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X science AJAY PARMAR 1 GROUP TUITION Chapter – 14, control and coordination in organisms 1. What is stimulus? Explain the response to various stimuli in organisms. All the living organisms respond to the changes occurring in their surroundings. The change in the environment, to which the living organisms respond or tend to respond, is called stimulus. The various kinds of stimuli to which living beings respond are heat, cold, sound, pain, touch, etc. The response to any stimuli is a characteristic feature of living beings. e.g. If a man touches a very hot vessel he quickly pulls away himself from the vessel. Plants always grow and bend towards the light. This characteristic is not shown by animals. Thus the response to stimuli is different in plants and in animals. The response of animals is quicker and more towards various stimuli as compared to the plants as the plants do not possess nervous system like animals. 2. Differentiate between the response to stimuli in plant and animals. Plants and animals respond to various stimuli in different manners Plants grow and hence bend towards light while the animals do not show such characteristics. Response to stimulus in plants is slower and generally not visible while that in animals it is fast and visible. Plants do not have nervous system or any other system meant to respond against stimulus but most of the animals have well developed nervous system and sense organs. Plants have hormones but no endocrine glands for secreting the hormones. Most of the animals have specialized endocrine glands to secrete hormones. 3. Explain control and coordination in plants. Plants neither have nervous system not sense organs to respond against various stimuli. The respond to various environmental changes like gravity, light, water, chemicals, touch, etc with the help of the hormones in them and change their behaviour. These plant hormones are called Phyto – hormones. This mechanism of response to various stimuli in plants is totally different from that in the animals. The action of hormones of plants towards various stimuli is very slow and not visible. The two types of Phyto – hormones are (1) Growth promoting hormones – Auxin, Gibberellin and Cytokinin and (2) Growth – inhibiting hormones – Abscissic acid and ethylene. 4. Mention the various types of movement response to external stimuli in plants. The two different types of movement response to external stimuli in plants are (1) Tropism and (2) Nastism. Tropism: If movement of curvature in plants organ is induced by an externals and directional stimuli, then it is called tropism. The five common types of stimuli are light, gravity, chemical, water and touch. The names of tropism of plants in response to these stimuli are as follows: Stimulus Tropism Light Phototropism Gravity Geotropism Chemical Chemotropism Water Hydrotropism Touch Thigmotropism Nastism: If movement in plants organ depends on the presence and intensity of the external stimulus and the direction of the movement is not determined by the direction of stimulus, then it is called nastism. The nastic movements due to touch, light, temperature and water are called thigmonastic, photonastic and thermonastic and hydronastic movments. 5. What is meant by ‘Tropisms’? Explain with an example. [Mention the types of tropisms. Define each type of tropism. Write the name of the stimulus in each case.] c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61 X science AJAY PARMAR 2 GROUP TUITION Tropism: If movement of curvature in plants organ is induced by an externals and directional stimuli, then it is called tropism. If the growth of the plant is towards the stimulus then the tropism is called positive tropism. If the growth of the plant is away from the stimulus then the tropism is called negative tropism. The five common types of stimuli are light, gravity, chemical, water and touch. Types of tropism Phototropism: [What is meant by positive phototropism and negative phototropism? Give one example of each type.] The stimulus responsible for this tropism is light. The movement in plants in response to light is called phototropism. Stem and shoot system show positive phototropism while root system shows negative phototropism. Geotropism: The stimulus responsible for this tropism is gravity. The movement in plants in response to gravity is called geotropism. The root system shows positive