Respiratory System

Question 1

functions

Answer 1

1. air conduction/transport - alveoli
2. conditioning w/ moisture and warmth
3. filtration to remove particles/pathogens
4. **mechanical **respiration aka exchange b/t air and blood
5. reservoir for megakaryocytes maybe

Question 2

air conduction specifics

Answer 2

1. ventilation = move air in/out lungs
2. carry olfactory stimuli to receptors in region of nasal cavity
3. move air past larynx to generate speech

Question 3

system components

Answer 3

1. extrapulmonary portion of resp tract
2. intrapulmonary portion of tract
3. CT stroma (divides lungs into lobes)
4. visceral + parietal pleura
5. muscles of respiration

Question 4

tract divisions

Answer 4

1. conducting (extra + intrapulmonary) for air transport/filtration/conditioning only
2. respiratory (alveoli, bronchioles) where gas exchange with blood actually occurs

Question 5

conducting portion contents

Answer 5

trachea
primary bronchi
secondary bronchi
tertiary bronchi
small bronchi
bronchioles
terminal bronchioles

Question 6

respiratory portion contents

Answer 6

respirator bronchioles
alveolar duct
alveolar sac
alveolus

Question 7

tract layers

Answer 7

1. mucosa (surface epithelium + lamina propria + musculars mucosae)
2. submucosa
3. muscularis externa
4. adventitia/serosa

not every tract will have every layer

Question 8

adventitia layer

Answer 8

maybe cartilage usually hyaline but in larynx elastic

keeps large airways patent

Question 9

submucosa layer

Answer 9

dense irregular fibroelastic CT
maybe seromucous glands

Question 10

respiratory system mucosa layer

Answer 10

-surface epithelium
-lamina propria
-muscularis (reg diameter of airways via smooth muscle + structure)

acetylcholine causes SM contraction and restrict airways

Question 11

olfactory region

location

Answer 11

only has olfactory mucosa with epithelium and propria
@periosteum of cribiform plate in ethnoid bone (roof of nasal cavity)

Question 12

olfactory mucosa histology

Answer 12

1. olfactory epithelium- pseudostratified ciliated columnar w/o goblet cells + receptor cells
2. lamina propria- LCT + vessles + swell bodies (venous plexus) + nerves aka CN I + bowmans glands (serous, dissolve odorants)

nerves are unmyelinated

Question 13

cells in olfactory epithelium

Answer 13

1. receptor cells w/ dendrite bulb and cilia, bipolar, unmyelinated
2. supporting cells/sustentacular aka glial cells
3. basal stem cells
4. brush cells for general sensory recption via CN V (columnar w/microvilli)

Question 14

olfactory N

clinical relevance

Answer 14

axons of receptor cells route to CNS so pathogens could bypass BBB>viruses entering olfactory cells can trigger apoptosis

receptor cells are exposed to circulating air in nasal cavity

Question 15

respiratory epithelium

Answer 15

pseudostratified columnar with
-goblet cells for mucus to trap particles
-ciliated columnar cells to move mucus to mouth, motile
-basal cells for stem
-brush cells for general sensory
-neuroendocrine cells aka kulchitsky to secrete hormones (catecholamines, serotonin, calcitonin) dec after birth
-mast cells and intraepithelial lymphocytes (T)

line most of respiratory tract

Question 16

mucociliary clearance

Answer 16

if mucus too thick cilia have more diff time clearing it or can’t at all

goblet cells and cilia

Question 17

nasal cavity/sinuses/nasopharynx

histology

Answer 17

nasal mucosa: LP has
numerous swell bodies
vessels and glands (condition air)

swell bodies rupture in nose bleeds

Question 18

oral cavity/oropharynx /laryngopharynx

Answer 18

shared with digestive tract
mucosa = nonkeratinized stratified squamous

food more abrasive than air so need thicker epi for protection

Question 19

larynx

histology

Answer 19

lined by respir epithelium except true vocal cords (nonker strat squamous)

LP = numerous mucous and seromucous glands

no muscularis or submucosa

adventitia = hyaline cartilage except epiglottis is elastic cartilage

epiglottis bends during swallowing then returns to og

Question 20

trachea and bronchi

mucosa

Answer 20

BM very thick in trachea/primary/secondary bronchi so harder for pathogens to cross

LP has BALT and seromucous glands

muscularis: absent in trachea and primary
-present as cont SM layer in secondary and tertiary
-SM strips in smaller bronchi

