Ketchum

Question 1

Cellular (biochemical) respiration

Answer 1

Deals w/gaseous exchange within cell.
O2 taken up by complex enzymatic process.
CO2 formed as waste and diffuses out of cell.

Question 2

External respiration

Answer 2

Occurs at level of blood cells

• rid themselves of CO2 from body cells
• recharge with O2 from atmosphere

Question 3

Conduction portion of lung

Answer 3

Includes: nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchioles.
Function: conduct air; removing particulates; warming, cooling, humidification of air

Question 4

Respiratory epithelium

Answer 4

ciliated pseudostratified columnar epithelium w/ goblet cells
		glands in lamina propria
		smooth muscle
		elastic fibers
		cartilage
cilia, glands & cartilage gradually disappear
		smooth muscle increases
		epithelium becomes cuboidal

Question 5

Trachea characteristics

Answer 5

Hollow rigid tube, 1.1 cm x 2.5 cm diameter
Respiratory epithelium
pseudo-stratified columnar, with cilia & goblet cells
rests on a thick BM
lamina propria
contains thin, fibrous layer
elastic fibers condense
forms elastic membrane
submucosa
beneath elastic membrane of lamina propria
contains seromucous glands

Question 6

Tracheal Characteristics

Answer 6

C-shaped cartilage “rings” deep to submucosa
16-20 “rings” composed of hyaline cartilage “rings “
smooth muscle span prongs of cartilag

Question 7

Primary Bronchus

Answer 7

trachea divides at carina
right and left branches called primary (1°) or main bronchi
histologic structure nearly identical to trachea
following exceptions:
horseshoe-shaped cartilage of trachea
replaced by cartilage plates of irregular shape
smooth muscle
more prominent & encircles lumen
composed of right & left spirals

Question 8

Bronchi

Answer 8

1°bronchi enter lung tissue at hilus
bronchi ramify
give rise to different orders of bronchial tree
lobar or large (secondary, 2°) bronchi
2 branches on left lung, 3 on right lung
segmental or small (tertiary, 3°) bronchi
8 to 10 branches on each lung

Question 9

Bronchioles

Answer 9

become bronchiole when caliber of bronchial tube <1mm
occurs when:cartilage plates no longer present
bronchioles undergo branching up to 20 generations
final stage known as terminal bronchiole

Question 10

Terminal bronchioles

Answer 10

as branching occurs, bronchiole gradually changes
epithelium changes from pseudostratified columnar to simple columnar
two types of columnar cells present
ciliated cells
club cells (non-ciliated secretory cells) smooth muscle increases
elastic fibers increase
called “terminal” because they are the termination of the conducting system

Question 11

Club Cells of Terminal Bronchioles

Answer 11

club cells (non-ciliated secretory cells)
secrete products which protect bronchiolar epithelium:
Clara cell secretory protein (CCSP)
solution similar to lung surfactant
engulf and break down toxins via cytochrome P-450
serve as progenitor cell population to regenerate ciliated epithelial cells

Question 12

Function of cilla

Answer 12

Mechanical host defense

Removal of particulate matter

Question 13

Respiratory region of Lung

Answer 13

site of gaseous exchange between air & blood
consists of:
    respiratory bronchioles
    alveolar ducts
    alveolar sacs
    alveoli

Question 14

Respiratory bronchioles

Answer 14

arises from terminal bronchiole
   200mm in diameter
   simple epithelium
	low columnar to cuboidal with no cilia
	becomes squamous in alveolus
    characterized by presence of alveoli
	(singular, alveolus)

Question 15

Branches of Respiratory Bronchioles

Answer 15

branches into:
alveolar duct
2-3 elongate branches of respiratory bronchiole
atrium
space between alveolar duct & alveolar sac
alveolar sacs (saccules)
alveolar duct ends in 2-3 alveolar sacs
alveolus
single outpocketing

Question 16

Alveoli

Answer 16

alveolus
75m to 300m in diameter
thin-walled polyhedral structures
walls are delicate and contain elastic fibers

Question 17

Alveolar pores

Answer 17

allows air to flow between adjacent alvioli
small, slit-like openings between adjacent alveoli
10m to 15m diameter in large alveoli
pores equalize inter-alveolar pressure
pores equalize inter-alveolar pressure
can prevent atelectacsis
allow alternate pathway for ventilation (in obstruction)
may permit spread of infection

Question 18

Cells of Alveolar Wall

Answer 18

alveolar wall consists of five different types of cells
described in two groups
	surface cells
		type I alveolar cell
		type II alveolar cell
	intramural cells
		endothelial cells
		fibroblasts (CT cells)
		smooth muscle cells

Question 19

Type I epithelial (alveolar) cell

Answer 19

Second most common alveolar cell and covers 90% of alveolar surface.
Cytoplasm attenuated to form alveolar lining
Have little or no endoplasmic reticulum

Question 20

Type II alveolar cell

Answer 20

More numerous than type I but only covers 5-10%.
Large round cell, may protrude from alveolar wall.
Lamellar bodies contain globular surfactant.

Question 21

Type II avleolar cells produce Surfactant

Answer 21

phospholipid material
released and spread over surface of squamous cell
thin coating acts as surface tension reducing agent
by reducing surface tension
prevents collapse of alveolus during expiration

Question 22

Intramural cells of alveolar wall

Answer 22

capillary endothelial cells (nuclei are most numerous)
fibroblasts (CT cells)
occasionally observe smooth muscle cells

Question 23

Alveolar Macrophages

Answer 23

dust cells
free of alveolar wall
contain phagocytosed material in cytoplasm
also known as heart failure cells
derived from monocytes

Question 24

Alveolar Membrane

Answer 24

O2 exchange between alveolus & RBC’s largely by ‘passive transport“
alveolar membrane a multilayered barrier 0.3-0.7m thick
consists of: attenuated cytoplasm of type I cell (0.05m) BM between type I cell & endothelium (0.15m) attenuated cytoplasm of endothelium (0.25um)

Question 25

Gas exchange and physiologic shunt

Answer 25

Mean pulmonary artery pressure = 15 mm Hg Mean systemic pressure = 100 mm Hg Shunt- transfer of deoxygenated blood from the venous circulation to the arterial circulation