Class 10 SELINA Solutions Biology Chapter 12 - The Endocrine System
The Endocrine System Exercise Ex. 1
Solution A.1
Solution A.2
Solution A.3
(b) diabetes insipidus
Solution B.1
(a) Adrenaline
(b) Hypoglycemia
(c) Insulin
(d) Isthmus
(e) Anti-diuretic hormone (Vasopressin)
(f) Adrenaline
Solution B.2
Solution B.3
(b) Scurvy
(c) Cretinism
(d) Cortisone
Solution B.4
A (Condition) |
B (Cause) |
(a) Dwarfism and mental retardation |
v. Hypothyroidism |
(b) Diabetes mellitus |
i. Excess of glucose in blood |
(c) Shortage of glucose in blood |
iii. Insulin shock |
(d) Gigantism |
ii. Over secretion of growth hormone
|
(e) Enlargement of breasts in adult males |
vi. Over secretion of cortical hormones
|
(f) Exophthalmic goitre |
iv. Over secretion of thyroxine |
Solution B.5
(a) Larynx
Reason- Larynx is the sound box while the rest three i.e. glucagon; testosterone and prolactin are hormones.
(b) Penicillin
Reason - Penicillin is an antibiotic while adrenaline; insulin; thyroxine are hormones.
(c) Adrenaline
Reason - Adrenaline is a hormone while the stomach, ileum and liver are the organs of the digestive system.
(d) Insulin
Reason- Insulin is secreted by the pancreas while TSH, GH, ADH are the hormones secreted by the pituitary gland.
(e) Iodine
Reason- Iodine is required for the synthesis of thyroxine hormone. While cretinism, goitre, myxoedema are the deficiencies occur due to the deficiency of thyroxine.
Solution B.6
Column I |
Column II |
1. Beta cells of islets of Langerhans |
(g) Insulin |
2. Thyroid |
(c) Exophthalmic goitre |
3. Cretinism |
(h) Under secretion of thyroxine in a child |
4. Addison's disease |
(b) Undersecretion of glucocorticoids |
5. Hypothyroidism |
(e) Thyroxine |
6. Myxoedema |
(a) condition due to under secretion of thyroxine in adults |
7. Adrenaline |
(d) Increases heart beat |
8. Cortisone |
(f) Adrenal cortex |
Solution B.7
(a) Beta cells : Insulin :: Alpha cells : Glucagon.
(b) Children : Cretinism :: Adults : Myxoedema.
(c) Undersecretion : Dwarfism :: Oversecretion : Gigantism.
(d) Diabetes mellitus : Insulin :: Diabetes insipidus : Antidiuretic hormone (ADH).
Solution C.1
a) Hyperglycemia
b) Simple goitre
c) Cretinism
d) Exophthalmic goitre
e) Acromegaly in adults and gigantism in children
Solution C.2
(a) Thyroid: It is situated in the front part of the neck just below the larynx.
(b) Adrenal: It is present as a cap on the top of each kidney.
(c) Pancreas: It is located behind the stomach in the upper left abdomen.
(d) Pituitary: It hangs from the base of the mid-brain below the hypothalamus.
