Tag: control and coordination in living organisms

Questions Related to control and coordination in living organisms

The secretion of aldosterone by adrenal cortex is directly controlled by

zoology control and coordination in living organisms adrenal gland thymus and adrenal gland adrenal glands

  1. Plasma $K^{+}$ concentration

  2. Plasma Ca concentration

  3. Level of blood angiotensin

  4. Both A and C

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Correct Option: A

Which gland does not originate from embryonic endoderm?

zoology control and coordination in living organisms adrenal gland thymus and adrenal gland adrenal glands

  1. Thymus

  2. Parathyroid

  3. Adrenal cortex

  4. Thyroid

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Correct Option: C
Explanation:

The endoderm gives rise to the epithelium 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. The adrenal glands develop from two separate embryological tissues; the neural crest ectoderm and the intermediate mesoderm.

Adrenal cortex also controls the carbohydrate metabolism through

zoology control and coordination in living organisms adrenal gland thymus and adrenal gland adrenal glands

  1. Adrenaline

  2. Noradrenaline

  3. Glucocorticoids

  4. Mineralocorticoids

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Correct Option: C
Explanation:

The adrenal cortex is located on the outer layer of the adrenal gland and makes different hormones, that help control the heart, kidneys, GI tract, bones, genitalia and immune system. 

These hormones control carbohydrate metabolism, muscular integrity, haemodynamic changes and sexual maturity. The cortex makes glucocorticoids, which are hormones, that control glucose production in the liver and protein breakdown in muscle. 

Retention of sodium in body depends upon hormone from

zoology control and coordination in living organisms adrenal gland thymus and adrenal gland adrenal glands

  1. Adrenal cortex

  2. Adrenal medulla

  3. Parathyroid

  4. Thyroid

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Correct Option: A
Explanation:

Aldosterone is a steroid hormone (mineralocorticoid) produced by the outer section (zona glomerulosa) of the adrenal cortex in the adrenal gland. Aldosterone promotes sodium ($Na^+$) and water retention and lowers plasma potassium ($K^+$) concentration.

Conn's disease is due to 

zoology control and coordination in living organisms adrenal gland thymus and adrenal gland adrenal glands

  1. Hyposecretion of aldosterone

  2. Hypersecretion of aldosterone

  3. Hyposecretion of STH

  4. None of the above

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Correct Option: B
Explanation:

Conn's syndrome is a condition associated with the development of high blood pressure and low potassium levels in the blood. In the majority of patients a small tumour is found in the adrenal cortex. Excess production of aldosterone by the tumour leads to the development of Conn's syndrome with high blood pressure and low potassium levels. In a small group of patients abnormal function of the adrenal cortex from a condition called as adrenal hyperplasia, may give rise to the Conn's syndrome.

A steroid hormone which regulates glucose metabolism is 

zoology control and coordination in living organisms adrenal gland thymus and adrenal gland adrenal glands

  1. 11-deoxycorticosterone

  2. Cortisone

  3. Cortisol

  4. Corticosterone

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Correct Option: C
Explanation:

Cortisol or glucocorticoid hormone is a steroid hormone produced by the adrenal cortex. It is released in response to stress and a low level of blood glucose. Its functions are to increase blood sugar through gluconeogenesis and to aid the metabolism of fat, protein, and carbohydrate. 

Reabsorption of Na$^+$ is controlled by which one of the following hormones ?

zoology control and coordination in living organisms adrenal gland thymus and adrenal gland adrenal glands

  1. Aldosterone

  2. Oestrogen

  3. Glucocorticoids

  4. Testosterone

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Correct Option: A
Explanation:

Renal reabsorption of sodium ($Na^+$) uses Na-H antiport, sodium-glucose symport, sodium ion channels (minor). It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide.

Mammals born without a thymus gland fail to manufacture 

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

  1. B - Lymphocytes

  2. T - Lymphocytes

  3. Plasma cells

  4. Basophils

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Correct Option: B
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.

T-cells mature in the

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

  1. Peyer's patch

  2. Lymph node

  3. Thymus

  4. Bursa of fabricius

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Correct Option: C
Explanation:

T cells or T lymphocytes are a type of lymphocyte, that plays a central role in cell-mediated immunity. They are called as T-cells because they mature in the thymus gland.

Damage to thymus in a child may lead to

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

  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

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Correct Option: A
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.