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.
Its reddish tinge is due to the oxygen-carrying pigment hemoglobin in the blood. The earthworm's body is made up of segments. On each segment, except the first and last, are four pairs of tiny bristles called setae that help the worm move through the earth. It also has five pairs of hearts in the front of its body.The hearts help circulate the worm's blood.ts reddish tinge is due to the oxygen-carrying pigment hemoglobin in the blood. The earthworm's body is made up of segments. On each segment, except the first and last, are four pairs of tiny bristles called setae that help the worm move through the earth. It also has five pairs of hearts in the front of its body.