Adaptation

Question 1

What is adaptation?

Answer 1

Adaptation is the compensatory changes observed in populations native to high altitude for many generations that facilitate existence at reduced barometric pressure (reduced PIO2)

Question 2

Examples of high altitude populations > 2500m

Answer 2

Andes
Tibet
East Africa

Question 3

What is the most studied pattern of high altitude and why?

Answer 3

The Andean pattern due to the high-altitude research laboratory at Morococha Peru (4540m)

Question 4

What happens adapted PCO2 at high alt?

Answer 4

Adapted PCO2 is lower than sea-level values (hypocapnic)

Question 5

What happens adapted PO2 at high alt?

Answer 5

Adapted PO2 is lower than sea-level values (hypoxic)

Question 6

What happens adapted SaO2 at high alt?

Answer 6

Adapted SaO2 is lower than sea-level

Question 7

What happens adapted Hb at high alt?

Answer 7

Adapted Hb is higher than sea-level

Question 8

What happens adapted Hct at high alt?

Answer 8

Adapted Hct is higher than sea-level

Question 9

Which gender has a higher ventilation at high altitude?

Answer 9

Males have a greater ventilation at high altitude

Question 10

Who has higher ventilation, sea-level or high-altitude dwellers?

Answer 10

Highland dwellers have a higher rate of ventilation than sea-level at rest

Question 11

What is the isocapnic hypoxic ventilatory response?

Answer 11

?

Question 12

Adaptations of high-altitude dwellers

Answer 12

Higher ventilation at rest
Higher exercise ventilation
Higher/similar hypoxic ventilatory response
Higher SaO2 at rest and during exercise

Question 13

How do the lungs adapt to high altitude?

Answer 13

Higher vital capacity
Higher FEV1 & max expiratory flow rate
Higher diffusing capacities
Lower A-aO2 gaps

Question 14

What study found O2 environment responsible for body size?

Answer 14

Drosophila - normoxia grew larger than hypoxia, high O2 sat animal grew even larger

Question 15

How do haemodynamics vary between HA and SL adults?

Answer 15

Increased Hb, PAP and PVR in HA adults compared to SL

Decreased SaO2 in HA adults

Question 16

How does RV vary compared to LV in Andean population?

Answer 16

RV increased in size relative to left in HA population (ECG, CXR, Postmortem studies)

Question 17

How does HVR alter vessels in HA adapted population?

Answer 17

Increased load = increased size, therefore, increased thickness, media and adventitia

Question 18

During exercise, how do haemodynamics of HA change?

Answer 18

Increased HR
Increased CI
Increased SI
Increased PPA
Increased PVR

Question 19

How do Andeans increased O2 delivery at HA?

Answer 19

Andeans increase O2 delivery at HA predominantly by increasing Hb concentration and thus O2 content of blood

Question 20

How did SaO2 change in HA natives that moved to SL for two years?

Answer 20

SaO2 increased meaning ventilation had not been impaired

Question 21

How did PVR change in HA natives that moved to SL for two years?

Answer 21

PVR reduced but not as low as you expect, meaning there could be irreversible changes as a result of adaptation

Question 22

How did the cardiovascular responses of pika (HA mammals) compare to rats exposed to HA?

Answer 22

No significant difference in HR or PSA

PPA of pika lower at every altitude, indicating that PPA is not increased in adapted animals

Question 23

How did the vessel remodelling of pika (HA mammals) compare to rats exposed to HA?

Answer 23

Pika vasculature remains unchanged, however, rats at HA have alterations including increased thickness, media & adventitia

Question 24

Alterations in HA adapted animals

Answer 24

Normal PAP
Normal RV size
Blunted HPV
Normal Hct
Maintain higher PaO2 than sea-level animals at HA