Animals: Respiration

Respiration is a chemical process that takes place in all living cells. It produces energy needed by animals for essential biological processes including movement, growth, repair, and maintaining body temperature.
There are two types of respiration in animals: aerobic respiration which requires oxygen and anaerobic respiration which does not require oxygen.
In aerobic respiration, glucose (from our food) and oxygen are used to create energy, carbon dioxide, and water. The chemical equation for this process is: glucose + oxygen -> carbon dioxide + water + energy.
Anaerobic respiration, often referred to as fermentation, occurs when the animal’s body cannot get or does not have enough oxygen. In this process, glucose is broken down to produce energy and a byproduct, which in humans is lactic acid. This is less efficient than aerobic respiration and is usually temporary.
Respiration happens in the mitochondria of cells, which are often referred to as the ‘powerhouses’ of the cell as they produce the energy the cell needs to function.
The rate of respiration can vary depending on factors including temperature, activity level, and the animal’s size. Respiration rate usually increases with higher temperatures, during exercise, and in larger animals.
In humans, the respiratory system involves several major organs, including the nose, mouth, throat (pharynx and larynx), windpipe (trachea), and lungs.
These parts of the respiratory system work together to inhale oxygen and exhale carbon dioxide. This is called gas exchange.
The inhaled oxygen is transported to the cells via the bloodstream where it is used in aerobic respiration. The carbon dioxide produced during respiration is a waste product and is removed from the body when we exhale.
Diseases of the respiratory system, such as asthma, can interfere with gas exchange and therefore with the process of respiration.
During intense exercise, when oxygen supply to the muscles isn’t enough, muscle cells may switch to anaerobic respiration. This can lead to a build-up of lactic acid, which may cause discomfort and fatigue.
This condition is resolved during the recovery period post-exercise, where oxygen is used to break down the accumulated lactic acid, a process often referred to as ‘oxygen debt’.