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NCERT Solutions for Class 11 Biology Chapter 22 - Chemical Coordination and Integration

iacst-2022

In the immediate above chapter, we have seen how the neural system maintains point-to-point rapid coordination between organs. This coordination provided by the neural system is fast, but not long. Therefore, a special form of coordination and integration is required, since the nerve fibres do not stimulate all cells of the body, and there is a necessity to regulate the functions of the cells continuously.

Hormones perform this special coordination function. The body's physiological functions are jointly regulated and coordinated by the neural system and the endocrine system. To know more about them read below.

  • What is Endocrine Glands and Hormones
  • The Endocrine System of Humans
  • Hormones present in Kidney, Gastrointestinal Tract, and Heart
  • Mechanics applied in Hormone Action

The last chapter for class 11 Biology' Chemical Coordination and Integration' explains the concept of endocrine glands present in the human body. The chapter has been explained minutely through diagrams so that students exactly trace the location of the endocrine glands inside the human body.

In this chapter, Hormones are defined as non-nutrient chemicals whose nature is like intercellular messengers and which generate in huge numbers to play a pivotal role in the endocrine system. Also discussed is an overview of FSH's process and the hormonal deficiencies occurring in different parts of the human body. Some other topics introduced in this chapter are the pituitary gland, thyroid gland, pineal gland, hypothalamus, thymus, parathyroid gland, pancreas, adrenal gland, ovary, testis, and the mechanism of hormonal action.

 

Q1. Define the following:
(a)
Exocrine gland
Answer:
Exocrine gland-
The glands which discharge their secretions into ducts are known as exocrine glands. Examples of exocrine glands include the sebaceous gland in the skin, the salivary gland in the buccal cavity, etc.
 

Q2. Define the following:
(b)Endocrine gland
Answer:
Endocrine glands-
The glands which do not discharge their secretions into ducts are known as endocrine glands. These glands discharge their secretions directly into the blood. Examples of endocrine glands include the Pituitary gland, thyroid gland, adrenal gland, etc.


Q3. Define the following:
(c)Hormone
Answer:
Hormones-
The hormones are chemical messengers that regulate physiological processes in living organisms. They act upon specific cells/tissues/organs.

 

Q4. Diagrammatically indicate the location of the various endocrine glands in our body.
Answer:
The location of the various endocrine glands in our body is depicted below.


 

Glands

Location

Hormones secreted

Functions

Hypothalamus

Brain

Anti-diuretic hormone (ADH), the oxytocin

Anti-diuretic hormone causes water reabsorption at the kidneys and oxytocin stimulates contraction of the uterus in childbirth and is important in breastfeeding.

Pituitary gland

Brain

Prolactin, growth hormone, thyroid-stimulating hormone (TSH),

These hormones act on the reproductive system to influence the behaviour and regulate the immune system.

Pineal gland

Brain

Melatonin

Melatonin influences the sleep cycle of a man

Thyroid gland

Throat

tri-iodothyronine (T3), thyroxine (T4), calcitonin

The general metabolism, bone health are functioned by these hormones parathyroid

Parathyroid gland

Brain

Parathormone

The hormone plays a role in regulating blood calcium levels, helping the body maintain adequate calcium stores in the bloodstream to protect bone health.

Adrenal glands

Top of kidneys

Adrenaline, noradrenaline, cortisol, aldosterone

They help in regulating the metabolism, immune system, blood pressure, response to stress, and other essential functions.

Pancreas

Abdomen

Insulin, glucagon, somatostatin

The blood sugar level control is maintained by the hormones secreted by the pancreas.

Ovaries (females only)

Lower abdomen

Oestrogen, progesterone

The female characteristics are functioned by the hormones secreted by ovaries.

Testes (males only)

Scrotum

Testosterone

The male characteristics are functioned by the hormones secreted by testes.

 

Q5. List the hormones secreted by the following:
(a)Hypothalamus
Answer:
The hormones secreted by the hypothalamus include divided into two groups-
1.
Releasing hormones- These include gonadotropin-releasing hormone, thyrotropin-releasing hormone, somatotropin-releasing hormone, adrenocorticotropin-releasing hormone.

2. Inhibiting hormones: These include somatostatin, growth-inhibiting hormone, melanocyte-inhibiting hormone

 

Q6. List the hormones secreted by the following:
(b)Pituitary
Answer:
The pituitary gland has two components i.e., adenohypophysis and neurohypophysis.
-Hormones secreted by the adenohypophysis are growth hormone (GH), prolactin, thyroid-stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), melanocyte-stimulating hormone (MSH)
-Hormones secreted by the neurohypophysis are oxytocin and vasopressin

 

Q7. List the hormones secreted by the following:
(c) Thyroid
Answer:
Thyroid gland- The thyroid gland secretes three hormones namely, thyroxin, tri-iodothyronine, and calcitonin.


