heart

[MIA6]

1. The pulse is a wave of alternate stretchings and contractions of artery walls that proceeds from the aorta along all arteries and arterioles. The stretching does not represent the advancing front of a wall of blood. I don't understand the last sentence, 'advancing front'?
2. What is 'fetal' (?) heart circulation?
3. My teacher usually put the 'blue' color to represent carbon dioxide in the heart, why? why is blue? it is supposed to be colorless i assume? Additionally, red color as oxygen?

thanks for help!

[Poison]

for 2: use a dictionary. Look it up, what is fetal?
for 3: both blood is red. the only difference is that Hb carries O2 or not. Venous blood is darker than artherial blood, probably that's why it is used like that.

[destiny]

For 1: Is that 'adanvcing front' means 'moving toward the front'? Like this: ->>>>> moving forward?

[jimmystang]

i'm not too familiar with this, but wit "fetal" circulation, isn't it a little different in some mammals because there's a ductus arteriosus that connects the pulmonary artery and the aorta?

i think this might be because the fetus does not yet use its lungs, so the pulmonary circuit isn't really active, and is, in a way, bypassed.

[victor]

so, no 1. means that the pulse generated from aorta to the artery (which usually you feel it at your wrist) is not representing the blood that flow through there at the time you feel the beat. The pulse is faster than the blood-flow

[sdekivit]

well they choose blue for deoxgenated blood, because deoxygenated blood causes cyanosis --> a blueish skin appearance.