Tag: zoology

Questions Related to zoology

Hassall's corpuscles are found in 

zoology control and coordination in living organisms thymus thymus gland pineal gland and thymus

  1. Pineal body

  2. Thymus gland

  3. Thyroid gland

  4. Adrenal gland

Show answer
Correct Option: B
Explanation:

Hassall's corpuscles (or thymic corpuscles) are structures found in the medulla of the human thymus, formed from eosinophilic type VI epithelial reticular cells arranged concentrically. 

The cytoplasm in Hassalls corpuscles contains keratohyalin granules and intermediate fibres and may be keratinised. 

Thymus gland develops from embryonic 

zoology control and coordination in living organisms thymus thymus gland pineal gland and thymus

  1. Mesoderm

  2. Endoderm

  3. Ectoderm

  4. All of the above

Show answer
Correct Option: B
Explanation:

The triploblastic animals have three prominent germ layers known as ectoderm, endoderm and mesoderm. Thymus gland develops from two hollow elongations (third and fourth pharyngeal pouches) of endoderm which descends to the embryonic thorax by the end of eight weeks of gestation. The lymphoid cells of the gland originate from mesoderm. Thus, the correct answer is option B.

Which endocrine gland is not an ectodermal origin?

zoology control and coordination in living organisms thymus thymus gland pineal gland and thymus

  1. Pineal body

  2. Anterior pituitary

  3. Adrenal medulla

  4. Thymus

Show answer
Correct Option: D
Explanation:

Endoderm, the innermost of the three germ layers, or masses of cells (lying within ectoderm and mesoderm), which appears early in the development of an animal embryo. The endoderm subsequently gives rise to the epithelium (tissue that covers, or lines, a structure) of the pharynx, including the eustachian tube, the tonsils, the thyroid gland, parathyroid glands, and thymus gland; the larynx, trachea, and lungs; the gastrointestinal tract (except mouth and anus), the urinary bladder, the vagina (in females), and the urethra. 

If thymectomy is done during adulthood then what is the probable result of it?

zoology control and coordination in living organisms thymus thymus gland pineal gland and thymus

  1. Immunosuppressant

  2. Die immediately

  3. No adverse reaction

  4. Myasthenia gravis

Show answer
Correct Option: C
Explanation:

Thymectomy is the process in which the thymus gland is removed. Thymus gland is located in the chest area. Thymus gland is responsible for T-cell differentiation. The gland is recommended to be removed in cases of people suffering from Myasthenia gravis. The gland is removed in childhood, which generally have no adverse effects. However, when the gland is removed in adulthood, certain immune functions get affected. T-cells differentiation may be affected leading to improper production of T-cells.

So, the correct answer is option C. 

Given are four statements(A-D) each with one or two blanks. Select the option which correctly fills up the blank in any two statements.
(A) Thymus secretes _____(i) which help in differentiation of _(ii).
(B) The adrenal medulla secretes _(i) which stimulates the breakdown of _(ii) to increase the blood glucose concentration during emergency situations.
(C) The Leydig's cells or __(i) present in the intertubular spaces in testis, produce a group of hormone called __(ii).
(D) Thyroid gland secretes ___(i) and triiodothyronine which contain ______(ii)

zoology endocrine system and chemical co-ordination thymus thymus gland pineal gland and thymus

  1. (A)-(i) melatonin, (ii) T-lymphocytes, (B)- (i) adrenaline, (ii) fat

  2. (B)- (i) catecholamine, (ii) glycogen, (C)-(i) interstitial cells, (ii) glycogen

  3. (B)-(i) catecholamine, (ii) glycogen, (D)- (i) thyroxine, (ii) iodine

  4. (D)- (i) parathyroid hormone, (ii) calcium, (A)-(i) thymosin, (ii) B- lymphocytes