Solution C.3
(a) Three hormones secreted from islets of Langerhans of pancreas:
- Insulin
- Glucagon
- Somatostatin
(b) Two types of cortical hormones:
1. Glucocorticoids
2. Mineralocorticoids
(c) Six hormones secreted from anterior pituitary:
1. Growth hormone (somatostatin)
2. Prolactin
3. Adreno-corticotropic hormone (ACTH)
4. Thyroid stimulating hormone (TSH)
5. Follicle stimulating hormone (FSH)
6. Luteinizing hormone (LH)
(d) Two hormones secreted from posterior pituitary:
1. Vasopressin
2. Oxytocin
(e) The emergency hormone:
1. Adrenaline
Solution C.4
Hormones |
Functions |
(a) Thyroxine |
Regulates the basal metabolism |
(b) Adrenaline |
Increases heart beat and blood pressure |
(c) Insulin |
Reduces the blood sugar level |
(d) Glucagon |
Increases the blood sugar level |
(e) Vasopressin |
Constricts blood vessels and raises blood pressure |
Solution C.5
Functions |
Hormones |
(a) Contraction of uterine muscles during child birth |
Oxytocin |
(b) Maintenance of corpus luteum |
Luteinizing hormone (LH) |
(c) Milk formation and secretion |
Prolactin |
(d) Development of external sex characters in males |
Testosterone |
(e) Stimulation of sympathetic nervous system |
Adrenaline |
Solution C.6
Solution C.7
S.No. |
Source Gland cells |
Hormone produced |
Chief function |
Effect of over secretion |
Effect of under secretion |
1. |
Thyroid |
thyroxine |
Regulates basal metabolism |
Exophthalmic goiter |
Simple goiter, cretinism in children and myxoedema in adults |
2. |
Beta cells of Islets of Langerhans |
Insulin |
Promotes glucose utilization by the body cells |
Hypoglycemia |
Diabetes mellitus |
3. |
Anterior pituitary |
Growth hormone |
Promotes growth of the whole body |
Gigantism |
Dwarfism |
4. |
Posterior pituitary |
Vasopressin |
Increases reabsorption of water from kidney tubule |
More concentrated and less amount of urine |
Diabetes insipidus |
Solution C.8
Gland |
Hormone secreted |
Effect on body |
Thyroid |
Thyroxine |
Regulates basal metabolism |
Pancreas ("beta" cells) |
Insulin |
Controls blood sugar level |
Adrenal gland |
Adrenaline |
Increases heart beat |
Anterior pituitary |
Thyroid stimulating hormone |
Stimulates thyroxine secretion |
Solution C.9
Gland |
Secretions |
Effect on body |
Ovary |
oestrogen |
development of secondary sexual characteristics |
Alpha cells of islets of Langerhans |
Glucagon |
Raises blood sugar level |
Thyroid |
Hypersecretion of thyroxine |
Protruding eyes |
Anterior pituitary |
Hypersecretion of Growth hormone |
Gigantism |
Solution D.1
(a) Endocrine system: Endocrine system consists of several endocrine glands/glandular cells which activate each other and work as a system to bring about chemical coordination in the body.
(b) Hormones: Hormones are secretions from specific cells or glands in the body, which are carried to all body parts through the blood, but exert their effect only on one or more specific body parts (target organ or cells).
(c) Myxoedema: Myxoedema is a condition which occurs in adults due to hypothyroidism in which the person becomes sluggish with swelling of the face and hands.
Solution D.2
(a) Differences between exocrine and endocrine glands (manner of secretion):
Exocrine glands |
Endocrine glands |
Secretions are carried through special ducts. |
Secretions are poured directly into the blood. |
(b) Differences between enzymes and hormones (chemical composition and mode of action):
Enzymes |
Hormones |
Enzymes are protein in nature. |
Hormones are peptides, amines or steroids. |
Enzymes are substrate specific. These are present in all cells and show their activity there |
Hormones are specific to the target cell, tissue, or system. They are produced at one site and show their activities at other sites. |
(c) Differences between nervous control and hormonal control (transmission and effect):
Nervous control |
Hormonal control |
Transmitted electro-chemically through nerve fibres and chemically across synapses. |
Transmitted chemically through blood. |
Effect is only short-lived. |
Effect is short term or long lasting. |
(d) Differences between diabetes mellitus and diabetes insipidus (cause and symptoms):
Diabetes mellitus |
Diabetes insipidus |
Caused due to insufficient secretion of insulin. |
Caused due to insufficient secretion of anti-diuretic hormone (ADH) |
High concentration of sugar in blood. |
No sugar in urine |
(e) Differences between Addison's disease and Cushing's syndrome (cause and sugar level):
Addison's disease |
Cushing's syndrome |
Caused due to hyposecretion of cortisone |
Caused due to hypersecretion of cortisone |
Low blood sugar level |
High blood sugar level |
Solution D.3
(a) Adrenaline is often described as the emergency hormone because it prepares the body to meet any emergency situation, for fight and face the danger or flight and run away from it. More adrenaline is secreted which makes the heart beat faster, increases the breathing, releases more glucose into the blood stream to fulfill the energy requirement.
