Comparative PHGY

Question 1

About insect circulation?

Answer 1

• Made of two components an aorta and a heart that pumps and contracts, can have many contractile structures, the number varies from insect to insect
• haemolymph not blood, no RBCs, gets O2 through different structures enters through ostia, one left and one right ostium (2 holes)
• open circulation, fluid leaves the CVS and does not stay within at all times

Question 2

About piscine circulation?

Answer 2

• Closed circulation, blood always in the heart or in the vessels
• Single-loop circulation, always that one direction
• 2 chambers: an atrium (receives deoxy from system) and a ventricule (pumps deoxy to get oxy in gills)
• Gill capillaries are wgere the exchange of O2 happens and at systemic capillaries, blood gets deoxygenated
  ( red is oxy, blue is deoxy )

Question 3

About amphibian and most reptilian circulations?

Answer 3

• Closed circulation
• Double-loop circulation (systemic circulation and pulmocutaneous circuit because there is some gaz exchange at the level of the skin)
• 3 chambers (2 atrium and 1 ish ventricule that has no septum (atriums are separated by a septum) so a little bit of mixing of oxy and deoxy blood streams when pumped out of the heart but surprisingly only very little to none) / left to system, right to lung and skin

Question 4

About avian and mammalian circulation?

Answer 4

• 2 hearts: right and left heart thanks to appearance of the interventricular septum also each “heart” is responsible for one and only one type of circulation (right is pulmonary and left is systemic), no mixing at all and is why thought to simply be two entirely different organs just glued together, some people may even say there are four hearts as there is also the muscle pump and the respiratory pump that participate in the movement of fluid
• Interatrial septum vs interventricular septum and septum on its own often simply refers to the interventricular septum
• closed circulation
• double loop circulation
• and what really distinguishes it from other circulatory systems is really the fourth chamber appearnace
• We have a higher PO2 in mammals and birds than in reptiles, we are warm blooded they are cold blooded

Question 5

Give an example of animals whose circulatory system is surprising

Answer 5

Crocodilians (alligator, crocodile, caiman, gharial) are reptiles but they are more closely related to birds and dinosaurs than to most animals classifed as reptiles, the three families being included in the group archosauria, the ruling reptiles, they have a four chamber heart and is thought that it is this way because they were in water but then these creatures moved to land where they needed more energy than in water where there is a buoyant force to move, so they developed a four chamber heart