geotropism while the stem and shoot system show negative geotropism. Chemotropism: The stimulus responsible for this tropism is chemical. The movement in plants in response to a chemical is called chemotropism. Growth of pollen tube towards the ovule during the process of fertilization is positive chemotropism. Hydrotropism: The stimulus responsible for this tropism is water. The movement in plants in response to water is called hydrotropism. The root system show positive hydrotropism. Thigmotropism: The stimulus responsible for this tropism is touch. The movement in plants in response to touch is called thigmotropism. The tendrils of ferns that coil spirally with the supporting object show positive thigmotropism. 6. How does phototropism occur in a plant stem? Explain with the help of labeled diagram. Phototropism in Plants When a tender plant in a small pot is kept inside an opaque box having only a small window on one side, the stem of the plant bends towards the window in the direction of light and comes out of the window. A tender plant in a pot, kept horizontally grows in upward direction towards light only. The direction of the shoot apex towards sun light that is in upward direction 7. How does hydrotropism occur in a plant? Explain with the help of labeled diagram. The movement in plants in response to water is called hydrotropism. Clay Pot Water Root curved in the direction of water Wet Clay Dry Clay c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61 X science 3 AJAY PARMAR GROUP TUITION Take a trough and fill it half with dry clay. Plant a small and tender plant cutting in this clay. Place a small cay pot filled with water close to the planted cutting. Dig out the plant after a week. The roots of the plant cutting are curved in the direction of the clay pot filled with water. Thus the root system shows positive hydrotropism. 8. What is nastism? Explain it different types giving one example of each. Nastism If movement in plants organ depends on the presence and intensity of the external stimulus and the direction of the movement is not determined by the direction of stimulus, then it is called nastism. The different types of nastic movements thigmonastic, photonastic and thermonastic and hydronastic movments. Thigmonastic movement: The movement of the plants in response to touch is called thigmonastic movment. When the leaves of Mimosa plant are touched, the leaflets of the leaf get folded and the leaf droops down for some time due to this touch. Photonastic movement: The movement of the plants in response to light is called photonastic movment. Flower of lotus and sunflower open in morning. Thermonastic movement: The movement of the plants in response to temperature is called photonastic movment. Flowers of Crocus and Tulip blossom at comparably higher temperature. Hydronastic movement: The movement of the plants in response to water is called photonastic movment. 9. Explain thigmonastic movement in Mimosa plant in detail. When the leaves of Mimosa plant are touched, the leaflets of the leaf get folded and the leaf droops down Shrinked for some time due to this touch. Pulvinus Hard Pulvinus Shrinked Pulvinus Before touch After touch The sensitive part in the leaves is soft, cushion – like swollen structure called ‘pulvinus’. The pulvinus cells contain lots of water. When touched, an electrical impulse is generated and it travels through cells. These impulses activate the hormones. The hormones induce water to migrate from the cells of one half of pulvinus to the intercellular space in the other half of the pulvinus. The loss of water causes loss in turgidity and hence the leaflet and then all the leaves fold. 10. How is tropism different from nastism? Tropism It is a growth based movement due to external stimuli. The response is in definite direction induced by stimuli. It may be positive or negative movement. Generally they are found in roots and shoots. e.g. phototropism, geotropism, chemotropism, etc c.g.road : 2646 08 03 Nastism It is due to external stimuli but not a growth based movement. The response is not in any definite direction There is nothing like positive or negative nastism. Generally they are found in leaves and flowers. e.g. thigmonsty, photonasty, thermonasty, etc :: 98792 12357 :: gurukul: 2745 70 61 X science 4 AJAY PARMAR GROUP TUITION 11. What are the functions of nervous system? Functions of Nervous system: To control and coordinate the activities of different parts of the body for its normal functioning. To control and coordinate the contraction and relaxation of muscles for various activities like walking, writing, dancing, etc. To coordinate the involuntary activities of heart, lungs, etc. To collect information of surrounding environment, interpret it and react suitably. To transfer information from one system to another in the form of impulses. 