Biology

Chemical Coordination and Integration

Question:

You have learnt that a characteristic feature of endocrine system is the presence of feed back loops. By this what is meant if hormone A stimulates gland ‘X’ to secrete hormone B, the production of ‘A’ could be modified when the level of B changes in our blood. An example is the relation between hormones LH and estrogen (  E2). An old woman exhibits the following features. High levels of LH in blood but low levels of  E2 in the blood. Another woman exhibits high level of LH in blood and also high level of E2 in the blood. Where is the defect in both these women? Provide suitable diagram to support this answer.

Answer:

When the secretion of hormone is under the control of factors or other hormones it is called feedback control.
ncert-exemplar-class-11-biology-solutions-chemical-coordination-and-integration-2
If there is high concentration of hormone B in our blood then it will have an inhibitory effect on the secretion of hormone A. Decreased secretion of A will eventually result in decrease in production of hormone. This is negative feedback control. If there is B low concentration of hormone B in our blood then it will have a stimulatory effect on the secretion of hormone A. Increased secretion of A will eventually result in increase in production of hormone B. This is positive feedback control.
Low level of E2 should have positive feedback control on secretion of LH resulting in increase in production of E2. But old woman shows low level of E2 and high level of hormone LH, this means LH is not stimulating gland X to secrete hormone E2.
High level of E2 should have negative feedback control on secretion of LH resulting in decrease in production of E2. But another woman shows high level of both E2 and LH, this means there is some defect in the negative feedback loop.

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Chemical Coordination and Integration

Q 1.

State whether true or false:
(a) Gastrointestinal tract, kidney and heart also produce hormones.
(b) Pars distalis produces six trophic hormones.
(c) B-lymphocytes provide cell-mediated immunity.
(d) Insulin resistance results in a disease called diabetes mellitus.

Q 2.

Name the only hormone secreted by pars intermedia of the pituitary gland.

Q 3.

Hypothalamus is a super master endocrine gland. Elaborate.

Q 4.

George comes on a vacation to India from US. The long journey disturbs his biological system and he suffers from jet lag. What is the cause of his diicomfort?

Q 5.

What is the role-played by luteinizing hormones in males and females respectively?

Q 6.

Name the hormone that helps in cell – mediated immunity.

Q 7.

Rearrange the following hormones in Column I so as to match with their chemical nature in Column II.
Column I                             Column II
(a) Oxytocin                       i. Amino acid derivative
(b) Epinephrine               ii. Steroid
(c) Progesterone in.        iii.Protein
(d) Growth hormone     iv. Peptide

Q 8.

A sample of urine was diagnosed to contain high content of glucose and ketone bodies. Based on this observation, answer the following:
(a) Which endocrine gland and hormone is related to this condition?
(b) Name the cells on which this hormone acts.
(c) What is the condition called and how can it be rectified?

Q 9.

Which hormonal deficiency is responsible for the following:
(a) Diabetes meilitus
(b) Goitre
(c) Cretinism.

Q 10.

Inflammatory responses can be controlled by a certain steroid. Name the steroid, its source and also its other important functions.

Q 11.

On an educational trip to Uttaranchal, Ketki and her friends observed that many local people were having swollen necks. Please help Ketki and her friends to find out the solutions to the following questions.
(a) Which probable disease are these people suffering from?
(b) How is it caused?
(c) What effect does this condition have on pregnancy? ,

Q 12.

A patient complain so fconstantthirst,excessive passing of urine and low blood pressure. When the doctor checked the patients’ blood glucose and blood insulin level, the level were normal or slightly low. The doctor diagnosed the condition as diabetes insipidus. But he decided to measure one more hormone in patients blood. Which hormone does the doctor intend to measure?

Q 13.

Briefly mention the mechanism of action of FSH.

Q 14.

Old people have weak immune system. What could be the reason?

Q 15.

Fill in the blanks:
Hormones                                           Target gland
(a) Hypothalamic hormones        ………………..
(b) Thyrotrophin (TSH)                  ………………..
(c) Corticotrophin (ACH)              ………………..
(d) Gonadotrophins (LH, FSH)    ………………..
(e) Melanotrophin (MSH)              ………………..

Q 16.

Match the following :
Column I         Column II
(a) T4              (i) Hypothalamus
(b) PTH          (ii)Thyroid
(c) GnRH      (iii)Pituitary
(d) LH            (iv) Parathyroid.

Q 17.

Write short notes on the functions of the following hormones:
(a) Parathyroid hormones (PTH)
(b) Thyroid hormones
(c) Thymosin
(d) Androgens
(e) Estrogens
(f) Insulin and Glucagon.

Q 18.

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-l Tract.

Q 19.

There are many endocrine glands in human body. Name the glands which is absent in male and the one absent in female.

Q 20.

What is erythropoiesis? Which hormone stimulates it?

Q 21.

A milkman is very upset one morning as his cow refuses to give any milk. The milkman’s wife gets the calf from the shed. On fondling by the calf, the cow gave sufficient milk. Describe the role of endocrine gland and pathway associated with this response?

Q 22.

What are the effects of hypothyroidism (observed during pregnancy) on the development and maturation of a growing baby?

Q 23.

Diagrammatically indicate the location of the various endocrine glands in our body.

Q 24.

Which of the two adrenocortical layers, zona glomerulosa and zona reticularis lies outside enveloping the other?

Q 25.

Hypothalamus is a super master endocrine gland. Elaborate.

Q 26.

Name the endocrine gland that produces calcitonin and mention the role played by this hormone.

Q 27.

Define the following:
(a) Exocrine gland,
(b) Endocrine gland,
(c) Hormone.

Q 28.

Give example(s) of
(a) Hyperglycemic hormone and hypoglyce-mic hormone
(b) Hypercalcemic hormone
(c) Gonadotrophic hormones
(d) Progestational hormone
(e) Blood pressure lowering hormone
(f) Androgens and estrogens.

Q 29.

What is the role of second messenger in hormone action?

Q 30.

Mention the difference between hypothyroid-ism and hyperthyroidism.

Q 31.

Calcium plays a very important role in the formation of bones. Write on the role of endocrine glands and hormones responsible for maintaining calcium homeostasis.

Q 32.

What is the role of second messenger in the mechanism of protein hormone action?

Q 33.

Correct the following statements by replacing the term underlined.
(a) Insulin is a steroid hormone.
(b) TSH is secreted from the corpus luteum
(c) Tetraiodothyronine is an emergency hormone.
(d) The pineal aland is located on the anterior part of the kidney.

Q 34.

You have learnt that a characteristic feature of endocrine system is the presence of feed back loops. By this what is meant if hormone A stimulates gland ‘X’ to secrete hormone B, the production of ‘A’ could be modified when the level of B changes in our blood. An example is the relation between hormones LH and estrogen (  E2). An old woman exhibits the following features. High levels of LH in blood but low levels of  E2 in the blood. Another woman exhibits high level of LH in blood and also high level of E2 in the blood. Where is the defect in both these women? Provide suitable diagram to support this answer.

Q 35.

Illustrate the differences between the mechanism of action of a protein and a steroid hormone.