Biology Test 15

Angiotensinogen is an inactive precursor of angiotensin. It is a large protein synthesised by the liver, secreted into the blood stream and converted into angiotensin by renin.

Bowman's capsule, is a part of the nephron, which is the cup-shaped structure and is attached to the end of the uriniferous tubule of the vertebrate kidney and which contains the glomerulus of blood vessels.

Alkaptonuria is a gentic disease. It is a metabolic disorder, in which patient excretes large amount of hemogentistic acid in urine. Such urine turns black when exposed to air.

A sarcomere is the basic unit of a muscle's cross-striated myofibril. Sarcomeres are multi-protein complexes composed of three different filament systems.

Axis vertebra possesses a peg-like structure called the odontoid process which projects forward from the centrum. It fits into the cavity of the atlas below the ligament so that it is separated from the neural canal. Such an arrangement gives a pivot joint which allows head to shake (rotate from one side to the other).

Main movements found in unicellular organism are ciliary, flagellar and amoeboid movements. In multicellular animals also, phagocytes migrate through tissues by amoeboid movements. Ciliary movement of cells lining the upper respiratory tract, fallopian tubes and vasa efferentia of testes transport, respectively dust particles, ova and sperms in specific direction in those organs. Mammalian sperms move into the female reproductive tract by flagellar movements.

Unstriated, involuntary, visceral muscles.

Tympanic bone is a hollow, flask shaped bone. Its main swollen part called tympanic bulla.

The affinity of haemoglobin for CO is approximately 210 times greater than O₂.