adapts 1.12 At elevated altitudes, the body to the reduced barometric pressure t
ID: 3505011 • Letter: A
Question
adapts 1.12 At elevated altitudes, the body to the reduced barometric pressure to extract sufficient oxy- gen to permit normal metabolic functions and do work. For example, at an altitude of 3,650 m (close to 12,000 feet above sea level) the barometric pressure drops to 485 mmHg. For an oxygen pressure drop in the lungs of 30 mmHg, determine the oxygen uptake rate for a respiration rate of 20 breaths per minute. Estimate the oxygen saturation in venous blood if the hematocrit rises to 0.60 and the partial pressure of oxygen blood is at a partial pressure equal to 98% of the alveolar level.Explanation / Answer
ANSWER:
At high altitudes the barometric pressure is low,the amount of oxygen in the atmosphere is same as it is at the sea level.
Due to the low barometric pressure,partial pressure of gases is proportionally reduced and this leads to hyoxia.
Carbondioxide in atmosphere is negligible and at high altitudes it depends on the metabolic and respiratory activities.
Bodily changes at high altitudes:
Due to the lowered oxygen at higher altitudes following changes takes place-
Hypoxia
Expansion of Gases
Fall in the atmospheric temperature
Light rays
1.HYPOXIA::
The effects of Hypoxia on different systems are as follows
a.Blood:
During Hypoxia erythropoietin is released from juxta glomerular apparatus of the kidney and this stimulates the red bone marrow.Hence the red blood cell count increases with increase in reticulocyte count,thus the oxygen carrying capacity of the blood can be maintained.there is alkalemia.
b.Cardiovascular System:
Due to reflex stimulation of cardiac and vasomotor centers, there is an increase in heart rate, force of contraction ,cardiac output and blood pressure, but later there is rate of reduction of all.
c.Respiration:
Initially the respiratory rate is increased due to reflex through chemoreceptors,because of this large amount of carbon dioxide is washed out leading to alkalemia.The respiration is shallow and periodic and finally the rate of force of breathing reduces to a great extent due to the failure of respiratory centers.
d.Digestive System:
Hypoixia is associated with loss of appetite,nausea and vomiting.Mouth becomes dry.
e.Renal System:
Hypoxia causes increased secretion of erythropoietin from the juxtaglomerular apparatus of kidney and alkaline urine is excreted.
f.Central Nervous System:
Depression,apathic,talkative,quarrelsome,illtempered, rude,disorientation,loss of power of judgement,impaired memory ,weakness,lack of coordination and fatigue,loss of consciousness nature is experianced by the person.
2.EFFECTS OF EXPANSION OF GASES:
Due to decreased barometric pressure the volume of gases increases also in the atmosphere and body.At high altitude of 18000 feet where the atmospheric pressure is 379 mm of Hg,the volume of the gas becomes 2 litres.
The expansion of gases in gastrointestinal tract may cause painful distension of the stomach and intestine.This effect can be minimised by supporting the abdomen with a belt.
Expansion of gases destroy the alveoli.
3.EFFECTS OF REDUCED ATMOSPHERIC TEMPERATURE:
Environmental temperature drops at high altitudes.
It is 0 degrees centigrade at 10000 feet.
Injury due to cold or frostbite occurs if the body is not adequately protected by warm clothing.
4.MOUNTAIN SICKNESS
Mountain sickness is the condition characterized by the ill effects of hypoxia at high altitude for the first time going people to higher altitudes,untill they get acclimatized to altitudes.
5.EFFECTS OF LIGHT RAYS:
Skin becomes susceptible for injury due to many harmful rays like Ultraviolet rays of sunlight.
The sunrays reflected by the snow might injure the retina of the eye.Hence protection of retina is important.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.