Brainscape's Knowledge GenomeTM

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


See full index

Respiratory > 8.1 Breathing and Respiration in special circumstances - ALTITUDE and DIVING > Flashcards

8.1 Breathing and Respiration in special circumstances - ALTITUDE and DIVING Flashcards

1
Q

ALTITUDE
how is the AIR

A

% Composition does NOT change

ASCENT: PARTIAL PRESSURES DECREASE with Decreasing Atmospheric/Barometric Pressure (climbing up)

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

ALTITUDE
PO2 at sea level vs at peak of Everest

A

sea level: 760 mm Hg

peak Everest: 43 mm Hg

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

ALTITUDE
PAO2 (ARTERIAL) in comparison to in DRY AIR and why

A

LOWER THAN IN DRY AIR

  • Airways ADD WATER during Inspiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ALTITUDE
effect of FALLING PAO2 on PARTIAL PRESSURE GRADIENT and what effect does this have

A

REDUCES PARTIAL PRESSURE GRADIENT

driving O2 UPTAKE

  • causes HYPOXIA (low O2 in tissues)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

ALTITUDE
effect of HYPOXIA

A

SENSORY and COGNITIVE Functions DECLINE

  • CNS DEPENDENT on O2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ALTITUDE
HYPOXIA sensed by..

A

PERIPHERAL CHEMORECEPTORS

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

ALTITUDE
3 EFFECTS of HYPOXIA

A
  1. detected by Peripheral Chemoreceptors.
    RESPIRATORY CENTRE responds by INCREASING VENTILATORY DRIVE
    - Increase O2, Decrease CO2
    - ACTIVATES CENTRAL CHEMORECEPTORS
    -> BLUNTS RESPIRATORY DRIVE (decreases rate and depth)
  2. Respiratory Centre INHIBITS CARDIOINHIBITORY CENTRE
    - Increases HEART RATE, CARDIAC OUTPUT, O2 UPTAKE by PULMONARY PERFUSION
  3. Hypoxia causes PULMONARY VASOCONSTRICTION
    - Increases PULMONARY VASCULAR RESISTANT (blood flow resistance from pulmonary artery to left atrium)
    - RIGHT HEART forced to generate HIGHER PRESSURE to MAINTAIN CARDIAC OUTPUT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

ALTITUDE
effects of HYPOXIA on HEART

A
  • RESPIRATORY CENTRE INHIBITS CARDIOINHIBITORY CENTRE
    so INCREASES HEART RATE, CARDIAC OUTPUT, and O2 uptake by Pulmonary Perfusion
  • Pulmonary Vasoconstriction (pulmonary vascular resistance) causes RIGHT HEART to generate HIGHER PRESSURE to MAINTAIN CARDIAC OUTPUT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

ALTITUDE
how does HYPOXIA affect VENTILATION

A

PERIPHERAL CHEMORECEPTORS: INCREASED VENTILATORY DRIVE (more O2)

LOW CO2 detected by CENTRAL CHEMORECEPTORS
- BLUNTS VENTILATORY DRIVE

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

ALTITUDE
ADAPTIVE RESPONSES (DAYS TO WEEKS)

A
  1. CENTRAL CHEMORECEPTORS adapt slowly over 8-24 HOURS so allow INCREASED VENTILATION
  • LOW PaCO2 causes RESPIRATORY ALKALOSIS
  1. KIDNEY COMPENSATES for alkalosis: LESS H+ SECRETION so blood pH renormalises
  2. ALKALOSIS stimulates 2,3-DPG PRODUCTION
    - LOWERS Hb O2 AFFINITY, dissociation curve shifts to RIGHT
    - MORE O2 UNLOADING to tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

ALTITUDE
how do you develop ALKALOSIS over few days/weeks

A

CENTRAL CHEMORECEPTORS ADAPT (8-24 hours)

  • allow INCREASED VENTILATION

-> LOW CO2 (PaCO2) causes respiratory alkalosis

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

ALTITUDE
how do KIDNEYS compensate for ALKALOSIS development over few days/weeks

A

LESS H+ SECRETION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

ALTITUDE
how does the ALKALOSIS Help

A

STIMULATES PRODUCTION of 2,3-DPG

  • LOWERS Hb AFFINITY for OXYGEN (shift RIGHT)
  • more O2 UNLOADING
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

ALTITUDE
ACCLIMATION: how do these people ADAPT LONG-TERM (over MONTHS/YEARS)

A
  1. Hypoxia stimulate ERYTHROPOIETIN from KIDNEYS
    - Increase RBC
    - INCREASE Hb CONC
    - Increased BLOOD VOLUME

-> Blood’s OXYGEN-CARRYING CAPACITY INCREASES
by 50%

  1. Hypoxia stimulates ANGIONEOGENESIS (Production NEW CAPILLARIES)
    - Increased CAPILLARY DENSITY
    - Increased Tissue PERFUSION

