THE CIRCULATORY SYSTEM
OBJECTIVES
At the end of this topic:
1. You should know exactly where in the heart the following components are:-
i. Auricle v. Vena Cava
ii. Ventricle vi. Pulmonary Artery
iii. Tricuspid/Biscuspid Valves vii. Pulmonary Vein
iv. Aorta
2. You must know how the circulatory system works and how the heart acts as a
pump in the double circulatory system.
3. You must be able to define:-
a. heart rate
b. stroke volume
c. cardiac output
4. You must be able to say how the heart is affected by physical exercise.
5. You must be able to define what the following are:-
i. Arteries
ii. Veins
iii. Capillaries
6. You must be able to compare and contrast the 3 types of blood vessels [see
and note their SIMILARITIES and DIFFERENCES.
WHAT'S IN THE HEART?
A. In the back of your exercise book write down:-
i. How heavy do you think your heart is?
ii. How big do you think your heart is?
iii. What is the name of the heart muscle called?
Now using the books available find out the correct answers - how close were you? - Now write them in the front of your exercise books.
[Make sure you write your answers in sentences].
B. Collect the sheet on the heart and on the diagram fill in the following components in the heart.
i. Pulmonary Artery vi. Aorta
ii. Vena Cava vii. Pulmonary Vein
iii. Right Auricle viii. Left Auricle
iv. Right Ventricle ix. Left Ventricle
v. Tricuspid Valve x. Bicuspid Valve
Colour the LEFT HAND SIDE OF THE HEART IN BLUE
[de-oxygenated blood]
Colour the RIGHT HAND SIDE OF THE HEART IN RED
[oxygenated blood]
THE HEART AT WORK
The heart is a pump, in fact it is two pumps working together. The right side pumps blood to the lungs to get Oxygen and the left side pumps blood to all parts of the body except the lungs.
Read 'Sport Examined' and 'Fundamentals of Health and PE' then copy and complete the following:-
The heart is really two ______________ working together. The right side pumps blood only to the ________________ to get O ________________. The left side pumps blood to all _______________ of the body except the ____________. D_____________ B_________________ has a lot of Carbon Dioxide and very little Oxygen, and comes to the heart from all parts of the body. It is carried to the R_____________ A______________ in the _______________
_______________. When it is sucked down into the R______________ V______________ the muscle is _________________. This is called D______________.
When the muscle of the ventricle contracts, the blood is forced up the ________________ ___________________. The T___________ V___________ is shut to stop blood going back up into the Atrium. This is called ______________.
The blood goes to the _________ where it picks up oxygen and leaves carbon dioxide. It is now O____________ B_____________ and flows along the P_________ V__________ from the lungs to the L___________ A_______________. It is sucked into the L_____________ V_______________ through the open B______________ V_____________ while the muscle is relaxed [DIASTOLE]. When the muscle of the left ventricle contracts, the blood is forced up the A____________. The Bicuspid Valve is shut during SYSTOLE to stop the blood going back up the Atrium. The Aorta is the giant artery which has many branches to take oxygenated blood to all parts of the body.
The transport of blood in the pulmonary artery through the lungs and back to the heart along the pulmonary vein is called P______________ C___________. The transport of blood in the Aorta to all other parts of the body and back to the heart along the Vena Cava is called S___________________ C_______________.
TO THE BEAT
What is meant by the following terms? - Answer in your exercise book.
i. Heart beat/ Heart rate iii. Cardiac Output
ii. Stroke Volume iv. How can you work out Cardiac Output
[You may need to go to the Library for the answers].
CHANGES DURING PHYSICAL EXERCISE
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 following examples:-
Person A Person B
Heart Rate 180 per minute 65 per minute
Stroke volume 115 mls per beat 80 mls per beat
Cardiac Output ? litres per minute ? litres per minute
Copy the table above into your book and work out the CARDIAC OUTPUT for person A and person B.
REMEMBER:- THERE ARE 1000 MILLILITRES IN A LITRE
Which of the persons above are exercising and which are at rest?
PRACTICAL SKILLS
These figures below give the rate of a person's heart beat before and during a period of intense exercise.
TIME HEART RATE BEATS PER MINUTE
0 60
1 64
2 EXERCISE STARTS 68
3 130
4 150
5 161
6 171
7 167
8 110
9 98
10 90
11 82
12 74
13 68
14 64
15 60
Using a piece of graph paper plot a graph.
Use Time on your horizontal axis and heart rate on the vertical axis.
* Draw a smooth curve through the points. Give your graph a title
NOW In your books - describe [in words] what happens to the person's heart rate during the 15 minutes it was measured.
The following data was collected from a group of 16 year old boys whilst they were sitting in the classroom. Two of the boys in the sample had run from the playground to the classroom because they were late for the lesson.
Pulse Rate in Beats per Minute Number of Boys
70 6
73 7
76 9
79 10
82 3
85 2
88 1
91 0
94 0
97 1
100 1
Using a piece of graph paper draw a Histogram (bar chart) from the data - give your graph a title.
Now answer the following questions in your exercise books.
1. How many boys have a pulse rate of less than 82 beats per minute?
2. Which are most likely to be the pulse rates of the boys who arrived late?
3. 3 boys selected at random had the following pulse rates:-
Boy 1 70 beats per minute
Boy 2 88 beats per minute
Boy 3 97 beats per minute
What is the average pulse rate for the 3 boys ( show your working ).