Lecture 21: The Lungs

Question 1

what is the R lung divided into

Answer 1

R upper, R middle, R lower (has horizontal and oblique fissure)

Question 2

what is the L lung divided into

Answer 2

L upper and lower (only oblique fissure)

Question 3

what is the function of the lung lymphatics

Answer 3

channel lymph towards hilum and to mediastinal lymph nodes

Question 4

what do the lung lymphatics look like

Answer 4

white lines under shiny visceral surface

Question 5

what is the pleura composed of in terms of cells

Answer 5

a single layer of mesothelial cells

Question 6

two types of pleura in lungs and what is in between them

Answer 6

visceral and parietal, pleural cavity is in between

Question 7

sensory innervation of parietal pleura (receptors, afferent nerve, resulting action)

Answer 7

receptors: tear/puncture
afferent nerve: intercostal and phrenic
resulting action: GSA pain

Question 8

sensory innervation of visceral pleura (receptors, afferent nerve, resulting action)

Answer 8

rec: tear/puncture
afferent nerve: vagus and sympathetics
result: little/no GVA pain

Question 9

sensory innervation of smooth muscle (receptors, afferent nerve, resulting action)

Answer 9

receptor: stretch
afferent nerve: vagus
resulting action: herin breuer reflex (limits inspiration)

Question 10

sensory innervation of mucosa of trachea and bronchi (receptors, afferent nerve, resulting action)

Answer 10

receptor: irritation
afferent nerve: vagus
resulting action: coughing, gasping, prolonged inspiration

Question 11

sensory innervation of C pain fibers in alveoli and bronchi (receptors, afferent nerve, resulting action)

Answer 11

receptor: inflammation
afferent nerve: vagus
resulting action: stimulates respiration

Question 12

sensory innervation of pulmonary veins and cardiac plexus (receptors, afferent nerve, resulting action)

Answer 12

receptor: chemical (chemo)
afferent nerve: vagus
resulting action: stimulates respiration if O2 is low

Question 13

sensory innervation of aortic arch and wall, pulmonary arteries (receptors, afferent nerve, resulting action)

Answer 13

receptor: pressure (baro)
afferent nerve: vagus
resulting action: regulates change in blood pressure

Question 14

what fibers are in phrenic and where do they go

Answer 14

GSE to diaphragm

Question 15

what does the pulmonary artery carry

Answer 15

deoxygenated blood

Question 16

what does the pulmonary vein carry

Answer 16

oxygenated blood

Question 17

what is the dual blood supply to the lungs

Answer 17

bronchial arteries from aorta, intercostal arteries or subclavian arteries entering at the hilum (oxygenated blood!!!)
pulmonary arteries carry deoxygenated blood!

Question 18

what do the pulmonary arteries look like

Answer 18

follow bronchial tree to form capillaries around alveoli

Question 19

what are broncho pulmonary segments

Answer 19

lung sub units corresponding to bronchial tree, no visible lines demarcating these

Question 20

outline the tracheobronchial tree

Answer 20

trachea to intrapulmonary bronchus

each branch of bronchus has main (1) lobar (2 on R, 3 on L) and bronchioles

Question 21

what don the bronchioles turn into

Answer 21

terminal bronchioles then respiratory bronchioles then alveolar duct then alveolar sac then alveolus

Question 22

what separates the trachea (muscle name)

Answer 22

the carina

Question 23

what is the trachea composed of

Answer 23

Adventitia 
C-shaped rings –
Trachealis & Longitudinal
Submucosa
Mucosa

Question 24

what is the adventitia

Answer 24

connective tissue on outside of trachea

Question 25

what is the c shaped ring

Answer 25

hyaline cartilage in trachea which is incomplete dorsally

Question 26

what is trachealis and longitudinal

Answer 26

smooth muscles in trachea

Question 27

what is the submucosa

Answer 27

mucous and serous glands in the trachea

Question 28

what is the mucosa comprised of

Answer 28

epithelium and lamina propria

Question 29

what is epithelium in trachea

Answer 29

pseudostratified ciliated columnar and goblet cells

Question 30

what is the lamina propria in trachea

Answer 30

connective tissue and elastic fibers

Question 31

what other cells (other than main ones) are present in respiratory epithelium

Answer 31

endocrine (kulchinsky cells) which secrete serotonin etc and regulate airway reflexes (smooth muscle contraction) also basal cells (not columnar) which are undifferentiated precursors

