RBSE Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration

Rajasthan Board RBSE Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration Textbook Exercise Questions and Answers.

RBSE Class 11 Biology Solutions Chapter 22 Chemical Coordination and Integration

RBSE Class 11 Biology Chemical Coordination and Integration Textbook Questions and Answers

Question 1. 
Define the following:
(a) Exocrine gland
(b) Endocrine gland
(c) Hormone.
Answer:
(a) Exocrine gland: The gland that releases its secretion through duct. It is called exocrine gland.
(b) Endocrine gland: The gland that releases its secretion directly into the blood. It is called endocrine gland.
(c) Hormone: The nonnutrient chemicals which acts as intercellular messangers and are produced in traces by endocrine gland.

Question 2. 
Diagrammatically indicate the location of the various endocrine glands in our body.
Answer:
The endocrine system consists of glands widely separated from each other with no physical connections. Endocrine glands are groups of secretory cells surrounded by an extensive network of capillaries that facilitates diffusion of hormones from the secretory cells into the bloodstream.
The endocrine glands in the body are:

1. Pineal gland-  located in the epithalamus, near the center of the brain.
2. Pituitary gland- located at the base of the brain, just below the hypothalamus.
3. Hypothalamus- located below the thalamus and above the pituitary gland and brain stem
4. Thyroid gland- located in the neck in front of the larynx and trachea
5. Parathyroid gland- located in the neck in the posterior surface of the thyroid gland
6. Adrenal gland- located on the upper pole of each kidney enclosed within the renal fascia
7. Pancreas- located deep inside the abdomen. The head of the pancreas is on the right side of the abdomen and is connected to the duodenum
8. Ovaries- located in the lower abdomen, laterally to the left and right of the uterus and inferior to the fallopian tubes
9. Testis- located between upper thighs suspended by the spermatic cord in a skin pouch called scrotum
10. Thymus gland- located in the upper anterior part of the chest directly behind the sternum and between the lungs
11. Heart- lies in the thoracic cavity in the mediastinum (space between the lungs)
12. Stomach- located in the superior aspect of the abdomen
13. Kidney- located against the back muscles in the upper abdominal area. The left kidney is located slightly more superior than the right kidney due to the larger size of the liver on the right side of the body.  

Question 3. 
List the hormones secreted by the following:
(a) Hypothalamus 
(b) Pituitary 
(c) Thyroid 
(d) Parathyroid 
(e) Adrenal 
(f) Pancreas 
(g) Testis 
(h) Ovary 
(i) Thymus 
(j) Atrium 
(k) Kidney 
(l) G - I Tract.
Answer:
(a) Hypothalamus: Neurohormone, Gonadotrophin releasing hormone.
(b) Pituitary: Growth hormone, prolactin, gonadotrophin.
(c) Thyroid: Tetraiodothyronin (T₄ ), Triodothyronin (T₃ ).
(d) Parathyroid: Parathormone.
(e) Adrenal gland: Adrenaline, corticosterones.
(f) Pancreas: Insulin, glucagon.
(g) Testis: Testosterone, aldosterone.
(h) Ovary: Estrogen, progesterone.
(i) Thymus: Thymosin.
(j) Atrium: Atrial natriuretic factor (ANF).
(k) Kidney: Erythropoietin, renin.
(l) G - I tract: Gastrin, secretin, cholecystokinin (CCK). 

Question 4. 
Fill in the blanks:

Answer:
(a) Hypothalamus.
(b) Thyroid
(c) Adrenal cortex
(d) Testis, ovary
(e) Melanocytes

Question 5. 
Write short notes on the functions of the following hormones: 
(a) Parathyroid hormone (PTH)
(b) Thyroid hormones
(c) Thymosins
(d) Androgens
(e) Estrogens
(f) Insulin and glucagon.
Answer:
(a) Parathyroid hormone 
The principal/chief cells of the parathyroid produce the parathyroid hormone, also called the parathormone. The function of this hormone is 
To maintain calcium and phosphate balance in the blood and other tissues.
To increase calcium reabsorption from the intestine as well as from the nephrons of the kidney
To initiate bone resorption (e.g. reabsorption of calcium from bones), in case the blood calcium levels drop.