Show answer
Correct Option: C
Explanation:
The adrenal medulla secretes catecholamine  which stimulates the breakdown of glycogen to increase the blood glucose concentration during emergency situations.
Thyroid gland secretes thyroxine and triiodothyronine which contain iodine.
So, the correct option is '(B)-(i) catecholamine, (ii) glycogen, (D)-(i) thyroxine, (ii) iodine'

Which of the following statements is/are INCORRECT regarding the immune system of an adult human being when compared to a child?

zoology endocrine system and chemical co-ordination thymus thymus gland pineal gland and thymus

  1. Thymus degenerates in old individuals
    resulting in a decreased production of thymosins

  2. The immune responses of old persons become weak

  3. The immunity of old person becomes weak

  4. Vaccination is mostly given in childhood as an immune response is weaker in children

Show answer
Correct Option: A,B
Explanation:

The thymus gland is a lobular structure located between the lungs behind sternum on the ventral side of the aorta. The thymus plays a major role in the development of the immune system.
 Thymosins play a major role in the differentiation of T-lymphocytes, which provide cell-mediated immunity. In addition, thymosins also promote the production of antibodies to provide humoral immunity. 
 the immune responses of old persons become weak because Thymus is degenerated in old individuals resulting in a decreased production of thymosins.
So, the correct option is 'Both A and B'.

Which of the following hormone is correctly matched with it's source and function?

zoology endocrine system and chemical co-ordination thymus thymus gland pineal gland and thymus

  1. Vasopressin - Anterior pituitary - Induces reabsorption of water in nephron

  2. Oxytocin - Anterior pituitray - Contraction in uterine muscles during birth (parturation)

  3. Thymosin - Thymus - Helps in differentiation of T - Lymphocyte

  4. Glucagon - Pancreatic $ \alpha $ cells- Induces the uptake of utilization of glucose inside cells

Show answer
Correct Option: C
Explanation:

The thymus gland, located behind the sternum and between lungs, is only active until puberty. After puberty, the thymus starts to slowly shrink and become replaced by fat. Thymosin is the hormone of the thymus, and it stimulates the differentiation of disease-fighting T cells.

So, the correct answer is 'Thymosin - Thymus - Helps in the differentiation of T - Lymphocyte'.

A person without thymus would not be able to

zoology endocrine system and chemical co-ordination thymus thymus gland pineal gland and thymus

  1. Reject a tissue transplant

  2. Receive a tissue transplant

  3. Develop an inflammatory response

  4. Produce antibodies

Show answer
Correct Option: A
Explanation:
Thymus gland is a lobular structure which is present on the dorsal side of the heart and aorta. It plays an important role in the development of immune system. It contains lymphoid tissue which is involved in the proliferation and maturation of T-lymphocytes.
Hence, a person without thymus would not be able to reject a tissue transplant because as the immune system won't be developed, there will be no autoimmune response to reject the transplant. The T-lymphocytes which can distinguish between self and non-self, will not be produced. So, the transplant won't get rejected by the body.
So, the correct answer is 'Reject a tissue transplant'.

If thymectomy is done during adult hood then what possibility is there?

zoology endocrine system and chemical co-ordination thymus thymus gland pineal gland and thymus

  1. Immunosuppresant

  2. Die immediately

  3. No advice reaction

  4. Myasthenia gravis

Show answer
Correct Option: A
Explanation:

The thymus gland plays an important role in the immune function of the body by acting as an reservoir for T cells. Thymectomy or removal of the thymus gland in new born does not show any effect. However, the removal of the thymus gland during adulthood will result in suppression of the immune system. 

So, the correct option is 'Immunosuppresant'.

Which glands helps to maintain immunity

zoology endocrine system and chemical co-ordination thymus thymus gland pineal gland and thymus

  1. Hypothalamus

  2. Adrenal

  3. Thymus

  4. Pancreas

Show answer
Correct Option: C
Explanation:

Thymosins secreted by thymus  play a major role in the differentiation of T-lymphocytes, which provide cell-mediated immunity. In addition, thymosins also promote production of antibodies to provide humoral immunity.