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The Importance of Oxygen In Animals
The primary function of the respiratory system is to intake (inhalation) of oxygen and the release (exhalation) of carbon dioxide, as the reactants and waste products respectively of cellular respiration, through breathing. Cellular respiration is the process by which cells use oxygen to release energy from molecules (like glucose) in the form of ATP in their mitochondrion, creating waste products of water and carbon dioxide [the equation being C6H12O6 + 6 O2 -------> 6 CO2 + 6 H2O + Energy (ATP)]. The energy is stored as ATP, three bonded phosphate groups, which are then broken to provide energy for all life processes. While it is possible for bacteria, yeasts, some prokaryotes, red blood cells and muscle cells to perform respiration without oxygen, the process of anaerobic respiration (which utilizes a respiratory electron transport chain) releases very little energy (two ATP molecules in contrast the the aerobic 36-38 ATP molecules), results in incomplete combustion and produces lactic acid (the cause of cramps).
The primary function of the respiratory system is to intake (inhalation) of oxygen and the release (exhalation) of carbon dioxide, as the reactants and waste products respectively of cellular respiration, through breathing. Cellular respiration is the process by which cells use oxygen to release energy from molecules (like glucose) in the form of ATP in their mitochondrion, creating waste products of water and carbon dioxide [the equation being C6H12O6 + 6 O2 -------> 6 CO2 + 6 H2O + Energy (ATP)]. The energy is stored as ATP, three bonded phosphate groups, which are then broken to provide energy for all life processes. While it is possible for bacteria, yeasts, some prokaryotes, red blood cells and muscle cells to perform respiration without oxygen, the process of anaerobic respiration (which utilizes a respiratory electron transport chain) releases very little energy (two ATP molecules in contrast the the aerobic 36-38 ATP molecules), results in incomplete combustion and produces lactic acid (the cause of cramps).
For clarification on ATP and respiration, check out this video:
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Gas Exchange in Humans
Drawn into the body by contractions of the diaphragm, oxygen is inhaled through the nose or the mouth, then entering the nasal cavity. Filled with tiny cilia and mucus, the nasal cavity warms, humidifies, and filters the incoming air before it passes the epiglottis (a small flap of skin over the windpipe, which prevents food, or any substance other than air, from going down the windpipe), through the larynx (also known as the voice box, the muscle responsible for producing all sounds and forms of speech) and down the trachea (a pathway for air that is lined with mucus, as a second line of defense against any pathogens) Splitting as the tubes diverge into the bronchi (canal-like airways following the the trachea), air flows into the lungs (the muscles responsible for inflating and deflating for the inhalation and exhalation of oxygen), into the bronchioles (subdivisions of the bronchi, which are subdivisions of the trachea)) and to the alveoli (the small air sacs, with a likeness to broccoli, where gas exchange occurs as oxygen and carbon dioxide diffuse in and out of the bloodstream to be delivered or removed from the body ).
For a more in depth explanation, check out this video:
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Gas Exchange in the Morning Sun Star
The respiratory systems of starfish like the Morning Sun Star are extremely primitive, differing greatly from that of humans. Lacking lungs and diaphragms, these starfish employ dorsal skin, ventral tube feet, and protruding ridges of the endoskeleton (papillae) to take in oxygen and release carbon dioxide. [1] Like the villi located in the stomachs of humans, these papillae are thin, finger-like projections used to increase surface area. Unlike the villi located in the stomachs of humans, these papillae are used for the interchanging of gases between starfish and the surrounding sea water, and a faster rate of diffusion. [2] Diffusion is the natural, passive movement of molecules with the concentration gradient, from areas of high concentration to areas of low concentration, without requiring chemical energy. Like the diffusion that occurs in the alveoli of humans, the diffusion of gases in starfish allows oxygen and carbon dioxide to pass through walls of cells. Unlike the diffusions that occurs in the alveoli of humans, the diffusion of gases in starfish allows oxygen and carbon dioxide to enter the body, rather than the bloodstream.
The circulatory, water vascular systems of starfish aid in the gas exchange, transporting the reactants and wastes throughout the body and along the rays.
The digestive system, of course, is aided.