Question 21

BALT

Answer 21

diffuse lymphoid tissue

common in infants > adolescents but in adults only assoc w/ illness or smoking

Question 22

trachea and bronchi

submucosa

Answer 22

submucosal glands/seromucous
dec in size and number as bronchi get smaller

Question 23

trachea and bronchi

adventitia

Answer 23

in all bronchi + hyaline cartilage
trachea + primary = C rings with trachealis muscle to contract

2/3/smaller = irregular plates, dec in size

Question 24

asthma

Answer 24

chronic inflamm disease of intrapulmonary airways (bronchi) so trouble air in and out

first attack b/t 0-6 yr old

triggers: allergens, exercise, breathing cold air

Question 25

asthma histology changes

Answer 25

bronchospasms irritate mucosa = inc mucus > inflammation edema and elevated WBC in tissues repeated attacks = inc # of goblet cells so more mucus and perm thickening of walls esp small bronchi

Question 26

bronchioles | layers

Answer 26

epithelium = simple cuboidal, no goblet cells, club cells LP= no glands or balt but lots of elastic fibers muscularis= thick in all, cont sheets around circumference of largest>strips in terminal/respir | no cartilage

Question 27

club cells

Answer 27

stem cells and secretion 1. surface active agent to prevent luminal adhesion and bronchial walls from collapsing and sticking to walls, soapy 2. CC16 antioxidant and antiinflammatory molecule, elevates when bronchioles damage

Question 28

terminal bronchioles

Answer 28

end of conducting portion mucosa is solid wall w/o gaps, short simple columnar, no glands, discont muscularis no submucosa adventitia = fibroelastic CT

Question 29

respiratory bronchioles

Answer 29

first airways in respiratory division walls have alveoli budding off air flow b/t respir bronchioles directly into alveoli

Question 30

alveoli

Answer 30

gas exchange occurs w/ continuous capillaries pores of Kohn: collateral gas circulation b/t adj alveoli if blocked, passageway for macrophages/pathogens

Question 31

alveolar ducts

Answer 31

no cuboidal epi or SM have gaps opening into alveoli terminates in a alveolar sac

Question 32

cell types in alveolar epithelium

Answer 32

1. type I- pneumocytes, gas exchange, 95% of alveolar surface, cannot divide, thin/delicate 2. type II- stem cells, secrete surfactant (lipids and proteins) to reduce surface tension from lamellar bodies

Question 33

associated cells | not in alveolar epi

Answer 33

alveolar macrophages/dust cells -patrol surface of lumen so not embedded w/i, travel thru pores or burrow into CT -also patrol CT of alveolar septum

Question 34

neonatal respiratory distress syndrome | NRDS

Answer 34

type II cells not differentiate until week 22-34, lungs not differentiate until week 35 premature babies (under 28) underdev lungs and type II cells not enough surfactant to prevent collapse | can lead to hypoxemia and metabolic acidosis

Question 35

interstitium

Answer 35

LP of alveolar wall= pulmonary intersistium mostly elastic fibers, no glands -allow to expand during inhalation then relax, passive way of getting air out of alveoli

Question 36

emphysema

Answer 36

form of COPD (from smoking, pollution) destruction of elastic fibers in alveolar walls = reduced ability to get air out neutrophils secrete elastases that destroy fibers so alveoli lose elasticity > walls destroy so less surface area for gas transfer

Question 37

alveolar septum

Answer 37

2 alveolar epi + BM +pulmonary interstitium +cont capillary + BM

Question 38

epithelium trends

Answer 38

more cell types in larger airways tall pseudostratified columnar in most of tract > simple squamous in alveoli

Question 39

alveolar septum | TEM

Answer 39

thin portion= BM of capillary endo fuses with BM of alveolar epi thick portion= alveolar epi DM sep by interstitium so no fusion

Question 40

smooth muscle trends | muscularis

Answer 40

1.continous sheets in larger bronchi 2.strips in smaller 3.continuous sheets in largest bronchioles 4.small circumferential strips in terminal and respir bronchioles 5.absent in alveolar ducts/sacs/alveoli

Question 41

elastic fibers trends | in LP and submucosa

Answer 41

fairly consistent esp important in alveoli

Question 42

cartilage trends | adventitia

Answer 42

only in trachea and bronchi absent in bronchioles and alveoli

Question 43

blood gas barrier | air-blood

Answer 43

physical barrier includes everything gasses must cross site of gas transfer to RBCs prevents bubbles from forming in blood prevent blood from entering alveoli