Respiratory System Flashcards
Lung epithelium’s specialisation down the airway, their characteristic.
Bronchi - bronchioles- alveoli
Bronchi is ciliated, has goblet (secret mucus) and glandular cells.
Bronchioles can be ciliated or non ciliated. Also had goblet cells. Has Clara cells as additional secretory cells.
Alveoli are squamous (large SA and flat thin cells) enable good gas exchange and have cuboidal cells for secretory and host defence function.
What’s parenchyma consist of?
Terminal bronchioles, respiratory bronchioles, alveolar duct, pulmonary artery and vein
Alveolus, capillary, type 1 and type 2 epithelial cells, macrophage
What are the two types of alveolar epithelial cells? (Pneumocytes)
Type 1 and type 2
Type 1: v large SA, covers 95% of alveolus, 10% of cells, squamous, gas exchange.
Type2: cuboidal,secretory (surfactant) respond to damage of type 1 and divide itself into type 1, progenitor of both 1and 2
What’s surfactant?
90% lipid mostly phospholipid
Protein SP A B C D
Use of surfactant?
Reduce surface tension- prevent alveoli from sticking together or collapse (atelectasis) maintain alveolus open
Innate immunity function
Instilled into babies with infant respiratory distress syndrome to keep airway open
Curosurf, beractant
What stimulates development of Lungs in pre mature babies?
Corticosteroids
Lung is filled with fluid in foetus, what empties it?
Surge in steroid and catecholamines at birth
Active Epithelial Sodium Channel (ENaC) increase reabsorption of fluid into blood.
Pressure change- increase pressure in lung when squeezing through birth canal, therefore increase the fluid push out of lung
Caesarian- reduced drive for fluid absorption
Blood flow to lungs
Pulmonary circulation
Right heart- Pulmonary artery - alveoli - left heart
Bronchial circulation
Left ventricle - aorta - conducting airways
What’s the functional unit of lung and what’s its functions?
Parenchyma.
Gas exchange, defence and metabolic.
What’s the metabolic function of lung
Inactive circulating hormone
Activated ag1, converts to ag2 increase BP.
Fibrinolytic- break up blood clots
What increases lung compliance?
Surfactant, emphysema (loss of elasticity)
What reduces compliance of lung?
Pulmonary fibrosis (scarring, harder to stretch)
Charcacteritcs of pleural membrane?
What does pleura sac do?
1) double membrane surrounding the lungs
2) right and left pleura are very distinct
3) very thin layer of pleura fluid between membrane (few ml
4) lubricant
Help lung wall stuck to the inside of thorax
