chapter 1.1 past paper questions Flashcards
(13 cards)
If endurance events take place in warm conditions, cardiovascular drift can occur.
Analyse how cardiovascular drift may result in lower levels of performance. (5)
- Athletes will sweat reducing the plasma volume of blood. (1)
- Blood becomes more viscous/thicker which reduces venous return. (1)
- Due to Starling’s law stroke volume/ejection fraction will decrease. (1)
- As stroke volume/ejection fraction decreases heart rate increases to maintain/increase cardiac output.
(1) - Having a higher heart rate at a lower than normal intensity increases the athlete’s rate of perceived
effort/the performer mentally thinks they are working harder than they are. (1)
Describe how an increase in carbon dioxide in the blood during exercise would lead to
an increased breathing rate.
- Increased blood acidity/decreased blood pH. (1)
- Detected by chemoreceptors. (1)
- Impulse sent to the respiratory centre/medulla. (1)
- Increased impulses to respiratory muscles to contract faster. (1)
Explain the role of the atrioventricular node in the cardiac conduction system.
- Receives impulse from sinoatrial node/SAN (1)
- Delays (transmission of) impulse (1)
- To allow ventricular filling/enable the atria to fully contract (1)
- Sends impulse down septum/through bundle of His/to purkinje fibres (1)
Training can increase an athlete’s maximum A-VO2 diff.
Analyse how the body systems adapt to allow this (3)
- Increased oxygen content in arterial blood due to more red blood cells/haemoglobin/oxygen carrying
capacity of the blood (1) - Increased gas exchange at the muscle due to increased capillarisation/increases blood supply/surface
area (1) - Increased gas exchange at the muscle due to more myoglobin which has a greater affinity for oxygen
than haemoglobin so pulls more oxygen into muscle/can store more oxygen in muscle (1) - Increased gas exchange at the muscle due to larger/more numerous/more efficient mitochondria
allowing for more oxygen to be used in a muscle cell so less returned to venous blood (1)
Describe how heart disease can result in a heart attack
- Hardening of coronary arteries/build-up of plaque/cholesterol/fat in the
coronary arteries/atherosclerosis/arteriosclerosis (1). - Causes blockage/blood clot (1).
- Limiting the supply of oxygen to the heart/angina (1).
Outline two ways an active lifestyle can reduce the risk of heart disease.
- Decrease in cholesterol/LDL/fat in coronary arteries (1).
- Lower blood pressure (1).
- Stronger heart/cardiac hypertrophy/higher stroke volume (1)
Analyse how changes in venous return occurring during exercise help performance in
aerobic events such as a triathlon. (8)
Possible content may include:
AO1 Knowledge of venous return mechanisms
Reference to and description of venous return mechanisms:
* valves – prevent backflow of blood
* skeletal muscle pump – working muscles contract and compress veins to push blood back towards the
heart
* respiratory pump – increased respiration/changes in pressure in the thorax compress veins to push
blood back towards the heart
* smooth muscle – found in veins and contracts to push blood back towards the heart
* suction pump of the heart – pulls blood back toward the heart.
AO2 Application to increased venous return during exercise
Changes in venous return during exercise:
* during exercise increased use of muscles in arms (swimming) and legs (swimming, cycling, running)
compresses veins more pushing more blood back to the heart
* increased breathing rate during exercise causes increased effect of respiratory pump returning more
blood to the heart
* suction pump of the heart increase as the heart beats harder and faster during exercise
* overall increase in venous return during exercise.
AO3 Analysis of reasons why these changes are required to occur
* Starling’s law.
* This causes the heart muscle to stretch more increasing ejection fraction/stroke volume/cardiac
output.
* More blood leaving the heart means more blood sent to the lungs for greater gas exchange (removal
of CO2 and uptake of O2).
* More blood to working muscles supplying O2 for resynthesis of ATP.
* The more O2 that is supplied the longer the performer can work aerobically for, limiting the production
of fatiguing by-products such as lactate.
* Can work at higher intensities for longer periods of time
Describe the process of gas exchange which occurs at a muscle.
- Oxygen diffuses from the capillary to the muscle cells and carbon dioxide diffuses from
the muscle cells to the capillary (1) - Oxygen/carbon dioxide moves from areas of high concentration/partial pressure to areas
of low concentration/partial pressure (1) - Myoglobin transports and stores oxygen in the muscle/has a higher affinity to oxygen then
haemoglobin/pulls more oxygen in to the muscle (1)
Gas exchange at the muscle will change during exercise as the Bohr shift will occur.
Describe the Bohr shift
- Occurs as a result of increased CO2 in the blood/increased blood acidity/decreased
blood pH/increased temperature (1) - Increase in hydrogen ions (1)
- Bohr shift is when an oxyhaemoglobin disassociation curve moves to the right (1)
- Haemoglobin has a lower affinity for oxygen at working muscles/gives up oxygen more
easily/at higher partial pressures (1
Which receptor is responsible for detecting a change in blood pressure?
barioreceptor
Define the term A-VO2 diff
Difference between oxygen content/partial pressure of oxygen in arterial and venous blood (1)
How much O2 is extracted and used by muscles (1)
Explain the change in A-VO2 diff during exercise. Use the data in Table 1 in your
answer.
paper 1 2019
A-VO2 diff increases from 5 to 15ml.
Means more oxygen is needed / extracted by the muscles.
Used / needed for energy / ATP production for endurance / stamina / aerobic exercise /
delays fatigue.
