L4 - pulmonary circ

Question 1

functions of pulmonary circ (PULMC)

Answer 1

gas exchange
-reservoirs for blood
filter
synthesis and metabolism

Question 2

structure of pulm vessels

Answer 2

thin walled and highly branched than systematic vessels

-

Question 3

why is the pressure lower in PULMC than SYSTMC

Answer 3

the pulm vessels are wider and shorter so the blood move slower
- it has a lower resistance

Question 4

does pulmc receives all of right ventricular output

Answer 4

yes

Question 5

what features are low in pulmc

Answer 5

pressure due to thin wall and resistance due to short vessles and larger raduis

Question 6

other features of pulmc

Answer 6

vessels can change shape easily

• have large SA capillary
• returns blood to left ventricle

Question 7

whats the value of pulm ABP at the pulm artery value

Answer 7

28/8 mmHg

Question 8

whats the pulm capillary pressure at pulmon artery level

Answer 8

8~10mmHg

Question 9

difference in distance and its pressure between heart level to apex and base seperately

Answer 9

15cm and 12 mmHg for both distances

Question 10

whats the pressure near base of the lungs when standing upright

Answer 10

28/8+12/12= 40/20 mmHg.

- the pressure becomes greater so the vessels becomes distended

Question 11

whats the pressure near apex of the lungs when standing upright

Answer 11

28/8-12/12= 16/-4

• pressure not high enough so the vessels collapse
• no perfusion

Question 12

when standing upright, what happends to pulm perfusion

Answer 12

increases from apex to base

Question 13

when lying, what happens to pulm

Answer 13

perfusion is evely distributed from apex to base

Question 14

what is capacitance of the pulm blood vol

Answer 14

when lying, there’s greater blood vol so higher capacitance

Question 15

capacitiance functions

Answer 15

• standing upright increases return to left chambers
• CO and pulm ABP increases, perfusion increases
• increases blood vol
• if left ventr failure happens, filling towards the apex occurs

Question 16

vasocont influences on pulmc

Answer 16

increased SNS activity increases pressure in pulmc and perfusion

• inflamm mediators like histamine
• hypoxia - pulm vasocon

Question 17

what is hypoxia

Answer 17

when O2 supply not enough and not being supplied

Question 18

what happens when theres hypoxia in one of the capillary

Answer 18

-vasocon of that capillary occurs
-this diverts the blood flow to other capillaries
=improves O2 exchanged

Question 19

what happens if the hypoxia occurs throughout the lungs

Answer 19

• generalised pulm vasocon
• increases intravascular pressure
• limits O2 supply

Question 20

effects of generalised pulm vasocon (chronic hypoxia)

Answer 20

• increases resistance in pulmc
• widens vascular SM so increases vasc R
• increases capillary hydrostatic pressure so more filteration out of capillaries > pulm odema
• impaired gas exchange

Question 21

what happends during filteration across the pulm capillaries

Answer 21

• net outward filteration due to capillary HP higher than tissue HP
• tissue OP is higher in pulmc than sysmc so smaller OP pulls filteration into capillaries
• excess fluid taken away from lymph

Question 22

what happends during filteration in the capillaries in lungs when the pulm CAP increases

Question 23

what occurence it can lead to in the capillaries in lungs when the pulm CAP increases too much

Answer 23

alveolar odema which is not good as the alveoli need to be kept dry

Question 24

what occurences does pulm odema occur in

Answer 24

hypoxia, inflammation, extreme exercises, anaphyliatic responses, left ventricular failure

Question 25

what is microthrombi

Answer 25

• small particles of blood cells and fibrin together aggregrate
• get stuck in pulm ciric

Question 26

what is pulm embolism

Answer 26

blood clot, air or fat that block pulm vessels

Question 27

what do pulm cells syntheisise

Answer 27

NO to cause Pulm vasodil in response to stress
-PGI2- cause dilation
ACE

Question 28

what do pulm endothelial cells remove

Answer 28

serotonin (5-HT) and NAdr