For the completion of the Applied Physiology assignment, students are asked to research and discuss the structure and function of three of the bodies systems, these systems are respiratory, cardiovascular and renal.

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For the completion of the Applied Physiology assignment, students are asked to research and discuss the structure and function of three of the bodies systems, these systems are respiratory, cardiovascular and renal.

Research will then be done on the composition and function of blood, explaining the normal function of red and white blood cells and platelets. This will also include the destruction process and the normal clotting mechanism.

Students are also asked to describe the relationship between the three systems and homeostatic mechanisms in maintaining physiological function. This will also mean looking at the structure of the trachea and nose, the bronchi and the lungs and the heart and the lungs to explain homeostasis.

All of these systems may experience disorders within their normal mechanisms i.e. coronary heart disease, cardiovascular disease, chronic respiratory diseases and renal diseases.

Blood groups will also be identified and the Rhesus factor described, this will also include the causes of iron deficiency and anaemia.

Relate structure and function of the respiratory system, the cardiovascular system and the renal system

The respiratory system

The respiratory system consists of the nasal cavity, pharynx, larynx, trachea, bronchi, the lungs, alveoli, rib cage and the diaphragm. Working together with breathing muscles the respiratory system carries air in and out of the lungs.

The nasal cavity is the first of the respiratory organs and is made up of a large irregular cavity, divided by the septum. It is lined with ciliated epithelium, this ensures that the air is warm, filtered and moistened as it passes through the nose. As the air is warm as it passes through the nose any mucus which comes in contact with the nose will be filtered in the sense that dust particles and other impurities stick to the mucus membrane which lines the nasal cavity. The surface hairs called cilia also trap dust particles ready for them to be sneezed out. A similar membrane also lines the larynx and trachea; the cilia will move the particles towards the oropharynx to be swallowed.

Once the air has passed through the nose it moves into the pharynx (the throat). The pharynx is also a common passageway for food and water. It is a funnel shaped tube, which begins at the internal nasal passages; the tube is on average 12 to 14cm long and extends from the base of the skull to the level of the sixth cervical vertebra. It lies behind the nose, mouth and larynx and is wider at its upper end. The pharynx consists of three layers of tissue:

  • Mucus membrane lining
  • Fibrous tissue
  • Muscle tissue

The pharynx is an organ, which is involved, in both respiratory and digestive system; air passes through the nasal and oral parts and food passes through the oral and laryngeal parts. Using the same methods, the air, which passes through the pharynx is filtered, warmed and moistened. When the air has passed through the pharynx it continues its journey through to the larynx.

The larynx is also known as the voice box. It is made up of pieces of cartilage, which are connected to by ligaments and moved by various muscles. The larynx produces a small bump in the neck, which is called the Adams apple. The larynx extends from the root of the tongue and the hyoid bone until it reaches the trachea. Until puberty is reached, we see very little difference in the size of the larynx between males and females. The larynx is larger in the male than it is in the female causing male voices to become deeper. The larynx provides a passageway for air in between the pharynx and the trachea, as air passes through; it continues to stay moistened, warm and filtered as it was in the nose. When swallowing the larynx moves upwards, occluding the opening into it. The pharynx makes sure that the food, which passes into and through the oesophagus, does not go into the lower respiratory passages.

The trachea or the windpipe is a cylindrical tube measuring around 10 to 12cm in length, it is made up of 16 to 20 incomplete c-shape rings of cartilage, these are joined together by fibrous and muscular tissue.

There are three layers of tissue, which ‘clothe’ the cartilages of the trachea:

  • The outer layer consists of fibrous and elastic tissue
  • The middle layer consists of cartilages and bands of smooth muscle, which wind around the trachea in a helical arrangement. There is also some areolar tissue, which contains blood and lymph vessels
  • The inner lining consists of ciliated columnar epithelium, containing mucus – secreting goblet cells.
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These three layers of the trachea help to keep it firm, strong and enables the air which passes through it keep warm, filtered and moistened, ready to be passed into the lungs. The mucus – secreting goblet cells line the trachea making sure that no unknown substances reach the lungs and cause irritation.

When the trachea divides, the two bronchi are formed. The right bronchus is shorter and wider than the left bronchus and lies in a more vertical position; it is around 2.5cm in length. After the bronchus enters the lung at the hilum it divides into ...

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