12. Name the structural and functional unit of nervous system. Explain its structure by drawing a neat and labeled diagram. Dendrite Axon terminal button Soma (Cell Body) Nucleus Axon Myelin Sheath Nerve cell is the structural and functional unit of nervous system. The three main components of nervous system are (1) Cell body, (2) Dendrites and (3) Axon. Cell body: It consists of cytoplasm and nucleus. Nerve fibres: A number of short and long fibres stretching out from the cell body are called nerve fibres. The shorter nerve fibres are called dendrites while the longer nerve fibre is called axon. Dendrites and axon both arise from cell body. Dendrites: The shorter nerve fibres stretching out from the cell body are called dendrites. They obtain message and set off chemical reaction that creates electric impulse known as nerve impulse. They pick the messages from the receptors (sense organs) and pass the message to cell body and then to the axon. Axon: The longer nerve fibre stretching out from the cell body is called axon. Axon is covered by a protective and an insulating sheath of myelin. It is made of fat and protein. The axon receives the message from cell body. Then it passes the message to the next nerve cell through the junction between axon terminal button and the dendrites of the next nerve cell. Synapse: A small gap between the two adjoining nerve cell is called synapse. 13. Write a note on human brain. Human brain: Forebrain Cerebrum Skull Thalamus Midbrain Hypothalamus Cerebellum Pituitary gland Pons c.g.road : 2646 08 03 :: 98792 12357 :: Medulla Oblongata Spinal cord gurukul: 2745 70 61 X science AJAY PARMAR 5 GROUP TUITION Human brain is located in the cranium (Skull cavity). Here it is protected by cranium and three layers of meninges with cerebrospinal fluid in between them. The weight of an adult human brain is approximately 1350 gm. Structure: It is mainly made of nervous tissue. The grey matter in the brain is formed of two types of matter. (1) Grey matter on the outer surface and (2) White matter in the inner surface. The space between the meninges is filled with cerebrospinal fluid to protect the brain. It absorbs the shocks and acts as cushion. It is mainly divided into three parts (1) Fore brain, (2) Mid brain and (3) Hind brain. Fore Brain: The fore brain consists of (1) Cerebrum (with olfactory lobes), (2) Thalamus and (3) Hypothalamus. Cerebrum: It is the largest and most complex part of the brain. It is consists of two cerebral hemisphere joined by a band called corpus callosum. Each cerebral hemisphere is divided into 4 lobes. (1) Frontal lobe, (2) Parietal lobe, (3) Temporal lobe and (4) Occipital lobe. Functions of cerebral lobes: [Mention the functions of cerebrum.] Frontal lobe: To control and coordinate specific voluntary and involuntary muscular activities like thought speech and memory. Parietal lobe: Sense like smell, touch and temperature are associated with this lobe. Temporal lobe: It is related with auditory reception. Occipital lobe: It is related with visual reception. Cerebral cortex: The outer region of the cerebral hemispheres is densely packed with the nerve cells called cerebral cortex. The cerebral cortex is highly convoluted to increase its surface area. It is divided into following regions: Sensory area Information is received from sense organs Motor area Impulse is sent to muscles and other effector organs. Thalamus: It is present in the centre of the fore brain. Function: All the cerebral messages passing through the thalamus and directs the sensory information to the cerebral cortex. Hypothalamus: It is located just below the thalamus. Function: It regulates the blood pressure, hunger, body temperature, thirst and functioning of eyes and ears. It connect the mid brain with the fore brain. Hind brain: [Write the names of the regions of hind brain. Give functions of each.] The hind brain consists of (1) Cerebellum, (2) Pons and (3) Medulla oblongata. Cerebellum: It lies on the dorsal side of pons. Functions: It maintains the