When we say Metabolic Respiration, we do not mean the mechanical respiration that transpires in pulmonary passage from nose and mouth to lungs. Here the metabolism process is of two types: (1) Carbon Dioxide and Oxygen Exchange between Blood and Lung's Alveolar sacks, where Pulmonary Vein's Capillaries and Pulmonary Artery's Capillaries make a passage like a two trees meeting on top of each other over branches of each other - one root and trunk is the Pulmonary Vein representation and the other root and trunk is the Pulmonary Arterial representation, and (2) Oxygen and Carbon Dioxide Exchange between blood and cells over a capillary mesh of arteries and veins all over the body.
The exchange of chemicals between blood and cell membrane happens because of osmosis which is dependent on: (1) Chemical Density Potential Difference, (2) Electric/Ion Potential Difference , (3) Pressure Potential Difference and (4) Permeability - which is a function of previous factors in a complex feedback cycle. If the cell has a lot of deposits of impurities, the cell can become less permeable.
In breathing , where Carbon Dioxide rich blood - the blue blood in veins - pumped from the Heart to Lungs via Pulmonary Artery, gives out its CO2, and the same blood now absorbs O2 in the lungs and Oxygen rich blood is returned to the Heart via Pulmonary Vein. After reaching the Heart, in the right side Atrium, the red blood is pumped to different parts of the body via Arota and its arteries. The oxygen rich blood now reaches cells and the O2 is delivered via the cell membrane along with other food nutrients necessary as fuel for the cell to metabolize and generate energy for the cells to ensure their functionality. Like all muscles tissues need this to provide motor and locomotive functions. The oxygen is carried in a compound Iron compound called Hemoglobin, which gives the red color to the blood in artery. The Vacuoles in the cell are the food and waste storage units and the Mitochondria is the energy generator for the cell.
There are two types of metabolism: (1) anabolism which provides energy by converting complex molecules into simple molecules via two pathways and (2) catabolism which consumes energy to make complex molecules for growth and regeneration of cells.
Cellular Respiration are of two types: (1) Aerobic, where Glucose with Oxygen is broken down into Water, CO2 and Energy and (2) Anaerobic, where Glucose without Oxygen is broken down into Lactic Acid, which happens when someone exercises beyond a point - due to the lack of oxygen in proportion to the energy required during an exercise.
In Anabolism, the first pathway, Glycolysis, requires no Oxygen and is referred to as Anaerobic Metabolism. In lower forms of organisms, Glycolysis is the only method for harnessing energy. The second pathway is called the Krebs cycle, also called Citric Acid Cycle, occurs inside the mitochondria. In the Kerbs cycle, Carbohydrate/Glucose, Protein/Amino-Acids and Fatty Acid/Lipids/Glycerides are broken into waste products and energy. The waste side products are Urea, Lactic Acid, Water and Carbon Dioxide, which are discharged by a cell into the blood stream. Also, when cell metabolises nutrients into Energy, Water, Salt and Urea are also discharged as sweat. This process is called Perspiration, and is also a skin cleansing and nourishing process.
The carbon-oxide rich blood - the blue blood - now is carried back to the heart via veins to the left side atrium of the heart, from where the blood is pumped to the lungs, via Pulmonary Artery. In the lungs the Pulmonary Artery blood dislodges Carbon Dioxide and Pulmonary Vein blood gathers Oxygen, thus completing a cycle of Cardiac-Pulmonary Circulation.
The blood which is still rich in other waste products, like Lactic Acid, Urea, and water is carried to Kidneys from the Heart and here the filteration happens to extract the excess water and other wastes.
Some key points to take are: (1) increased oxygen level means increased energy level - provided nutrients are available, (2) the brain is the most demanding and sensitive consumer of this energy, except when one is exercising or jogging where muscular system demands a lot of energy, and (3) breathing, respiration, and perspiration play a key part in cleansing of the body.
