respiratory cell biology

Question 1

purpose of folding round of tubules

Answer 1

surface area massive in small space

Question 2

cross sectional area increases peripherally - 23 generations

Answer 2

diagram from slide 5

Question 3

5 functions of entire epithelium

Answer 3

forms continuous barrier, produces secretions to facilitate clearance and protect undelying cells and maintain surface tension, metabolises foreign and host-derived compounds, releases mediators, triggers lung repair process

Question 4

goblet cells: type of cell and abundance in types of airways

Answer 4

polarised columnar cells; more in large, then central, then small airways surrounded by stratified squamous

Question 5

goblet cells: % of epithelial cells

Answer 5

20% of epithelial cells

Question 6

goblet cells: function

Answer 6

synthesise, store and secrete mucus via apical membrane

Question 7

ciliated epithelial cells: type of cell and abundance in types of airways

Answer 7

ciliated; more in large, then central, then small airways

Question 8

ciliated cells: % of epithelial cells

Answer 8

60-80% of epithelial cells

Question 9

ciliated cells: name given to type of beat

Answer 9

monochronal (metasynchronous)

Question 10

club cells: location, % and type of cell

Answer 10

rich in bronchiolar regions; 20% small airway epithelia; non-ciliated secretory cells

Question 11

club cells: function

Answer 11

contain secretory granules with detoxifying enzymes; protect bronchiolar epithelium, act as repair or progenitor cells, replace damaged epithelium, produce secretions for xenobiotic metabolism

Question 12

function of type 1 pneumocyte

Answer 12

fascilitates gas exchange and solute transport across alveoli

Question 13

properties and abundance of type 1 and 2 pneumocytes

Answer 13

type 1: very thin so covers most of lung surface (95%); type 2: 5% surface

Question 14

function of type 2 pneumocyte

Answer 14

contain lamellar bodies for storing surfactant, which they sythesise and secrete - maintains surface tension; act as progenitor cells (precursor of type 1); some detoxification

Question 15

ratio of type 1: type 2 pneumocytes

Answer 15

1:2 (twice as many type 2 pneumocytes as type 1)

Question 16

location and function of stromal cells (myofibroblasts; interstitial cells)

Answer 16

subepithelially in mucosal surfaces; deposit ECM to give elasticity and compliance (elastin and collagen); divide to repair

Question 17

functions of all secretory cells (goblet, club, type II)

Answer 17

secrete protective lining layer to trap deposited particles; surfactant and mucus, synthesise and release antioxidants e.g. glutathione, superoxide dismutase; synthesise and secrete antiproteinases e.g. secretory leukoproteinase inhibitor (SLPI); release lysosyme; carry out xenobiotic metabolism (e.g. process and detoxify
foreign compounds such as carcinogens in cigarette smoke); contain cytochrome P450, phase I and II enzymes etc

Question 18

what do phase I enzymes do

Answer 18

convert procarcinogen to carcinogen in lung

Question 19

what do phase II enzymes do

Answer 19

normally make them water soluble and excreted in metabolite, but if pathway overload or inactivated causes DNA binding, adduct formation and no repair so mutation

Question 20

airway smooth muscle functions

Answer 20

structure, tone (airway calibre - contraction and relaxation)

Question 21

what is mucin stored in as a condensed form

Answer 21

mucin granules in goblet cells

Question 22

what do ciliated cells have and why

Answer 22

high mitochondria to ensure beating

Question 23

what happens when mucin secreted

Answer 23

mucin takes on water and expands massively

Question 24

what are functional mucus secreting units called and where do they secrete mucus

Answer 24

acini, into collecting duct

Question 25

where are serous acini located in relation to mucus acini and what is their function

Answer 25

serous acini deeper secrete antibacterials (e.g. lysozyme - more water based); wash mucus into collecting duct

Question 26

ciliary structure

Answer 26

apical hooks, rods slide over each other to allow movement; 9+2 arrangement

Question 27

define metachronal rhythm

Answer 27

layer of mucus; leading edge; field of cilia will move leading edge a little way along; cilia then move back and waft again after other cilia have moved

Question 28

define mucus flakes

Answer 28

so much mucus can’t see cilia