GCSE Physical Education The Circulatory System An example of some activities to use during this particular topic.

At the end of this topic you should know the following… The role and components of the circulatory system; The structure of the heart; How the circulatory system works; Definitions of… Heart rate, stroke volume, cardiac output; The roles and characteristics of the 3 types of blood vessels; The functions of blood cells; How the circulatory system is affected by exercise. Give detailed hand-out from Edexcel – the slide is a summary

The Circulatory System Components are… 1 The heart 2 Blood vessels 3 Blood Major functions include… 1 Transport of 0² & CO² to & from the muscles 2 Temperature regulation 3 Preventing infection Major functions: Transport of O2 & CO2: why is this important for daily living and during exercise? Temp reg: during exercise blood is transported from the body core or from areas of increased metabolic activity to parts of the body that are not involved in exercise, such as the skin Infection from invading organisms prevented through role of white blood cells and platelets

The Heart The heart is a special type of muscle called…? Why is it special? What is its main job? Why is the heart often described as a ‘double pump’. Approximately how big do you think the heart is? Start topic of by asking the questions – establish pupil’s knowledge at basic level. Personal answers written in files – compare to correct answers Heart muscle is called cardiac muscle – this is involuntary Double pump refers to the heart’s role in systemic and pulmonary circulation. Adult heart size of a clenched fist.

Answers Cardiac muscle Because it never tires Pump blood around the body There are 2 circuits, the pulmonary and the systemic Size of a fist

The Structure of the Heart Describe the heart’s structure – 4 compartments, separated by valves to stop blood from flowing back. Where does the heart pump blood to and receive blood from? Complete the blank sheets as best you can, colour the left side of the heart in blue and right side in red.

Labelling of the Heart; Point out that this diagram contains a few extra labels that are not on original worksheet (and not required at GCSE level). Explain the pathway of the blood and the differences in oxygenated and de-oxygenated blood

This illustrates the heart as a ‘double pump’. Highlight pulmonary and systemic circulation Play the ‘Sport Examined’ animation with sound. – this links into blood vessels At this point ask what is meant by ‘oxygenated’ and ‘de-oxygenated’ blood.

The Circulatory System Using diagram of heart on previous slide describe the flow of blood through the circulatory system. Deoxygenated blood from the body enters the right atrium via the vena cava. Following its journey through the body, the blood has now collected a number of waste products including CO². From the atrium the blood is now forced into the right ventricle through the tricuspid valve Blood is then forced up into the pulmonary artery which leads to the lungs Here blood picks up O² and deposits CO² The newly oxygenated blood is then forced back to the heart through the pulmonary vein into the left atrium. Blood is then forced into the left ventricle through the bicuspid valve and then into the aorta to supply oxygenated blood to all parts of the body. Students to complete a ‘fill in the gaps’ worksheet Follow up with Sport Examined animation – this will link into blood vessels

Blood vessels Blood vessels are needed to transport blood around the body Arteries: carries oxygenated blood away from the heart to the organs & muscles Veins: carry de-oxygenated blood back to the heart. This blood carries excess CO² Capillaries: the smallest blood vessels. Lie close to the muscle allowing O² & CO² to pass to & from the blood & the muscles.

Blood Vessels Vessels Characteristics Arteries Connective tissue and smooth muscle (elastic) Blood travels under high pressure Oxygenated blood away from the heart Linked to arterioles Have pulses & thick walls Capillaries One cell thick Allow gaseous exchange Linked to arterioles and venules Veins Smooth muscle (non-elastic) Blood travels under low pressure Deoxygenated blood to the heart Thinner walls Linked to venules Summary of blood vessels

Why are arteries have to have some ‘elastic’ quality about them? Questions to class – lead to more in-depth explanation of the reasons for the answer Why are arteries have to have some ‘elastic’ quality about them? Why do veins contain valves? Why are capillary walls so thin?

