B1- Lungs Flashcards
What is boyles law
Inverse relationship between volume eg of thorax and rhe pressure
What two types of resp are there
Cellular generating atp (internal)
External is breathing
Why is air humidified in upper resp tract
So exchnage tissues dont dry out
and so gas transfers freely into blood in alveoli
What is rhe diameter and csa of trachea
20 mm diamter and small csa of 2.5cm = airflow resistance
Alveoli are what diameter and sa
0.3mm
Large sa of 1 x 10^6 (tennis court)
Which area of airway is first line of defence eg by cilia and ifn
Ciliated epihtelial pseudostratified columnar (eg nasal)
Where is contona ideal colonisation
In nasal epi cells or govlet secretort cells
Which article disxusses sars cov 2 effects on airway epi cells
Zhu et al 2020
What sorts of effects do they have in the cells
Destroy cilia by staying at apical surfaces
Form gisnt syncytial cells (fusion of cells)
Destroy tight cell junctions
Which article discusses ifn in naaal epi cells /sexretory and covid
Hatton et al 2020
Is ifn blocked by covid in nasal and sexreotry
No iust delayed
How
Downrefulation of Isg (ifn stimulating genes)
Which mutstion seen in severe xovid patients
Ifn receptor which sigansl vis jak stat for antigirql wffects
What is point of ifn 1 and 3
Epithelial integrity and refcued viral replication and t regs too
What do capillaries on alveoli allow for ventilation
Ventilstion perfusion matching (v/q)
What % do capillaries cover alveoli surface
80-90%
How does alveoli connextive tissue of lungs allowing recoil and expanding
Elastin and collagen
What is condition callrd shich causes consfant dilstion of sireays whcih forms mucus build up and infection
Bronchiecstasis
What is it caused by
Inflammatory damage eg to elastic and muscular components of bronchi
Which article discusses alveolar cells
Guillot 2013
What types of cells are type 2
Large cuboidal cells
What growth factor allows conversion of orsophagual to respiratory epitheliumeg after infection
Fgf
What are bacs cells which are upregulated after ciral infection
Bronchioalveolar cells near ducts which differentiate to rype 1 and type 2 cells
Which alveolar cells are self renewable and form the other
Type 2
What causes surface tension of alveoli
Air blood barrier (reduced to 1micronetre by flat type 1)
How is surfsctant responsible in precenting collapse
Reduce surface tension
Which right junctions are a barruwr to infection in alveolar cells to block interstitial
Claudin 3
Which alveolar cells have tlr and contsct macrophages for clearance of infection
Type 1
During which infection
Pneumococcal pneumonia
Ofher than opsonins whag are surfactant p a and d
They are antininflam by rleeasing tgf b and il10
What allows thoracic cage and lung moving up together
Parietal pleura (costal which adheres thoracic wall)
What allows passive exp
Recoil of elastic connrctive tissue
In inspirstion what forms 70% of the volume change so pressure is lower than atmospheric
Dipahragm (moves 1-2cm)
What are the other 30%
Accesory and intercostals
What measures lung function
Spirometer
What is fev1 which is reduced in smoking etc eg copd due to obstruction
Maximal vol of air expired in 1 second after maximal nspiratioj
What is it depeendant on
Body tempersture and sateuation of rhe air
What is fvc alsonreduced
Max amount of air breathed out with msximal force applied after maximal inspiration
Give an example of ehat causes lower fvc
Pulmonary fibrosis which reduces elasticity due to scarring