Q8. List the hormones secreted by the following:
(d)Parathyroid
Answer:
Parathyroid- It secretes parathyroid hormone
 

Q9. List the hormones secreted by the following:
(e)Adrenal
Answer:
Adrenal gland - The adrenal gland is divided into two parts, the outer adrenal cortex, and the inner adrenal medulla.
-Hormones of the adrenal cortex include aldosterone and cortisol.
- Hormones of the adrenal medulla are adrenaline and nor-adrenalin. 
 

Q9.List the hormones secreted by the following:
(f)
Pancreas
Answer:
Pancreas: Hormones secreted by the pancreas are insulin, glucagon and somatostatin.


Q10. List the hormones secreted by the following:
(g)Testis
Answer:
Testis: The hormone secreted by the testis is testosterone.


Q11. List the hormones secreted by the following:
(h)Ovary
Answer:
Ovary: The hormone secreted by the ovary includes estrogen and progesterone.


Q12. List the hormones secreted by the following:
(i)Thymus
Answer:
Thymus: Hormones secreted by the thymus are thymosin.


Q13. List the hormones secreted by the following:
(j)Atrium
Answer:
Atrium: The walls of the atrium secrete atrial natriuretic factors.


Q14. List the hormones secreted by the following:
(k)Kidney
Answer:
Kidney: The hormone secreted by the kidney is erythropoietin.

Q15. List the hormones secreted by the following:
(l)G-I Tract
Answer:
G-l tract- The hormones secreted by the G-l tract are Gastrin, secretin, cholecystokinin (CCK), and gastric inhibitory peptide (GIP).


Q16. Fill in the blanks:

Hormones Target gland
a. Hypothalamic hormones 
b. Thyrotrophin (TSH) 
c. Corticotrophin (ACTH) 
d. Gonadotrophins (LH, FSH) 
e. Melanotropin (MSH) 

Answer:

Hormones Target gland
a. Hypothalamic hormones- Pituitary gland.
b.
Thyrotrophin (TSH) -Thyroid gland 
c. Corticotrophin (ACTH)- Adrenal gland
d. Gonadotrophins (LH, FSH)- Testis and ovaries 
e. Melanotropin (MSH)- Pigment cells of the dermis of the skin


Q17. Write short notes on the functions of the following hormones:
a. Parathyroid hormone (PTH)
Answer:
The function of Parathyroid hormone (PTH):
-The parathyroid hormone maintains the calcium levels in the body.
-It increases the calcium levels of the blood.
_It stimulates bone resorption which demineralizes bones increasing blood calcium levels.
-It also stimulates calcium absorption by renal tubules and from the digested food.


Q18. Write short notes on the functions of the following hormones:
b. Thyroid hormone
Answer:
The function of Thyroid hormones are given below:

Thyroxine/tetraiodothyronine (T4):
-It regulates the basal metabolic rate (BMR).
-It regulates body growth such as ossification of bones and mental development.
-It controls body weight.
-It also controls tissue differentiation and metamorphosis of the tadpole larva into an adult frog._It suppresses RBC formation.

Tri-iodothyronine (T3):
-It increases the body's oxygen and energy consumption.
-It increases the heart rate and force of contraction which increases the cardiac output.


Q19. Write short notes on the functions of the following hormones:
c. Thymosin
Answer:
The function of Thymosins is given below:

-Thymosin stimulates the differentiation of T-lymphocytes and provides cell-mediated immunity.
-It promotes the production of antibodies to provide humoral immunity.
-It also stimulates the rate of cell division in kids and hence promotes growth.


Q20. Write short notes on the functions of the following hormones:
d. Androgens
Answer:
The function of Androgens are given below:

Testosterone:
-Testosterone helps in the maturation of sperms.
-It stimulates the growth and development of the male reproductive system.
-It stimulates the development of secondary sexual characters such as beards and moustaches.
-It produces anabolic effects on protein and carbohydrate metabolism.


Q21. Write short notes on the functions of the following hormones:
e. Estrogen
Answer:
The primary function of estrogens in the development of female secondary sexual characteristics. These include breasts, endometrium, regulation of the menstrual cycle, etc. In males, estrogen helps in the maturation of the sperm and the moustaches of a healthy libido.


Q22. Write short notes on the functions of the following hormones:
f. Insulin and Glucagon
Answer:
The function of Insulin and Glucagon are given below:

Insulin:
-It plays a major role in the regulation of glucose homeostasis. It acts on hepatocytes and adipocytes.
-
It stimulates the transport of glucose from the blood to the muscle.
-It promotes the oxidation of glucose and the conversion of glucose to glycogen, i.e. glycogenesis, resulting in hypoglycemia.

