December 15, 2014

Tenth Class Biology Imporant Questions - New Syllabus

Q: Do you know why people who go to high altitudes carry an oxygen cylinder on their back? Blood cannot carry enough oxygen required by the body when we go above the sea level. What are the possible consequences if we don't get enough oxygen supply?

A: At sea level the atmospheric concentration of oxygen is approximated 21% and the barometric pressure averages 760 mmHg. At higher altitudes the 21% remains the same; however the number of oxygen molecules per breath is reduced. At about 5,500 meters (18,000 ft) each breath contains approximately half the normal amount of oxygen (compared to sea level). In order to compensate for the oxygen shortfall the person has to breathe faster and their heart has to beat faster too. Even though breathing faster raises blood oxygen levels, they do not reach sea level concentrations.

Rising to higher altitudes can also cause fluid to leak from tiny blood vessels (capillaries), resulting in potentially dangerous fluid accumulation in the lungs and / or the brain. If a human continues rising to higher altitudes without adequate acclimatization, there is a serious risk of life-threatening illnesses.

(Write the information you collected in tabular form. Put relevant words in columns related to your survey. Write about the experiences you gained while doing your project work.)

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