Lecture 21: Lung Macro & Micro

Question 1

lung lymphatics

Answer 1

white lines under visceral surface, channel lymph towards hilum and mediastinal lymph nodes

Question 2

pleura composition and components

Answer 2

pleura is made of one layer of mesothelial cells, visceral (inner, intimate with lung) and parietal (outer)

Question 3

pneumothorax

Answer 3

shrunken lung, associated with air in the pleural cavity

Question 4

hemothorax

Answer 4

blood in the pleural cavity

Question 5

sensory innervation of the lung and pleura

Answer 5

vagus nerve, vagus and sympathetic fibers for the visceral pleura, phrenic and intercostal for parietal pleura

Question 6

vagus nerve in relation to lung position

Answer 6

vagus runs posterior to hilum of lung

Question 7

phrenic nerve in relation to lung position

Answer 7

phrenic runs anterior to hilum

Question 8

phrenic nerve diaphragm

Answer 8

provides motor (GSE) fibers to diaphragm

Question 9

orientation of hilum components on right and left side

Answer 9

On left side artery, bronchi, vein (Are Brides Vain?)
On right side bronchi, artery, vein (You’re Right, Brides Are Vain!)
This is only true at point of exit from the lung, things can cross if the cross section is taken at a different point

Question 10

Impressions on two lungs

Answer 10

Right lung impressions –> cardiac, azygos vein/arch, S. vena cava, I. vena cava, esophagus, brachiocephalic trunk
Left lung impressions –> cardiac, aortic arch, left subclavian, left brachiocephalic vein

Question 11

The lungs have a dual blood supply

Answer 11

De-ox. from the pulmonary arteries, ox. from the bronchial arteries that come directly off of the aorta

Question 12

bronchopulmonary segments

Answer 12

segments corresponding to bronchial tree, there are many of them

Question 13

tracheobronchial tree components, switch from macro to micro

Answer 13

trachea –> intrapulmonary bronchus (primary/main, secondary/lobar, tertiary/segmental) –>bronchiole –> SHIFT TO MICRO STRUCTURES –> terminal bronchiole, respiratory bronchiole –> alveolar duct –> alveolar sac –> alveolus

Question 14

components of trachea, outer to inner

Answer 14

adventitia, c-shaped rings, trachealis and longitudinal smooth muscles, submucosa, mucosa

Question 15

adventita

Answer 15

outer covering of trachea, made of connective tissue

Question 16

c-shaped rings

Answer 16

hyaline cartilage, incomplete dorsally

Question 17

trachealis and longitudinal

Answer 17

smooth muscles

Question 18

submucosa

Answer 18

mucous and serous glands

Question 19

mucosa

Answer 19

epithelium and lamina propria

Question 20

Epithelium of the trachea

Answer 20

part of the mucosa, made up of pseudostratified columnar ciliated cells with goblet cells

Question 21

lamina propria

Answer 21

made up of connective tissue and elastic fibers

Question 22

purpose of cilia and trachea

Answer 22

move small debri out of respiratory pathway, active movement

Question 23

other cell types present in trachea epithelium

Answer 23

endocrine (kulchisky) cells secrete seratonin to regulate airway breathing reflex, undifferentiated basal cells

Question 24

which mainstream bronchii is more verticle

Answer 24

the right one, more likely to choke on the right side

Question 25

Intrapulmonary bronchus

Answer 25

branches off of trachea, usually next to main branch of pulmonary artery at hilum, made up of smooth muscle, irregular cartilage plates, goblet cells, ciliated pseudostratified columnar cells. Transition to simple ciliated columnar as bronchii get smaller

Question 26

broncho-pulmonary segment/secondary and tertiary bronchii

Answer 26

branches off intrapulmonary bronchus, travel along side pulmonary artery/arterioles, branch in same pattern, epithelium fully ciliated simple columnar

