KEY KNOWLEDGE KEY SKILLS functions responsible for short

term (acute) responses to physical activity in the cardiovascular, respiratory and muscular systems

Participate in data collection, analyse and report on the acute responses occurring at the cardiovascular, respiratory and muscular systems in response to exercise.

Robert Malpeli - Balwyn High School 2010

Robert Malpeli - Balwyn High School 2010

Acute responses :

•Only occur for the duration of exercise and recovery

•Are dependent on the intensity, duration and type of exercise being undertaken

•Involve the respiratory, cardiovascular and muscular systems working together to supply more energy / ATP and oxygen to working muscles and then again to remove any waste products

Robert Malpeli - Balwyn High School 2010

Acute Respiratory responses↑ Ventilation (air breathed in & out per minute)

Ventilation (litres/min) = Tidal Volume (litres) x Respiratory rate (breaths/min)

↑Tidal Volume ( amount of inspired & expired air per breath)

↑ Respiratory Rate (breaths per minute)Ventilation vs. submaximal and maximal exercise

Robert Malpeli - Balwyn High School 2010

↑ Gas Exchange / Diffusion

Gases such as oxygen and carbon dioxide always move from areas of high pressure to areas of low pressure.

Lungs•oxygen concentration is high so it moves from the alveoli into the blood stream to be taken to muscles•carbon dioxide concentration in the blood stream is high so it moves into the alveoli to be exhaled

Muscles (opposite concentrations to lungs)•oxygen concentration is low so it moves from the blood stream to be taken in by the muscles•carbon dioxide concentration in the muscles is high so it moves into the blood stream to be transported to the lungs and exhaled

Robert Malpeli - Balwyn High School 2010

Acute Cardiovascular responses

All of these responses are aimed at getting more blood, oxygen & fuels to working muscles and speed up removal of wastes.

↑ Stroke Volume (ml of blood pumped out of the left ventricle per beat)

↑ Heart Rate (beats per minute)

↑ Cardiac Output (litres per minute) = SV x HR

Robert Malpeli - Balwyn High School 2010

Robert Malpeli - Balwyn High School 2010

↑ Blood pressure (mainly systolic)

↑ Venous return to heart (assisted by muscle pump, respiratory pump and venoconstriction – still approx 4% but 5 times as much blood compared to rest)

↓ Blood volume (plasma loss)

↑ Blood directed towards working muscles (vasoconstriction of arterioles supplying inactive muscles reduces blood flow here and vasodilation of arterioles supplying muscles increases blood flow here)

Robert Malpeli - Balwyn High School 2010

Acute Muscular responses

↑ Increased blood flow to working muscles↑Motor unit / fibre recruitment↓ Fuel stores (PC, ATP, glycogen, triglycerides)

↑Lactate production (then ↑ H+ if not removed)

↑ Muscle temperature↑ Oxygen Consumption

Robert Malpeli - Balwyn High School 2010

↑ Arteriovenous oxygen difference (a-vO2 diff)

The greater the extraction of oxygen by working muscles, the greater the a-vO2 diff

Robert Malpeli - Balwyn High School 2010

Robert Malpeli - Balwyn High School 2010

Factors affecting Maximum Oxygen Uptake

Body SizeGenderGeneticsAgeTraining Status (Cardio respiratory Fitness)

Robert Malpeli - Balwyn High School 2010