balance of the body and posture. It coordinates the body movements like dancing, walking and riding bicycle. Medulla Oblongata: Functions: It controls various involuntary movements like breathing, heatbeats, blood pressure, peristaltic movements c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61 X science AJAY PARMAR 6 GROUP TUITION of alimentary canal, etc. It also controls the centre of reflexes like coughing, sneezing, swallowing, secretion of saliva and vomiting. Pons It takes part in regulation of respiration and helps to move head as per audio – visual perception in coordination with medulla oblongata and spinal cord. 14. What is voluntary nervous system? Explain the working of voluntary nervous system with an example. The nervous system that is concerned with the control and coordination of the voluntary nervous system. It is divided into two parts (1) Central nervous system and (2) Peripheral nervous system. The central nervous system includes the brain and the spinal cord. The peripheral nervous system consists of cranial nerves. The voluntary organs are under the control of the will or the animal concerned. Function: The voluntary nervous system is directly or indirectly in contact with voluntary muscles. Before any activity is being carried out, the brain prepares for the response and the message is sent to the respective muscle, and accordingly the muscles performs functions. E.g. speaking, walking, writing, hearing, eating, etc are some of the voluntary movements. These activities are under the control of will of the animals. Thus the voluntary activities are performed under the control and coordination of voluntary nervous system. 15. Write a note on spinal cord. It is posterior extension of medulla oblongata. Structure: It is cylindrical in shape enclosed in vertebral column. It is surrounded by three layers of meninges. Cerebrospinal fluid is filled in the central part of the spinal cord. The central part of spinal cord is made of grey matter arranged in H – shape. It consists of neurons and cytons of the motor cells. White matter surrounds the grey matter along the periphery of the spinal cord. It consists of modulated nerve fibres. 31 pairs of nerves arise from the spinal cord. A bundle of nerve fibres run ascending and descending tracts and connect the spinal cord with the brain. Ascending tracts conduct sensory information from the spinal cord to the brain. The descending tracts conduct motor information from brain to spinal cord. 16. What is reflex action? Explain with an example. An unconscious and involuntary response of effectors to stimulus is called reflex action. Reflex action is governed by the spinal cord. The brain does not take active part in the reflex action but it is brought to its knowledge later on. It is a simple response of the nervous system. Reflex action is beneficial in sudden unexpected circumstances. Examples of reflex actions: Coughing: It helps in cleansing of throat. Reduction of diameter of pupil in the bright light: It helps in preventing exposure of retina to bright light. Sneezing, yawning. Knee jerk responded. Movement of diaphragm. 17. Explain reflex arc. Draw a neat and labeled figure. The nerve impulse pathway involved in a reflex action is known as reflex arc. Rapid response is allowed by the reflex arc. Reflex arc can be explained by following example. Suppose we touch a hot plate. We pull our hand quickly without thinking about it. c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61 X science 7 AJAY PARMAR GROUP TUITION Heat is sensed by thermo receptor in our hand and it triggers an impulse in a sensory neutron. This sensory neuron transmits an impulse to a muscle of hand. Now the muscle then contracts and pulls the hand way from the hot plate. The muscle of hand is effectors because it responds to stimulus. This pathway along which the impulse transmits is called reflex arc. Message passes towards brain Spinal cord (CNS) Sensory nerve Sensory Organ Motor nerve Effected muscle 18. What is autonomous nervous system? What is its function? The self governing nervous system is called autonomous nervous system. It is responsible for the control of the activities of the organs located in the body automatically even without our thinking involuntarily. This system has a specific network of nerves in the body which controls and regulates the processes like digestion, sweating, breathing, heartbeat, etc. The nerves of the autonomous nervous system are connected to the smooth muscles of head, heart, blood vessels, lungs, alimentary canal, kidneys, glands and skin. They are of two types (1) sympathetic and (2) parasympathetic. The involuntary functions are controlled and coordinated with these two autonomous nervous systems. The effects of sympathetic and parasympathetic nervous systems are complimentary and contradictory to each other. The sympathetic nervous system increases the heart beat while the parasympathetic system decreases it and brings it back to normal. 