Home Studies Course to understand the heart, lungs and blood; and how these things affect health, fitness and overall wellbeing. This course may develop career and job opportunities for anyone working in:

  • Fitness
  • Life Coaching
  • Allied Health
  • Sports
  • Medical support

This course covers: blood, blood pressure, pulmonary ventilation, gas exchange & transport, blood flow and gas transport, cardiorespiratory control, cardiorespiratory disease and more.
Prerequisite: Human Anatomy & Physiology BSC101 or equivalent.

Learn about, the heart, the lungs, heath, fitness and cardio respiratory well being.

There are 7 lessons as follows:

  1. The Science of Blood
  2. Blood Pressure
  3. Pulmonary Ventilation
  4. Gas Exchange and Transport
  5. Blood Flow and Gas Transport
  6. Cardio Respiratory Control
  7. Cardio Respiratory Disease

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

What is the Cardio Respiratory System?

In short; this is the lungs, heart and tubes that move blood around the body.
Together, this system is largely responsible for catching oxygen, putting the oxygen into the blood, then moving that oxygen along with chemicals you eat (good chemicals) around the body. As it does so, it also picks up and removes bad chemicals. There's more; but for a full understanding, you need to understand blood, and a whole lot more.

Blood is a fluid connective tissue comprised of red blood cells (erythrocytes) white blood cells (leukocytes) and platelets (thrombocytes), all suspended in a pale straw-coloured fluid known as plasma. Plasma makes up approximately 55% of the blood volume. The red colour of the blood is due to the erythrocytes, which are the most abundant cell type in blood. Erythrocytes make up approximately 45% of the blood volume. This means that white blood cells make up only a tiny fraction of the blood volume. The blood functions to:

  • Transport oxygen and nutrients to the cells of the body
  • Transport cellular and tissue waste products to the kidneys for excretion
  • Transport different biomolecules such as hormones to cell surfaces in order to induce, modify or halt events in the cell
  • Transport immune cells to different areas of the body to fight infections and recognise foreign organisms
  • Transport toxins to the liver or kidneys for detoxification and excretion respectively
  • Store clotting factors that can be transported to sites of injury to form clots and stop bleeding
  • Help maintain body temperature


On successful completion of the course you should be able to do the following:

  • Explain the how blood affects human health, including its nature, how it works and its significance.
  • Explain blood pressure and its relationship to health and fitness.
  • Explain the physiology of pulmonary ventilation.
  • Explain the physiology of gas exchange and transport.
  • Explain relationship between blood flow and gas transport in the body.
  • Explain the physiology of cardio-respiratory control.
  • Explain the physiology of cardio-respiratory disease.

Here are just some of the things you will be doing:

  • Describe the composition of blood by discussing:
    Different proteins
    Regulatory substances
  • Explain the functions of blood, including transportation, regulation and protection, including examples of the roles played by some of the different blood components in the performance of these functions.
  • List fifteen different substances which are transported by blood.
  • Explain the movement of blood through the human body, including:
    where it moves and how it moves
  • Explain the physiology of three different blood disorders.
  • List physical changes which occur in different parts of the body when the heart beats.
  • Calculate cardiac output in two different specified situations.
  • List factors which can affect blood pressure.
  • Explain how blood pressure can be measured, using a gauge and inflatable sleeve.
  • Distinguish between systolic and disystolic pressure, in a specific case study.
  • Explain how pulse rate and blood pressure indicate different aspects of a subjects condition.
  • Label the parts of an electrocardiograph, including:
    the p wave
    the QRS complex
    the S-T segment
    the T wave
  • Describe in one paragraph each, the phases of the cardiac cycle, including:
    Relaxation period
    Ventricular filling
    Ventricular contraction
  • Analyse two electrocardiographs for two different people.
  • Draw electrocardiographs to illustrate five different types of heart malfunction, including:
    S.A. Block
    A.V. Block
    Sinus Arrhythmia
    Ventricular fibrillation
    S.T. Depression
  • Compare ventilation during rest, exercise and recovery, for a specific case study.
  • Explain lung capacity, for two people of similar demographics except one being a smoker and the other a non smoker.
  • Explain lung function; including gas movements, and related muscle and bone movements.
  • Explain intra pulmonary and interpleural pressure changes during breathing.
  • Develop a chart which compares symptoms of breathing disorders, with scientific explanations of different problems.
  • Explain the relevance of partial pressure gradients to gas exchange in the body.
  • List factors affecting gas exchange in the human body.
  • Explain how diffusion capacity is related to exercise.
  • Explain one pathway where carbon absorbed as carbon dioxide is transported through the body.
  • List factors which may limit effective blood flow and gas transport.
  • Explain the way in which stroke volume can indicate a persons state of health.
  • Explain how blood flow is redistributed through the body, during exercise.
  • List factors which can stimulate cardio respiratory activity.
  • Describe factors listed which can stimulate cardio respiratory activity.
  • Explain characteristics of cardio respiratory control during rest.
  • Explain characteristics of cardio respiratory control during exercise.
  • Explain the physiological effects of three different coronary risk factors.
  • Explain the anatomical changes to the body caused by atherosclerosis.
  • Describe body changes that may occur (anatomical and physiological) during:
    a heart attack
    a stroke
  • Develop a checklist of indicators of different cardio respiratory complaints.
  • Develop guidelines to minimise the risk of heart disease, in an specified person.


