Endocrine and Metabolic Disorders

The parathyroid glands secrete a peptide hormone called parathyroid hormone or parathormone (PTH). The release of parathromone is regulated by the circulating levels of calcium ($Ca^{2+}$) ions in the blood. PTH plays an important role in calcium balance of the body. It maintains the calcium balance between the blood and other tissues. When the calcium level in the blood decreases, parathyroid hormone is released in order to increase the calcium level in the blood. PTH acts on bones and other skeletal structure and mobilizes the calcium ($Ca^{2+}$) from the bones into the blood. This is called bone resorption/dissolution/demineralization. The parathromone also increases the reabsorption of calcium by the renal tubules and absorption of calcium from the digested food. Hence, parathormone induces increase in serum calcium.

Parathyroid glands located behind the thyroid gland, produce a hormone called parathormone. This hormone maintains calcium and phosphorus balance in the body. Thus, if a person is having problem with calcium and phosphorus metabolism in the body, this means, his parathyroid glands are not functioning properly.

Homeostasis is the process wherein normal body variables are actively regulated inside a defined environment to remain very near to constant. The regulation of  concentration of sodium ($Na^+$) and Calcium ($Ca^{++}$) ions in the blood as well as  glucose levels in blood plasma are examples of Homeostasis.
In the human body, the concentration of blood sugar levels is regulated by the  beta cells of the pancreatic islets by secreting insulin into the blood and inhibits the secretion of glucagon into the blood. The table given in the question shows the effect of a substance on the normal body variables after an intravenous injection of the same. According to the given data,  the  injection of substance A tends to decrease the concentration of Serum glucose below the baseline value. Hence, the substance that was injected is identified as insulin.

Calcitonin is a polypeptide hormone secreted by the parafollicular cells (C-cells) of the thyroid gland in mammals. The concentration of calcium ion in extracellular fluids is the principal stimulus for the secretion of calcitonin by C-cells. Calcitonin acts as an emergency hormone to protect against the development of hypercalcemia. 

Calcitonin hormone stimulates temporary reduction in number and activity of osteoclasts and thereby reducing the blood calcium level to normal. Oxytocin facilitates uterine contractions to push the foetus downward which in turn stretches cervix more during childbirth. Oversecretion of thyroid hormones causes Graves’s disease. ADH stimulates absorption of water by collecting ducts resulting in production of concentrated urine and lower down the urine volume. Option B is correct answer.

Insulin is a peptide hormone produced by beta cells of the pancreatic islets; it is considered to be the main anabolic hormone of the body. Diabetes is a condition caused by little or no secretion of insulin hormone. If too much insulin is present in the body,a person can go into shock, a condition called insulin shock. Parathyroid hormone is secreted by the parathyroid glands and is the most important regulator of blood calcium levels. Tetany is a condition marked by intermittent muscular spasms, caused by malfunction of the parathyroid glands and a consequent deficiency of calcium. Osteoporosis is a medical condition in which the bones become brittle and fragile from loss of tissue, typically as a result of hormonal changes, or deficiency of calcium or vitamin D. It is a type of hyperthyroidism, meaning hypersecretion of parathormone(parathyroid) hormone.

Lathyrism is a disease caused by eating seeds of species of Lathyrus (the grass pea), mainly L. sativus (the chickpea or khesari), L. cicera (flat-podded vetch) and L. clymenum (Spanish vetchling). It affects mostly people in Bangladesh, India, Pakistan, Nepal and Algeria but is sometimes found in France, Italy, Spain and Australia. This disease affects horses and cattle as well as in man.
Beta-Oxalyl-amino-L-alanine acid (BOAA), an excitatory neurotoxin and glutamate agonist, has been identified as the constituent of the chick pea responsible for the disease. BOAA appears to exert its effects through mitochondrial toxicity.
Prolonged use of seeds of Lathyrus sativus causes a debilitating disorder is not due to presence of glucodsinolates, amygdalin and cyanogenic glucosides. 
Therefore, the correct answer is option C.

Myxoedema occurs due to deficiency of thyroxine is adults. It is characterised by low BMR, low body temperature, reduced heart rate, pulse rate, cardiac output Face and hands become swollen.