1. AREA OF STUDY 2 – PHYSIOLOGICAL RESPONSES TO PHYSICAL ACTIVITY

2. Key knowledge 1 Mechanisms responsible for the acute responses to exercise in the cardiovascular system. Mechanisms responsible for the acute responses to exercise in the respiratory system. Mechanisms responsible for the acute responses to exercise in the muscular system.

3. Key skills 1 Participate in physical activities to collect and analyse data relating to the range of acute effects that physical activity has on the cardiovascular, respiratory and muscular system of the body.

4. Copy down the chart of page 98 Write it big enough to fill the page, and leave space to write around it

5. What is an acute response? The body’s immediate, short term responses that last only for the duration of the training or exercise session and for a short time afterwards during the recovery period.

6. What does “mechanism” mean? It is what has made the change occur. For example: ◦What has made your heart rate increase? ◦What has made your respiratory rate increase?

7. Acute responses of the respiratory system Comprehensive and detailed analysis of collected data, thorough and insightful understanding of the mechanisms responsible for acute effects of the cardiovascular, respiratory and muscular systems of the body.

8. Respiratory system

10. Respiratory rate Respiratory rate or respiratory frequency, also known as breathing rate Respiratory rate = the number of breaths taken per minute RR at rest = 12 breaths/min RR during exercise can increase to 30-48 breaths/min

11. Respiratory rate What causes RR to increase? ◦An increase in CO2 concentration in the blood ◦This increases stimulates the respiratory control centre in the brain which increases RR

12. Respiratory rate Lets time you Respiratory Rate for 1minute Record this number

13. Tidal Volume Tidal Volume (TV) is the amount of air breathed in and out in one breath At rest TV is approx 0.5Litres During exercise TV can reach 2.5-4L per breath

14. Ventilation Ventilation is the amount of air inspired or expired by the lungs per minute Ventilation = respiratory rate x tidal volume V = RR x TV This varies between each individual depending on gender and size At rest ventilation is approx 4-15L/min During max exercise it can increase beyond 190L/min It can increase to approx 25 to 35 times resting levels

15. Ventilation At the beginning of exercise, receptors in the working muscles stimulate ventilation by sending a message to the respiratory centre in the brain to increase the respiratory rate (RR) and tidal volume (TV)

16. Ventilation – Fill in the gaps Conditions Rest120.56 Moderate exercise 302.575 Maximal exercise 484.0192

17. Ventilation ConditionsRespiratory rate (breaths per minute) RR (breaths per minute) Tidal volume (litres) X TV (litres) Ventilation (litres per minute) = V Rest120.56 Moderate exercise 302.575 Maximal exercise 484.0192

18. Question Do you breathe faster or bigger breathes when you exercise? What does breathing faster mean? What does breathing deeper mean?

19. Respiratory responses Ventilation Respiratory rate Tidal volume

20. At high intensities, tidal volume plateaus and any further increase in ventilation is due to further increases in respiratory rate The point where ventilation is no longer increasing linearly with the increase in exercise intensity is called Ventilation threshold

21. Diffusion The gas exchange occurring in the lungs at the alveolar-capillary interface and in the muscles at the tissue-capillary interface Diffusion of gas always occurs from high pressure to an area of low pressure

22. Diffusion in the lungs Oxygen is high in the lungs, so it diffuses from the alveoli into the blood stream Carbon dioxide is high in the blood, so it diffuses from the blood stream into the alveoli

23. Diffusion in the muscles Oxygen is high in the blood, so it diffuses from the blood stream into the muscles Carbon dioxide is high in the muscles, so it diffuses from the muscles into the blood stream

24. Diffusion During exercise the diffusion capacity is increased (due to increase surface area of the alveoli and muscle tissue)so that greater amounts of oxygen and carbon dioxide can be exchanged at the alveoli and muscles