19. How do involuntary actions and reflex actions differ from each other? Involuntary actions: Reflex actions: It is controlled by autonomous nervous system. It is controlled by central nervous system. It is a conscious or unconscious process. It unconscious and involuntary process. It takes place only in involuntary organs. It takes place in voluntary or involuntary organs. Its main function is to maintain the living state Its functions in the benefit of the body. of the body. It is comparably slower process. It is a very rapid process. It is not affected by external stimulus. It is caused due to external stimulus. Its impulse is carried through nerve fibre of Its impulse is carried through nerve fibre of autonomous nervous system. cranial nerves and spinal nerves. 20. What are endocrine glands? A gland which does not have a duct and secretes its product directly into blood stream is called endocrine gland. They are also called ductless gland. Generally they secrete hormones. 21. Write the names of five endocrine glands found in human body. Name the hormones secreted by each gland. Endocrine glands Name of the hormones Hypothalamus gland: Releasing hormones (RH) like TSH – RH (Thyroid Stimulating Hormone releasing hormone), GH – RH (Growth Hormone releasing hormone), ACTH – RH (Adrenocorticotropic Hormone releasing hormone), GTH – RH (Gonadotropic Hormone releasing hormone), Inhibitory hormones i.e. GH – IF (growth hormone inhibitory factor) and PIF (Prolactin Inhibiting Factor) c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61 X science AJAY PARMAR Pituitary gland: Thyroid gland: Parathyroid gland: Pancreas: Adrenal gland: Testis (In males): Ovary (In females): 8 GROUP TUITION Anterior lobe: TSH (Thyroid Stimulating Hormone), ACTH (Adreno Cortico Tropic Hormone), FSH (Follicle Stimulating Hormone), LH (Leutenizing Hormone), Prolactin and GH (Growth Hormone). Intermediate lobe: MSH (Melanocyte stimulating hormone) Posterior lobe: Vasoprassin, Oxytocin Thyroxine Parahormone Insulin Steroid Hormones: Mineral corticoids, Glucocorticoids and sex corticoids. Adrenaline and non – adrenaline. Testosterone Estrogen and Progesterone 22. Name the gland which controls the secretion of hormones of pituitary gland. Explain its action. [Write a note on hypothalamus and state the functions of the hormones secreted by it.] Hypothalamus gland controls the secretion of hormones of pituitary gland. It secretes two types of hormones: (1) Releasing hormones and (2) Inhibitory hormones. Releasing hormones (RH) They activate the anterior pituitary and makes it release certain hormones as follows: TSH – RH (Thyroid Stimulating Hormone releasing hormone) causes release of TSH from the anterior pituitary. GH – RH (Growth Hormone) causes release of growth hormone from the anterior pituitary. ACTH – RH (Adrenocorticotropic Hormone releasing hormone) causes release of adrenocorticotropic hormone from the anterior pituitary. GTH – RH (Gonadotropic Hormone releasing hormone) causes release of FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone) from the anterior pituitary. Inhibitory hormones They inhibit the secretion of certain hormones as follows: GH – IF (growth hormone inhibitory factor) inhibits the secretion of growth hormone. PIF (Prolactin Inhibiting Factor) inhibits the secretion of prolactin hormone. 23. Write a note on pituitary gland and state the functions of the hormones secreted by it. Pituitary gland It is located just below the hypothalamus. It is called master gland. It is divided into three lobes. (1) Anterior lobe, (2) Intermediate lobe and (3) Posterior lobe. Pituitary lobe Hormone Functions TSH (Thyroid Stimulating Hormone) Cause release of Thyroxin in Thyroid gland Anterior lobe Intermediate lobe ACTH (Adrenocorticotropic Hormone) Cause release of hormone in Adrenal gland FSH (Follicle Stimulating Hormone) Cause maturation of ovarian follicle. LH (Luteinizing Hormone) Cause secretion of sex steroids from gonads Prolactin Cause secretion of milk by mammary glands. GH (Growth Hormone) MSH (Melanocyte stimulating hormone) Cause development in bones and muscles. It is concerned with pigmentation of skin, colour of eyes, hair, etc. It activates the reabsorption of water during urine formation and controls loss of water through urine. Vasopressin Posterior lobe Oxytocin c.g.road : 2646 08 03 It causes contraction of uterine muscles during child birth and ejection of milk from mammary gland. :: 98792 12357 :: gurukul: 2745 70 61 X science AJAY PARMAR 9 GROUP TUITION 24. Explain the disorders caused due to GH. Disorders caused due to GH: Dwarfism: Hypo or under secretion of GH from childhood leads to dwarfism. Gigantism: Hyper or excess secretion of GH from childhood leads to gigantism i.e. height of more than 7 ft. Acromegaly: Too much secretion of GH after adolescence causes enlargement of hand, feet, jaws, etc. 25. Write a note on pancreas and state the functions of the hormones secreted by it. Pancreas: It is located in the abdominal cavity just beneath the stomach. It is an accessory digestive gland. It secretes a hormone called insulin. The main function of insulin is to lower the blood sugar level. Deficiency of insulin causes diabetes mellitus. Diabetes mellitus Diabetes causes high sugar level in blood and urine. It causes harmful side effects in the body. Persons suffering from diabetes should take less amount of sugar. Control of diabetes: Diabetes is controlled by (1) controlling diet, (2) doing physical activities, (3) reducing body weight, (4) taking medicines and (5) taking insulin injections regularly. 26. Write a note on thyroid and parathyroid glands and state the functions of the hormones secreted by it. Thyroid Gland: It is attached to wind pipe in our body. It secretes hormone called thyroxin. Thyroxin contains iodine. Functions of Thyroxin: It controls the rate of metabolism of carbohydrate, protein and fat. Disorders related to Thyroid: Deficiency of iodine in the body causes deficiency of thyroxine. Thus deficiency of iodine leads to hypothyroidism causing enlargement of thyroid gland. This disease is called goitre. Its preventive measure is to take iodized salt in daily food. Condition of hyperthyroidism is called exophthalmic goitre. It causes bulging of eyes. Parathyroid Gland: They are four small glands embedded in the thyroid gland. They secrete a hormone called parahormone which regulates calcium and phosphate levels in the blood. 27. Write a note on adrenal gland and state the functions of the hormones secreted by it. Adrenal gland: It is located on the anterior end of kidney. It is conical and composed of two regions: (i) an outer cortex and (ii) an inner medulla. Adrenal cortex: It secretes three types of steroid hormones. Mineral corticoid: To regulate balance of water and ions like Na+, Cl–, K+ in our body. Glucocorticoid: To stimulate metabolism of carbohydrate, proteins and fat. Sexual corticoid: They are responsible for secondary sexual characters. Adrenal medulla: It secretes two types of hormones adrenaline and non – adrenaline. Adrenaline is called fight or flight hormones. Hence adrenal glands are called glands of emergency. 28. Write a note on the glands which produce sex hormones. Testes and ovaries are the glands producing sex hormones in males and females respectively. c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61 X science AJAY PARMAR 10 GROUP TUITION Testes: It is located in the scrotum in the exterior part of the body. It secretes sex cells (spermatozoa) and sex hormone called testosterone. The main functions of testosterone are (1) development of sex organs, (2) developing secondary sexual characters like development of deeper voice, beard and moustache. Ovary: It is located in the lower abdominal region inside the body. It produces sex cells (ovum) and sex hormones progesterone and estrogen. Estrogen mainly controls the development of female sex organs, development of secondary sexual changes like feminine voice, soft skin, mammary gland, etc. Progesterone controls the changes in uterus during menstrual cycle and production of ova in the ovaries. 