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Cardiovascular - Coggle Diagram
Cardiovascular
Cardiac output
Stroke volume
Stroke volume is the amount of blood pumped by the left ventricle in one contraction. About two-thirds of the blood in the ventricle is put out with each beat. During exercise, stroke volume increases progressively and gradually levels off at a higher level ranges between 70 and 80 ml per beat, a trained athlete’s stroke volume can be 110 ml. During exercise, blood flow increases sharply, allowing for a greater oxygen supply to the skeletal muscles.
Heart rate
Heart rate changes according to the body’s needs. It increases during exercise (see Figure 1.4) to deliver extra oxygen to tissues and remove carbon dioxide. At rest, a normal adult heart beats approximately 75 times per minute, peaking at around 200 beats per minute for strenuous activity, depending on age.
Cardiac output is the volume of blood pumped out of the heart in 1 minute. It is expressed as Q and is equal to heart rate multiplied by the stroke volume. Cardiac output may reach up to 30 litres per minute during extreme exercise.
Cardiac cycle
The sequence of systole-during which the cardiac muscle contracts and diastole-during which cardiac muscle relaxes, that takes place during a single heartbeat.
Vasodilation-During exercise the vascular portion of active muscles increases through dilation of arterioles, a process known as vasodilation that involves an increase in the diameter of the blood vessels resulting in an increased blood flow to the muscle area.
Vasoconstriction- Vessels also shut down blood flow to tissues and involves a decrease in diameter of a blood vessel by contraction of involuntary muscle fibres in the vessel walls
starlings law
this is a theory where stroke volume increases in a response to an increase of blood filling the heart. this stretches the ventricular wall forcing the cardiac muscle to contract with more force. the stroke volume may also increase due to stringer contractions in the cardiac muscle during exercise. therefore, the reduced heart rate of a trained athlete allows for greater filling during the longer diastole , so the stretch of the cardiac muscle is greater. this in turn increases the stroke volume
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anticipatory rise
an anticipatory increase in heart rate occurs before the start of exercise. heart rate can be changed by neurotransmitters such as adrenaline and noradrenaline released from the brain. therefore before exercise the heart rate increases and the subsequent increase in blood flow has already begun to supply oxygen and nutrients to the muscle or muscles about to be worked
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