Brainscape's Knowledge GenomeTM

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


See full index

LSS: respiratory > pulmonary circulation > Flashcards

pulmonary circulation Flashcards

1
Q

what are the two circulation systems of the lungs?

A
  • bronchial circulation

- pulmonary circulation

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

what are the two arteries of the circulations

A

systemic (thicker muscle)

pulmonary

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

what are features of the pulmonary arteries?

A
  • they have a greater lumen to wall thickeness ratio to give them more compliance
  • the pulmonary arteries still need to be elastic to convert the pulsatile flow into continuous flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

compare the pressures of the systemic and pulmonary arteries ?

A
  • the systemic circulation operates at higher pressures

- the pressure gradient drives blood flow

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

compare the cardiac volume and the volume for the pulmonary and systemic arteries?

A
  • cardiac volume = same on both sides
  • volume in systemic is much higher
  • less pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why is less pressure needed in the pulmonary arteries?

A
  • less distance to cover
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

compare compliance in pulmonary and systemic arteries:

A
  • compliance is higher in the pulmonary circulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the functions of pulmonary circulation?

A
  • gas exchange
  • metabolism of vasoactive substances
  • filtration of the blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the gas exchange carried out by pulmonary circulation:

A

♣ CO2 and O2 are the main exchanged gases.
♣ Pulmonary transit time is 0.75s.
o Gas is usually equilibrated in 0.25s.

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

how are vasoactive substances metabolised?

A

♣ ACE is exhibited within pulmonary endothelium.
o ACE can mediate production of ANG-II.
ACE can degrade bradykinin

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

how is the blood filtered

A
  • The entire circulation is a closed circuit but when things get in, the pulmonary circulation filters the blood before it reaches the systemic arteries.
  • This can be bad though, in the case of a pulmonary embolism = death.
  • The pulmonary circulation acts as a good defence against emboli heading to the brain to cause a stroke.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is an embolus?

A

a ‘mass’ within the circulation that is capable of causing an obstruction.

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

what is an embolism?

A

♣ – an ‘event’ characterised by obstruction of a major artery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are three examples of pulmonary shunts?

A
  • bronchial circulation
  • foetal circulation
  • congenital defect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how does the bronchial circulation act as a shunt?

A

The blood goes through the left side of the heart twice (bronchial and systemic circulations) without getting oxygenated.

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

how does foetal circulation work?

A

Has two shunts:
a. Foramen Ovale.
Hole between the left and right atria with low resistance.

b. Ductus Arteriosus.
Between aorta and pulmonary arch. This is because O2 is from mother’s placenta, not the lungs.

17
Q

how does a congenital heart defect act as a shunt?

A

Congenital Heart Defect – 2 forms:

  • Atrial Septal Defect or Patent Foramen Ovale.
  • Ventricular Septal Defect.
18
Q

what happens when the cardiac output is increased?

A
  • Pulmonary circulation is a low resistance, high capacity circuit at a resting Q of 5Lmin-
  • what you might think would happen is because there is an increase in MAP
  • this increases hydrostatic pressure which forces fluid out
  • this leads to pulmonary oedema
  • so pulmonary function does not happen effectively
  • however, this does not happen :
    because the pulmonary system is low resistance high capacity an increase in CO leads to a small increase in MAP
  • this is because the pulmonary vessels are distensible so they can stretch
  • there is increased perfusion to the hypoperfused capillary beds
  • so increase in CO increases perfusion
19
Q

what happens when ventilation is increased?

A
  • inspiration compresses alveolar vessels and expiration compresses the extra-alveolar vessels
  • these vessels affect the changes in resistance
  • so the resistance is highest at inspiration and expiration
20
Q

what is the effect of hypoxemia on systemic vessels?

A
  • this causes vasodilation
21
Q

what is the effect of hypoxemia on pulmonary vessels?

A
  • vasoconstriction
  • when the alveoli are not being ventilated the oxygen levels are very low
  • the gases continue to be exchanged until they reach equilibrium
  • without a fresh supply of air, they become hypoxic
  • at a low pp of oxygen, the pulmonary circulation is going to cause vasoconstriction
22
Q

how does vasoconstriction of the pulmonary vessels happen?

A
  • oxygen sensitive K channels
  • no oxygen causes the K to close
  • this decreases K efflux
  • the surface moves towards its threshold membrane potential
  • then there is depolarization
  • which causes an influx of calcium
  • causing vasoconstriction
23
Q

the vasoconstriction of pulmonary vessels in response to altitude:

A
  • there is low pressure of oxygen across the lungs
  • so there is vasoconstriction
  • so more resistance
  • this is good during hypoxia because perfusing unventilated alveolus is wasteful
  • so the lack of perfusion is good
24
Q

when is vasoconstriction in response to hypoxia very useful?

A
  • fetal development
  • blood flows down least resistance
  • high resistance means the blood flows through shunts
25
Q

when is vasoconstriction in response to hypoxia very bad?

A
  • in COPD
  • reduced alveolar ventilation and air trapping already
  • so high resistance might cause heart failure or hypertension
26
Q

what are the two pressures in the pulmonary fluid balance?

A
  • hydrostatic (pushing)
  • oncotic ( pulling)

plasma hydrostatic
interstitial hydrostatic

plasma oncotic
plasma oncotic

27
Q

what is the interstitial hydrostatic pressure in healthy people

A

0

28
Q

what does the lymph system do?

A
  • it drains the excess fluid
  • which can’t be pulled back in
  • if the fluid accumulates then it causes pulmonary oedema
29
Q

what are some causes of pulmonary oedema?

A
  • mitral valve stenosis
  • hypoproteinaemia
  • infection
  • cancer
30
Q

explain how mitral valve stenosis causes oedema?

A
  • increased plasma hydrostatic pressure
31
Q

explain how hypoproteinaemia causes oedema?

A
  • the oncotic force is less

- so more fluid is in the interstituim so there os oedema

32
Q

explain how infection causes oedema?

A
  • in infection, there are lots of proteins and blood cells in the fluid
  • this means there is a bigger pulling force of water into the interstitium
33
Q

explain how cancer causes oedema?

A
  • if the lymphatics stop working so cannot clear up excess fluid
  • then the fluid is going to build up

LSS: respiratory (17 decks)

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