-> INCREASED PULMONARY ARTERY PRESSURE promotes VASCULAR and VENTRICULAR REMODELLING (change shape to cope with pressure)

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

ALTITUDE
adverse EFFECTS of ACUTE (Short term) altitude sickness

A
  • Headache
  • Irritability
  • Insomnia
  • Dyspnoea (struggling to breathe)
  • Dizziness
  • Nausea and Vomiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

ALTITUDE
adverse EFFECTS of CHRONIC (Long term) altitude sickness

A

BRONCHOCONSTRICTION
-> stresses RIGHT side of heard
can cause
- PULMONARY OEDEMA
- RIGHT HEART FAILURE
- DEATH

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

ALTITUDE
how do KIDNEYS help LONG-TERM ADAPTATION (ACCLIMATION)

A

produce ERYTHROPOEITIN which increases RBC, INCREASEs Hb,
blood carries 50% MORE OXYGEN

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

ALTITUDE
LONG-TERM adaptation of HEART

A

VASCULAR and VENTRICULAR REMODELLING

due to ANGIONEOGENESIS
- increased CAPILLARY DENSITY, tissue perfusion
- increased PULMOANRY ARTERIAL PRESSURE causes change in shape

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

DIVING
how is the PRESSURE

A

EXTERNAL HYDROSTATIC PRESSURE

  • pressure INCREASES quickly with INCREASED DEPTH

water SQUEEZES and COMPRESSES from all sides

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

DIVING
a COLUMN of WATER OF 10m exerts a PRESSURE EQUIVELENT to…

A

ATMOSPHERIC PRESSURE

21
Q

DIVING
at DEPTH 30 m a diver subject to PRESSURE of approximately..

A

4 ATMOSPHERES

(10 m Equivalent to atmospheric pressure)

22
Q

DIVING
EFFECTS of DEPTH on ALVEOLI

A

COMPRESSES GAS within the ALVEOLI
- INCREASES PARTIAL PRESSURES of all gases
- DECREASES ALVEOLAR VOLUME

23
Q

DIVING
INCREASED PARTIAL PRESSURE of gases in ALVEOLI and DECREASED ALVEOLAR VOLUME causes 2 issues:

A
  1. at sea level, ONLY O2 and CO2 can dissolve in blood.
    diving increases partial pressures of all gases so
    ALL GASES DISSOLVE IN BLOOD (potentially lethal effects)
  2. PRESSURISING a GAS DECREASES its VOLUME
    - at 30m 1L of gas (sea level volume) SHRINKS down to occupy250ml
  • surfacing above 30m 1L of gas EXPANDS to fill 4L

-> can cause SEVERE DAMAGE

24
Q

DIVING
at SEA LEVEL which GASES can DISSOLVE in BLOOD

A

ONLY O2 and CO2

diving: all dissolve

25
Q

DIVING
PRESSURISING a GAS has what effect

A

DECREASES its VOLUME

deeper - gas occupies less volume (shrinks down)

26
Q

DIVING
which GASES are TOXIC when INHALED UNDER PRESSURE

A

N2 and O2

(air 78% N2, 21% O2)

(CO2 only of concern if breathing apparatus traps exhaled air causing CO2 to rise)

27
Q

DIVING
why does NITROGEN (N2) have no effect on body function at SEA LEVEL

A

DOES NOT DISSOLVE in tissues

28
Q

DIVING
when can N2 CAUSE HARM

A

DEPTH 40m OR MORE

29
Q

DIVING
what HARM does N2 CAUSE at Depth 40m or More

A

PARTIAL PRESSURE (PN2) RISES
- DISSOLVES in CELL MEMBRANES
DISRUPTS ION CHANNEL FUNCTION

-> NARCOTIC EFFECTS similar to of ETHANOL
(severity of effects related to depth and pressure, worsen further down)

30
Q

DIVING
N2 NARCOTIC EFFECTS INITIALLY and ULTIMATELY at 80M or BELOW

A

Initially: feeling of WELLBEING (jolly)

Ultimately: cause LOSS OF FUNCTION at 80m or below

31
Q

DIVING
when can N2 cause LOSS OF FUNCTION

A

80m or Below

32
Q

DIVING
why can O2 be TOXIC

A

FORMS FREE RADICALS

33
Q

DIVING
why is O2 SAFE at SEA LEVEL

A

amount O2 being delivered to tissues is CLOSELY REGULATED by Hb
- acts as a vehicle for Transport and a BUFFER

Hb HIGHLY SATURATED under normal circumstances

34
Q

DIVING
how is Hb at SEA LEVEL (normal circumstances)

