Heart Dissection.

QUESTIONS:

1. Atria have thin muscular walls, blood enters them through a blood vessel and leave through a valve. Ventricles have thick muscular walls, blood enters them through a valve and leave through a blood vessel.The ventricles need to have thicker muscular walls because they have much further to pump the blood.

2. Arteries - transports oxygenated bloog from the heart (except in pulmonary artery which contains deoxygenated blood). Arteries have:

-thick muscular wall
-much elastic tissue
-small lumen relative to diameter
-not permeable
-valves in pulmonary artery and Aorta only
-blood under high pressure (10-16kPa)
-blood moves in pulses
-blood flows rapidly

Veins transport deoxygenated blood back to the heart (except in pulmonary vein which carries oxygenated blood)
-thin muscular wall
-little elastic tissue
-large lumen relative to diameter
-not capable of constriction
-not permeable
-valves throughout all veins
-blood under low pressure (1kPa)
-no pulses
-blood flows slowly

3. SEMILUNAR VALVES:

semilunar valves prevent the back flow of blood from the arteries to the ventricles

ATRIOVENTRICLE VALVES:

when going from the right atrium to the the right ventricle, it closes acting as a "wall" so that the pumped blood won't go back into the right atrium.The same when the blood goes from the left ventricule to the left atrium

4. What I found interesting about dissecting the heart was both how big and how small it was. Very contradicting, but I can explain. Firstly, at first glance I thought it was humongous. To think that was in a living creature was outstanding. That's in your body and you don't even think twice about it. Secondly, at closer inspection I thought it was actually kind of small. For the really big job it has, it seems really small. Which of course, it really isn't, but that was my initial reaction.