Any living organism has the attributes of living: food, breathing, reproduction, growth and development, excretion, movement.
I became interested in the topic of animal breathing: how their respiratory system works, which organs are part of it, what types of breathing exist in the world of living organisms.
The purpose of research – to expand my knowledge about breathing of representatives of the kingdom of Animals.
– To study various types of breathing of animals.
– 2.To find out peculiarities and significance of breathing in animals of different groups.
– 3.To get acquainted with the structure of respiratory system.
Definition of the term “breathing”.
Breathing – a set of physiological processes occurring in the body, during which the flow of oxygen and removal of carbon dioxide, as well as the use of oxygen by cells and tissues to oxidize organic matter to release the energy needed for their life.
Most organisms (aerobes) use oxygen from the air to breathe. A minority (anaerobes) get the oxygen they need to live by breaking down organic compounds containing oxygen, i.e. by fermentation.
Anaerobes are organisms capable of living in an oxygen-free environment (bacteria, ciliated infusoria, some worms and molluscs); aerobes are organisms capable of living only in an environment containing free molecular oxygen (almost all animals and plants).
2. Types of respiration
According to the way of breathing and the structure of the respiratory apparatus of the animals are distinguished 4 types of breathing: cellular, gill, tracheal and pulmonary.
Organisms – unicellular animals (amoebae, green euglena, slipper infusoria); coelenterates (jellyfish, coral polyps); some worms.
Process – single-celled organisms absorb oxygen dissolved in water with their entire body surface. The carbon dioxide produced by breathing is also released to the outside through the entire body surface.
Organisms – Many aquatic animals (fish, crayfish, mollusks)
Process – Fish breathe oxygen dissolved in water by means of special branched skin outgrowths called gills. Oxygen flows from the water that washes over the gills into the blood, and carbon dioxide is removed from the blood into the water.
A distinction is made between internal and external gills.
Organisms – Class Insects (beetles, butterflies, grasshoppers, flies)
Process – Each insect body segment has a pair of respiratory openings from which branching tracheal tubes branch inward. These tracheas carry oxygen-rich air into the cells of the insect’s body.
Organisms – Amphibians (salamanders, frogs)
Process – Amphibian lungs are poorly developed, so additional gas exchange occurs through wet skin. The thin skin of amphibians has many glands which secrete mucus. Thanks to the mucus, a liquid film is created on the skin surface in which atmospheric oxygen dissolves and, thus, breathing through the skin is possible.
Organisms – terrestrial vertebrates (amphibians, reptiles, birds, animals, humans)
Process – The lungs are cellular sacks. Each lung (left and right) has highly branched bronchi which end in numerous pulmonary vesicles. Each pulmonary vesicle is braided by a network of blood vessels. From pulmonary vesicle air oxygen passes into blood and carbon dioxide from blood into air.
3. Peculiarities of breathing of animals of different groups
Breathing is a set of processes ensuring consumption of oxygen and release of carbon dioxide in the body.
A distinction is made between internal and external breathing.
External respiration provides the exchange of gases between the body and the environment, and internal respiration – oxygen intake and release of carbon dioxide in the tissues and cells of the body.
In small organisms, whose body thickness is less than 1 mm, respiration is carried out by the entire body surface through direct difusional exchange. In larger animals gases must be transported inside the body either directly (tracheal system of insects) or with the help of special transport means (blood, hemolymph) after penetration through external exchange membranes (respiratory epithelium).
A number of sufficiently large animals have no special respiratory organs. They exchange gases through wet skin equipped with a large number of blood vessels (earthworm). Some animals with special respiratory organs have skin respiration as an additional one. For example, in eels that have gills, 60% of the oxygen demand is provided by skin respiration, in frogs that have lungs, 50% of the oxygen comes through the skin, as well as in aquatic snails.
Specialized respiratory organs in the aquatic environment are the gills; in the land-air environment, the trachea and lungs.
Gills are the thinnest breathing surfaces turned outward and pierced with a large number of blood vessels; that is, gills are bulges. They most efficiently extract oxygen from the water in fish. It is based on the countercurrent phenomenon: blood in the capillaries of the gill lobes flows in the opposite direction to the flow of water that bathes the gills.
The tracheae are air-filled, thin-walled, branching, tubular inserts inside the body. They have inside the RI iial ribs and are almost incompressible. They communicate with the environment through openings – spiracles. Branches of trachea (in insects) braid all internal organs, penetrate inside some species of leeks, and provide gas exchange of tissues.
Principle difference of tracheal breathing from lung and gill breathing is that while tracheal breathing doesn’t involve blood, gill and lung breathing must transport oxygen and carbon dioxide by blood.
Lungs. Their respiratory surfaces are immersed in the recesses of the body, so they are protected from drying out. There are two types of lungs: diffuse and ventilated.
In the diffuse lungs, gas exchange is carried out only by diffusion. (Diffusion – a phenomenon in which there is a mutual penetration of molecules of one substance between the molecules of another). Such lungs have relatively small animals: lung mollusks, scorpions, spiders.
Only terrestrial vertebrates with large body sizes and intense metabolism have ventilating lungs.
The complication of the lung structure occurs from amphibians to mammals. This is due to the fact that the area of respiratory surfaces increases. Simultaneously with the increase of respiratory surface area, the mechanism of lung ventilation is perfected: starting from reptiles it is carried out at the expense of changes of the thorax volume, and in mammals – also with participation of the diaphragm. (The diaphragm is the chest-abdominal septum, which divides the internal part of the body into the thoracic and abdominal cavities).
In the course of my work I came to the following conclusions:
1. Breathing in animals is determined by their way of life and is carried out with the help of covers, tracheas, gills, and lungs.
2 the main function of the respiratory system is gas exchange with the external environment: inflow of oxygen and release of carbon dioxide.
3. All animals need oxygen for life processes.