Haemodynamic is the opposite of haemostatic, in other words, it deals with the flowing blood. The force that keeps our blood flowing is provided by the pumping of the heart. The physiology of circulation incorporates velocity and volume of blood flow, as well as capillary exchange. The volume of blood that flows through any tissue in a given period of time is called blood flow. This flow occurs under pressure, and the pressure exerted by the flowing blood on the wall of the blood vessel it is travelling in is known as the blood pressure (BP). Resistance and blood volume affect the BP, making it higher or lower. The blood slows down as it comes to the hair-like capillaries and that is where the blood exchanges materials with the tissues and cells. This capillary exchange happens in three ways: diffusion, vesicular transport, and bulk flow.


There are four sub-systems of networks that can be highlighted within the major circulatory system. Together, these networks make up the entire circulatory system. Individually, they serve particular purposes as can be seen below:

  • The pulmonary (lung) circulation - this network allows for blood to be recirculated via the lungs so that it can be enriched with oxygen.
  • The systemic system - this network allows blood to take nutrients to the cells and to remove waste products from the cell.
  • The hepatic portal system - this directs blood from the spleen, intestines, pancreas and stomach towards the liver. Here, nutrients are exchanged (for example glycogen) while harmful substances are removed.
  • The lymphatic system - this system removes excess fluid from the cells. This fluid was originally taken to the cells by the blood.


The blood is tested to gather information about a person's health status. From blood tests we can learn the relative numbers of different blood cells, detect abnormalities in different blood cells, detect toxins, micro-organisms or antigens, evaluate blood chemistry, electrolyte levels, abnormal events such as large scale tissue death or renal failure, identify cancers of the blood cells and assess clotting and blood oxygen levels. Using the white blood cells, DNA tests can also be done.

To obtain blood a phlebotomist (literally a person who cuts veins) draws blood by puncturing the vein (venipuncture) with a hollow needle and the low pressure in the vein forces the blood out into a tube. If an artery were punctured, the pressure would be very high and blood would flow out with too great a force, and in too great a volume.

Some of the more common blood tests include:

Full blood count

As the name suggests, this test counts the number of different blood cells present in a given volume of blood. This is done by placing a small sample of blood on a slide and examining it under a microscope, generally using stains to highlight the different cell types, or it can be done by inserting a sample into a machine which performs the count automatically.

This test can determine whether the levels of different cells are abnormal and this in turn can indicate what condition a person may be suffering from. Where the suffix -philia is used, it means there is an abnormally high number of a particular type of cell. For example basophilia is a condition where a person has unusually high numbers of basophils. Knowing basophils are involved in allergic reactions, we could deduce that a person with lots of basophils in their blood is reacting to an allergen. Conversely, the suffix -penia refers to an abnormally low number of cells. Leukopenia is a general reduction in the number of all white blood cells and knowing that white blood cells are important for the immune response, we could deduce that this person is more at risk of getting ill than someone with normal white cell levels.

Full blood counts also give a range of different data on red blood cells (number, shape, size, and distribution), haemoglobin levels, as well as a variety of data on thrombocytes.

Cross matching

Blood type can be identified with only a small blood sample. The blood is mixed with samples that contain different blood antigens (A and B) as well as Rhesus factor. What antigens cause the blood to clot determines what blood type the sample is. For example, B negative blood will react to and clot when mixed with a sample with A antigen or a sample with Rhesus factor. Knowing a persons blood type then helps narrow the selection of donor blood of the same or compatible types. However, there are a variety of other factors that affect compatibility of blood, so when a transfusion is required, small amounts of the patient and donor blood, after their types are known/established will be mixed together to check for any clotting or other abnormal reaction. This is known as cross matching.

Blood cultures

These tests are used to identify any micro-organisms in the blood, or living inside blood cells (as viruses do). Blood samples are collected by venipuncture (after the skin is sterilised so you don't contaminate the sample with the bacteria living on the skin) and transferred into special culture vials. Different vials contain different nutrients in solution, and can be either oxygenated or the vial can be completely oxygen free. These are then incubated at normal body temperature. If there are micro-organisms present, machines detect the carbon dioxide they produce. The blood sample can then be used for further analyses, typically staining and microscopy, to determine exactly what micro-organism is infecting the person who gave the sample. The different blood culture vials also help in the identification of organisms (bacteria that require oxygen will not grow in an anaerobic culture for example).

