Explain the Physiology of Two Named Body Systems in Relation to Energy Metabolism in the Body

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Explain the physiology of two named body systems in relation to energy metabolism in the body

The respiratory system

Respiration can be subdivided into four sections to aid study, there are three that are grouped under external expiration; breathing, gaseous exchange and blood transport, and the internal or tissue respiration carried out inside body cells.

• Breathing

The thorax is an airtight box that holds the lungs and the associated tubes, the heart and the bronchi. Air can enter the thorax either through the nose or the mouth, the nose is adapted for the entry of the air in breathing and it is the recommended route.0.

• Role of the air passages in the nose

The nose holds fine bones on the side walls that are curled like scrolls and is also covered in moist ciliated mucous membrane which is rich in blood capillaries. All these things make a large surface area where incoming air flows. The air that goes through the passage of the nose is warmed and moistened by the close contact with the mucous membrane; it is then filtered by the ciliated cells. By the time the air has reach the throat it has be warmed almost to the body temperature, they are also moistened almost to the point of saturation and almost all the foreign materials have been filtered out like dust and carbon particles.

• The structure and function of the trachea and bronchi

The trachea is at the back of the throat and it divides into two bronchi, and they each serve one lung on each side of the heart. The first part of the trachea is specialised to make sound, it is called the voice box. This is protected by the moveable cartilage flap called the epiglottis and it prevents food from entering during swallowing. If any material like a crumb passes through the epiglottis it will cause an intense bought of coughing which is a reflex action to try to expel the foreign body. The trachea and the bronchi have rings of cartilage to stop them from collapsing; those that are in the trachea are c-shaped with the gap at the back against the main food tube, the oesophagus. This is due to the fact that when food is chewed in the mouth it’s formed into a ball shape before its swallowed. The bolus stretches the oesophagus as it passes to the stomach and the whole rings of cartilage within the trachea hampers its progress. Also, the gap is full of soft muscle which stretches easily; this allows the bolus to pass down the oesophagus. Each bronchus divides and sub-divides repetitively, which spreads each part of the lung. The smallest sub-divisions is called the bronchioles, which supplies oxygen to the air sacs in the lung, the bronchioles are held open by the minute parts of the cartilage. The inner lining of the trachea and bronchi is made of mucus-secreting and ciliated, columnar epithelial cells. [pic 3]