Glucagon:
-It plays a major role in the maintenance of normal blood glucose levels.
-It acts on hepatocytes and stimulates the conversion of glycogen into glucose. It also stimulates the process of gluconeogenesis, i.e. the conversion of non-carbohydrate substances such as fats and proteins to glucose.


Q23. Give example(s) of:
a. Hyperglycemic hormone and (b)hypoglycemic hormone
Answer:
a. Hyperglycemic hormone- glucagon.
b. Hypoglycemic hormone
-insulin



Q24. Give example(s) of:
c. Hypercalcemic hormone

Answer: Parathormone 


Q25. Give example(s) of:
d. Gonadotrophic hormone
Answer:
-Luteinising hormone (LH)
-Follicle-stimulating hormone (FSH)


Q26. Give example(s) of:
e. Progestational hormone
Answer: Progesterone


Q27. Give example(s) of:
f. Blood pressure-lowering hormone
Answer:Atrial natriuretic factor


Q28. Give example(s) of:
g. Androgens and estrogens
Answer:
Androgens: Testosterone 
Estrogens : estradiol


Q29. Which hormonal deficiency is responsible for the following:
(a)Diabetes Mellitus
Answer:
Insufficient secretion of insulin is responsible for Diabetes Mellitus.


Q30. Which hormonal deficiency is responsible for the following:
(b)GoitreAnswer:
Insufficient secretion of thyroxine is responsible for Goitre.


Q31. Which hormonal deficiency is responsible for the following:
(c)Cretinismthe a the The locationHypothalamusthyrotropin-releasing the the factorsThefunctione function funfunction in thethe
Answer:
Insufficient secretion of thyroxine is responsible.


Q32. Briefly mention the mechanism of action of FSH.

Answer:
Follicle-stimulating hormone (FSH) is a glycoprotein polypeptide hormone. It is insoluble in lipid and hence cannot enter the target cell. This hormone binds to the cell surface and activates cellular systems to perform functions.

Steps in athe ction of FSH:
-A molecule of FSH binds on the receptor protein present on the cell surface and forms the hormone-receptor complex.
-The formation of the hormone-receptor complex activates the enzyme adenylate cyclase.
-
Adenyl cyclase converts ATP into cell cyclic adenosine monophosphate (cAMP) as a second messenger.
-cAMP activates the follicular cells of membrane granulosa to secrete estrogens.


Q9. Match the following:

 

Column I

 

Column II

 

(a) T 4

 

(i) Hypothalamus

 

(b) PTH

 

(ii) Thyroid

 

(c) GnRH

 

(iii) Pituitary

 

(d) LH

 

(iv) Parathyroid

Answer:

Column I

Column II

(a) T 4

(ii) Thyroid

(b) PTH

(iv) Parathyroid

(c) GnRH

(i) Hypothalamus

(d) LH

(iii) Pituitary

 

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Also See    
NCERT Solutions for Class 11 Biology Chapter 1 - The Living World NCERT Solutions for Class 11 Biology Chapter 2 - Biological Classification NCERT Solutions for Class 11 Biology Chapter 3 - Plant Kingdom
NCERT Solutions for Class 11 Biology Chapter 4 - Animal Kingdom NCERT Solutions for Class 11 Biology Chapter 5 - Morphology of Flowering Plants NCERT Solutions for Class 11 Biology Chapter 6 - Anatomy of Flowering Plants
NCERT Solutions for Class 11 Biology Chapter 7 - Structural Organization in Animals NCERT Solutions for Class 11 Biology Chapter 8 - Cells: The Unit of Life NCERT Solutions for Class 11 Biology Chapter 9 - Biomolecules
NCERT Solutions for Class 11 Biology Chapter 10 - Cell Cycle and Division NCERT Solutions for Class 11 Biology Chapter 11 - Transport in Plants NCERT Solutions for Class 11 Biology Chapter 12 - Mineral Nutrition
NCERT Solutions for Class 11 Biology Chapter 13 - Photosynthesis in Higher Plants NCERT Solutions for Class 11 Biology Chapter 14 - Respiration in Plants NCERT Solutions for Class 11 Biology Chapter 15 - Plant Growth and Development
NCERT Solutions for Class 11 Biology Chapter 16 - Digestion and Absorption NCERT Solutions for Class 11 Biology Chapter 17 - Breathing and Exchange of Gases NCERT Solutions for Class 11 Biology Chapter 18 - Body Fluids and Circulation
NCERT Solutions for Class 11 Biology Chapter 19 - Excretory Products and their Elimination NCERT Solutions for Class 11 Biology Chapter 20 - Locomotion and Movement NCERT Solutions for Class 11 Biology Chapter 21 - Neural Control and Coordination

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