Anatomical Adaptations to Extreme Environments

Question 1

Describe and explain some adaptations of the respiratory system to high altitudes

Answer 1

High altitudes often have a lower oxygen pressure. This means that there is a general increase in the amount of lung tissue in order to maximise SA:V ratio. Also, animal studies show a thinner alveolar wall - gas exchange.

Question 2

Describe and explain some adaptations of the circulatory system to high altitudes

Answer 2

The circulatory system responds to low O2 with hypoxic pulmonary vasoconstriction allowing regions of the lung not receiving enough O2 to be “cut off”, maximising gas transport to other areas. Also, there is an increased HR, myocardial contractility, and cardiac output for the first few days of high altitude living. Prolonged hypoxia leads to an enlargement of the right ventricle, thickening of the pulmonary arterial wall, and an increase in pulmonary arterial pressure

Question 3

Describe and explain some adaptations of the respiratory system in very hot climates (Kenya/Tanzania)

Answer 3

Wide nose with low wide nasal passages - don’t really need the air to be warmed up before entering the respiratory system.

Question 4

Describe and explain some adaptations of the circulatory system in very hot climates (Kenya/Tanzania)

Answer 4

Blood vessels near the skin dilate to increase heat loss from skin and sweat glands work harder. As we sweat more, fluid is lost from the blood, which makes the blood more viscous, making the heart pump harder

Question 5

Describe and explain some adaptations of the respiratory system in very cold climates (Inuits)

Answer 5

Narrow and high nasal passages allow the air to be warmed up by the vascular structures in the nose, which prevents the lungs being damaged by the cold air

Question 6

Describe and explain some adaptations of the circulatory system in very cold climates (Inuits)

Answer 6

There is peripheral vasoconstriction which increases blood pressure. In people with cardiovascular diseases, this can result in angina symptoms or short breath. When cold air is inhaled through the mouth, nerve endings in the back of the throat are stimulated, causing reflex vasoconstriction of coronary arteries. Also, local peripheral vasoconstriction in extremities can occur, making tissue white or blue - Raynaud syndrome

Question 7

Describe and explain some adaptations of the respiratory and circulatory system for astronauts living in the ISS

Answer 7

Respiratory - basically none. Circulatory - Exercise is vital to maintain the size and strength of the heart, as in space it doesn’t fight against gravity so it works less hard, leading to a shrinkage of the heart. This becomes a problem when they get back to earth, so they keep exercising while in space.