What are the three main parts of the circulatory system.

The parts of your circulatory system are your:

1)Heart, a muscular organ that pumps blood throughout your body.

2)Blood vessels, which include your arteries, veins and capillaries.

3)Blood, made up of red and white blood cells, plasma and platelets.

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.