Answer: They are found in babies.
Yes, you are correct. They are the rough endoplasmic reticulum.
Yes it is. This is because during the warmup you are quite literally "warming up" your muscles and ligaments through stretching. Also, many like to incorporate some light cardio into their warmup. Without a warmup you are more prone to injury and will not have a good performance during the main section of your workout, especially if you are lifting.
The cardiac cycle consists of two phases; a period where the heart muscle is relaxed, called <u>diastole</u>, and a period of contraction, called <u>systole</u>.
These are then divided into four stages. These are;
1.<u>Ventricular Filling Period (VPF)</u>
2. <u>Isovolumetric Contraction Period (ICP)</u>
3. <u>Ventricular Ejection Period (VEP)</u>
4.<u> Isovolumetric Relaxation Period (IRP)</u>
At rest, cardiac diastole lasts for approximately 0.5 seconds, and cardiac systole lasts approximately 0.3 seconds to complete. However, during exercise, when the heart rate is increased the time period of <u>diastole</u> , especially, is reduced.
Exercise and flexibility training.