29. State the characteristics of hormones. Characteristics of hormones Each hormone is produced by a specific kind of cells. Hormones are not effective at their site of synthesis. Hormones are poured directly into blood. They are transported through blood to a specific organ and influence specific processes occurring there. This influence may be stimulatory or inhibitory. Thus hormones are regulator chemicals. Hormones are used up in producing their regulatory effects. Chemically they are peptides, steroid and some are biogenic amines. 30. Answer the following questions in brief: 1. Name the plant which shows thigmonasty. Mimosa (Touch me not plant) 2. Give scientific terms used to represent: (A) Bending of a shoot towards light:– (B) Growing of roots towards the earth:– (C) Growing of a pollen tube towards ovule:– (D) Bending of roots towards water:– (E) Winding of tendril around a support:– Phototropism Geotropism Chemotropism Hydrotropism Thigmotropism 3. Give one example of the movement of a plant part which is caused by the loss of water. Sensitive plant Mimosa. 4. What does a root do in response to gravity? What is this phenomenon known as? The roots give positive response to gravity. This is called positive geotropism. 5. What does a stem do in response to gravity? What is this phenomenon known as? A stem grows away from gravity. This is called negative geotropism. 6. What does a root do in response to light? What is this phenomenon known as? A root grows away from light. This is called negative phototropism. 7. What does a stem do in response to light? What is this phenomenon known as? A stem grows towards light. This is called positive phototropism. 8. Name the two systems of control and coordination in higher animals. Nervous system and endocrinal system are the two systems of control and coordination in higher animals. 9. Name the three components of a nerve cell. Cyton, axon and dendrites are the three components of a nerve cell. 10. Name the most important part of the human brain. Cerebrum is the most important part of the human brain. c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61 X science AJAY PARMAR 11 GROUP TUITION 11. State one function each of cerebellum and pons. Cerebellum: Coordination of movement of various body parts and body equilibrium. Pons: Regulation of process of breathing. 12. Give the functions of medulla oblongata. To maintain the involuntary processes like breathing, heartbeats, peristalsis of alimentary canal, etc. 13. What does CNS stand for? Central Nervous System. 14. Name one hormone secreted by pituitary gland. TSH, ACTH, FSH, LH, Prolactin GH, MSH, Vasoprassin, Oxytocin. 15. Where are hormones synthesized in human body? In the endocrine glands. 16. Which gland secretes growth hormone? Pituitary gland. 17. Name the disease caused by the deficiency of insulin in the body. Diabetes Mellitus. TEXTBOOK MCQs 1. What is called movement of plant towards the gravity? (A) hydrotropism (B) geotropism (C) chemotropism (D) phototropism 2. The plant part which exhibits negative geotropism is … . (A) root (B) stem (C) branch (D) leaves 3. The growth of a pollen tube towards the ovule is caused by … . (A) phototropism (B) hydrotropism (C) gravitropism (D) chemotropism 4. Bending of the shoot of a plant in response to light is known as … . (A) geotropism (B) phototropism (C) thigmotropism (D) photonasty 5. The stimulus in the process of thigmotropism is … . (A) touch (B) gravity (C) light (D) chemical 6. Which of the following helps in maintaining posture and balance of the human body? (A) cerebellum (B) cerebrum (C) medulla oblongata (D) pons 7. How many pairs of nerves arise from the spinal cord? (A) 21 (B) 31 (C) 41 (D) 51 8. Cerebellum, medulla oblongata and pons are the parts of … . (A) mid – b rain (B) hind – brain (C) fore – brain (D) spinal cord 9. For the synthesis of which of the following hormone iodine is necessary? (A) adrenaline (B) auxin (C) thyroxine (D) insuline 10. Which of the following is a mis – matched pair? (A) adrenaline : pituitary gland (B) estrogen : ovary (C) pancreas : insulin (D) progesterone : ovary 11. The spinal cord originates from … . (A) cerebrum (B) cerebellum (C) medulla oblongata (D) pons 12. Which of the following hormone prepares our body for action in emergency situation? (A) testosterone (B) growth hormone (C) adrenaline (D) insulin 13. Which is the male sex hormone? (A) estrogen (B) adrenaline (C) testosterone (D) progesterone 14. Which of the following endocrine gland does not occur as a pair in the human body? (A) adrenal (B) pituitary (C) testis (D) ovary c.g.road : 2646 08 03 :: 98792 12357 :: gurukul: 2745 70 61
