2d. What\'s the driving power for the oxygen to move from blood vessel and enter

Question

2d. What's the driving power for the oxygen to move from blood vessel and enter the surrounding tissue cells? Describe the process (5 points) 3. There are two types of blood, oxygen-rich and oxygen-poor in cardiovascular system 3a. What's the partial pressure of O2 and CO2 in the blood in aorta respectively? How do they affect the pH value of the blood? (5 points) 3b. What's the partial pressure of 02 and CO2 in the blood in superior vena cava respectively? How do they affect the pH value of the blood? (4 points) 3c. Usually the color of oxygen-rich and oxygen-poor blood are different, why? (4 points) 4. One scientist established a technique that could map the pathways of oxygen movement in human body. When he traced the movement of oxygen molecules, he found two facts in normal healthy people: (1). Some oxygen molecule (02) was inhaled into the lung, but never make up its way to reach the heart; (2). Some oxygen molecules (02) could pass through the heart more than ten times after entering the blood. 4a. Explain how and why (1) happened (4 points). 4b. Explain why and how (2) happened (4 points).

Explanation / Answer

Ans 2d) Blood vessels consists of arteries , arterioles , capillaries , veins and venules that help in circulation of blood throughout body tissues. Alongwith circulation there is exchange of gases like oxygen , carbon dioxide that happens in capillaries.

Capillaries are tiny blood vessels that connect arterioles and venules by branching out of arteries. The size of capillaries is so small that they cannot hold more than 5% of blood , but they are in large quantiy. Capillaries are essential for delivery of oxygen to the tissues and exchange of nutrients between blood and interstitial cells. This exchange of gases takes place through process of Diffusion as capillaries are thin layered epithelial lining vessels. Inhaled Oxygen moves from the Alveoli  to the blood in the capillaries and carbon dioxide moves from the capillaries blood to the air in the alveoli in form of deoxygenated blood. Oxygen gets dissolved into the plasma and combine with hemoglobin to form oxyhemoglobin Hbo2 and is thus flows to the deficient tissues. Hence the generous amount of capillaries in airsacs allows more oxygen and exchange of gases for tissues to get sufficient oxygen.

3a) Aorta is the main and largest artery that supplies oxygenated blood into the circulatory system. This arterial or oxygenated blood has partial pressure of oxygen PaO2 in between 75 mm of Hg to 100 mm of Hg.

Partial pressure of carbon dioxide in arterial blood PaCo2 is between 30 mm of Hg to 40 mm of Hg.

Blood ph in oxygenated blood is not acidic as a fact because oxygen concentration due to more partial pressure of oxygen in arterial blood than carbon dioxide does not allow carbon dioxide to dissolve with water and form bicarbonate and hydrogen ion. Hence blood Ph is maintained normal at around 7.4

3b) Superior vena cava is the large vein that carries deoxygenated blood to the heart.

Partial pressure of oxygen in superior vena cava is 40mm of Hg

Partial pressure of carbon dioxide in deoxygenated blood is 45 mm of Hg.

Normal blood Ph is 7.35 to 7.45 , Blood ph reprsents the acidity of blood which is done by more hydrogen ions in blood. In deoxygenated blood or blood in superior vena cava the acidity of blood increases by decreasing the blood Ph value , as due to presence of carbon dioxide with more slightly more partial pressure. This pressure causes carbon dioxide to form carbonic acid alongwith water and then dissociated into bicarbonate and hydrogen ion. More hydrogen ion means more power of hydrogen and more acidic value of blood. Ph of blood in vena cava is around 7.32 making it more acidic.

3c) oxygen rich and oxygen poor blood colours are different , reason lies in the fact that in oxygenated blood there is presence of Hemoglobin which imparts red colour to the blood. Oxygen deficient blood means deoxygenated blood contains carbon dioxide and other waste products too that imparts dark blue colour due to deoxyhemoglobin also. One more reason is due to scattering of blue light from deeper veins.

4a) The alveoli of lungs are surrounded by thin epithelium capillaries which favours oxygen and gas transport. When air is inhaled in the partial pressure of oxygen is different in alveoli and inspired air making its way more to the lung alveoli and through diffusion process of capillaries it allows a pressure gradient to form and oxygen is then entered. The red blood cels has capacity for oxygen in the inhaled air and so the oxygen attaches to the hemoglobin for making oxyhemoglobin and further the exchange takes place and almost all oxygen is utilised in lungs rather entering to the heart directly.

4b) After entering blood Oxygen molecules travel more faster as with pulmonary vein which is largest vein that carries oxygenated blood from lungs to heart unlike other veins that carry deoxygenated blood to heart. This oxygenated blood that heart recieves from pulmonary directly to left atrium is pumped by heart to other parts of body and is a fast process.

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