AO5

1.            Label the diagram of the respiratory system

2.            What does VO2 Max mean and what unit is it measured in?

VO2 Max is the most amount of oxygen that can be used by your body (muscles) in one minute.  It is measured in units of mL per kg of body weight per minute.  Let's assume a healthy adult male has a VO2 max value of 50 mL/kg/min, which is actually good for a trained individual and excellent for an untrained one..  If this man weighed 71 kg (156 lbs.) then his muscles, at maximum exercise would be consuming 3550mL of oxygen every minute, or roughly the equivalent volume of ten cans of soda.  

3.            Can you give me an example of VO2 max for a normal person and a highly trained athlete?

 The average young untrained male will have a VO2 max of approximately 3.5 litres/minute and 45 ml/kg/minute the average young untrained female will score a VO2 max of approximately 2.0 liters/minute and 38 ml/kg/min. These scores can improve with training and decrease with age, though the degree of trainability also varies very widely: conditioning may double VO2max in some individuals, and will never improve at all in others.

4.            Explain Pulmonary Ventilation?

Pulmonary ventilation, or breathing, exchanges gases between the outside air and the alveoli of the lungs. Ventilation, which is mechanical in nature, depends on a difference between the atmospheric air pressure and the pressure in the alveoli. When we expand the lungs to inhale, we increase internal volume and reduce internal pressure. Lung expansion is brought about by two important muscles, the diaphragm and the intercostal muscles. The diaphragm is a dome-shaped sheet of muscle located below the lungs that separates the thoracic and abdominal cavities. When the diaphragm contracts, it moves down. The dome is flattened, and the size of the chest cavity is increased, lowering pressure on the lungs. When the intercostal muscles, which are located between the ribs, contract, the ribs move up and outward. Their action also increases the size of the chest cavity and lowers the pressure on the lungs. By contracting, the diaphragm and intercostal muscles reduce the internal pressure relative to the atmospheric pressure. As a consequence, air rushes into the lungs. When we exhale, the reverse occurs. The diaphragm relaxes, and its dome curves up into the chest cavity, while the intercostal muscles relax and bring the ribs down and inward. The diminished size of the chest cavity increases the pressure in the lungs, thereby forcing out the air.

5.            Explain External Respiration?

Exchange of gases between the external environment and a distributing system of the animal body (as the lungs of higher vertebrates or the tracheal tubes of insects) or between the alveoli of the lungs and the blood.

 

6.            Explain internal respiration?

The metabolic processes whereby certain organisms obtain energy from organic molecules; processes that take place in the cells and tissues during which energy is released and carbon dioxide is produced and absorbed by the blood to be transported to the lungs

7.            Why does the left lung only have two lobes and the right three?

The left hand side of the body contains the heart, this takes up a substantial amount of space. Therefore, the lung is slightly smaller on this side. On the right hand side of the body where there is no heart, the lungs are larger meaning more lobes are required.

8.            The alveoli are surrounded by capillaries why is this?

 They work with the alveoli to complete the gaseous exchange, without the alveoli the capillaries would be pointless and vice versa.

9.            Can you describe the 5 factors that happen during inspiration (explaining whether they are active or passive)?

1.     Diaphragm, external intercostals, sternocliedomastoid, scalenes and pectoralis minor contracts.

2.     Diaphragm flattens with more force, increased lifting of the ribs and sternum.

3.     Increased thoracic cavity volume

4.     Lower Air pressure in the lungs

5.     More air rushes into the lungs

10.          Can you describe the five factors that happen during expiration (explaining whether they are active or passive)?

·         Diaphragm relaxes, external intercostals relax. Internal intercostals contract rectus abdominus/obliques contract.

·         Diaphragm is pushed upwards with more force and the ribs and sternum are pulled in and down

·         Greater decrease in thoracic cavity volume

·         Higher air pressure in lungs.

·         More air pushed out of the lungs.

11.          What is Tidal Volume?

This is the volume of air inspired or expired per breath approximately 500ml when at rest

12.          What is inspiratory reserve volume?

The maximal amount of gas that can be inhaled from the end-inspiratory position.

13.          What is expiratory reserve volume?

The maximal amount of gas that can be exhaled from the resting end-expiratory level. Abbreviated ERV.

14.          What is residual volume and why is it needed?

 The amount of gas remaining in the lung at the end of a maximal exhalation.This is required to stop the lung collapsing.

15.          What is inspiratory capacity?

 The volume of gas that can be taken into the lungs in a full inhalation, starting from the resting inspiratory position; equal to the tidal volume plus the inspiratory reserve volume.

16.          What is vital capacity?

 VC; the volume of gas that can be expelled from the lungs from a position of full inspiration, with no limit to duration of inspiration; equal to inspiratory capacity plus expiratory reserve volume.

17.          What is total lung capacity?

The amount of gas contained in the lung at the end of a maximal inhalation.

18.          What is minute ventilation?

The amount of oxygen breathed in, in 1 minute. 

19.          What happens to minute ventilation during exercise, explain why this happens?

It increases due to the higher demand for oxygen by the muscles. More beats per minute means more oxygen will go around the body as each beat is carrying oxygen.