Respiratory

Question 1

What is the difference between conducting and respiratory airways?

Answer 1

conducting- no alveoli and no exchange with blood

respiratory- contains alveoli and does gas exchange with blood

Question 2

List the structures of the conducting and respiratory airways

Answer 2

CONDUCTING:
trachea
main bronchus
lobar bronchus 
segmental bronchus 
terminal bronchiole
RESPIRATORY:
respiratory bronchiole
alveolar duct
alveolar sac

Question 3

What is the total combined area for gas exchange?

Answer 3

40 - 100m2

Question 4

What is respiratory epithelium?

Answer 4

ciliated pseudo stratified columnar epithelium

Question 5

Define pseudostratified

Answer 5

comprising only a single layer of cells but has its nucleus positioned in a manner suggestive of stratified epithelium

Question 6

What is the role of cilia in the airway?

Answer 6

keeps airway clear by removing mucus which collects bacteria and dust that is inhaled

Question 7

What are the 2 types of pneumocytes and what are their functions?

Answer 7

type 1: thin barrier for diffusion, connected by tight junctions
type 2: secrete surfactant and decrease surface tension

Question 8

What % of alveolar area are type 1 pneumocytes?

Answer 8

95%

Question 9

What percentage of pneuocytes are type 2?

Answer 9

60%

Question 10

What is surfactant?

Answer 10

a compound that lowers the surface tension between 2 liquids, a gas and a liquid, or a liquid and a solid

Question 11

What do alveolar macrophages do? What are they derived from?

Answer 11

derived from monocytes

ingest bacteria and particles

Question 12

What keeps the lungs ventilated?

Answer 12

Pores of Kohn- holes that keep lungs ventilated but allows transmission of infection

Question 13

Why do Pores of Kohn look black?

Answer 13

often contain dark pigment due to phagocytosis

Question 14

List the layers of gas exchange from the alveoli to the RBC.

Answer 14

fluid lining alveoli
layer of epithelial cells (type 1 pneumocytes)
basement membrane
interstitial space between alveoli epithelium and capillary endothelial cells
basement membrane of capillary endothelium
capillary endothelial cells
RBCs

Question 15

How many oxygen molecules can one molecule of haemoglobin carry?

Answer 15

4

Question 16

What is an allosteric protein? Give an example.

Answer 16

a protein whose shape is changed when it binds to a particular molecule

e.g. haemoglobin

Question 17

What protein structure is haemoglobin?

Answer 17

quaternary

Question 18

What does a right shift of the O2 dissociation curve mean and what causes it?

Answer 18

reduced affinity of O2

increased temp
lower pH
higher CO2

Question 19

What does a left shift of the O2 dissociation curve mean and what causes it?

Answer 19

increased affinity of O2

lower CO2
higher pH
lower temp

Question 20

What is V/Q mismatch?

Answer 20

ventilation/ perfusion mismatch

when you don’t have the correct proportion of alveolar airflow (ventilation) and capillary blood flow (perfusion) available to each alveolus

Question 21

What is a “natural” V/Q mismatch and what causes it?

Answer 21

approx 5mmHg

due to gravity

Question 22

What are the 2 root causes for V/Q mismatch?

Answer 22

1. alveoli are ventilated fine but no blood supply (“deadspace”) due to a blood clot, for example.
2. adequate blood flow through lung but no ventilation (shunt) due to collapsed alveoli

Question 23

What are the two homeostatic responses set to correct V/Q mismatch? Explain each.

Answer 23

1. hypoxic pulmonary constriction

2. local bronchoconstriction

Question 23

What are the two homeostatic responses set to correct V/Q mismatch? Explain each.

Answer 23

1. hypoxic pulmonary constriction

2. local bronchoconstriction