Types Of Respiration, Meaning And Importance

Hi, welcome to this hall on the topic: The meaning and types of respiration in mammals.

Table Of Contents

1. Definition of respiration
2. Types of respiration
3. Conditions necessary for respiration
4. Characteristics of respiratory surface
5. Importance of energy to living organisms

Definition Of Respiration

Respiration is defined as a process in living organisms cells involving enzymecatalysed chemical reactions in which food substances or glucose are broken down within cells to release energy, in the presence or absence of oxygen. In other words, respiration is a biochemical activity of the cell in which glucose is broken down by series of reactions controlled by enzymes to release energy. In mammals, oxygen is breathe in and it breaks down the food substances (glucose) to release energy, carbon dioxide and water. Carbon dioxide and water are regarded as waste products of respiration. The energy released is used by living organisms for various life processes.

Read Also

• Excretion in mammals
• Respiratory Systems In Plants and mechanisms
• Meaning of cell, history and theory

Importance Of Energy To Living Organisms

1. Energy is required for transportation of materials within the body.
2. It is needed by animals for movement.
3. It is required for the maintenance of body temperature with heat energy.
4. It is required for the synthesis of substance such as protoplasm and other body materials needed for growth and repair of the body.
5. Energy is required for reproduction.
6. It is important in excretion in living organisms.
7. Energy is required in the transmission of nerve impulses and co-ordination.
8. It helps to produce sound e.g. speaking in human.
9. It helps to produce electrical shocks for offense or defense as in catfish.
10. Energy is required by all organism during reproduction.

Types Of Respiration

There are two major types of respiration. These are:

1. Aerobic respiration
2. Anaerobic respiration

Aerobic respiration: Aerobic respiration is a types of respiration which requires oxygen to break down glucose (substrates) into water, carbon dioxide and energy (ATP).

Anaerobic respiration: Anaerobic respiration is the type of respiration which does not require the presence of oxygen to provide energy. During anaerobic respiration, glucose is broken down to yield carbon dioxide, alcohol (ethanol) and energy.

Phases or Stages Of Respiration

Respiration takes place in two phases or stages. This are external and internal (tissue) respiration.

1. External respiration (breathing): External respiration or breathing is defined as the exchange of gases between the environment and the respiratory organs of living organisms. In other words, external respiration simply involves the breathing of air or oxygen into the respiratory organs such as lungs or gills otherwise called inspiration or inhalation and the breathing out of carbon dioxide and water vapour into the atmosphere otherwise called expiration or exhalation.

2. Internal (tissue) respiration: Internal or tissue respiration is defined as the oxidation of organic food substances within the cells leading to the release of energy, carbon dioxide and water. In other words, tissue respiration takes place when the oxygen taken in is used up by the individual cells in the body for the oxidation of food substances. Carbon dioxide, water and energy are giving out by this cells in return.

In summary, the main purpose of respiration in so generate energy required by the body for various life processes.

Conditions Necessary For Respiration

For efficient respiration (gaseous exchange) to take place, the following conditions must prevailed or be available:

1. Respiratory medium: Respiratory medium refers to the surroundings of the organism from which it obtains oxygen. Examples of respiratory medium are air and water.

2. Respiratory organ: This is the organ such as lungs in mammals and gills in fish through which oxygen is taken in to the body and carbon dioxide and water vapour are giving out. The taking in of one gas, e.g oxygen and the giving out of another, e.g. carbon dioxide and water vapour is called gaseous exchange.

3. Transport medium: This is a system which moves the dissolved gases, e.g. oxygen around the body to all the cells and collect the gases, e.g. carbon dioxide which needs to be eliminated from the body. Examples of transport medium in mammals is the blood.

4. Ventilation: The movement of water or air in One direction over the respiratory surface is called ventilation. This helps to renew the air or water in contact with or near a respiratory surface. Ventilation mechanism as in human breathing, increases the rate of gaseous exchange.

5. Respiratory surface: The respiratory surface refers to the definite surface of the body such as the surface of the lungs or a gills where gaseous exchange takes place.

Characteristics Of Respiratory Surface

Respiratory surfaces, be it in plant or animals, must have the following characteristics:

• Respiratory surface must be moist because gases diffuse in solution through them.
• It must be permeable to allow gases to pass in and out of them.
• It must be thin-walled to shorten diffusion distance and make diffusion easier and faster.
• It must have adequate supply of transport medium, e.g. blood.
• It must have a large surface area to aid easy diffusion of gases.
• Respiratory areas must be highly vascularized, i.e,. equipped with capillaries or similar network to bring in or take away diffused gases.

Types Of Respiratory Systems

Respiratory system includes all the structures and organs of living organisms associated with the process of taking oxygen into the body and giving out carbon dioxide and water vapour into the environment. Organisms adopt different types of respiratory system depending on their types, complexity, size and the habitat in which they are found.

Different Organisms and their Respiratory Systems

Organisms – Respiratory system/organs

1. Unicellular organisms, e.g. Amoeba and paramecium – Body surface.

2. Hydra and tapeworm – Cell membrane.

3. Earthworm – Wet skin or body surface.

4. Fishes, e.g. tilapia – Gills

5. Arthropod, e.g. insects – Tracheal system.

6. Arachnids, e.g. spiders – Lung books.

7. Tadpole – Gills

8. Reptile, e.g. lizard – Lungs.

9. Amphibians, e.g. toads and frogs – Mouth, skin and lungs.

10. Aves, e.g. birds – Lungs.

11. Mammals – Lungs.

12. Flowering plants – Stomata and lenticels

Revision Questions

1. (a) What is respiration? (b) Name two types of respiration (c) briefly describe (i) expiration (ii) internal respiration.
2. (a) state five conditions necessary for respiration to take place (b) state five characteristics of respiratory surfaces.
3. Name the respiratory systems or organs used by the following organisms for gaseous exchange. (a) amoeba (b) earthworm (c) fish (d) spider (e) tapeworm.
4. State two differences between aerobic and anaerobic respiration.