resp cell biology

Question 1

describe the epithelium

Answer 1

goblet cells
many mt - for cilia to beat
ciliated cells
continuous barrier - isolate from external, protection

Question 2

list the functions of the epithelium

Answer 2

secretion of mucins, water and electrolytes
mucous is to trap and remove microbes and particulates
mucocillary clearance
proteins in secretions - maintain reduced surface tension
metabolise foreign and host derived compounds - xenobiotic
physical barrier
trigger lung repair process
make:
NO from NOS - speed cilia up
CO by hemeoxygenase - theory: kill bacteria
arachidonic acid metabolites - prostaglandins
chemokines eg IL 8
cytokines - GM-CSF
proteases
inf mediators

Question 3

release of mucous

Answer 3

mucin tightly packed in goblet cells
when released - hit water = expands
submucosal glands made of acini - secrete mucous into collecting duct - wafted onto surface
human bronchial gland: mucous acini, serous acini - antibacterials and more watery
glands secrete water and salts
serous secretion help wash mucous into collecting duct and onto the airway surface

Question 4

mucocillary escalator

Answer 4

cilia beat in a metachronal way
the first group of cilia push the leading edge of the mucous
it is then pushed by subsequent cilia and the front cilia push the next section of the mucous
the cilia don’t actually move position.
highly synchronised

Question 5

recall the role of alveolar macrophages

Answer 5

reach out to particles
take up particles
lots of macrophages accumulate around 1 asbestos fibre

Question 6

where are polymorphonucelar neutrophils present

Answer 6

when present it is an infection

normally in smaller numbers than macrophages

Question 7

roles of macrophages and neutrophils

Answer 7

phagocytosis
antimicrobial defence
synthesise antioxidants eg glutathione
xenobiotic metabolism

Question 8

effect of smoking on macrophages and neutrophils

Answer 8

increase the number 10 fold
in smokers with respiratory infection - neutrophil increase from 10-30% in respiratory units
in smokers ratio of macrophages:neutrophils from 70%:30% to 30%;70% - number of both cells increased, neutrophils more because of bacteria

Question 9

what do neutrophils and macrophages release

Answer 9

serine proteases - neutrophil elastase

metalloproteinases- MMp9, Zn/metal reactive at site - dissolve own lung

Question 10

effect of proteinases from neutrophils and macrophages

Answer 10

substrates - proteins, connective tissue, elastin, collagen
activate other proteinases- eg NE degrade and activate MMP
inactivate antiproteinases - eg NE degrade a-1 antitrypsin
activate cytokines and pro-inf mediators

Question 11

neutrophil and macrophage releasing antioxidants

Answer 11

antimicrobial
generate reactive peroxides
inactivate a-1 antitrypsin
fragment connective tissue

Question 12

mediators released by macrophages

Answer 12

help repair wounded tissue
chemoattractant/cytokines - IL8 - attract more inf cells in infection or acter toxicant/microbial deposition/inhalation
GF and proteases - trigger growth and repair by cells eg epithelium/stromal fibroblasts

Question 13

function of the airways

Answer 13

conduit for O2 to alveoli and CO2 to lungs

for GE

Question 14

3 things that allow airways to perform their functions

Answer 14

mechanical stability - cartilage
control of calibre - sm
protection and cleansing

Question 15

organisation of airway structures

Answer 15

C shaped cartilage - slightly offset for tensile strength
submucosal gland - tip in SM - when contract mucus squeexzed onto surface
mucous inside lumen- 10ml, thinly spread
lumen

Question 16

cilia

Answer 16

have radial spokes and rods that go up and down
inner and outer arms slide over each other - go back and forwards
some cilia move in 1 dirn, others in the other
apical hooks that engage with mucous
9+2 arrangement
200 per ciliated cell
60-80% epithelial cells
shorter in small airways

Question 17

smooth muscle cells

Answer 17

contract and relax
involved in structure - hypertrophy and proliferation
secretion - mediators, cytokines, chemokines

Question 18

smooth muscle cells with inflammation

Answer 18

hypertrophic
make NO and prostaglandins
make cytokines, chemokines and adhesion molecules- cause inflammatory cell recruitment

Question 19

vasculature structure

Answer 19

trachea-bronchial circulation
systemic
perfusion 2nd to none
arteries from aorta, intercostal arteries and others
systemic veins to tracheal circulation
return to heart by bronchial and pul veins
plexus below the epithelium
good circulation so no need for pul circulation

Question 20

Tracheo-bronchial circulation: functions

Answer 20

GE 
warm air 
humidification of air 
clears inf mediators 
clears inhaled drugs 
supply lumen with inf cells and proteinaceous plasma

Question 21

describe plasma exudation

Answer 21

post capillary venules are leaky - leak plasma
C fibre nerve stimulates more holes
inf mediators histamine, PAF make more leaky
see this by using evans blue dye which binds to albumin and histamine - fluoresce orange

Question 22

goblet cells

Answer 22

chalice shape 
bulge into lumen 
produce mucin 
20% of epithelial cells
in large airway

Question 23

club cells

Answer 23

have secretory granules
detoxifying enzymes - destroy xenobiotics
repair damaged endothelium
in small airways - bronchiolar

Question 24

type 1 epithelial cell

Answer 24

covers 95% alveoli surface

flat and thin - GE , and solute transport back and forth

Question 25

type 2 epithelial cell

Answer 25

tiny and cuboidal
in corners of alveoli, in interstitium with apices facing the air
double number than type 1
secretory - make surfactant - release onto air-liquid interface
contain lamina bodies that store the surfactant - released when lung stretch
stem cell - divide into type 1

Question 26

stromal cells myofibroblasts

Answer 26

make ECM - that cells sit on
made of collagen, elastin = elasticity and compliance
divide to repair
when overdrive = interstitial pulmonary fibrosis

Question 27

function of secretory epithelial cells

Answer 27

secrete mucous and surfactant
release antioxidants - glutathione, superoxide mutase
secrete antiproteinases - secretory antiproteinase inhibitor (SPLI) - local - back up a 1 antitrypsin
release lysozyme - destroy bacterial cell wall
xenobiotic metabolism
contain chromosome P450, phase 1 and 2 enzymes

Question 28

phase 1 and 2 enzymes

Answer 28

in club cells, type 2 cells and macrophages

involved in xenobiotic metabolism and detoxification

Question 29

cigarette smoke and enzymes

Answer 29

procarcinogen
lung cell: phase 1 enz
phase 2 enz - normal: metabolism - make water soluble and metabolite is excreted
phase 2 enz - overload from phase 1 - no met - DNA binding, adduct formation, no repair = mutation
precursor for cancer

Question 30

identifying cells

Answer 30

use receptor on the cell surface, cell signalling, to isolate cells from lungs at different stages