Question

Some fish or reptiles can be larger than human infants. explain why the human requires a four-chamber heart (2 atria and 2 ventricles) 4 marks

Answer 1

• The human are warm-blooded animals are the so that they require a large amount of the energy to keep their homeostasis.
• Also this heart system helps it get-acquire required amount of oxygen and other energy requirements for various activities such as running, climbing, live in high altitude, etc.
• The reptiles have 3 chambered with 2 atria and one ventricle such that it receives deoxygenated from the left side and oxygenated from the right but in the ventricle, they both mix so that their efficiency to deliver oxygen is reduced so that their capacity to maintain body temperature cannot be done.
• Also other than the pulmonary system they have a respiratory pathway through the moist skin so that some of their oxygen requirement can be met in this way.
• In the case of fish they are having 2 chambered hearts the oxygenated blood is pumped from the gills and the heart will pump the blood to the entire blood so that systemic circulation.
• So that their efficiency of oxygen dispersion is low so that they are unable to maintain body temperature.
• The warm-blooded animals require more energy to maintain their body temperature but that is not needed in cold-blooded animals so that heart with 2 or 3 chambers is enough to maintain their energy requirement.
• Also this arrangement of the heart help in pumping the blood to the lungs at lower pressure whereas at high pressure to the systemic circulation.
• The right of the 4 chambered heart receives deoxygenated blood whereas left side receives oxygenated blood and also as the ventricles are separated there is no mixing of the blood so that their efficiency of the oxygen-carrying is high.
• This efficiency help the humans to survive at higher and lower altitude.