closed contract

1) The speed of circulation is more rapid due to the presence of muscular and contractile blood vessels. 2) The supply and removal of materials to and from the tissues by the blood is enhanced, thereby increasing the efficiency of circulation. 3) The volume of blood flowing through a tissue or orga..

Question: What are the 'lub' and 'dub' sounds produced by the heart? Answer: These are the sounds of the heartbeat and they are produced when the valves close during the contraction or relaxation of the heart. At the start of the ventricular contraction or s..

In the first stage, the auricles or the atria contract with enough pressure to squeeze out all the blood from their cavities into the corresponding ventricles. During this time, the openings from the vena cavae in the right auricle and opening of the pulmonary vein in the left auricles r..

The human circulatory system is a closed circulatory system. The blood flows in closed vessels without coming in direct contact with the cells of the body. The walls of the blood vessels are made up of three layers: Inner endothelium - single layer of cells Tunica media - made o..

The human circulatory system is a closed circulatory system. The blood flows in closed vessels without coming in direct contact with the cells of the body. The walls of the blood vessels are made up of three layers: Inner endothelium - single layer of cells Tunica media - m..

The number of times the heart beats per minute is called heart rate. For a normal adult human it is about 72 times per minute. For infants, it is a higher figure. It also goes up during physical exercise. The contractions and relaxations that the heart chambers undergo are felt all along ..

The male reproductive system comprises of a pair of testes that are present in a thin-walled sac called the scrotum . The scrotum is contained within the abdominal cavity in the embryonic stage. Shortly before birth, they come down and remain outside throughout life. This is because the testes ..

Adrenal Medulla is an internal soft dark reddish brown tissue, which helps the body to combat against stress or emergency situations. Its main function is to augment that of the sympathetic nervous system. It is not vital for survival and may be removed without causing death. It secretes two simil..

Question: Describe inspiration and expiration in fish. Answer: Water moves through the gills by the coordinated action of mouth and the operculum. Taking in water and thereby oxygen is called inspiration and exit of water is called expiration. Inspiration When the mouth is open, the ..

Property Eye Camera Type of lens Convex lens Convex lens Nature of the image Real, inverted and diminished Real, inverted and diminished Light control mechanism The pupil contracts and dilates according to the intensity of light Adjustments of aperture ..