packet 1 part 5

Question 1

respiratory zone

Answer 1

include respiratory bronchi,, alveolar duct, alveoli

only site of gas exchange

Question 2

alveolar ducts end in

Answer 2

clusters of alveoli called alveoli sacs

gas exchange takes place here in resp. membrane

Question 3

conducting zone structures/anatomical dead space

Answer 3

all other resp. passages

no gas exchange

serve to transport materials to and from resp. zone

Question 4

respiratory membrane/air-blood membrane

Answer 4

formed by:

1. alveolar + capillary walls
2. fused basement membranes
3. occasional elastic fibers

acts as air-blood barrier bc it has gas (air) flowing past on one side and blood flowing past on other

Question 5

function of alveoli

Answer 5

walls of alveoli are composed of single thin squamous type 1 epithelium

alveolar pores connect neighboring air sacs and provide alternate routes for air to reach alveoli when feeder bronchioles are clogged w/ mucus or blocked

covered by pulmonary capillaries

Question 6

gas exchange

Answer 6

gas crosses resp. membrane by diffusion

oxygen enters blood, CO2 enters alveoli

macrophages wander in+out of alveoli, pick up bacteria, carbon, other debris

Question 7

total gas exchange surface of healthy man

Answer 7

50-70 square meters provided by alveolar walls

abt. 40x greater than surface area of skin

Question 8

type 2 cells

Answer 8

chunky cuboidal cells scattered amongst alveolar walls

Question 9

surfectant

Answer 9

lipid molecule produced by type 2 cells

coats gas-exposed alveolar surfaces and reduce surface tension of alveolar fluid