The cardiovascular system
The cardiovascular system is made up of:
- The Heart
- Blood Vessels
The heart is a muscular pump that pushes the blood around the body through the blood vessels to the working muscles.
There are 3 blood vessels:
Comparing arteries and veins
|Take blood away from the heart||Take blood to the heart|
|Walls are thick and elastic||Walls are thin|
|Transport oxygenated blood||Transports de-oxygenated blood|
|Has small lumen||Has large lumen|
|Has a pulse and blood travels||Has no pulse and blood travels|
|Has no valves||Has valves|
It has the capacity to carry essential items around the body.
- Oxygen from lungs around body to muscles
- Waste carbon dioxide from body back to lungs
- Glucose and nutrients from digestive system to cells
- To transport nutrients and hormones around the body
Blood is pumped out of the heart under pressure.
Pressure is calculated by measuring the pressure needed to stop the flow of blood through an artery.
Two readings are taken, the systolic pressure when the heart contracts and the diastolic pressure when the heart relaxes.
This is given as a number.
120/80 is the average reading for a young adult.
Blood pressure can be used as an indicator of general health.
Constant high blood pressure is known as hypertension and has become associated with a number of cardiovascular diseases.
This is usually caused by a restriction of blood through the arteries making the heart work harder to move blood around the body.
What happens to the cardiovascular system during exercise?
You need to know the immediate, short term and long term effects of excercise on the cardiovascular system.
We use our heart as a guide when training to see how hard our body is working. We measure our heart rate in beats per minute (BPM).
Blood pressure - 'the force exerted by circulating blood on the walls of the blood vessels.'
Heart rate - 'The number of times the heart beats per minute'
Stroke volume - 'the volume of blood pumped out of the heart by each ventricle during one contraction'
Cardiac output - 'the amount of blood ejected from the heart in one minute'
Resting heart rate
The average heart rate when we are at rest is 60-80 BPM
Your resting heart rate can be a sign of fitness. people with high cardiovascular fitness have lower resting heart rates as the body is more efficient at transporting the blood around the body.
Immediate effects of exercise on the cardiovascular system
- Heart rate increases and contracts more strongly
- Breathing becomes faster and deeper
- Body temperature increases
- Blood pressure rises
- Sweating starts and the body requires replacement fluids
Exercise makes the body work harder. When we exercise the body releases adrenaline. Adrenaline causes our heart rate to increase and glycogen stores to be released into the blood.
Working muscles need a supply of oxygen and glycogen to make energy and create movement. The more the muscles are used the more glycogen and oxygen is needed. As the chemical reactions occur in our muscles heat is also produced.
As we exercise we breathe deeper to get more oxygen into the blood, our heart beats quicker and harder to get that oxygen to the working muscles and we sweat to try and cool the body down.
To help our body cool down our blood is redirected closer to the skin so that heat can easily be lost. This is why we become red when we exercise.
Long term effects of regular exercise on the cardiovascular system
- Size and volume of the heart increases
- Lower resting heart rate
- Lower blood pressure
- Good recovery rate (returning to resting heart rate quicker)
- Increased stroke volume (the heart pumps more blood per beat)
- Veins & Arteries become healthier reducing the risk of coronary heart disease
- More capillaries in muscles (more areas to exchange oxygen)
The resting heart rate gives an indication of fitness. This is because the heart is a muscle. As you train it the heart becomes bigger and stronger. This means it can push more blood out per beat and doesn't have to beat as many times to deliver the same amount as it used to.
This graph shows the difference between the heart rate of a fit person who exercises regularly and someone who does not exercise. You can see the following:
- The fit person has a lower resting heart rate, before they begin to exercise
- The fit persons heart rate rises more slowly
- The maximum heart rate reached by the fit person is a lot lower than the unfit person
- The fit persons heart rate drops quicker when they finish exercise
- The heart rate of the fit person returns to their resting heart rate in a quicker time
Can you remember how to figure out your maximum heart rate?
Do you know your training thresholds?
Aerobic – 60-80%
Aerobic and anaerobic training and exercise
Training and exercise for CARDIOVASCULAR FITNESS can be aerobic, anaerobic or a combination of both, but whatever method is used, certain effects will be brought and these include:
•Aerobic respiration happens in the cells of the working muscles. Aerobic respiration is the process of making energy from glycogen combined with a good supply of oxygen.
