HE 20 & 21 Respiratory System

Question 2

Trends of Tracheobronchial Tree

Answer 2

Epithelium: pseudostrat column to simple cuboidal-less cleaning cellsWalls: less layers-no more mucosa or cartilageStructure: (cartilage) (sm + cart) (sm + EF)

Question 3

trachealis muscle

Answer 3

smooth muscle bundle posterior to C rings of cartilage in trachea

Question 4

kulchitsky cell

Answer 4

signals and regulates-secretes basally serotonin and peptide hormone-may affect nerve endings, goblet, & ciliated cells-regulated secretion-related to enteroendocrine of the gut

poorly stain
endocrine cell
enteroendocrine or ENES cell

trachea and bronchi

Question 5

key features of Trachea

Answer 5

cartilage ringsthickest epitheliumTrachealis MuscleNo muscularishigh in mucus from two places-mucosal epithelium-submucosal glandsepithelium/LP/submucosa

Question 6

Four types of cells in tracheal epithelium

Answer 6

goblet: mucus in lumenciliated: move mucusbasal cell: regenerates epitheliumkulchitsky cell: signals and regulates, basally secretes serotonin and peptide hormone, affects goblet, ciliated cells

Question 7

mucocilliary escalator and dysfunction

Answer 7

combination of ciliated cells that sweep mucosa out of the airway (mucosa contains particles trapped)Cystic Fibrosis caused by mutation of Cl- channel in respiratory epithelium. Ion gradient becomes unbalances and luminal mucus dehydrates. This thick mucus impedes mucocilliary escalator, making this area prone to infection

Question 8

Intrapulmonary Bronchi Characteristics

Answer 8

Lobar and segmental-hyaline cartilage plates-continuous muscularis (corresponds to increasing role of bronchioconstriction)segmental bronchus >bronchiole> lobule lobule: independent blood drainage)

Question 9

Bronchioles and dysfunction

Answer 9

NO cartilagethick muscularis: throws epithelium into folds-NO MUCUS PRODUCTION-simple columnar or cuboidal -ciliated cells present but gradually lostASTHMA: inflammation of bronchi and bronchioles-mast cells degranulation cause sudden constrictions of muscularis, narrowing lumen

Question 10

epithelial cells of bronchioles

Answer 10

ciliated cells present but gradually lostsimple columnar or cuboidal-clara cellsL bulge into lumen: secrete surfactant keeping lumen openterminal bronchiole: mostly clara, few ciliated, no alveoli buds

Question 11

components and significance of bronchiolar unit

Answer 11

respiratory bronchiolealveolialveolar ductalveolar sacmost gas exchange here-appear lacey with islands (resp bronch) in histo

Question 12

resp bronchiole

Answer 12

alveoli budscuboidal clara cellsbronkens islands of smooth muscle(trunk part: beginning of gas exchange)

Question 13

alveolar duct:

Answer 13

leads to alveolar saclacks smooth muscle islandswalls composed of alveolihas sacs as base

Question 14

alveolus

Answer 14

small air capsulsurrounded by thin continuous extremely tight capillaries -Type I and Type II pneumocytes-alveolar macrophagesalveolar wall: simple epithelium +BL

Question 15

Type I pneumocyte

Answer 15

flat wide cell95% of SA of wallcannot regeneratepart of blood/air barrierlook for flat cell with nucleus that bulges into space

Question 16

type II pneumocyte

Answer 16

bubbly look from lamellar bodies (secretory vescicles with surfactant)-different surfactant than claramore abundant but only 5% of surface area of wall. CAPABLE OF REGENERATION

Question 17

blood/air barrier

Answer 17

thin: gas exchange- continuous with blood vessels along alveolar septum (two alveolar walls)thick areas: contain fibroblasts/elastic fibers, macrophages- serve to support

Question 18

dust cells

Answer 18

alveolar macrophages, phagocytose particulate matter in lumen and septum

Question 19

emphysema

Answer 19

too many particulatesdust cells become overactivedust cells release enzymes that break down alveolar septa -less surface area, less gas exchange, less recoil to expire air

Question 20

week 3, 4, 5 conceptualization

Answer 20

3: lateral plate mesoderm splits into parietal and visceral4. lateral body folding-creates gut tube in embryonic cavity (coelom)cephalocaudal folding: pushes thick plate (septum transversum) between thoracic cavity and yolk sac-creates large openings (pericardioperitoneal canals)4&5canals compressed by lung buds to make two pairs of folds-pleurocardial membranes (fuse witheachother and root of lunch to form pericardial and two pleural cavities-lung budding also causes pleuroperitoneal folds to extend btween thor and ab. cavities creating thoracic diaphragm

Question 21

congenital diaphragmatic hernia

Answer 21

incomplete closure of one or both pleuroperitoneal membranes. abdominal gut tube herniates into the pleural cavity compressing the lungs and prevents full development in infants

Question 22

Respiratory Diverticulum and dysfunction

Answer 22

buds off ventral aspect of foregut: is the beginning of trachea and esophagus -driven by Retinoic acid expression of adjacent visceral mesoderm driving TBX4 Esophageal atresia/tracheoesophageal fistulae- incorrect partitioning of the trachea and esophagus-choking and regurg of food, pneumonitis, polyhydramnios-most common (90)-atretic esophagus

ESOPHAGUS is the one screwed up

Question 23

lung embryonic origin

Answer 23

endoderm: epithelium of resp systemvisceral mesodermL lamina propria, muscularis, submucosa, cartilage, adventitia, visceral pleura

Question 24

week five to early post natal lung development

Answer 24

primary-secondary-tertiarybronchopulmonary segmentation-continues after birth (six more divisions)

Question 25

month 7 to prenatal (10yrs)

Answer 25

at seven months, TRUE barrier for gas exchange is formed. continue to develop to 10 yrs. see figure of capillaries micrating to alveoli (month 6)

Question 26

pericardioperitoneal canals

Answer 26

lateral body folding (all body folding) leaves spaces on either sides of the gut tube, later a place for lungs to grow

Question 27

pleruopericardial membranes/folds

Answer 27

one pair of folds from lung budding causing them to divide the lungs and the heart, FUSION at root of lung, divides lungs into two different cavities and heart into a cavity

Question 28

pleuroperitineal membranes/folds

Answer 28

second pair of folds from lung budding causes them to move down and attach to the septum transversum (actually two separate ones with a loop division in middle) -mesoderm plate started from caphalocaudal body folding