1. Exercise results in an increase in the volume of gas exchanged in the lungs. Define Tidal Volume and describe how a performer is able to increase lung volumes during exercise using neural control.

Definition: ‘The amount of air breathed in/out of the lungs in one breath’. Description: Movement detected by proprioreceptors Emotional influences/lung stretch receptors Change in blood pH via chemoreceptors/ drop in oxygen. Changes in blood pressure via baroreceptors Respiratory Centre (in medulla) controls breathing. Inspiratory/Expiratory centre initiate impulses Impulses sent via phrenic nerves Impulses received by respiratory muscles This leads to increased rate and depth of breathing.

2. Describe how more oxygen is diffused into the muscles during exercise.

Gas diffuses from an area of high pressure to an area of low pressure There is a high partial pressure of oxygen in blood, low P02 in muscle. There is a decreased partial pressure of oxygen in the muscle during exercise. Therefore there is an increased diffusion gradient. Increase in temperature encourages greater release of oxygen (from haemoglobin)

3. At rest and during physical activity the performer varies the volume of gas exchanged in the lungs. Give typical minute ventilation values for a fit 20 year old at rest & during maximal exercise. Show your calculations.

ANSWER VE=TV x f AT REST = 5-10 LITRES/MIN MAXIMAL = 100 – 180 LITRES/MIN

4. Name four structural features of the lungs that assist diffusion.

One cell thick alveoli/thin (epithelial) membrane and capillary walls The inside of the alveoli is moist Large surface area of alveoli/capillary density A short diffusion pathway/nearness of capillaries Blood cells travel through the capillary relatively slowly/almost in single file compression of red blood cells A large concentration of gradient always exists

5.Describe how the mechanics of breathing during exercise expire greater volumes of C02.

This process becomes active due to intercostals contracting Abdominal muscles contracting Diaphragm pushed up harder/rib cage pulled in & down Decrease in volume of thoracic cavity Causing an increased pressure within thoracic cavity.

6. Explain how the gas exchange system operates at muscles.

6. A. Process of diffusion – high concentration/partial pressure to low B. Requires thin membranes/short distance C. High pO2 in blood/low pO2 in muscles and oxygen moves into muscles D. Low pCO2 in blood/high pCO2 in muscles and carbon dioxide moves into blood E. Oxygen into myoglobin/ (disassociates) from haemoglobin

7. Explain the long term effects of training on the respiratory system.

Cardiac Hypertrophy/Hypertrophy of heart/athletes heart Lower resting heart rate/bradycradia Increased thickness of ventricle wall/larger ventricular cavity/thicker myocardium Increased ejection fraction/increased proportion of blood ejected Increased contractility/increased force of contraction/heart beats stronger/more powerful Increased stroke volume/blood ejected per beat Greater diastolic filling/pre-load Starlings Law Increased maximum cardiac output (Increased) capilliarisation