Causes of Chest Pain or Discomfort. We can divide the causes of chest pain into two major categories: those caused by cardiac issues, and those caused by other, non-cardiac issues. Causes of cardiac chest discomfort (pain) Canadian Cardiovascular Society Classification of Angina Class I â Angina occurs only with strenuous exercise. Class III â Angina occurs with mild activity such as climbing 1 fight of stairs or walking level for 1 to 2 blocks. Class IV â Angina occurs with any physical activity and may be present at rest. See also: Types of Angina. Other Cardiac Causes of Chest Pain or Discomfort Acute Pericarditis.
NEPHRIDIA:- In earthworm excretion occurs through nephridium. The excretory system in earth worm is closely associated with its closed circulatory system. Each segment of ea â¦ rthworm consists of a pair of nephridia or in some species cluster of nephridium.he excretory system in earth worm is closely associated with its closed circulatory system. Each segment of ea â¦ rthworm consists of a pair of nephridia or in some species cluster of nephridium.
The earthworm takes in a mixture of soil and organic matter through its mouth, which is the beginning of the digestive tract. The mixture enters the pharynx, which is located in segments 1 6. The esophagus, in segments 6 13, acts as a passageway between the pharynx and the crop. The crop stores food temporarily. The mixture that the earthworm ingests is ground up in the gizzard. In the intestine, which extends over two-thirds of the body length, digestion and absorption take place. Soil particles and undigested organic matter pass out of the worm through the rectum and anus.