Blood pressure Blood Pressure Pressure under which the blood travels as it is ejected from the left ventricle Blood vessel constriction increases BP; dilation reduces BP DIASTOLE: Heart is relaxed, BP is reduced 2. SYSTOLE: Heart contracts, BP is increased BP during aerobic exercise; Systolic BP increases in direct proportion to increased exercise intensity Diastolic BP changes little if any during endurance exercise, regardless of intensity Why does BP increases more during resistance exercise? Vaso-constriction caused by muscular contraction. This increase is proportional to size of muscle.

Muscles help squeeze the blood through the veins back to the heart. Note how valves work together.

Blood – what is it?? Blood accounts for __8__% of total body weight. It is made up of cells & platelets, which are suspended in plasma. There are 3 parts to the blood: 1. Red & White Blood cells 2. Platelets 3. Plasma

Blood cells, Platelets & Plasma; Red blood cells (erythrocytes) are extremely small and give the blood its red colour. A typical adult has about 4.8 to 5.4 million red blood cells. The main function of these cells is to transport O² & CO² around the body Oxygen is transported via a chemical called Haemoglobin White blood cells (leukocytes) have the function of protecting the body from bacteria, viruses, infections & foreign bodies Platelets (thrombocytes) are small cell fragments which help blood clotting Plasma is mainly made up of water, but also includes waste, hormones, glycogen and nutrients. Need more on this part – any images or animations? Video?? Copy these points into files

Heart Rate Heart rate defines as …….. ‘The number of times the heart beats per minute’ RHR averages 60 to 80 beats per minute (bpm); can range from 28 bpm to above 100 bpm. HR tends to decrease with age and with increased cardiovascular fitness. Therefore resting heart rate is often used to indicate a person’s fitness levels. HR is also affected by environmental conditions such as altitude and temperature Other factors to affect RHR? Weight, sex, age, digestion, illness

Stroke volume Stroke Volume defines as .... ‘The amount of blood pumped out of the heart by each ventricle during 1 beat/contraction’ SV increases with increasing rates of work. It also influences aerobic endurance capacity when working maximally. Stroke Volume Increases During Exercise Frank Starling mechanism—more blood in the ventricle causes it to stretch more and contract with more force.

Cardiac output Cardiac Output is defined as ..… ‘The amount of blood pumped out of the heart by each ventricle in one minute.’ Resting value of cardiac output (Q) is approximately 5.0 L/min. Q increases directly with increasing exercise intensity to between 20 to 40 L/min. Value of increase varies with body size and fitness level How can you calculate the Cardiac Output? Q = HR x SV When exercise intensity exceeds 40% to 60% of maximum, further increases in Q are more a result of increases in HR than SV. SV decreases as we change from supine to sitting or standing positions – mainly because of gravity causing blood to pool in legs, which reduces volume of blood returning to heart. To compensate for this HR increases to maintain cardiac output.

CHANGES IN HR, SV, AND Q Explain this????? SV decreases as we change from supine to sitting or standing positions – mainly because of gravity causing blood to pool in legs, which reduces volume of blood returning to heart. To compensate for this HR increases to maintain cardiac output. SV continues to increase during exercise up to 40-60% max, then rate of increase slows and plateaus – because of pooling of blood causing decreased amount of blood returning to heart.

The Heart in Action Homer Flanders Heart Rate [beats per minute] 100 65 Stroke Volume [mls per beat] 90 70 Cardiac Output [litres per minute] During physical exercise the body requires more oxygen in order to perform the additional work. As oxygen is supplied by the blood there must, therefore, be an increase in the blood supply. One of the ways in, which this is carried out is by an increase in CARDIAC OUTPUT [i.e. both the heart rate and stoke volume increase as well]. Look at the example in the table. Which person is the fitter of the 2? Homer Q = 9 L/min Flanders Q = 4.6 L/min What is the typical adult resting HR? (72) What is typical HR for moderate exercise? (140) Complete the table [remember there are 1000ml in a litre!]