(b) Thyroid hormone
Both the thyroid hormones T4 (Thyroxine) and T3 (active form) are secreted by the thyroid gland.
The thyroid hormones control the metabolism of carbohydrates, protein and fats. They play an important role in regulating the Basal Metabolic Rate (BMR)
They are also important for maintenance of water and electrolyte balance. 
Thyroid hormones also regulate the RBC production.
The thyrocalcitonin maintains the blood calcium levels and promotes the bone formation.

(c) Thymosins
The thymus actively secretes the hormones called thymosins (only till pre-pubescence)
The stimulation, development and differntiation of T-lymphocytes.
The development of cell-mediated immunity (T-lymphocytes mediated immunity)
The production of antibodies (Humoral immunity).

(d) Androgens
Androgens are the hormones which are responsible for the development of secondary sexual characters. The Leydig cells of testis produce androgens such as testosterone. 
Androgens are also produced by the adrenal cortex of the adrenal gland and the ovaries 

(e) Estrogens
In Non-pregnant females, they are predominantly secreted by the ovaries. However, during pregnancy, the placenta secretes a lot of estrogens.
The three types of estrogens are; β-estradiol, estrone and estriol.
The most active and the principal estrogen produced by the ovaries is the  β-estradiol. 
They play an important role in the growth and development of ovarian follicles and breast
They are responsible for the development of secondary sexual characteristics (e.g. high pitch voice)
They inhibit osteoclastic activity and stimulate bone growth. Osteoporosis in menopausal women is because of reduced estrogen levels.
They also influence the texture of the skin and female sexual behaviour

(f) Insulin and Glucagon
Glucagon
It increases the blood glucose levels by initiating glycogenolysis (glycogen degradation) and stimulating gluconeogenesis (synthesis of glucose from non-carbohydrate molecules) in the liver cells.
Since it increases the blood glucose levels it is a hyperglycemic (hyper-more, glycemic-sugar levels) hormone
It also initiates lipolysis (degradation of lipid) in the adipose tissue.
Insulin
It is released when the glucose level in the blood raises.
It lowers blood sugar levels in different ways; increasing the uptake of glucose by all the cells in the body, initiating glycogenesis (glycogen synthesis) in the liver and muscle.
It initiates lipogenesis (synthesis of lipids/fat) and storage of fat in adipose tissue and inhibits gluconeogenesis
It is a hypoglycemic (hypo=less) hormone as it reduces the sugar levels in the blood.

Question 6. 
Give examples(s) of:
(a) Hyperglycemic hormone and hypoglycemic hormone.
(b) Hypercalcemic hormone
(c) Gonadotrophic hormone
(d) Progestational hormones
(e) Blood pressure lowering hormone
(f) Androgens and estrogens
Answer:
(a) Glucagon and glucocorticoids, Insulin and glucocorticoids
(b) Parathormone
(c) Luteinising hormone (LH), Follicle stimulating hormone (FSH)
(d) Progesterone
(e) Atrial natriuretic factor (ANF)
(f) Testosterone, Estrogen.

Question 7. 
Which hormonal deficiency is responsible for the following:
(a) Diabetes mellitus 
(b) Goitre
(c) Cretinism.
Answer:
(a) Insulin 
(b) Thyroxin 
(c) Thyroxin.

Question 8. 
Briefly mention the mechanism of action of FSH.
Answer:

FSH is follicle stimulating hormone produced by adenohypophysis of pituitary gland. This hormone is produced in both male and female human that along with male sex hormone testosterone and in female LH helps in the spermatogenesis and oogenesis respectively. This hormone binds to hormone receptor present in the ovarian cell membrane. It binds and forms a hormone receptor complex and generates second messangers such as cyclic AMP or Ca⁺⁺. Due to which biochemical responses and physiological growth of ovarian follicles takes place in ovary. The mature/full grown follicle/ ovum is called graafian follicle - ovum.

Question 9. 
Match the following:

Answer: