CARDIOVASCULAR FITNESS- THE CIRCULATORY SYSTEM

WHAT ARE THE FUNCTIONS OF THE CIRCULATORY SYSTEM ? Circulates blood through the body Transports water, oxygen and food to cells and removes wastes from the cells. Helps fight disease Helps maintain the correct body temperature

CARDIOVASCULAR FITNESS is the ability to exercise the entire body for long periods of time. It requires a strong heart and clear blood vessels to supply the muscles with plenty of oxygen via the blood. Cardiovascular fitness has some benefit to all sportspeople as it concerns the fitness of the most important muscle in the body- THE HEART

THE HEART The heart is a muscular pump. It is divided into two halves by a central partition called the SEPTUM. It has four main chambers to it.

Each half is then also divided by valves into an ATRIUM above (A for above) and a VENTRICLE below.

We therefore have a right and left ATRIUM and a right and left VENTRICLE.

How the Heart works. USING YOUR DIAGRAM OF THE HEART LETS PLOT HOW THE HEART WORKS AS A DOUBLE CIRCULATORY PUMP SYSTEM.

YOUR DIAGRAM SHOULD LOOK SOMETHING LIKE THIS.

BLOOD VESSELS There are 3 vessel types:- Arteries Veins Capillaries

ARTERIES The wall of the heart is supplied with blood from two small vessels called the coronary ARTERIES. These can be blocked by blood clots and when this happens blood supplied to part of the heart wall is cut off, resulting in sudden death. The structure of ARTERIES, VEINS and CAPILLARIES is different.

The ARTERIES have a relatively thick wall The ARTERIES have a relatively thick wall. Most ARTERIES and ARTERIOLES (very small arteries) carry oxygenated blood away from the heart. They pulsate as the heart beats. They are more elastic than VEINS and also have higher pressure. The PULMONARY ARTERIES are different, they carry de-oxygenated blood from the heart to the lungs.

Any vessel LEAVING the heart is called an ARTERY.

VEINS VEINS carry de-oxygenated blood to the heart. They have much thinner walls than arteries. They contain many VALVES which keep de-oxygenated blood flowing to the heart and avoid the possibility of blood flowing backwards. VEINS rarely pulsate.

They are less elastic than arteries. They carry blood at a lower pressure. The PULMONARY VEINS, which leave the lungs on the way to the heart, are different from other veins, they carry oxygenated blood. Any vessel ENTERING the heart is called a VEIN.

CAPILLARIES CAPILLARIES are vessels that link the ARTERIES with the VEINS. At one end they carry oxygenated blood which transfers supplies of oxygen and nutrients to the muscles. At the other end CAPILLARIES pick up waste and so carry de-oxygenated blood into the VEINS.

TO SUM UP THE DIFFERENCES BETWEEN CAPILLARIES, VEINS AND ARTERIES.

COPY THE DIAGRAM ON THE NEXT SLIDE AND FILL IN ALL THE MISSING DETAILS.

SMOKING The ARTERIES need to be clear and free from obstruction in order to carry blood and supplies to the working muscles. But these passageways can be blocked by lipids which can be caused by smoking. Nicotine, one of the main components of tobacco, affects the nervous system, which controls the HEART RATE.

HEART RATE increases which raises BLOOD PRESSURE. Other conditions associated with smoking include CHD and STROKES. It is said that risk of a heart attack is decreased after the smoker has stopped smoking for one year.

WHY DO WE NEED TO TAKE OUR BLOOD PRESSURE ? If you go to a doctor for a check up, you are very likely to have your blood pressure checked.

WHAT IS BLOOD PRESSURE ?

As you get older the blood vessel walls become less elastic and the small vessels do not expand to let through the blood pumped from the heart. This means that resistance to the flow of blood is increased and this means that blood pressure rises.

Blood pressure varies with: AGE GENDER ALTITUDE MUSCULAR DEVELOPMENT STRESS TIREDNESS

What can I do to reduce the risk of high blood pressure ? Check your weight Limit your alcohol consumption Avoid smoking In some people too much salt may unbalance the body chemistry and affect blood pressure. Avoid situations that cause stress, anxiety or worry.

6. Exercise regularly- this will help to control stress, keep your blood pressure normal and your whole system in good shape.

REVISION