Question 32

where do objects lodge

Answer 32

R bronchus (2 parts) more vertical

Question 33

where is the intrapulmonary bronchus usually located

Answer 33

next to a branch of the pulmonary artery

Question 34

what types of cells in intrapulmonary bronchus

Answer 34

irregular cartilage plates, smooth muscle, goblet cells, ciliated pseudostratified columnar epithelium, transitions to ciliated simple columnar as bronchi get smaller

Question 35

what is the bronchopulmonary segment

Answer 35

secondary/tertiary bronchi travel alongside, and branch in parallel with pulmonary arteries/arterioles

Question 36

what cells in bronchiole

Answer 36

No cartilage, smooth muscle, very few or no goblet cells, epithelium transitions from ciliated simple columnar to ciliated simple cuboidal

Question 37

what is the autonomic innervation of bronchial glands

Answer 37

sympathetics (inhibitory, 4Fs) | parasympathetic (vagus, secretomotor)

Question 38

what is the autonomic innervation of bronchial smooth muscle

Answer 38

sympathetic (4Fs, bronchodilation) | Parasympathetic (vagus, bronchoconstriction)

Question 39

what is notable about bronchi and bronchioles and what is the physiologic result

Answer 39

no gas exchange so want a larger diameter lumen!

Question 40

sympathetic and parasympathetic function of bronchial vaculature

Answer 40

sympathetic is vasoconstriction | parasympathetic is vasodilation

Question 41

what is notable about alveolar vasculature

Answer 41

no effect of ANS innervation

Question 42

function of sympathetics in lungs

Answer 42

secretory inhibition, bronchodilation, vasoconstriction

Question 43

function of parasympathetics in lungs

Answer 43

secretomotor bronchoconstriction vasodilation?

Question 44

what does the pulmonary plexus contain

Answer 44

contains both sympathetic & parasympathetic axons, and parasympathetic ganglia *Vagus, L recurrent laryngeal

Question 45

what are clara cells precursors to

Answer 45

bronchiolar epithelial cells

Question 46

what is the function of clara cells

Answer 46

detox of carcinogens, synthesizes surfactant like protein, secretes alpha 1 antitrypsin that inhibits digestion of elastin

Question 47

what happens with elastic tissue breakdown

Answer 47

emphysema

Question 48

what does the alveolar wall contain

Answer 48

elastic tissue

Question 49

what is an acinus (acini is plural)

Answer 49

functional subunit of lung supplied by single respiratory bronchiole

Question 50

what is a resp bronchiole encircled by

Answer 50

smooth muscle

Question 51

what is interesting about capillary walls

Answer 51

potrude into lumen to provide more surface area

Question 52

what type of cells are endothelial cells (shape and function)

Answer 52

thin/flat for gas exchange

Question 53

type I pneumocytes

Answer 53

thin/flat, for gas exchange

Question 54

what percent of alveolar cells are type I pneumocytes

Answer 54

40% but cover 90% of surface of alveoli

Question 55

what percent of cells are type II pneumocytes

Answer 55

60%

Question 56

what is the function of type II pneumocytes

Answer 56

replace damaged type I cells, secrete surfactant | NO GAS EXCHANGE

Question 57

what are lamellar bodies

Answer 57

secretory vescicles that product surfactant in the form of tubular myelin weaves

Question 58

where is surfactant found

Answer 58

alveolar surface

Question 59

what does surfactant do

Answer 59

1) acts as a detergent to decrease alveolar surface tension 2) keeps cell surface water layer thin, increasing gas exchange 3) increases compliance (stretchability) 4) prevents alveolar collapse 5) reduces fluid flow from capillaries into airways

Question 60

what is surfactant made of

Answer 60

mix of phospohlipids, cholesterol, carbohydrates, proteins

Question 61

what happens with low surfactant levels

Answer 61

low surfactant levels = respiratory distress syndrome

Question 62

what do alveolar macrophages do

Answer 62

phagocytose extra surfactant

Question 63

smokers lungs

Answer 63

XS carbon particules trapped in macrophages chronic bronchitis as XS mucus from goblet cells loss of elasticity (emphysema, fibrosis)

Question 64

what is the cellular change in smokers lungs

Answer 64

metaplasia (bronchi epithelium changes to stratified squamous)

Question 65

pore of kohn

Answer 65

discrete holes in walls of alveoli