Exercise physiology 2: Cardiovascular stuff no. 2

Question 1

Long QT durations are indicative of what?

Answer 1

Arrhythmogenic right ventricular cardiomyopathy

- can cause sudden death in athletes unaware of the condition

Question 2

ST segment elevation ( or depression ) is a sign of what?

Answer 2

Ischaemia, often following myocardial infarction (heart attack)

Question 3

Changes to ECG during exercise (in a healthy person)

Answer 3

SLight increase in P wave amplitude

Shortening of P-R interval

Shift to the right of the QRS axis

S-T segment depression (slight)

Decreased T wave amplitude

Question 4

What is an exaggerated S-T depression indicative of?

Answer 4

Coronary heart disease -> due to blocked artery not supplying heart with enough blood / oxygen

Question 5

LQT1 and LQT2 mutations affect what in the heart?

Answer 5

LQT1 -> loss in function in IKs ->”repolarisation reserve”

LQT2 -> loss in function in IKr -> “Main” repolarising delayed rectifier

-> Torsade de pointes

Question 6

Give a description of Hypertrophic cardiomyopathy and its affect on regular heart beat

Answer 6

Abnormal thickening of the left ventricular wall via hypertrophy -> caused by genetic mutation or steroids

Force generation in heart is impaired

• > reduced stroke volume and cardiac output
• > increases likelihood of arrhythmia

Question 7

What is tidal volume?

Answer 7

Volume of air moving in and out in each breath

Question 8

What is vital capacity (VC)?

Answer 8

Greatest amount of air that can be expired after a maximal inspiration

Question 9

What is residual volume (RV) ?

Answer 9

Amount of air remaining in the lungs after maximum exhalation

Question 10

What is total lung capacity? (TLC)

Answer 10

VC + RV

Question 11

Describe the 2 portions of an oxyhaemoglobin saturation / PO2 curve

Answer 11

Loading portion (at top, higher PO2) - saturation stays high even with large changes in partial pressure (arteries PO2 resides here)

Unloading portion (middle - bottom, lower PO2) - Saturation changes quickly even with small changes in PO2, allowing O2 unloading to tissues
(Veins PO2 resides here)

Question 12

Purpose of myoglobin?

Answer 12

O2 transferred from haemoglobin to myoglobin
-> myoglobin then transports O2 into cell across membrane

Does this due to higher affinity than haemoglobin for O2

Question 13

Which areas of the brain house respiratory control centres?

Answer 13

Medulla oblongata and pons

Question 14

What is the ventilatory threshold?

Answer 14

Ventilation will increase disproportionately to O2 consumption

Believed to be due to the VE/VCO2 ratio -> the need to remove excess CO2