Breathing in different Circumstances

Question 1

Pregnancy

Answer 1

• Filled up with a baby
• Fundus of the uterus is found at the xiphoid process
• Diaphragm is moved up 4cm–> tidal volume decreases which means ventilation must increase
• More CO2 is removed–> more Bicarbonate is excreted by kidneys to compensate
• compensated respiratory alkalosis

Question 2

Altitude

Answer 2

• pO2 is lower and air is less humid so the body has to secrete water (allows air to move across into the blood)
• Short term: increase in ventilation, increase in heart rate, pulmonary vasoconstriction to increase cardiac output
• Long term: permanent increase in volume and rate, Kidneys decrease the amount of H+ ions they remove to keep pH the same, 2,3-DPG produced which increases Hb affinity for O2 (bohr effect)
• Kidneys produce erythropoeitin and Angioneogenesis (more vessels to perfuse in tissues)

Question 3

Diving

Answer 3

• Increase of partial pressure of gasses further down you dive
• N2 is able to dissolve in your blood: may lead to Nitrogen Narcosis(causes disruption to cell membranes and ion channels)
• Oxygen poisoning: overpowers Hb buffering ability

The bends–> if you ascend too quickly, dissolved gases reforms as air gas

Question 4

Obesity

Answer 4

• Extra fat around chin and neck area

- May completely occlude upper airway which can cause a fall in O2 saturations when sleeping

Question 5

Age

Answer 5

• Past 30, FEV1 decreases; due to reduced compliance and loss of elascity
• Loss of muscle mass decreases inspiratory ability