Question 27

bronchiole

Answer 27

branches off broncho-pulmonary segment, no cartilage, smooth muscle, very few to no goblet cells, epithelium transitions from ciliated simple columnar to ciliated simple cuboidal

Question 28

Autonomic innervation of bronchiole glands and smooth muscle

Answer 28

Glands: Sympathetic is inhibiting, Parasympathetic is secretomotor
Bronchiole smooth muscle: Sympathetic is bronchodilation (greater need for O2, fight or flight), parasympathetic is bronchoconstriction

Question 29

Autonomic innervation of bronchiole and alveolur vasculature

Answer 29

Bronchioles: Sympathetic is vasoconstriction, parasympathetic is vasodilation (maybe, could have no affect)
Alveolar: no affect, capillaries not capable of constriction or dilation. Flow is hormonally regulated

Question 30

Affects of sympathetics on the lungs

Answer 30

secretory inhibition, bronchiodilation, vasoconstriction

Question 31

Affects of parasympathetics on lungs

Answer 31

increased secretomotor, bonchioconstriction, maybe vasodilation

Question 32

pulmonary plexus

Answer 32

cluster of nerve trunks, contains sympathetic and parasympathetic axons, and parasympathetic ganglia

Question 33

terminal bronchiole

Answer 33

branches off bronchiole, surrounded by layer of smooth muscle, no goblet cells, ciliated simple cuboidal epithelium, clara cells

Question 34

What are clara cells

Answer 34

Found in terminal bronchiole, precursor to bronchiolar epithelial cells, synthesizes surfactant, inhibits elastin digestion (elastin digestion leads to emphysema), detoxes carcinogens. Contains many secretory vesicles seen on EM. Have a rounded top that bulges above ciliated cuboidal cells

Question 35

alveolar wall

Answer 35

contains elastin, which stains black on resorcin-fuschin stain

Question 36

acinus

Answer 36

functional subunit of the lung supplied by a single respiratory bronchiole

Question 37

respiratory bronchiole

Answer 37

branches off of terminal bronchiole, simple cuboidal epithelium, wall encircled by smooth muscle that is punctured by alveolus, supplies single acinus

Question 38

alveolar duct

Answer 38

branches off of respiratory bronchiole, a space whose wall is made up of alveolar sacs and alveoli, basically leads towards them from the bronchiole

Question 39

alveolar sac

Answer 39

terminal part of alveolar duct, contains may alveoli

Question 40

alveolar capillaries relationship to lumen

Answer 40

protrude into lumen of alveoli, provide more surface area

Question 41

How wide is blood-air barrier?

Answer 41

.3 microns, alveoli epithelium, basement membrane, endothelium

Question 42

Alveolar wall cells

Answer 42

Type I pneumocytes –> thin, gas exchange, 40% of cells but 90% of surface
Type II pneumocytes –> thick/bulging, no gas exchange, 60% of cells, replace damaged type I cells, produce surfactant

Question 43

lamellar bodies

Answer 43

structure inside of type II pneumocytes that creates surfactant, made up of secretory vesicles made of tubular myelin weaves

Question 44

functions of surfactant

Answer 44

keep alveoli inflated, reduces fluid from from capillaries into alveoli, increases compliance (Stretchability), decreases alveolar surface tension, keeps cell water surface layer thin

Question 45

alveolar pores

Answer 45

holes in the epithelium surrounding alveoli connecting different alveoli together. equalizes pressure and facilitates flow between acini when a certain bronchiole might be blocked (kind of like collateral circulation)
also called alveolar pore of kohn

Question 46

function of alveolar macrophages

Answer 46

ingest extra surfactant, also ingest inhaled particulate matter so they have the name “dust cells”

Question 47

issues in smoker’s lungs

Answer 47

excess carbon particles trapped in macrophages, chronic bronchitis caused by excess mucus production, increased risk for pneumonia, increased risk for emphysema (loss of elastin, fibrosis of tissue), metaplasia (bronchii epithelium changes to stratified squamous), interstitial disease (alveolar walls are thickened), cancer