Lung Histology I

Question 1

What is the visceral pleura?

Answer 1

Serous membrane covering lung

Question 2

What is the parietal pleura?

Answer 2

Serous membrane lining parietal wall

Question 3

What is between the visceral and parietal pleura?

Answer 3

Intrapleural space or “cavity”- has a small amount of fluid

Question 4

What three things do the pleural membranes do?

Answer 4

Reduce friction, acts as a lubricant
Creation of a pressure gradient, pleural pressure helps keep lungs inflated
Compartmentalization- Puts lungs in different compartments
Each lung is separate, preventing infection from moving from one lung to the other

Question 5

What is air in the pleural cavity? Blood?

Answer 5

Pneumothorax

Hemothorax

Question 6

What is the cluster of sacs at the end of the alveolar duct?

Answer 6

Alveolar sac

Question 7

The _______ ______ is “the bunch of grapes” while the ______ is “one grape”

Answer 7

Alveolar sac

Alveolus

Question 8

How many alveoli are in the lungs?

Answer 8

300 million alveoli in the lungs (150m/lung)

Question 9

What epithelium lines the alveoli?

Answer 9

Simple squamous

Question 10

What surrounds each alveolus?

Answer 10

Surrounded by an extensive network of capillaries for O2/CO2 exchange
Elastic fibers surround each alveolus

Question 11

What is an alveolar pore? What does it do?

Answer 11

These connect adjacent alveoli, allow air pressure to be equalized

Question 12

What are the 3 types of cells in an alveolus?

Answer 12

Type 1
Type II
Alveolar Macrophages

Question 13

What is a type I alveolar cell?

Answer 13

Simple squamous lining cells, forming 95% of the surface area
Thinness allows for rapid gas diffusion to blood capillary

Question 14

What is a type 2 alveolar cell? What does it produce? What are they also called?

Answer 14

Round to cuboidal in shape, 5% of the surface area, not flat
Produce the alveolar fluid, which contains antimicrobial proteins and surfactant
Great alveolar cells

Question 15

The alveolar macrophage is also known as a…

Answer 15

Dust cell

Question 16

What do dust cells do?

Answer 16

Wander around inside the lungs and “tree”

Although we breathe in huge numbers of infectious microbes in each breath, the alveolar surfaces are usually sterile

Question 17

What happens to dead dust cells?

Answer 17

Dead dust cells get swept up by the ciliary current and are carried passively to the pharynx

Question 18

What does alveolar surfactant do?

Answer 18

Lowers the surface tension of alveolar fluid

Question 19

What substances make up alveolar surfactant?

Answer 19

A lipoprotein and phospholipid containing fluid

Question 20

How thick is the layer of alveolar surfactant? What would happen without it?

Answer 20

These surfactant molecules form a mono-molecular layer over the surface of all alveoli
The attractive force of the molecules would collapse the alveoli

Question 21

What is the respiratory membrane?

Answer 21

The barrier between alveolar air and blood

Question 22

How thick is the respiratory membrane?

Answer 22

0.5 μm total thickness, 15 times thinner than a piece of paper

Question 23

How much surface area for respiration do we have in the lungs?

Answer 23

Total surface area for gas exchange in adult lungs is 35x total body surface area
760 cubic feet or half a tennis court

Question 24

What supplies blood to the lungs?

Answer 24

Pulmonary arteries: Supply deoxygenated blood

Bronchial arteries: Supply oxygenated blood

Question 25

How does O2 get from inside an alveolus to the blood?

Answer 25

Alveolar air
Surfactant
Alveolar fluid
Type I cell
Basement membrane (type I cell)
Basement membrane (endothelium)
Endothelial cell
Blood

Question 26

What is a nasal sinus?

Answer 26

Air-filled spaces in bones of the skull

Question 27

What are the 4 nasal sinuses?

Answer 27

Maxillary sinus
Frontal sinus
Ethmoidal air cells
Sphenoidal sinus

Question 28

Nasal sinuses are lined with _______ ______ and drain into the _______ _______.

Answer 28

mucous membranes

nasal cavities

Question 29

Where do the paranasal sinuses drain?

Answer 29

Superior and middle meatus

Question 30

Where does the lacrimal duct drain?

Answer 30

Inferior meatus

Question 31

What are two other functions of the sinuses?

Answer 31

These sinuses reduce the weight of the skull and serve as a resonating chamber for voice

Question 32

What is sinusitis?

Answer 32

Acute or chronic inflammation of the sinuses.

Question 33

Physiologically, what happens when we have a sinus headache?

Answer 33

If the membranes swell enough to block drainage into the nasal cavity, fluid pressure builds up in the paranasal sinuses, and a sinus headache results

Question 34

What is the medical term for a collapsed lung?

Answer 34

Atelectasis