(a) The two examples of effectors are .................and .....................
(b) Our..................system allows us to react to our surroundings. Information from receptors passes along.................neurons to our brain. Our brain sends impulses along...........neurons to our muscles.
(c) A neuron which carries an impulse to the brain is called a .................... neuron.
(d) The neuron which carries a message for action to a muscle or gland is known as a.................... neuron.
Answer
→ (a) The two examples of effectors are glands and muscle.
(b) Our nervous system allows us to react to our surroundings. Information from receptors passes along sensory neurons to our brain. Our brain sends impulses along motor neurons to our muscles.
(c) A neuron which carries an impulse to the brain is called a sensory neuron.
(d) The neuron which carries a message for action to a muscle or gland is known as a motor neuron.
Short Answer Type Questions-Pg-116
32A. What are the various sense organs in our body?
Answer
→ In human body, there are 5 sense organs present. They are eyes, ears, nose, tongue and skin.
32B. What is meant by receptors and effectors? Give two examples of each.
Answer
→ A receptor is an organ or cell able to respond to heat, light or other external stimulus and transmit a signal to a sensory nerve. Example: Photoreceptor (a receptor which detects light) and phonoreceptor (a receptor which detects sound).
An effector is a muscle, gland or an organ capable of responding to a stimulus, especially a nerve impulse.
33A. What is spinal cord? What is its main function?
Answer
→ The cylindrical bundle of nerve fibres and associated tissue which is enclosed in the spine and connects nearly all parts of the body to the brain. It functions primarily in the transmission of neural signals between the brain and the rest of the body.
33B. Give the functions of medulla.
Answer
→ The medulla helps regulate breathing, heart and blood vessel function, digestion, sneezing and swallowing. It is a center for respiration and circulation.
34A. Name the three types of nerves which constitute the peripheral nervous system.
Answer
→ Spinal nerves, cranial nerves and visceral nerves are the three types of nerves which constitute the peripheral nervous system
34B. What is the difference between a reflex action and walking?
Answer
→ A reflex action is voluntary action which is a rapid and autonomic response to stimuli while walking is a voluntary action which requires our thinking and it’s in our control.
34C. How do we detect the smell of an incense stick (agarbatti)?
Answer
→ Agarbatti produces vapors on burning and generates a characteristics a fragrance which is detected by the olfactory receptors present in the nose. The electrical impulses are generated by the action of smell of agarbatti which sets off chemical reactions. Cerebrum, a sensory area present in the fore brain, receives these electrical impulses by which we can identify the smell of burning agarbatti.
35A. What substances are made by endocrine glands?
Answer
→ Hormones are produced by the endocrine glands. These hormones are responsible for different functions in the various organs of the body.
35B. What is the function of receptors and effectors in our body?
Answer
→ A receptor is an organ or cell able to respond to heat, light or other external stimulus and transmit a signal to a sensory nerve. It detects all the information from our surroundings and carries it to the nervous system.
An effector is a muscle, gland or an organ capable of responding to a stimulus, especially a nerve impulse.
36A. Name the hormones secreted by the following endocrine glands:
(i) Thyroid gland
(ii) Parathyroid glands
(iii) Pancreas
(iv) Adrenal glands
Answer
→ (i) Thyroxine hormone is secreted by the thyroid gland.
(ii) Parathormone is secreted by the parathyroid glands.
(iii) Insulin hormone is secreted by the pancreas gland.
(iv) Adrenaline hormone is secreted by the adrenal glands.
36B. Write the functions of testosterone and oestrogen hormones.
Answer
→ Testosterone is the principle male sex hormone and is responsible for reproductive growth and development in male vertebrates.
Oestrogen is the principle female sex hormone and is responsible for development of female secondary sexual characteristics.
37A. Write the names of the regions in hindbrain. Give one function of each region.
Answer
→ There are mainly 3 regions present in hindbrain. They are:
(i) Pons: It regulates the breathing process. It also takes part in sensations such as hearing, taste and balance.
(ii) Cerebellum: It controls motor movement coordination, balance, equilibrium and muscle tone.
(iii) Medulla: It is the controlling centre for reflex actions like coughing, sneezing and swallowing etc. It also controls various involuntary actions like blood pressure and peristaltic movements of the elementary canal.
37B. Name the functions of cerebrum.
Answer
→ Function of cerebrum: It is the largest part of the brain and also known as cortex. It is associated with higher brain function such as thought, memory and action.
38A. The human brain can be broadly divided into three regions. Name these three regions.
Answer
→ Forebrain, midbrain and hindbrain are three regions of human brain.
38B. What is cranium? What is its function?
Answer
→ Cranium is a part of the skull in which brain is located. It protects the brain from damage.
39A. How does chemical coordination take place in human beings?
Answer
→ In human beings and other animals, the chemical coordination takes place through the chemical messengers, called hormones. These hormones are produced by specific organs and carry through blood stream to other body parts. They are affected only a particular place of specific organ which is known as target organ. The organs control and coordinate different functions like growth, development, behavior, metabolism and secondary sexual characteristics etc.
39B. Why is the use of iodized salt advisable?
Answer
→ Iodine is required to synthesize of thyroxine hormone in the body. This hormone is secreted by the thyroid gland and is responsible for metabolism of carbohydrates, fats and proteins. Taking of iodine is advisable to prevent from goiter disease.
