Environmental Effects on Body Systems

What Environmental Effects on Body Systems covers

Environmental Effects on Body Systems is examined in Component 01, Physiological factors affecting performance. It covers altitude and oxygen delivery, acclimatisation and timing arrival at altitude and exercise in the heat and cardiovascular drift.

The 3 subtopics

Each one has its own page.

• Altitude and oxygen deliveryBarometric pressure and pO₂ at altitude, slower diffusion at the alveoli, lower haemoglobin saturation and VO₂ max, heart rate, stroke volume and ventilation on arrival, dehydration, and endurance and explosive events at Mexico City 1968.Open →
• Acclimatisation and timing arrival at altitudeAcclimatisation above about 2,400 m, the kidneys, EPO and red blood cells, how long it takes, arriving a day or two to three weeks before competing, altitude sickness, ventilation, plasma volume and fluid intake.Open →
• Exercise in the heat and cardiovascular driftThe hypothalamus and thermoreceptors, radiation, conduction, convection and evaporation, humidity, sweating and falling plasma volume, venous return and stroke volume, cardiovascular drift and how to reduce it, and early-morning marathons.Open →

What you need to know

Answer each one before you reveal it.

Take Environmental Effects on Body Systems further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Barometric pressure vs Partial pressure of oxygen

  Barometric pressure: the total force per area exerted by the whole atmosphere. Partial pressure of oxygen: the share of atmospheric force contributed by O₂ molecules alone.

• Evaporation vs Radiation

  Evaporation: heat loss as sweat turns to vapour on the skin. Radiation: heat loss as infrared energy given off from the warm body surface.

• Conduction vs Convection

  Conduction: heat transfer through direct contact with a cooler surface. Convection: heat transfer by moving air or water carrying warmth away.

Questions from this topic

Each one with the model answer underneath.

1. 1

   How does barometric pressure change as altitude increases?

   Model answer

   Barometric pressure falls as altitude increases. The air is less dense, so each breath contains fewer oxygen molecules.

2. 2

   Does the percentage of oxygen in the air change at altitude?

   Model answer

   The percentage of oxygen stays at about 20.9% at altitude. The partial pressure of oxygen falls because the total air pressure is lower.

3. 3

   Why does a reduced pO₂ at altitude slow oxygen diffusion at the alveoli?

   Model answer

   Alveolar pO₂ is lower, so the gradient between the alveoli and the blood is shallower. Less oxygen diffuses into the blood.

4. 4

   How does altitude affect the saturation of haemoglobin?

   Model answer

   Haemoglobin is less saturated with oxygen at altitude. The arterial blood therefore carries less oxygen to the muscles.

5. 5

   Why is oxygen delivery to the muscles impaired at altitude?

   Model answer

   Arterial pO₂ is reduced, so the gradient between the blood and the muscle is smaller. Less oxygen diffuses into the muscle for aerobic respiration.

6. 6

   How does altitude affect VO₂ max?

   Model answer

   VO₂ max falls at altitude because less oxygen reaches the muscles. Aerobic performance declines and fatigue sets in sooner.

What is inside Levo

Six ways to work the same material.

Environmental Effects on Body Systems revision questions

What does Environmental Effects on Body Systems cover in OCR A-Level Physical Education?

3 subtopics: altitude and oxygen delivery, acclimatisation and timing arrival at altitude and exercise in the heat and cardiovascular drift. Each one has its own page with questions and model answers.

How is Environmental Effects on Body Systems organised?

By the OCR H555 specification, subtopic by subtopic, so it matches the order you are taught it in.