L12 - respiratory anatomy and histology Flashcards
what cells line alveoli
type 1 and type 2 pneumocytes
type 1 pneumocyte function
involved in gas exchange - line alveoli
what epithelia are type 1 pneumocytes
squamous
what epithelia are type 2 pneumocytes
cuboidal
what type of pneumocyte is most abundant
1
how are type 1 pneumocytes connected to eachother
tight junctions
type 2 pneumocyte function
produce surfactant
are type 1 or 2 pneumocytes bigger
2
what two things increase thoracic volume
diaphragm
ribs
explain inspiration at rest
- diaphragm contracts and flattens
- abdominals relax
- external intercostals contract pulling ribs up and out
increases thoracic vol, decreases pressure, air in
explain expiration at rest
- diaphragm relaxes into dome shape
2. passive recoil of lungs expels air
explain inspiration during exercise
- forceful diaphragm contraction
- accessory inspiratory muscles contract
- further outward expansion
what are the accessory muscles
external intercostals
scalenes
etc
explain expiration during exercise
- abdominals and diaphragm contract - rapid collapse of lungs
- internal intercostals contract pulling ribs down
name the two pleural membranes
parietal (outer) visceral pleura (inner - covers lungs)
what is the function of the fluid filled space between the pleural membranes
- allows membranes to move across eachother
2. cohesion - lungs adhere to thoracic cavity and expand with thorax
what does upper respiratory tract include
nasal cavity to larynx
what does lower respiratory tract include
trachea - alveoli
what is the conducting zone
trachea - terminal bronchiole
where no gas exchange takes place
what lines the conducting zone
respiratory epithelium
pseudostratified columnar, ciliated , goblet cells
what is the respiratory zone
below terminal bronchioles (respiratory bronchiole, alveoli)
where gas exchange takes place
how does epithelium differ from conducting zone to respiratory zone
changes to cuboidal
goblet cells replaced by club cells
no cilia
function of club cells
release surfactant
act as stem cells for other epithelial cells in bronchioles
