i) The structure that separates the left and right sides of the heart.
j) The ability of the heart to contract at its own inherent rhythm.
k) The layer found on the inside of veins.
l) The blood vessel connecting the stomach and intestine to the liver.
m) Veins that have lost their elasticity and form small sacs of blood.
n) The smallest blood vessels in the body.
o) The pacemaker of the heart254 8.5. Summary