The SA node sends out regular electrical impulses from the top chamber )the atrium) causing it to contract and pump blood into the bottom chamber (the ventricle).
Diffusion.
diffusion is passive, and the oxygen and carbon dioxide move to the area of lower concentration
Both warm-up and cool down exercises can help prevent injuries associated with workouts. They allow the heart rate to increase and decrease slowly which prevents light headedness and also improves blood flow to the muscles.
Answer:
yeah I really dont know what happen there
Explanation:
