Practice MCQ Questions and answers on Biology-GK

Polycythemia is a condition that results in an increased level of circulating red blood cells in the bloodstream.

Platelets, also known as thrombocytes, are blood cells. They form in your bone marrow, a sponge-like tissue in your bones. Platelets play a major role in blood clotting.

Antibodies are produced by plasma cells.

Oxygenated blood is carried from the lungs to the left auricle by the pulmonary veins.

Monocyte is the largest cells in white blood corpuscles.

The inner layer of the heart wall is the endocardium, composed of endothelial cells that provide a smooth, elastic, non-adherent surface for blood collection and pumping.

Insulin is a peptide hormone made in the beta cells of the pancreas that is central to regulating carbohydrate metabolism in the body. After a meal, insulin is secreted into the bloodstream.

Thyroxin is secreted by thyroid gland (the largest gland), situated in neck region. Thyroxine regulates the metabolic rate, thus, called as pacesetter of the body. If there's more of thyroxine present in the blood, processes take place at a faster rate, energy is utilized at a faster rate, and if the amount of thyroxine secreted is less than required, the processes of the body take place at a slower pace, lesser energy utilization. Thus, functioning of thyroid gland has major effect on all the organs of our body.

The rate of heartbeat is accelerated by the hormone. The hormone adrenaline also called epinephrine is known as a stress hormone. In emotional upsets( like fear, anger etc.) this hormone is poured into the blood and it accelerates heart beat.

Cortisol is released from the adrenal cortex and allows the body to continue to stay on high alert.