• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The circulatory system.

Extracts from this document...

Introduction

The circulatory system The circulatory system can be greatly affected by the type and amount of training a person does and therefore has to be considered very closely compared to other body systems. The main functions of the circulatory system are: * Transport- carrying blood, water, oxygen and nutrients throughout the body, and transport the removal of waste. * Body temperature control- the blood absorbs the body heat then carries it to the lungs and to the skin, where it is then released. * Protection- it helps to fight disease, e.g. antibodies, which fight infection, are carried in the blood and the clotting of seals cuts and wounds. The circulatory system has four main parts: * The heart * The blood vessels * The blood * The pulmonary and systemic circuits. ...read more.

Middle

There is an outer layer of tough fibrous tissue. The aorta is the largest artery in the body this divides into arterioles then into capillaries. Capillaries- These are so small they are only one cell thick, because of this they are semi-permeable and allow things to pass through the wall. Capillaries are found in clusters and feed the muscles and organs. At the end of the capillaries the blood flows into veins. Veins- The structures of veins are the same as arteries but they are smaller; the fibrous tissue and involuntary muscle is smaller. The veins pump blood back up to the heart; they have valves to stop the blood from flowing backwards. The skeletal pump also helps the blood in veins. Arteries near the veins push against them when a surge of blood goes through them, gravity assists veins above the heart, the action of breathing causes pressure changes and as the heart pumps, it also causes a sucking action that affects veins close to the heart. ...read more.

Conclusion

Plasma forms the remaining 55 per cent of the blood. This is the 'liquid section' and is mainly composed of water. It contains fibrinogen protein (which helps to clot), nutrients such as glucose and amino acids, waste products such as urea and some carbon dioxide and oxygen. The pulmonary and systemic circuits The pulmonary circuit carries deoxygenated blood through the heart to the lungs where it exchanges carbon dioxide for oxygen to become re-oxygenated. The pulmonary vein transports oxygenated blood to the left atrium of the heart. The systemic circuit carries oxygenated blood through the aorta from the left ventricle of the heart to all over the body, through capillaries. Having deposited most of the oxygen the blood flows back through the veins, into the right atrium through the vena cava. In this circuit the blood visits the cardiac muscle of the heart, the stomach, the intestines and liver, the muscles and skin. Oxygen transported through this system is vital for physical activity. Dayna Edwin 10GB 05/12/03 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Humans as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

This is a well researched and structured report.
1. The structure is good throughout, although the introduction subheading is missing.
2. The language used is strong throughout and includes some degree level terms.
3. The sources of researched information need to be included.
****

Marked by teacher Luke Smithen 16/07/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Humans as Organisms essays

  1. Marked by a teacher

    Biology Revision notes - Human Biology

    5 star(s)

    because we are getting too little of something and this is not a balance. If we eat as much energy as we use up, we don't gain or lose weight. Obesity This is a type of mal-nourishment. It increases the risk of: * Arthritis * High blood pressure * Type

  2. Marked by a teacher

    How Does Lifestyle Affect the Circulatory System?

    3 star(s)

    There are also drug therapies, bypass surgeries, valve replacements, pacemakers and many more. The heart is the central organ of the circulatory system, a muscular pump that continuously forces blood around the body and through the lungs where it takes on oxygen.

  1. Human biology short notes

    blood plasma proteins and formation of cellular structures * Extra proteins cannot be stored * So they are carried to the liver by the hepatic portal vein * In the liver extra amino acids are deaminated Fatty Acids and Glycerol * Absorbed by the villi * Again joined to make

  2. Compare and contrast the role of the endocrine system and the nervous system, in ...

    Additionally it is also important to note that hormones have a widespread effect meaning they affect more than one organ at a time, whereas nerve impulses typically only affect one organ at a time.

  1. The Mammalian Heart and Circulatory System

    Inside the heart and at the base of the vessels that leave the heart are valves. These valves only open one way, which ensures that there is no backflow of blood. The valves are held open or closed by tendons, which are attached at the other end to the papillary muscles in the ventricle walls.

  2. Describe how the structure of arteries, veins and capillaries enables them to fulfil their ...

    Blood in the veins is under low pressure, it doesn't move in pulses as it does through the arteries but instead flows slowly. As a result the lumen is large in relation to the diameter to allow a larger volume of blood to pass through.

  1. Should the cloning of humans be allowed?

    This process of removing the nucleus is called enucleation. An egg cell is needed to complete the cloning process, so after the body cell has been enucleated (has its nucleus taken out), a female animal (the egg mother) who has been treated with a hormone to simulate ovulation, has her oocytes (immature eggs)

  2. Human Circulatory System Revision Notes.

    away from the heart by arteries The heart is made up of special cells that can carry an electrical impulse called cardiac muscle Cardiac cycle: The cardiac cycle consists of two parts: systole ? contraction of the heart muscle, diastole ? relaxation of the heart muscle Atriums contract while ventricles

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work