(b) Pituitary is popularly called as the master gland because it controls the functioning of all the other endocrine glands.
(c) People living in the low Himalayan hilly regions often suffer from goitre because iodine is deficient in soil and hence, in the food grown there. Insufficient iodine produces less thyroxine which results in goitre.
(d) Iodised salt contains iodine which is an active ingredient in the production of thyroxine. Hence, it is recommended to use iodised salt in food to prevent simple goitre.
Solution D.4
Chemically hormones are peptides, amines or steroids. They are involved in regulating the metabolism of the body. They can bring about specific chemical changes during metabolic process. Therefore hormones can be termed as 'chemical messengers'.
Solution E.1
a. Glucagon: Alpha cells of the islets of Langerhans
Insulin: Beta cells of the islets of Langerhans
b. Insulin: It maintains the levels of glucose (sugar) in the blood.
Glucagon: It raises the blood glucose levels by stimulating the breakdown of glycogen to glucose in the liver.
c. An endocrine gland is one which does not pour its secretions into a duct, while an exocrine gland is a gland which pours its secretions into a duct. Because the pancreas produces hormones such as insulin, glucagon and somatostatin directly into the blood and not into a duct, it functions as an endocrine gland. Because it secretes the pancreatic juices for digestion via a duct, it functions as an exocrine gland. Hence, the pancreas is an exo-endocrine gland.
d. Insulin is not administered orally because the digestive juices degrade insulin, and thus the insulin is ineffective in the body.
e. Islets of Langerhans
f. The pancreas is located in the abdomen behind the stomach.
Solution E.2
(a) This portion is located in the neck region above the sternum.
(b) 1- Larynx, 2 - Thyroid gland, 3 - Trachea
(c) Larynx is the voice box containing vocal cords. It helps in producing sound.
Thyroid gland produces thyroxine and calcitonin which are essential hormones.
Trachea is the wind pipe that helps in passing air to and from the respiratory system while breathing.
(d) Structure 2 is the thyroid gland. It is an endocrine gland, so it is ductless and pours its secretions directly into the blood. Hence, there is no duct.
Solution E.3
(a) 1- Pituitary gland, 2 - thyroid gland, 3 - pancreas, 4 - adrenal glands
(b) All the glands shown in the above diagram are endocrine glands. They secrete essential hormones and pour their secretions directly into the blood.
(c) Iodine is essential for the normal working of thyroxine.
Solution E.4
(a) A
(b) Hormone secreted by the endocrine gland is shown in the image A to be moving only in one direction i.e. towards the target organ. But actually the hormones poured into the blood stream may have one or more target sites at a time. The arrows shown are carried to all parts by the blood and their effect is produced only in one or more specific parts.
Solution F.1
Hormonal Response |
Nervous Response |
Hormonal response is slow. |
Nervous response is immediate. |
Hormones are chemical messengers transmitted through blood stream. |
Nerve impulses are transmitted in the form of electro-chemical responses through nerve fibres. |
This response brings about a specific chemical changes. Therefore it regulates the metabolism. |
This response does not bring any chemical change during metabolism. |
Solution F.2
Action of Hormones |
Action of Nerves |
The effect of hormones is wide spread in the body. They can show their effect on more than one target site at a time. |
The nerve response affects only particular glands. |
The effect of hormones can be short-lived or long lasting. |
The effect of nervous response is always short-lived. |
Cannot be modified by the previous learning experiences. |
Can be modified by the previous learning experiences. |