In: Biology
The human heart has four chambers (two atria and two ventricles). In the human foetus, there is an opening between the right and left atria, and they function as one atrium. This opening closes after the birth. In some cases, it does not close completely. In most of these cases, this incomplete closure remains undetected throughout life. If a large opening occurs between the right and left ventricles, as seen in normal reptiles, children with this condition cannot survive without surgical intervention.
Please answer the following sub-questions separately.
1)What is the name of the opening between the right and left atria?(1 mark)
2)In rare cases, an infant with this incomplete closure shows a clinical sign. What is the most likely sign?(1 mark)
3)Briefly explain the pathophysiological process that leads to this clinical sign.
4)How many chambers does the frog usually have? (0.5 mark)
5)Briefly explain the circulation system of the fish including the anatomy of its heart.(1.5 mark)
6)Some fish or reptiles can be larger than human infants. Generate your own hypothesis and explain why the human requires a four-chambered heart (two atria and two ventricles).
1. Foramen ovale is the opening between the right and left atria.
2. An infant with PFO could have a blue tint to their skin when crying or passing stool. This is called cyanosis. Neonatal cyanosis, particularly central cyanosis, can be associated with significant and potentially life-threatening diseases due to cardiac, metabolic, neurologic, infectious, and parenchymal and non-parenchymal pulmonary disorders
3. Cyanosis typically occurs when the amount of oxygen bound to hemoglobin is very low. Oxygen in the blood is carried in two physical states. Approximately 2% is dissolved in plasma and the other 98% bound to hemoglobin. The presence of cyanosis might be an indication of inadequate oxygen delivery to the peripheral tissues. It also could be related to an increased oxygen extraction by the peripheral tissues. when the level of deoxygenated hemoglobin is around 3 to 5 g/dL, cyanosis becomes very evident.
4. The frog heart has three chambers.
5. Fish have a single circulation for blood flow and a two-chambered heart that has only a single atrium and a single ventricle. The atrium collects blood that has returned from the body and the ventricle pumps the blood to the gills where gas exchange occurs and the blood is re-oxygenate this is called gill circulation. The blood then continues through the rest of the body before arriving back at the atrium; this is called systemic circulation.
6. Human unlike fish and reptiles are warm-blooded animals, expend a lot of energy and need a lot of oxygen. In the mammal heart, the oxygenated and deoxygenated blood is not allowed to mix, and this is achieved by the separation of the heart into right side and left side. Such a separation of heart provides an efficient method of supplying oxygen to the body. This configuration ensures the separation of low-pressure circulation to the lungs, and high-pressure pumping into the rest of the body.