T3, T4 and Their Functions

Q. Choose the incorrect statement with respect to thymus gland.

1. Situated anterior to thyroid gland
2. Participates in cell mediated immunity
3. Secretes peptide hormone thymosins
4. Begins to degenerate as the age increases

Q.

Metamorphosis in insects is controlled by the adrenaline hormone.

1. True
2. False

Q. Which of the following is not a function of the thymus gland?

1. Development of immune system
2. Differentiation of T-lymphocytes
3. Antibody production
4. Regulate blood calcium level

Q.

The amino acid tyrosine is the precursor for the synthesis of
(i) Melatonin
(ii) Triiodothyronine
(iii) Thyroxine
(iv) Calcitonin

1. ii and iii
2. iii and iv
3. i and iv
4. i and ii

Q. Which of the following is not true about the thyroid gland and thyroid hormone?

1. Deficiency of iodine in our diet results in hypothyroidism and enlargement of the thyroid gland, commonly called goitre.
2. Thyroid hormone plays a major role in the differentiation of T lymphocytes.
3. The thyroid gland also secretes a protein hormone called thyrocalcitonin (TCT) which regulates blood calcium levels.
4. Maintenance of water and electrolyte balance is also influenced by thyroid hormones.

Q.

Which protein hormone produced by the thyroid gland regulates the blood calcium levels?

Q. Meroblastic cleavage refers to which type of division of egg?

Q. A tadpole with surgically removed thyroid gland can be made to metamorphose if

1. given an injection of thyroxine
2. all of the above
3. given an injection of growth hormone
4. given an injection of oxytocin

Q.

Amino acid which takes part in the formation of thyroxine is

1. Thyroglobulin

2. Lysine

3. Iodine

4. Tyrosine

Q.

Name one peptide hormone secreted by the thymus?

Q.

What is a Blastocyst?

Q. Blood levels of which of the following substances is decreased in Graves’ disease?

1. $T_3$
2. $T_4$
3. DIT
4. TSH

Q.

The amino acid tyrosine is the precursor for the synthesis of
(i) Melatonin
(ii) Triiodothyronine
(iii) Thyroxine
(iv) Calcitonin

1. i and ii
2. ii and iii
3. iii and iv
4. i and iv

Q. TSH from the anterior lobe of the pituitary controls the production of thyroxine from the thyroid gland. If the half-life of thyroxine is about 4 days, what will be the level of TSH after 8 days of the removal of the thyroid?

1. It will be increased.
2. No TSH will be produced.
3. It will remain unaffected.
4. It will be decreased.

Q.

Oxytocin is secreted by

1. Hypothalamus

2. Thyroid

3. Thymus

4. Adrenal

Q. Purine adenine pairs with pyrimidine thymine through how many hydrogen bond(s)?

1. One
2. Two
3. Three
4. Four

Q.

Maximum iodine is stored in

1. Parathyroid

2. Thyroid

3. Pituitary

4. Suprarenal

Q. Graves' disease is caused due to

1. Hyposecretion of adrenal gland
2. Hypersecretion of adernal gland
3. Hyposecretion of thyroid gland
4. Hypersecretion of thyroid gland

Q. Which is useful in metamorphosis of tadpole into frog?

1. Pituitary
2. Oxytocin
3. Aldosterone
4. Thyroxine

Q. In frog, holoblastic cleavage is not found due to

1. A dark pigment in animal pole
2. Heavy yolk in vegetal pole
3. Yolk concentrated in center of egg
4. Nucleus is assymetrical in position

Q. What is the difference between hypothyroidism and hyperthyroidism?

Q.

The amino acid tyrosine is the precursor for the synthesis of
(i) Melatonin
(ii) Triiodothyronine
(iii) Thyroxine
(iv) Calcitonin

1. ii and iii
2. i and iv
3. iii and iv
4. i and ii

Q. Which of the following is not a function of the thymus gland?

1. Development of immune system
2. Differentiation of T-lymphocytes
3. Antibody production
4. Regulate blood calcium level

Q. In absence of which of these the conversion of Angiotensinogen into angiotensin $I$ is not possible?

1. ANF
2. ADH
3. Aldosterone
4. Renin

Q. In the branched uterus of a gravid there may be large number of shelled zygotes. Their number is approximately

1. 300
2. 3000
3. 30, 000
4. 30, 00, 000

Q. What is holoblastic equal and holoblastic unequal cleavage? Explain.

Q.

Thyroid hormones synthesized in cuboidal epithelium are stored as

1. Tyrosine molecules in follicular cells

2. Thyroglobulin colloids in lumen

3. Iodine molecules in lumen

4. None of the above

Q.

Thyroid hormones synthesized in cuboidal epithelium are stored as

1. Tyrosine molecules in follicular cells

2. Thyroglobulin colloids in lumen

3. None of the above

4. Iodine molecules in lumen

Q. Which of the following statements concerning thyroid function are correct?

1. T3 and T4 stimulate the secretion of TSH by the anterior pituitary
2. People who have an underactive thyroid gland have a low BMR
3. Most of the iodine in the body is present in the thyroid gland
4. Thyroid hormones are essential for the early development and maturation of the central nervous system

Q. Goitre is related to which of the following glands of human body?

1. Thymus
2. Thyroid
3. Parathyroid
4. Pancreas