question_answer

  State reason for the following   (a) Walls of ventricles are thick and more muscular than walls of atria. (b) Arteries have thick and elastic walls. (c) Arteries form capillaries.

Answer:

                  (a) Ventricles have to pump blood into various organs. They need more strength and energy to perform this function. Thus, they have thicker walls.                                                      (1) (b) Arteries are the vessels that carry blood away from the heart to various organs of the body. Since, the blood emerges from the heart under high pressure, the arteries have thick, elastic walls.                                             (1) (c) On reaching an organ or tissue, the artery divides into smaller and smaller vessels to bring the blood in contact with all the individual cells.                                                  (1)