Tag: biology

Homologous organs are the organ which has the same origin but performs different functions. Wings of honey bee and crow are the analogous as they perform the same function. Where thorn of Bougainvillea and tendrils of Cucurbita are the homologous organs. Nictitating membrane is the vestigial organ of the human eye but not the blind spot. Whereas nephridia is the excretory organ of earthworm and malpighian tubule of the cockroach. Thus, the correct answer is option C.

• The diaphragm is the type of skeletal muscle found in mammals which plays a major role in respiration. It is a dome-shaped structure and moves in and out at the time of respiration. Its muscles separate the thoracic cavity having heart and lungs from the abdominal cavity. 
• During inhalation, the diaphragm contracts and chest cavity increases to get more oxygen while in exhalation diaphragm relaxes and the chest cavity decreases and releases carbon dioxide.

The ribs and the various muscles of respiration aid in both inspiration and expiration, which require changes in the pressure within the thoracic cavity. The important respiratory muscles are the diaphragm, the external intercostal and the internal intercostal muscles. The ribs and the respiratory muscles work to achieve this by changing the dimensions of the thoracic cavity.
When a person inhales, the rib cage move out and up in order to accommodate the incoming air. On the other hand, when a person exhales, the rib cage move in, in order to expel the carbon dioxide. Both the external intercostal muscles and the internal intercostal muscles elevate the ribs, thus increasing the width of the thoracic cavity, while the diaphragm contracts to increase the vertical dimensions of the thoracic cavity, and also aids in the elevation of the lower ribs. The muscles that connect the ribs together ensure that the diaphragm can expand and contract appropriately as air is breathed in and expelled. Thus, in mammals, breathing depends more on ribs and their muscles for breathing than diaphragm.

• Spiracles are openings on the surface of some animals, which usually lead to respiratory systems. 
• The spiracle is a small hole behind each eye that opens to the mouth. Insects and some more derived spiders have spiracles on their exoskeletons to allow air to enter the trachea.
•  In the respiratory system of insects, the tracheal tubes primarily deliver oxygen directly into the animals' tissues. 
• The spiracles can be opened and closed in an efficient manner to reduce water loss. Hence, The respiratory organs in cockroach are spiracles.

Diaphragm is a muscular and tendinous sheath that closes the opening between thorax and abdomen and is pierced by structures that pass between these two regions of the body. The diaphragm is the primary muscle of respiration. Diaphragm is the primary respiratory muscle of the body. It, on contraction, increases the vertical diameter of the chest cavity by pulling its central tendon downwards. In this way, the lungs get extra space to expand and air rushes into them.