Arterial blood gas

As the name suggests this test examines arterial blood, to determine the concentrations of dissolved gases (oxygen and carbon dioxide) as well as the blood pH and the presence of bicarbonate ions which help maintain normal blood pH. Typically the blood is drawn from an artery in the wrist.

Biochemical and Metabolic Tests

This category of tests encompasses an array of tests for individual molecules. Levels of glucose, cholesterol, sodium, potassium, calcium, iron and urea are most commonly tested, but there are a huge variety of tests that can be performed. They can give information about poisoning, as well as identify nutrient imbalances, and identify some medical conditions, such as diabetes.

INR (Prothrombin Time)

This is a test common because of the number of people with diseases that complicate blood clotting and viscosity. It tests the clotting time of a person's blood and is used to monitor treatment and disease severity in people who are taking blood thinning or thickening medications, such as warfarin. It can also identify people suffering from vitamin K deficiency or conditions that damage the liver.


Blood disorders include a wide range of medical problems that can lead to poor blood clotting and continuous bleeding (coagulopathy, abnormal bleeding and clotting disorders), compromised immune response (HIV/AIDS, leukaemias and so on) conditions which affect oxygen/carbon dioxide transport (haemoglobinopathies) and infections of the blood (bacteremia). These disorders can result from defects in the blood vessels, inherited genetic mutations in blood cells, infection by micro-organisms, some nutrient imbalances (vitamin K and vitamin E for example), or cancers. Blood can also become too acidic or basic, (acidosis and alkalosis respectively) or have an imbalance in the electrolytes dissolved in it.

Some of the blood disorders that can occur are:

Red Blood Cell Disorders


These are a group of diseases characterised by some deficiency in oxygen transport. This may be due to low levels of erythrocytes (erythropenia), low levels of haemoglobin in the erythrocytes, misshapen erythrocytes (such as in sickle cell anaemia) or low iron levels or genetic conditions adversely affecting haemoglobin production.


Inherited conditions that are characterised by abnormal production of haemoglobin. Haemoglobin is made up of units, thalassemias result in too few of some units being produced. This results in an overall lower level of haemoglobin.

White Blood Cell Disorders


Leukaemias are cancers of the leukocytes or the bone marrow that produces them. Leukaemias can be classified according to the specific white cell lineage (myeloid or lymphoid) affected. It may result in a lack of mature leukocytes, or excessive numbers of immature leukocytes which in turn negatively impacts on the production of other blood cells, such as thrombocytes.


Human immunodeficiency virus invades helper T cells, as well as macrophages and dendritic cells. Inside them it takes over the cellular machinery and uses it to reproduce itself. When there are many more new virus molecules, they leave the cell and in the process kill it. They can then move on to find new cells to infect. The disease causes leukopenia as the infected cells die, or try to combat the infection by committing suicide (apoptosis) or when they are recognised as sick/abnormal by cytotoxic T cells that then kill them. Without normal levels of these leukocytes, the immune system can't combat infections as well and eventually the person develops AIDS (acquired immunodeficiency syndrome) and can die from infections that a healthy person could readily combat.

Blood Clotting Disorders


Probably one of the best known genetic and blood disorders. Haemophilia is an inherited condition where the normal clotting process is compromised. Sufferers can suffer severe injury and may die from seemingly minor injuries. Where a blood vessel injury occurs in a healthy person a cascade of events occurs to form a clot, blocking the flow of blood out of the vessel. In haemophiliacs one of the components of this clotting cascade is not produced and this renders the clotting mechanism non-functional. People with this condition may be treated with the missing clotting factor.

Other Disorders

Blood poisoning (septicaemia)

This is a condition where an infection which results in the release of toxins into the blood stream and the multiplication of micro-organisms in the blood stream. It is an extremely serious condition as the blood is in contact with all cells and tissues, which may take up the toxin and be adversely affected also.


The lymphatic system is part of the circulatory system. It is a network of vessels which transports excess fluid from the tissues and organs of the body to the veins. At the capillary networks, fluid leaves the blood vessels and surrounds the tissue cells. Not much of this fluid re-enters the blood vessels as most of it is carried away by the lymphatic vessels. Lymphatic vessels are very thin-walled and have valves similar to those found in veins.

Small lymph vessels unite to form larger vessels which, in turn, unite and eventually drain into the vena cava which enters the heart.

While passing along the lymph route, the lymph passes several lymph nodes for filtration. Harmful material is filtered out and this is attacked by leucocytes in the nodes. During this process the nodes swell (you may have experienced these swellings in the groin or under the arm pit if you have had an infection).