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Assignment - Respiration

In this assignment I will be explaining the functions of the respiratory systemduring exercise and how it deals with the transportation of gases.

There are two types of respiration:

Internal - This is the process by which the oxygen in the air that enters thelungs by external respiration and is exchanged for carbon dioxide thought thecapillary walls. As we breath in the intercostals muscles contract to lift theribs upwards and outwards which the diaphragm is forced downwards and thesternum forwards. The expansion of the thorax in all directions causes a dropin pressure below that of the atmospheric pressure, which then helps air toflood the lungs.

External-External respiration is a follow on from internal respiration as theintercostals muscles relax the diaphragm extends upwards and sternumcollapse. At that point the pressure in the lungs is increased and air isexpelled. The air is expelled from the lungs in order to remove carbon dioxidefrom to body.

Another key function of the respiratory system is gaseous exchange. Thisrefers to the process whereby oxygen and carbon dioxide move between thelungs and blood.

The concept of partial pressures applies to the diffusion of gases from a gasmixture to a gas in solution. They then dissolve into a solution by diffusionuntil the equilibrium is accomplished. The partial pressures of the gases arethe same in both gaseous and liquid states.

Blood entering the capillaries from the pulmonary arteries has lower oxygencontent and a higher carbon dioxide content than the air in the alveoli. The

oxygen diffuses into the blood via the surface of the alveoli then through the

http://www.teachpe.com/anatomy/blood.phphttp://www.teachpe.com/anatomy/blood.php

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thin walls of the capillaries. Then through the blood cells its latches on tohaemoglobin which then diffuses the carbon dioxide in opposite directions.

Increased breathing rate as part of the respiratory system is often whilst inexercise. During exercise your muscles demand more oxygen and the

corresponding increase in carbon dioxide production stimulates faster anddeeper breathing. The network, which surrounds the alveoli, expandsincreasing blood flow to the lungs and pulmonary diffusion.

An increase in the breathing rate is known as an anticipatory rise. This isdue to the receptors working in both the muscles and joints. After a period ofexercise the breathing continues to increase however at a slower rate. Afterexercise the breathing rate returns to normal and it rapidly begins with andthen becomes slower.

Breathing is controlled by neural and chemical factors. When the rate of

breathing and depth increases it is due to the receptors being stretched in thelungs.

Another key part of the respiration cycle that increases is the tidal volume.Under normal conditions this represents about 500 cm of air breathed, bothinhaled and exhaled. Of this about two thirds eg 350 cm3 reaches the alveoliin the lungs where gaseous exchanged takes place. The remaining 150 cm3fills the pharynx, larynx, trachea, bronchi and bronchioles and is known asdead or stationary air. During exercise tidal volume increases to allow moreair to pass though the lungs each minute. This is known as the minute volumeand is the product of the breathing rate. The lungs usually contain 350 cm3 of

fresh air, 150 cm3 of dead air and 2500 cm3 of air that has already undergonegaseous exchange with the blood.

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Tidal volume is increased by aerobic and anaerobic exercise. During exerciseoxygen is depleted from your body, triggering a deeper tidal volume.There are two types of reserve volume. They include:

Inspiratory reserve volume

Expiratory reserve volume

Inspiratory reserve volume

This is the maximum amount of gas that can be inhaled when breathing indeeply. It is possible to take in the usual 350 cm of fresh air that reachesthe alveoli. This is important during exercise and you can breathe in up toan additional 3000 cm 3 amount of fresh air. The inspiratory reservevolume decreases during exercise.

Expiratory reserve volume

This is the amount of additional air that can be breathed out after normalexpiration. This is about 1.500cm3