Heart

Question 1

hearts of basal chordates

Answer 1

thin sheets of contracting mesoderm

Question 2

What meant blood could be pumped at higher pressures

Answer 2

myocardium and endocardium

Question 3

the evolution of separate sinus and pumps meant

Answer 3

blood collected whilst also pumped - quickening supply of oxygenated blood

Question 4

how do shark and teleost fish hearts differ

Answer 4

shark hearts have a conus arteriosus to prevent backflow where as teleost have a bulbos arteriosus

Question 5

lungfish are …

Answer 5

bimodal breathers

Question 6

lungfish rely on..

Answer 6

changes in circulatory system to move bloods towards or away from the lungs

Question 7

amphibians have how many heart chambers

Answer 7

3

Question 8

What does the shunt of an amphibian heart do

Answer 8

allows blood to bypass the lungs whilst allowing the animal to remain underwater for long periods

Question 9

reptilian heart has how many chambers

Answer 9

3

Question 10

how do shunts affect the crocodile heart

Answer 10

blood shunted to avoid lungs which carry air enriched with co2. ensures 02 is directed to tissues that need it

Question 11

What evolved from a typical anuran heart

Answer 11

double circulation and 4 chambered heart