A

acts as a vehicle for TRANSPORT

and a BUFFER

CLOSELY REGULATES O2 delivered to tissues

  • HIGHLY SATURATED
35
Q

DIVING
why can breathing O2 at HIGH PRESSURE be harmful

A

DISSOLVE in BLOOD in HIGH AMOUNTS that EXCEED BUFFERING CAPACITY of Hb

  • TISSUES exposed to PO2 that EXCEEDS NORMAL SAFE RANGE (20-60 mm Hg)
36
Q

DIVING
EFFECTS of BREATHING O2 at HIGH PRESSURE

A

NEUROLOGICAL EFFECTS
- VISUAL disturbances
-SEIZURES
- COMA

37
Q

DIVING
why do Divers who work at Depth breathe a HELIUM/OXYGEN MIX (HELIOX)

A
  • O2 CAREFULLY TAILORED to yield PARTIAL PRESSURE that is SUPPORTIVE not harmful
  • HELIUM REPLACES N2 because it DISSOLVES in body tissues LESS READILY
    -> LESS NARCOTIC
  • HELIUM LESS DENSE than N2
  • HELIOX REDUCES AIRWAYS RESISTANCE (smaller molecule)
    and DECREASES the WORK OF BREATHING
38
Q

DIVING
why is HELIUM used to REPLACE N2 in HELIOX

A
  • LESS DENSE
  • DISSOLVES LESS READILY
    -> LESS NARCOTIC
  • HELIOX LESS AIRWAYS RESISTANCE (smaller)
    and less work of breathing
39
Q

DIVING
what is DECOMPRESSION SICKNESS / ‘THE BENDS’

A

presence of N2 BUBBLES in the BLOODSTREAM
(can block blood vessels)

from ASCENT / coming back up to surface (too QUICKLY)

and N2 loses pressure and solubility

40
Q

DIVING
what is the AVERAGE AMOUNT of N2 contained in the body at SEA LEVEL

A

approx 1L

41
Q

DIVING
AVERAGE AMOUNT of N2 in the body INCREASES to …. at PROLONGED DIVE at 30 m

A

as much as 4L

(N2 accumulates in tissues at high pressure and so increased solubility - DISSOLVES)

42
Q

DIVING
how is N2 in the body at PRESSURE

A

DISSOLVES

  • DIFFUSES across BLOOD-GAS INTERFACE and then DISTRUBUTED by CIRCULATION to ALL TISSUES
  • PREFENTIALLY partitions (stays) in FAT TISSUE
43
Q

DIVING
what happens to divers N2 as they ASCEND BACK to the SURFACE (after N2 dissolved at high pressure)

A

N2 no longer subject to PRESSURE

DECREASED PARTIAL PRESSURE & SOLUBILITY

-> COMES OUT of SOLUTION and FORMS N2 BUBBLES (IF ASCEND TOO QUICKLY)
(DECOMPRESSION SICKNESS/’THE BENDS’)

44
Q

DIVING
Why are N2 BUBBLES in the BLOODSTREAM HARMFUL (decompression sickness/’the bends’)

A

BLOCK BLOOD VESSELS
as small bubbles form larger bubbles, progressively LARGER VESSELS Affected

-> Tissues dependent on these vessels become ISCHAEMIC (LACK BLOOD SUPPLY)

cause PAIN in JOINTS and LIMB MUSCLES

45
Q

DIVING
SYMPTOMS of DECOMPRESSION SICKNESS / ‘THE BENDS’ (N2 bubbles)

A
  • JOINT and LIMB MUSCLES PAIN

more severe:
- NEUROLOGICAL DEFICITS
- DYSPNOEA
- DEATH

46
Q

DIVING
how can you PREVENT DECOMPRESSION SICKNESS

A

SLOWING RATE of ASCENT
- allows MORE TIME for excess Gas to DISSUFE OUT of tissues and INTO LUNGS for EXHALATION

47
Q

DIVING
what SLOWS the RATE at which N2 can be REMOVED

A

FAT is AVASCULAR (no blood supply)
(N2 mostly in FAT tissues)

  • INCREASES DISTANCE of N2 DIFFUSION to be carried away by circulation
48
Q

DIVING
how long can COMPLETE RENORMALISATION of N2 LEVELS take after ASCENT

A

SEVERAL HOURS

49
Q

DIVING
what is the TREATMENT for DECOMPRESSION SICKNESS

A

DECOMPRESSION CHAMBER for HYPERBARIC TREATMENT

  • in a sealed vessel with PRESSURE EQUAL to PRESSURE AT DEPTH that they were diving at before ascent
    -> N2 DISSOLVES AGAIN (driven back into solution) to RELIEVE SYMPTOMS
  • PRESSURE in chamber SLOWLY DECREASED over a period of several HOURS
    so N2 can come out of solution SLOWLY and Diffuse back into Blood WITHOUT FORMING BUBBLES

Respiratory (16 decks)

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