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.
Excretion in flatworms. -they have an excretory system that consists of a small network of tubes throughout the body-flame cells They sweep water and excretorysubstances into tubles. These substances then exit through poresoutside ofthe body.Theykeep the flatworm from becoming waterlogged.parasitic adapted to life in intestines of host-tapeworms-scolex proglottids-when eaten by cattle, tapeworms burrow through intestinal walls and enter blood and eventually muscle 0if this affected beef is enaten rare or undercooked, human is affected-not common in developed countries. î î î.