Cardiovascular system

Question 1

What is stroke volume? And what are resting values?

Answer 1

• The volume of blood pumped by the left ventricle of the heart per beat
• Untrained average vol - 70ml

Question 2

What is heart rate? And what are resting values?

Answer 2

• The number of beats per minute
• Average resting HR:
  Males: 70 bpm
  Females: 72 bpm

Question 3

What is cardiac output? And what are resting values?

Answer 3

• The volume of blood pumped by the left ventricle of the heart in one minute (SV X HR)
• Untrained person at rest - 5.6 litres per min

Question 4

What are the short-term effects of exercise?

Answer 4

• Increased HR due to increased adrenaline levels
• Increased SV due to stronger ventricular contractions
• Increased Cardiac Output

Question 5

What are the long-term effects of exercise?

Answer 5

• Decrease in resting HR
• Increase in resting SV
• Increase in Cardiac Output during exercise
• Hypertrophy of the heart
• Thicker left ventricle wall
• Increased number of capillaries in muscles
• Increase in blood volume - increase in red blood cells to carry oxygen

Question 6

Describe the changes that take place to stroke volume from rest to maximal exercise levels

Answer 6

• SV increases
• SV plateaus
• SV decreases slightly during maximal exercise
• SV decreases slightly as the HR is so high that there is not enough time for the ventricles to fill completely during the diastole phase (relaxation) before the systole phase (contraction)
• Maximal SV between 120-200ml per contraction

Question 7

How is oxygen transported?

Answer 7

• More than 98% with haemoglobin in the red blood cells (4-6 billion RBC’s)
• Less than 2% dissolved in the blood plasma

Question 8

How is carbon dioxide transported?

Answer 8

• Dissolved in blood plasma
• Bound to haemoglobin
• As bicarbonate ions resulting from the dissociation of carbonic acid