2. Pulse Rate Investigation Introduction:  The following notes will enable you to gain an understanding of the theory needed for the pulse rate investigation. - And get those hearts racing!  Points discussed will be…  What is a pulse?  Pumping those muscles!  Making energy Getting those hearts racing!

3. What is a pulse?  A pulse is a series of pressure waves in an artery, caused by contraction of the left ventricle of the heart.  Where can it be felt? It can be felt where arteries are close to the skin. e.g. The carotid artery in our neck, or the radial artery in our wrist.

4. What is it measured in?  The pulse rate corresponds to the number of times the heart beats in a minute. So, it is measured in the units Beats Per Minute (BPM).  The average resting pulse in an adult is 60 – 80 beats per minute. Variables such as exercise, stress, age, illness and emotion can produce faster rates. Can you think of any more variables?

5. Pumping those Muscles!  When we exercise, we use our muscles to work. Our muscles are continually contracting and relaxing, to do this they need ENERGY.

6. Making Energy  In our diet there are high energy foods, such as fats and carbohydrates (sugars). RESPIRATION. RESPIRATION.  We can release the energy from the food we eat by using a process called RESPIRATION. RESPIRATION.  This is a process which occurs in all our cells. In our muscle cells as we exercise and in our brain cells when we think!

7. Making Energy ….  Respiration needs the reactants glucose (sugar) and oxygen.  The word equation is….  Glucose + Oxygen Carbon Dioxide + Water + Energy  The chemical equation is… C 6 H 12 0 6 + 6O 2 6CO 2 + 6H 2 0 + Energy

8. Respiration Below is a diagrammatic representation of respiration. Click on the mouse to see what happens. GlucoseOxygen Carbon Water Dioxide The reactants and products of respiration are carried to and from the cells by the blood.

9. Getting those hearts racing!  When we exercise are muscles need energy to do work. They can get this energy by respiration.  The more exercise we do, the greater work our muscles do, so more energy is needed.  As the demand for energy increases, more respiration has to occur.  Respiration releases the energy from our food (glucose).  The blood carries a fresh supply of oxygen and glucose to the muscle cells.  As exercise increases, the demand for glucose and oxygen increases, so the blood is needed to be pumped faster by the heart, so that our muscles can receive the reactants for respiration quickly.  As the blood is being pumped faster the pulse rate will increase.

10. Respiration Recap Select from the options below to look at the above points again…  What is a pulse? What is a pulse?  What is it measured in? What is it measured in?  Pumping those Muscles! Pumping those Muscles!  Making Energy Making Energy  Respiration Respiration  Respiration diagram Respiration diagram  Getting those hearts racing! Getting those hearts racing!