CBSE Questions for Class 11 Medical Biology Chemical Coordination And Integration Quiz 13 - MCQExams.com

• The adrenal medulla secretes 2 hormones - adrenalin and noradrenalin. 
• Adrenalin is also called an emergency hormone. 
• Adrenaline brings about increased heartbeat, the rate of respiration and dilation of pupils, thereby preparing the body to face an emergency situation. 
• Adrenalin is also called as 3F hormone because it takes care of emergency functions of the body during fear, fight, and flight. 
• Hence, the adrenal gland is also known as the 3F gland. 

• Decreased blood pressure, low sodium levels are the stimuli for the production of renin from the kidney.
• The renin secreted has enzymatic activity and is an important part of the renin-angiotensin-aldosterone system (RAAS).
• The RAAS plays an important role in regulating the cardiac output and arterial pressure. It does it by regulating the ultrafiltration in the kidneys. 
• The main function of renin in the RAAS system is the conversion of angiotensinogen to angiotensin I (proteolytic activity).
• Though the mechanism is not clearly understood the renin-angiotensin system (RAS) also plays an important role in the hematopoiesis. 

Solution:

• Correct answer is option A. 

• The adrenal gland is made up of two parts- the outer portion called the cortex and the inner portion called the medulla. 
• The cortex produces cortisol which is an important hormone for controlling blood pressure. 
• While the medulla produces hormone adrenaline also called as epinephrine and these are both released in response to stress. Thus an injury to the adrenal cortex will affect cortisol secretion not an hormone adrenaline.

• Though hormones are released into the blood stream and hence can reach all cells, yet they affect only those cells which have hormone specific receptors.
• Thus, binding of hormone to receptor is crucial irrespective of presence of receptors inside the cell or on its surface. 
• This makes options A and D incorrect as absence of receptors renders the cell unaffected by hormonal action. 
• Option B is incorrect as hormone-receptor binding is essential step in hormonal action. 
• Thus, in absence of receptors, the target organ will no longer respond to hormone. Option C is correct. 

$$\textbf{Correct option:B}$$ 

$$\textbf{Solution:}$$

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

$$\bullet$$ Increased blood calcium level stimulates the increased release of calcitonin from thyroid glands which suppresses the release of calcium from bones to blood.

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

$$\bullet$$ Decreased level of calcium stimulates the release of parathormone which increases the absorption of calcium from intestine and nephrons, release of calcium from bones and inhibits the synthesis of collagen from osteoclasts which stores calcium.

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

$$\bullet$$ Increased blood sugar stimulates the release of insulin from pancreas which results in glucose conversion to glucagon, protein synthesis and reduced oxidation of fats.

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

$$\bullet$$ Decreased blood sugar stimulates the release of glucagon from alpha cells which results in glucose production,protein and fats breakdown.

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

• A- 6 -The pituitary gland is a small pea-sized gland located at the base of the brain that plays a major role in regulating vital body functions and general wellbeing. The pituitary gland is also called the “master gland” because its hormones control other parts of the endocrine system.
•  B- 5 -Adrenaline is a hormone secreted by adrenal medulla during stress. Adrenaline is called an emergency hormone because it initiates quick action which makes the individual think and responds quickly to the stress. Hence adrenaline is also called a stress hormone.
• C- 4-The testes are two oval-shaped male reproductive glands that produce sperm and the hormone testosterone. Leydig cells of the testis secrete a hormone called testosterone.
  
• D- 1 -Follicular cells of thyroid gland secrete hormones called thyroid hormones. The deficiency of these hormones results in enlargement of the thyroid gland, commonly called goiter. 
• E- 2- Diabetes is a disease in which your blood glucose, or blood sugar, levels are too high. Glucose comes from the foods you eat. Insulin is a hormone secreted by the pancreas that helps the glucose get into your cells to give them energy. With type 1 diabetes, your body does not make insulin. Hence deficiency of pancreatic secretion causes diabetes.
•  F- 3 -Ovary is the primary female sex organ that produces one ovum during each menstrual cycle. In addition, ovary also produces two groups of steroid hormones called estrogen and progesterone.
• So, the correct answer is 'A- 6, B- 5, C- 4, D- 1, E- 2, F- 3'.

• The pituitary gland controls the level of testosterone in the body. When the testosterone level is low, the pituitary gland releases a hormone called as luteinizing hormone (LH). 
• This hormone stimulates the testicles to make more testosterone.