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Description
Flashcards by Camilla Donaldson, updated more than 1 year ago
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Created by Camilla Donaldson
over 9 years ago
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| Question | Answer |
| What are the responses of the cardiovascular system to exercise? (4) | -increased stroke volume -increased heart rate -increased cardiac output -redistribution of blood flow to working muscles |
| Why does the heart rate rise rapidly during exercise? (4) | -chemicals such as lactic acid produced by contracting muscle stimulate nerve endings which send messages to the cardiovascular system to increase the heart rate. -similiar messages are sent when higher levels of carbon dioxide are detected in the blood -nerved endings in the aorta and the carotid arteries register changes in oxygen and carbon dioxide content of the blood, and pH change. -stretch of cardiac muscle and sino atrial nodes due to increased venous rate, and a rise in temperature of the heart muscle. |
| Why would a response be increased stroke volume? | When an untrained person exercises they can experience a 400% increase in cardiac output-20 litres of blood per minute compared to 4-5 litres at rest, an trained athlete can experience an 800% increase in cardiac output. Increased heart size (cardiac hypertrophy), which means as venous return increases/speeds up during exercise the heart can hold a greater capacity and more blood can be pumped out. |
| What are the effects of exercise on blood pressure? (3) | IT INCREASES, due to: -increased cardiac output -constriction of the walls of the arteries -greater resistance in the contracting muscles -constriction of blood vessels to organs such as the kidney, liver and digestive system, instead blood is diverted to dilated blood vessels of working muscles. |
| Why does isometric exercise increase blood pressure but isotonic exercises do not to the same extent? | Static exercise (isometric) causes constant compression on the walls of the blood vessels, which creates constriction on the flow of the blood in the working muscles. People with high blood pressure should avoid isometric exercise. |
| When fully dilated how many litres of blood will blood vessels hold? | 20 litres |
| How does redistributing blood flow help to meet the demands of exercise? | Arteries are able to change their size and shape to manipulate blood flow and blood pressure through vasoconstriction and vasodilation. At rest only 15-20% of cardiac output is directed towards skeletal muscle, whereas during intensive exercise this may rise to 80%. Blood is shunted and redirected to where it is needed in the body, increased blood flow to the muscles increases the exchange of oxygen and heat, as well as more efficient removal of waste products; lactic acid and carbon dioxide. |
| What are the adaptations of the cardiovascular system to exercise? (4) | -size of heart -stroke volume -cardiac output -number of capillaries |
| How does the heart adapt structurally to exercise? (3) | -increase in size, particularly in the left ventricle (cardiac hypertrophy). -The cardiac muscle increase in thickness, so there will be an increased strength in contraction. -increased vascularisation of the heart, so coronary arteries can deliver more oxygenated blood to the contracting cardiac muscle in the heart wall. |
| How does the heart adapt to aerobic exercise? (2) | by being able to pump more blood per stroke: -doesn't need to pump as frequently, so resting heart rate decreases. -as there is increased cardiac output the athlete can work harder and longer. |
| What are circulatory changes? (3) | -the more frequent the body is exposed to the stimulus that produces these responses the more rapid and efficiently they occur. -the number of red blood cells may increase through continued exposure to hypoxic conditions. -the blood may become thinner, as during exercise we lose water which increases the viscosity of blood, although with regular hydration our body can respond to regular aerobic training by increasing the volume of water and dissolved proteins within the plasma. Reducing the viscosity and concentration of red blood cells in the blood. |
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