Glucose + Oxygen = Carbon Dioxide, Water, Energy
C6H12O6 + 6 O2 = 6 CO2 + 6 H2O + energy
Aerobic fitness is the ability to exercise or compete for a long time without getting breathless.
AEROBIC FITNESS will help in the endurance events and games that go on for long periods of time, examples include swimming, squash, tennis, football and rugby.
Anaerobic respiration also happens in the cells of the working muscles. Anaerobic respiration is the process of making energy from glucose in the absence of Oxygen.
Anaerobic exercise can only supply quick bursts of energy. Working with Anaerobic Respiration alone can only supply energy for about 10-15sec, about the time it takes to run a 100m race.
Glucose = Energy, Carbon Dioxide, Lactic Acid
C6H12O6 = Energy +2CO2 +2C2H5OH
ANAEROBIC FITNESS is the ability to work at a high intensity for a short period of time.
ANAEROBIC FITNESS will help in the activities where shorter, faster bursts of energy are required, examples include sprint events up to 400m, shorter races in swimming and any sprints in the games mentioned above where a combination of aerobic and anaerobic fitness is required.
When we work hard over 80% of our maximum heart rate, our body produces energy through anaerobic respiration. Anaerobic respiration makes energy without oxygen. It is a
you the anaerobic our muscles work and produce energy through aerobic and anaerobic respiration lactic acid body works up to 75% of its maximum work rate then lactic acid
Lactic acid is a poison. It builds up slowly during exercise that is up to 75% of maximum work rate. During higher intensity work it builds up much more quickly.
If you train you improve your muscles ability to produce energy and they work more effectively. Lactic acid can also occur when glycogen stores begin to run low in the muscles after prolonged exercise.
After a while lactic acid makes the muscles ache. It will eventually cause cramp and the muscles will stop working. Athletes need to rest while the blood brings fresh supplies of oxygen.
•When we produce energy through anaerobic respiration we are doing so without the use of Oxygen. Our body then needs to recover and take on oxygen before the muscles can work properly again. The repayment comes in the form of gasping breaths at the end of an activity.
•This is to enable as much oxygen as possible to get back into the respiratory system and to eliminate as much of the waste product as possible (lactic Acid).
Oxygen debt – the amount of oxygen consumed during recovery above that which would have ordinarily been consumed in the same time at rest (this results in a shortfall in the oxygen available).
The effect of lifestyle on the cardiovascular system.
When athletes train it is really important for them to allow time to rest so the body can repair and recover. This is particularly important after cardiovascular training sessions. Rest allows the heart to grow and thicken in size and allows the capillary network to grow.
When you start training you should allow the body one day rest after a cardiovascular training session.
As you get fitter and stronger you can reduce the amount of rest days a week you need.
Damage to the cardiovascular system
There are a few lifestyle traits than can have negative effects on the cardiovascular system and can increase the chance of developing coronary heart disease. These are:-
Sedentary lifestyle and lack of exercise
Your body needs cholesterol but there are 2 types
Bad - Low-density lipoprotein (LDL) - too much can clog up your arteries and put strain on your cardiovascular system.
Good - High-density lipoprotein (HDL) - helps keep arteries clear and break down LDL's. This process is increased and improved if combined with regular exercise
Eating foods that are high in fat increases your cholesterol intake. Although your body needs fat you should keep track of the fat you consume and try to have god fats instead of low bad fats.
Alcohol and Nicotine increase blood pressure
Sedentary lifestyle and lack of exercise
If you do not exercise you do not get the benefits that exercise have on the cardiovascular system. Also lack of exercise can be linked to gaining weight as calories are not burnt off with exercise.
Ongoing stress in everyday life has a negative effect on your cardiovascular system as it increases resting heart rate and raises blood pressure.
Red blood cells
Red blood cells contain haemoglobin that is a compound of protein and iron.
Haemoglobin combines readily with oxygen to form a compound called oxyhaemoglobin.
It will combine with oxygen where oxygen is plentiful and yet readily lose it where oxygen is scarce, as in the body tissue.
Red blood cells are produced in the red marrow of bones such as the sternum, ribs and vertebrae.
White blood cells
White blood cells form a mobile guard and repair system to keep disease from the body.
They are made in the bone marrow, the lymph nodes and the spleen.
Platelets are tiny structures.
They produce clotting when a blood vessel is damaged.
Plasma is a pale, straw coloured, liquid.
It is 92% water.
The remaining 8% consists of food substances.
It also maintains the correct balance of chemicals, water content and temperature levels within the body.