VTCT A & P M68 Respiratory & Olfactory System

Unit M68 Respiratory and Olfactory Systems

1. See diagram
2. Describe & state the functions of the organs that make up the respiratory system
· Alveoli: Found at the end of the bronchioles, these allow for exchange of gases to take place. Oxygen is absorbed from these to the blood, and carbon dioxide returned.
· Bronchus: The two main air passages into the lungs.
· Diaphragm: The main muscle used for breathing; separates the chest cavity from the abdominal cavity.
· Heart: The muscular organ that pumps blood throughout the body.
· Intercostal muscles: Thin sheets of muscle between each rib that expand (when air is inhaled) and contract (when air is exhaled).
· Larynx: Voice box.
· Lungs: The two organs that extract oxygen from inhaled air and expel carbon dioxide in exhaled air.
· Nose: Consists of nasal cavity - Interior area of the nose; lined with a sticky mucous membrane and contains tiny, surface hairs called cilia; Nose hairs - Located at the entrance of the nose, these hairs trap large particles that are inhaled.
· Pharynx: The throat.
· Pleural membrane: Covering the lung and lining the chest cavity, this membrane has 2 thin layers.
· Ribs: Bones attached to the spine and central portion of the breastbone, which support the chest wall and protect the heart, lungs, and other organs in the chest.
· Trachea: Tube through which air passes from the nose to the lungs (also known as the windpipe).

3. See diagram

4. Describe the position & functions of the diaphragm & internal & external intercostal muscles, explaining why these muscles are essential
The diaphragm originates in a number of places: the lower tip of the sternum;
the first 3 or 4 lumbar vertebrae and the lower borders and inner surfaces of the cartilages of ribs 7 - 12. All fibres insert into a central tendon (aponeurosis of the - iaphragm). It acts as a partition between the cavity of the chest and that of the abdomen. The chief muscle used in respiration, it is relaxed and dome-shaped during exhalation. During inhalation it contracts, pulling downward, and with the combined contraction of the chest muscles allows the chest cavity to expand. Any interference with its free movement, as in the paralysis of poliomyelitis, seriously impedes the function of the lungs and therefore endangers life.

External Intercostals run from the lip on the lower border of each rib inferiorly and medially to the upper border of the rib immediately below. They serve to strengthen the thoracic wall so that it doesn't bulge between the ribs. They provide a checking action to counteract relaxation pressure. Because of the direction of attachment of their fibres, the external intercostals can raise the thoracic cage for inhalation.

Internal intercostals run from the anterior limits of the intercostal spaces to the angle of the ribs posteriorly. In front, they run inferiorly and laterally, and in back
inferiorly and medially. Each muscle runs from the subcostal groove of one rib to the top of the rib immediately below it. They assist the external intercostals in strengthening the intercostal spaces. The internals are also the chief muscle in forced exhalation, for example during phonation. The internal intercostals - aided by the abdominal muscles - pull down the rib cage because of the direction of their fibres.

5. What causes bronchiospasms and what effect would this have on the individual?
These are spasmodic contractions of the smooth muscle of the bronchi that occur most commonly during an asthma attack. They are usually caused by the bodies’ reaction to allergens. During an attack the airways constrict so that only partial expiration is possible, resulting in the characteristic wheezing and breathing difficulties.

6. What would be the negative physiological effects of not breathing correctly?
Incorrect breathing means that the individual is not taking in enough oxygen. This will lead to cell deoxygenisation throughout the body, breakdown of normal metabolic function, and the inability to functi