EXAM QUESTIONS - Circulation



EXAM QUESTIONS – Circulation

Blood Vessels

1 (b) During physical activity, oxygen is supplied to the muscles through the blood system.

Describe two characteristics of veins which assist the transport of blood. (2 marks)

Blood Pressure

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Blood Vessels

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Control of Heart Rate, Training

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Oxygen transport at the tissues

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Blood Pressure

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Cardiac Dynamics

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Control of Heart Rate

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Venous Return

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Cardiac Dynamics , Training

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Training and Control of Heart Rate

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Blood Shunting and Venous Return

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Blood Pressure

Jun 04 - Qu 5

When playing golf, a player’s blood velocity and pressure is similar to the graph below.

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(a) (i) Using the graph identify blood vessels represented by A, B, C, D and E. (3 marks)

(ii) Explain the variation in blood pressure and blood velocity occurring from A to E. (3 marks)

Jan 2002 - Qu 3

c) In a variation of baseball, the batter has to run every time he strikes the ball. At the end of an extended innings, the information in Table 2 was obtained.

Table 2 - Estimated blood flow in cm3 per minute

|Organ system |Prior to batting |% |After extended innings |% |

|Skeletal muscle |1200 |21.0 |12500 |72.0 |

|Heart |250 |4.0 |750 |4.0 |

|Skin |500 |8.5 |1900 |11.0 |

|Kidneys |1100 |19.0 |600 |3.5 |

|Abdominal organs |1400 |24.0 |600 |3.5 |

|Brain |750 |13.0 |750 |4.0 |

|Other |600 |10.5 |400 |2.0 |

|Total |5800 |100 |17500 |100 |

Using information from table 2 account for the changes in the blood flow during exercise to:

i) the skin;

(ii) the heart. (3 marks)

June 05 - Qu 4

The information in table 3 was obtained from a performer at rest and during a game of hockey.

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(c) (i) Explain why the blood flow to the brain remains the same at rest and during

the game. (2 marks)

(ii) Explain why there is a need for blood flow to increase to the skeletal muscles during the game and how this is achieved. (4 marks)

MARK SCHEME – Circulation

1 (b) Describe two characteristics of veins which assist the transport of blood.

|(2 marks) Veins: | | |

|A. Thinner muscle/elastic tissue layer | | |

|B. Valves | | |

|C. Wider lumen/diameter | | |

|D. Blood at low pressure | | |

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June 04 - Qu 5

(a) (i)

A – Arteries, B – Arterioles, C – Capillaries, D – Venules, E – Veins;

3 marks for 5 correct, 2 marks for 4 correct, 1 mark for 3 correct

(ii)

1. Velocity related to cross sectional area;

2. Smaller the area, faster the flow;

3. Capillaries – largest total cross sectional area – slow blood flow;

4. Veins/venules – smaller cross sectional area – faster flow;

5. Assisted by venous return mechanisms;

6. Pressure relates to resistance to flow;

7. Friction between blood and walls of vessels;

8. Friction depends on smoothness of lining and diameter of vessel/viscosity of blood;

9. Localised arterial constriction; max 3

Jan 2002 - Qu 3

(c) 1 Skin-more blood to surface( capillaries);

2 To lose heat by radiation/evaporation/conduction/convection;

3 (Heart - increased heart rate) hence more oxygen and nutrients to heart required.

(3 marks)

Jan 04 - Qu 1

(a) 1 Brain function needs to be maintained during exercise/or at rest;

2. Brain requires glucose/feeding/oxygen(O2). 2 marks

(b) 1 Digestion and absorption of food takes time;

2. During exercise, there is reduced blood flow to the gut;

(accept references to figures)

3. If the gut is full, blood will be diverted to the stomach;

4. Denying blood to the active muscles;

5. Affecting performance/lack of oxygen (O2 )to muscles/equiv;

(do not accept stitch or cramp)

6. Feeling nauseous/sick. 3 marks

(c) 1 Active muscles require nutrients/oxygen (O2);

2. Blood is redirected/shunted to (active) muscles;

3. This is achieved by the action of the autonomic/sympathetic system;

4. Vasodilatation/allowing greater flow to areas needing blood;

5. Vasoconstriction/restricting blood flow;

6. Pre-capillary sphincters/control blood flow into the capillary flow.

4 marks

June 05 - Qu 4

(c) (i) 1. Brain function needs to be maintained during exercise and at rest;

2. Brain requires nutrients/glucose/oxygen;

3. Cognitive thought requires nutrients. 2 marks

(ii) 1. Muscles need nutrients/oxygen to generate energy/work;

2. Stimulation by sympathetic nervous system;

3. Or adrenaline/noradrenaline is produced;

4. Controlled through arterioles;

5. By contraction of precapillary sphincters (control blood into capillaries);

6. Reduction of blood flow to the liver/kidneys/abdominal organs/gut;

7. Opening of vessels in the skeletal muscle/skin/Coronary circulation;

8. Vasoconstriction/vasodilation

9. This occurs due to drop in oxygen/rise in carbon dioxide levels/pH levels

drop/ increase in acidity/increase in temperature.

10. Detected by chemoreceptors;

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