CBSE Questions for Class 11 Medical Biology Chemical Coordination And Integration Quiz 11 - MCQExams.com

• Testis an organ that produces a hormone called testosterone plays an important role in the development of male reproductive tissues.
• The Adrenal is a gland, produces different types of hormones adrenaline during emergency conditions, for fight or flight actions by the body. So it is called the emergency gland of the body.
• The thymus is a gland, produces a hormone, thymosin, which stimulates the development of disease-fighting T cells.
• The pituitary is a gland, produces many hormones in the body, controls different glands like the thyroid, adrenal, ovaries, and testicles. Thus, it is called master gland of the body.

A.Cholecystokinin is a hormone which is secreted by cells in the duodenum and stimulates the release of bile into the intestine and the secretion of enzymes by the pancreas.
B.Erythropoietin is a hormone produced primarily by the kidneys. 
C.Secretin,a hormone released into the bloodstream by the duodenum.
So,the correct option is 'Epinephrine'.

$$\textbf{Correct option:A and B}$$ 

$$\textbf{Solution:}$$

$$\bullet$$ Thymus gland is an endodermal gland which is a primary lymphatic organ that is involved in the maturation of  lymphocytes to antigen specific lymphocytes. It is located in the mediastinum between the sternum and aorta.

$$\bullet$$ Thymus secretes a hormone called thymosin which promotes development of white blood cells T- lymphocyte that is associated with cell mediated immunity. It also delays attainment of sexual maturity. The size of thymus gradually decreases in size as a person ages and so is the immunity also decrease and the person becomes more prone to diseases.    

$$\textbf{Hence, the correct option is (A) and(B)}$$

• In humans, four parathyroid glands are present on the back side of the thyroid gland, one pair each in the two lobes of the thyroid gland.
• The parathyroid glands secrete a peptide hormone called parathyroid hormone (PTH) or parathormone.
• Parathormone increases the $$Ca^{2+}$$ levels in the blood.
  
• Increase in bleeding time and delay in blood coagulation is due to the deficiency of parathormone because its deficiency causes a decrease in blood calcium levels and calcium ion is essential for blood coagulation.
  
• So, the correct answer is 'Parathormone'.

• Melatonin is a hormone that regulates sleep-wake cycles. It is primarily released by the pineal gland. 
• As a supplement, it is often used for the short-term treatment of trouble sleeping such as from jet lag or shift work. 
• Melatonin is a hormone which is a protein made up of amino acids. 
• Hence, Melatonin is a modified Amino acid. 
• So, the correct answer is 'amino acid'.

$$\textbf{Correct option:B}$$ 

$$\textbf{Solution:}$$

$$\textbf{Option (A)}$$

$$\bullet$$ Cytoplasmic receptor are present on the surface of the plasma membrane of target cells, the substrate binds to these receptor and conformational change of these receptors brings about further changes inside the cell.

$$\textbf{Option (B)}$$

$$\bullet$$ Cyclic AMP  acts as a second messenger for steroid hormone as it can not pass through the plasma membrane such as epinephrine and norepinephrine, glucagon, luteinizing hormone, follicle stimulating hormone, thyroid-stimulating hormone, calcitonin, parathyroid hormone, antidiuretic hormone.

$$\textbf{Option (C)}$$

$$\bullet$$ Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells such as muscle contraction, nerve impulse propagation and other body functions.

$$\textbf{Option (D)}$$

$$\bullet$$ Epinephrine is secreted from the adrenal medulla in response to stress and emergency , as a hormone  it increases metabolic rate by accelerating heart rate ,constricting blood vessels ,increasing blood pressure and oxygen consumption. As a neurotransmitter when it transmits impulses at the synapse between axons and dendrites of two neurons.

$$\textbf{Hence, the correct option is (B)}$$

• Renin-angiotensin-aldosterone system secretes mineralcorticoids. These are the steroid hormones. They regulate the water and electrolyte balance in the body. The main mineralocorticoid present in our body is aldosterone.
• Whenever $$K^+$$ concentration rises or $$Na^+$$ concentration falls, the aldosterone is released. It stimulates the renal tubules to absorb $$Na^+$$ and water and excrete $$K^+$$ and phosphate ions from the body. 
• The aldosterone causes the active uptake of $$Na^+$$ ions from the nephric filtrate by acting over distal convoluted tubules and collecting tubules. As the sodium concentration in blood restores due to the action of aldosterone, the water also follows it by osmosis, so blood volume is restored. Thus, aldosterone maintains the electrolyte balance, body fluid volume, osmotic pressure, and blood pressure of the body.