40. What is the function of insulin hormone? What types of patients are given insulin injections?
Answer
→ The insulin hormone lowers the blood sugar (glucose) level in the body. The people suffering from severe diabetes are treated by injecting insulin in the body.
41. Compare the nervous system and endocrine system (hormonal system) for control and coordination in humans.
Answer
→ Nervous system coordinates the activities of body. It is responsible for the coordination of biological activities inside the body through the network of specialised cells called neurons. It receives the information from surroundings and processes through neurons and interprets it and then responds accordingly.
Endocrine system is a discrete set of glands that secrete different types of hormones to the circulatory system in order to regulate the functions of the body. Each gland of the endocrine system is responsible for the secretion of different hormones which act as messengers between the nervous system and the organs of body.
42. State the functions of the following hormones:
(a) Thyroxine
(b) Adrenaline
(c) Growth hormone
Answer
→ (a) Thyroxine: Controls the metabolic rate of carbohydrates, fats and proteins in the body.
(b) Adrenaline: Regulates blood pressure, heart rate, breathing rate, and carbohydrate metabolism.
(c) Growth hormone: Controls the growth of human body.
43. Write the names of all the major endocrine glands present in the human body. Which of these glands also function as exocrine glands?
Answer
→ The endocrine glands present in the human body are:
(i) Pineal gland
(ii) Hypothalamus
(iii) Pituitary
(iv) Thyroid
(v) Parathyroid
(vi) Thymus
(vii) Pancreas
(viii) Adrenal glands
(ix) Testes (in males)
(x) Ovaries (in females).
Pancreas, testes and ovaries function as exocrine glands.
44. Match the hormones given in column I with their functions given in column II:
| Hormones | Functions |
| (i) Thyroxine | (a) Causes breasts to develop in females |
| (ii) Adrenaline | (b) Causes the male to start producing sperms |
| (iii) Insulin | (c) Prepares the body for an emergency |
| (iv) Estrogen | (d) Controls the metabolic rate |
| (v)Testosterone | (e) Regulates the amount of sugar in blood |
Answer
→ The correct matching of hormones with their functions is as:
(i) – (d)
(ii) – (c)
(iii) – (e)
(iv) – (a)
(v) – (b)
45. A person walks across a room in bare feet and puts his foot on a drawing pin lying on the floor. He lets out a cry. Explain what happens in his nervous system in bringing about this response.
Answer
→ This is an example of reflex action. Here, drawing pin lying on the floor is the stimulus. The receptors located in the skin sense pain which triggers and impulse in a sensory neuron and transmits the message to the spinal cord. The impulse is passed onto a relay neuron which passes it to the motor neuron which passes the impulse to a muscle in the feet. It results contraction of muscle and pulling out feet away from the drawing pin.
46. In what ways are puberty and adolescence result of the activity of some glands in the human body?
Answer
→ In human beings, puberty and adolescence are the result of sex glands. Testes in males produce testosterone, a male sex hormone, which is associated with male puberty. In boys, this stage appears an age of 13-14 years. Ovaries in females produce oesterogen, a female sex hormone, is responsible for all the changes associated with female puberty. In girls, this stage is usually attains at an age of 10-12 years.
47. List three ways in which neurons are similar to other cells.
Answer
→ Neurons have cell membrane, nucleus and cytoplasm similar to other cells.
48. Explain the difference between each of the following pairs of terms:
(a) receptor and effector
(b) cerebrum and cerebellum
Answer
→ (a) A receptor is an organ or cell able to respond to heat, light or other external stimulus and transmit a signal to a sensory nerve.
An effector is a muscle, gland or an organ capable of responding to a stimulus, especially a nerve impulse.
(b) Cerebrum, a part of the forebrain, is responsible for controlling our thoughts, sensations, actions and movements.
Cerebellum, a part of the hindbrain, is responsible for maintaining the body posture and balance of the brain.
49. What is the difference between a voluntary and an involuntary action? Which kind of action is digestion? Explain your choice.
Answer
→ Voluntary action is controlled by the brain whereas involuntary action is controlled by the spinal cord. Riding a bicycle, dancing, and eating an apple are some examples of voluntary actions while breathing, flow of blood through our veins, blinking eye lids, heart beating, feeling emotions, growing for that matter are all involuntary actions.
Digestion is a kind of involuntary action.
50. What does CNS stand for? Which part of CNS:
(a) consists of two cerebral hemispheres, and
(b) has spinal nerves attached to it?
Answer
→ CNS stands for Central Nervous System.
(a) Cerebrum, a part of the forebrain, consists of two cerebral hemispheres.
(b) Spinal cord has spinal nerves attached to it.
51. Which hormone:
(a) prepares the body for action?
(b) controls the amount of glucose in blood ?
(c) gives boys a deep voice?
(d) gives girls soft skin?
Answer
→ (a) Adrenaline hormone prepares the body for action.
(b) Insulin hormone controls the amount of glucose in blood.
(c) Testosterone hormone gives boys a deep voice.
(d) Oestrogen hormone gives girls soft skin.
52. When you smell a favourite food your mouth begins to water (that is, you secrete saliva). Write down what the following are examples of:
(a) the smell of the food
(b) the cells in your nasal passages which perceive the smell
(c) the gland which is stimulated to secrete saliva.
Answer
→ (a) The smell of the food is a stimulus.
(b) Olfactory receptors are the cells in your nasal passages which perceive the smell.
(c) Salivary gland (effector) is the gland which is stimulated to secrete saliva.