GCSE Physical Education

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GCSE Physical Education

• The Circulatory System

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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.

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The Circulatory System

• Components are
• The heart
• Blood vessels
• Blood
• Major functions include
• Transport of oxygen carbon dioxide to from
  muscles
• Temperature regulation
• Preventing infection

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The Heart

• Use your textbooks to find out the correct
  answers to the following questions...
• 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?

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The Structure of the Heart
Use your text books to label the different parts
of the heart
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Group task

• Organise yourselves into groups of 4-5 people.
• You will need a sheet of A3 paper, a plastic
  wallet with labels inside, a pen/marker paper
  glue.
• Arrange the labels to accurately illustrate the
  structure of the heart, and the flow of blood
  around the cardiovascular system.
• Link your labels together by drawing arrows
  between them where appropriate.

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Group task

• When to use
• Early to check KS3 science knowledge.
• Late to check KS4 science knowledge.
• Revision.

• Differentiation
• Teacher decides on groups, or let students
  choose.
• Test answers with text book.
• Use more able student as observer.
• BW and/or red blue labels.

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The Structure of the Heart
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The Circulatory System

• Complete the worksheet.
• If necessary, use your textbooks to help you.
• Ask if you are unsure about any of the words.

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Blood vessels

• Blood vessels are needed to transport blood
  around the body
• Arteries carry oxygenated blood away from the
  heart to the organs muscles
• Veins carry de-oxygenated blood back to the
  heart. This blood carries excess carbon dioxide
  and other waste products
• Capillaries the smallest blood vessels, which
  lie close to the muscle allowing oxygen and
  carbon dioxide to pass to from the blood the
  muscles

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Blood vessels over to you

• Use your textbooks to find out about the
  different blood vessels.
• With a partner list the similarities and
  differences between arteries, veins and
  capillaries.

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Blood pressure

• BP pressure under which the blood travels as it
  is ejected from left ventricle
• Blood vessel constriction increases BP dilation
  reduces BP
• DIASTOLE heart is relaxed, BP is reduced
• 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

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

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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 types of blood cells
• Red blood cells
• White blood cells
• Platelets

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Homework Task

• Find out about red white blood cells and
  platelets (use your textbooks, other books in the
  library, CD ROMS or internet).
• In your own words, describe the function of each
  of the 3 blood cells.

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Blood cells

• 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
  oxygen and carbon dioxide 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 and foreign bodies
• Platelets (thrombocytes) are small cell fragments
  which help the blood to clot.

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Heart Rate

• Heart ratethe number of times per minute that
  the heart contracts.
• RHR averages 60 to 80 beats per minute (bpm) can
  range from 28 bpm to above 100 bpm.
• Tends to decrease with age and with increased
  cardiovascular fitness.
• Therefore resting heart rate is often used to
  indicate a persons fitness level.
• Is affected by environmental conditions such as
  altitude and temperature

What other factors can affect resting heart rate?
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Stroke volume

• Stroke Volumethe amount of blood pumped by the
  heart per contraction (beat).
• SV increases with increasing rates of work.
• Influences aerobic endurance capacity when
  working maximally.
• Stroke Volume Increases During Exercise
• Frank Starling mechanismmore blood in the
  ventricle causes it to stretch more and contract
  with more force.

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Cardiac output

• Cardiac Output the amount of blood pumped by the
  heart per 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.

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CHANGES IN HR, SV, AND Q
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The Heart in Action
Complete the table remember there are 1000ml in
a litre!
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Measuring pulse rate
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The Heart in Action

• The data on the next slide show a persons heart
  rate before and after a short period of intense
  exercise.
• Using graph paper or a spreadsheet package (e.g.
  Excel), plot a line graph.
• Use Time on the horizontal axis and Heart Rate on
  the vertical axis.
• Draw a smooth curve through the points and give
  your graph a title.
• Describe what happens to the persons heart rate
  during the 15 minutes it was measured.

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Heart Rate During Different Activities

• Resting
• 68 bpm
• Brisk uphill walking 142 bpm
• Running uphill
• 188 bpm

• Compare the data on the left by
• Drawing a bar chart.
• Writing a few sentences to explain why the values
  have changed.
• Working out the percentage of the persons
  maximum heart rate at each intensity. This is
  estimated as 220 age (the data is from a 17
  year old person).

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Circulatory system PEP

• What type of activities/training programmes might
  be affected by the efficiency of the circulatory
  system?
• Baseline data measure RHR, HR max HR rec.,
  plus BP are there changes during and after the
  training programme?
• If so, what are the changes caused by?

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Homework
1. What are the components of the circulatory
system? (3 marks) 2. What type of muscle makes
up the heart, why is it special? (2 marks) 3.
There are three types of blood vessels. Describe
each type. (5 marks)
4. Label the diagram below, which demonstrates
passage of blood through the heart and around the
body. (10 marks)