1. The cells of the SA node at the top of the heart are known as the pacemaker of the heart because the rate at which these cells send out electrical signals determines the rate at which the entire heart beats (heart rate).
2. septum : The septum is a thick wall of muscle that divides the heart. It separates the left and right sides of the heart.
3.The respiratory and circulatory systems work together to maintain homeostasis. The respiratory system moves gases into and out of the blood. The circulatory system moves blood to all parts of the body.
hope this helps! sorry I couldn't do all of them!
<em>Hi !</em>
D.
Fit test you for the appropriate respirator size and type
"Mitosis is a division in which the daughter cells formed are same as their parent cells.In humans all sorts of cells undergo this type of division Except cells of gametes(reproductive system).For example,mitosis for growth of body,for hair growth,tissue cells when repairing is required etc."
I hope all is well, and you end up passing!
I think it is uh... 549,196* people, but I may be wrong. I'm using a CDC PDF so, I may have read it wrong.
