Explain diastole and systole. How does the body increase blood flow during exercise?

a)

i) Diastole
Diastole is the phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood. This is the period of heart relaxation and blood filling.

ii) Systole
Systole is the phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries. This is the period of heart contraction and blood ejection.

b)
During exercise, the body increases the rate of blood flow primarily through two mechanisms:

• The heart rate increases, meaning the heart pumps more frequently.
• The stroke volume increases, meaning the heart pumps more blood with each beat. Additionally, vasodilation occurs in the blood vessels supplying active muscles, reducing resistance and allowing more blood to flow to those areas, while vasoconstriction occurs in less active areas.