Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 1: Respiratory System > 14. Hypoxia > Flashcards

14. Hypoxia Flashcards

1
Q

Define hypoxia

A

A disease where there is inadequate oxygen supply to the tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define hypoxaemia

A

A low concentration of oxygen in the blood - describes the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is considered to be hypoxaemia?

A

O2 of less than 8kPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What factors can put your body under hypoxic stress?

A

Disease

Altitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does the partial pressure of O2 change with increasing altitude?

A

It decreases as the barometric pressure decreases due to Dalton’s law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the saturation of blood and partial pressure arriving at the gas exchange surface?

A

75% saturated with a partial pressure of 5.3 kPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where does bronchial drainage return to?

A

It returns to the pulmonary veins and dilutes the blood decreasing saturation to 97%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the pKa of fully oxygenated blood?

A

at 100% = 13.5 kPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens to the mean pO2 in the alveolar space and in the arterial blood with age?

A

It decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define polycythaemia

A

An abnormally increased concentration of haemoglobin in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define oxygen cascade

A

This describes the decreasing oxygen tension from inspired air to respiring cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the amount of gas that will diffuse across a membrane proportional to?

A 
Surface area for gas exchange
Diffusion constant (CO2 is faster than O2
Diffusion gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the changes in the partial pressure of oxygen in ambient air down to the veins?

A 
Ambient air - 21.3kPa
Upper airways air -20kPa
Alveolar air - 13.5kPa this can vary depending on hypoventilation and hyperventilation
Post-alveolar capillaries -13.5kPa
Arteries - 13.3kPa bronchial drainage
Tissues - variable depends on exercise
Veins - 5.3kPa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How much of the haemoglobin desaturates when going form the arteries to the veins?

A

25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the proportions oxygen transported?

A

2% is dissolved

98% bound to haemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the big drop in the partial pressure of O2 from the arteries to the tissues associated with?

A

A big unloading of haemoglobin. The drop in partial pressure of O2 isn’t what is keeping you alive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the factors affecting the oxygen cascade?

A

Alveolar Ventilation
Ventilation/Perfusion matching
Diffusion capacity
Cardiac output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the shape of the oxygen cascade in really hypoxic air?

A

Everything decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When exercising what system is used for energy in the first 10 seconds?

A

The first 10 seconds uses ATP and ATP-Phophocreatine system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When exercising what system is used at 400m?

A

lactic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

For exercise longer than 60 seconds what method of energy production is used?

A

aerobic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to the demand for energy when you exercise?

A

Increase in demand for energy, increase in the demand for oxygen, increase ventilation and increase cardiac output thus increasing oxygen delivery. You also increase fuel utilisation and carbon dioxide produced

23
Q

Define VO2 max?

A

The capacity to deliver oxygen to tissues is termed VO2 max

24
Q

In sub-maximal exercise how many L/min of ventilation is required to meet the metabolic demand?

A

40 L/min

25
Q

Describe the change in ventilation with submaximal exercise?

A

There is a rapid rise followed by a steady rise in ventilation until the supply meets the demand

26
Q

What happens after ventilation?

A

Repaying the oxygen debt

27
Q

Where does the oxygen debt come from?

A

Intramuscular ATP, phosphocreatine and myoglobin

28
Q

When exercise initial begins describe the breathing rate?

A

The breathing rate rapidly increases from 12 to 20 breathes per minute

29
Q

When exercise initially begins why does the ventilation rate become stable?

A

increasing tidal volume is more efficient at increasing ventilation than increasing respiratory rate

30
Q

What happens to the respiratory rate when the TV starts to plateau?

A

The respiratory rate starts to increase because it is inefficient to increase the tidal volume. The TV will not reach vital capacity because it is energy inefficient

31
Q

What are five challenges of altitude?

A 
Hypoxia
Thermal stress
Solar radiation
Hydration
Dangerous
32
Q

Define accommodation

A

A rapid physiological change in response to a change in the oxygen environment

33
Q

Define acclimatisation

A

Phsiology becomes more efficient so you can get as much out of the air as possible

34
Q

What happens during acclimatisation?

A

Arterial partial pressure of O2 increases but CO2 falls. Erythropoietin is secreted from the renal cortex

35
Q

What does low arterial partial pressure of O2 stimulate?

A

Increased ventilation to increase alveolar partial pressure of O2 - hypobaric hypoxia

36
Q

What are some innate/developmental adaptations of those living in altitude?

A

Barrel Chest
Increased Haematocrit
Larger heart - Pulmonary vasculature constricts in response to hypoxia so a stronger heart is required to push blood throgh higher resistance circuit
Increased mitochondrial density

37
Q

Describe chronic mountain sickness

A

Secondary polcythaemia (as a result of hypoxia). This is a problem because this higher proportion of RBC leads to increased viscosity of the blood

38
Q

What is associated with acute mountain sickness?

A

High altitude cerebral oedema and high altitude pulmonry oedema. They are both associated with low oxygen environments
Ataxia - impaired ability to coordinate movement

39
Q

What is the consequence of AMS?

A

I may develop into HAPE or HACE

40
Q

What is HACE?

A

High altitude cerebral oedema

41
Q

What is the physiology behind HACE?

A

Due to vasodilation of the vessels in response to hypoxaemia, the increased blood flow means there is more fluid leakage resulting in an increase in ICP

42
Q

What is HAPE?

A

High altitude pulmonary oedema

43
Q

What is the physiology behind HAPE?

A

Due to vasoconstriction of pulmonary vessels in response to hypoxia, there is increased pulmonary pressure, permeability and fluid leakage from capillaries. If the fluid produced exceeds the lymph drainage there is oedema

44
Q

How do treat HACE?

A

Immediate descent, O2 therapy and dexamethasome

45
Q

How do you treat HAPE?

A

Descent, hyperbaric O2 therapy, nifedipine, sildenafil

46
Q

Define respiratory failure

A

The ineffective ability to exchange gas between the lungs and the blood

47
Q

What are the types of respiratory failure?

A

Type I: Hypoxic respiratory failure
Type II: Hypercapnic respiratory failure
Type III: Mixed respiratory failure

48
Q

What is indicative of Type I respiratory failure?

A

PaO2 < 8 kPa

49
Q

What is indicative of Type II respiratory failure?

A

PaCO2 > 6.7 kPa

50
Q

What is indicative of Type III respiratory failure?

A

PaO2 < 8 kPa

PaCO2 > 6.7 kPa

51
Q

What systems help to maintain PaO2 and PaCO2?

A

Mechanisms within the blood, renal system and respiratory system

52
Q

What are the main determinants of arterial gas tensions?

A

Alveolar ventilation and gas exchange

53
Q

What is type I respiratory failure?

A

Typically a ventilation/perfusion mismatch in the lungs; perfused alveoli are hypoventilated or perfused alveoli are hypoperfused

54
Q

What is type II respiratory failure?

A

Typically hypoventilated lungs; inadequate gas exchange as alveolar air stagnates and concentration gradients are poor

Year 1: Respiratory System (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions