Tag: thymus gland

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Questions Related to thymus gland

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

Mammals born without a thymus gland fail to manufacture 

  1. B - Lymphocytes

  2. T - Lymphocytes

  3. Plasma cells

  4. Basophils
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Removal of the thymus gland in the adult has little effect, but when the thymus is removed in the newborn, T cells in the blood and lymphoid tissue are depleted and failure of the immune system causes a gradual, fatal wasting disease. 

The animal whose thymus has been removed at birth is less able to reject foreign tissue grafts or to make antibodies to certain antigens. Moreover, certain parts of the white pulp of the spleen and lymph nodes are much reduced in size. Hence, the T cells produced in the thymus and transported to the lymphoid tissues are crucial elements in the development of immunity.

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

Damage to thymus in a child may lead to

  1. Loss of cell mediated immunity

  2. A reduction in the haemoglobin content in blood

  3. A reduction in the amount of plasma proteins

  4. Loss of antibody mediated immunity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The thymus gland is an organ in the upper chest cavity, that processes lymphocytes, a type of white blood cell, that fights infections in the body. 

The thymus is most important in children and young adults, when it programs lymphocytes to attack antigens, like viruses. 
People who do not have this gland, or in whom it does not function correctly, usually have compromised immune systems and difficulty fighting disease.

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

Which gland decreases in size with increasing age?

  1. Thyroid

  2. Adrenal

  3. Thymus

  4. Pituitary
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The thymus is a specialized organ of the immune system. Within the thymus, T cells or T lymphocytes mature. At birth, it is about 5 cm in length, 4 cm in breadth, and about 6 mm in thickness. The organ enlarges during childhood and atrophies at puberty. The thymus is at its largest in children. The thymus reaches maximum weight (20 to 37 grams) by the time of puberty. As one ages, the thymus slowly shrinks, eventually degenerating into tiny islands of fatty tissue. By the age of 75 years, the thymus weighs only 6 grams.

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

Hassall's corpuscles are found in 

  1. Pineal body

  2. Thymus gland

  3. Thyroid gland

  4. Adrenal gland
Reveal answer Fill a bubble to check yourself
B Correct answer
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. 

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

Thymus gland develops from embryonic 

  1. Mesoderm

  2. Endoderm

  3. Ectoderm

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

Which endocrine gland is not an ectodermal origin?

  1. Pineal body

  2. Anterior pituitary

  3. Adrenal medulla

  4. Thymus
Reveal answer Fill a bubble to check yourself
D Correct answer
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. 

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

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

  1. Immunosuppressant

  2. Die immediately

  3. No adverse reaction

  4. Myasthenia gravis
Reveal answer Fill a bubble to check yourself
C Correct answer
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. 

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

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)

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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'
Multiple choice zoology endocrine system and chemical co-ordination thymus thymus gland pineal gland and thymus

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

  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
Reveal answer Fill a bubble to check yourself
A,B Correct answer
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'.