Histology #4 (Respitory) Flashcards

Question

Clara cells

Answer 1

Non ciliated dome cells --> improtant for secreting proteins + creating epithelium + maintain bronchioles

Answer 2

1. Terminal brocnhioles 2. Respitory bronchioles Branching Function -- increases surface area = optimizes gas exhnage + decreases air veolicty as air flows through Image - se the terminal bronchiols branch into the respitory

Answer 3

Most distal conducting airways Each branch of Terminal bronchiole gives rise to 2-5 respotroy bronchioles (terminal bronchioles branch into respitory bronchioles)

Answer 4

Intial airways into where gas exchnage ahppens Contains Alveoli (allows for gas exchnage to occur)

Answer 5

TB = Terminal bronchiole AD = Alveolar Duct RB + Respirtpry Bronchiole Left - terminal have a distict epithelium then have trasnitiion to respitory (as transition to respitory you have aveoli)

Answer 6

Overall - Thin Walled sac Contain Type 1 and Type 2 Pnumocytes Function - Site of gas exchange Contains Elstic and Reticular fbers --> provide structural supoort + allow for expansion and contraction as air flows through Conatins Pores of Kohn --> promote collateral circulation + Route for alveolar macrophages Contains smooth musckes at opening -- smoth muscle controsl opening of Alveoli Image - Bottom left = see cross section of alveoli ducts Bottom Right - have cross section of alveoli (share a commmon wall where exchnage occurs) ; knobs at the top are smooth muscle cells controling opening

Answer 7

Pores of Kohn = small opening that connects airspace of adjacent alveoli --> creates collateral circulation + route for macrophages to travel

Answer 8

RB = Rspitory bronchioles AD = Aveolar duct ALV = Alveoli Left - Alveoli throughout (Cup and circular shaped) Right - See bronchi

Answer 9

Function - Facilitates gas exchnage between Alveoli and capilaries - Exchnage occurs when deoxygenated blood is brought to the lungs --> Swap CO2 and O2 --> Blood goes to heart Thin squamous cell shape Covers 97% of lung (avleoli) surfaces BUT only composes 10% of total lung cell population

Answer 10

Type 1 Pnumocytes - have basal lamina Tyoe 1 basal lamina are fused with the lamimae of pulminary capillaries that run in interalveolar septa Image - see flat cell (Tyoe 1 pnumocyte) -- cell is in communication with the aveoli space (Impritant for gas exchnage)

Answer 11

Tyoe 1 cells join other cells via tight junctions - Tight junctions = prevent fluid from leaking into alveolar space

Answer 12

Function - Secretes surfactant - Surfactnat = a mixture of proteins + phospholipids + Glycoaminoglycans Type I Pnumocyte = also functions as a stem cell that can differentiate into both Type 1 and Tye II Pnuemocytes (1% of cells are replaced on a daily basis) Has a large cuboidal cell shape Compse of 30% of the lung cells in the Alveoli

Answer 13

Tyoe II Pnemocytes = have numerous memebrane bound multi lamellar bodies in the cytoplasm - Lamelar bodies = make surfactnat - Pnumocytes = found at sites where alveoli walls join Type II Pnuemocytes = joined to type I pnuemocytes by tight junctions and desmosomes Image - swiry structure - lamalar bodies (secrete substances)

Answer 14

Fluid that covers the alveolar epithelium Function - Reduces the surface tension in the alveoli - facilitates alveoli epxansion during respiration + Prevents a;veolar collapse during expiratiion

Answer 15

Derived from monocytes in the blood Most numerous cell in the lung (90%-95%) Function - Clean up crew for Aveolar --> Patrol air spaces to phagocytose debris and bacteria - Called Dust cells - because they engulf particles Location - Found in the interveolar septa and on the surface of alveolar lumen - Macrophages in the lumen will make their way to the brinchioles and be released in the mouth

Answer 16

1. Interalverlar septa 2. Blood-Air Barrier

Answer 17

Alveolar wall shared by adjacent alveoli Contains a dense capilary network for gas exchange (contains the pulminary capilaries) Perferated by pores of Kohn Function - provides the structural basis for gase exchnage in the lung

Answer 18

1. Epithelum (of adjacent alveoli) 2. Interstitium (collegen and elastic fibers) - White color in image 3. Capilary endothelium - has capilaries Have sandwhich of epithelium with interstium between and sandhwich of the capilayr epitheliam with interstitium between (seen in image)

Answer 19

Septra structure gives the basis for gas exchange in the lung

Answer 20

Left - shows alveoli - Arrows show the inter alveolar septa Right - Arrows show the pores of Kohn (pores are connection around air spaces) - Pores = equilize the pressure between adjacent alveoli

Answer 21

Overall - Barrier between capilary blood and alveolar air Function - Specilized region of the Alveolar wall across which gas exchnage occurs - O2 enters the blood - CO2 enters the alveoli

Answer 22

1. Alveolar epithelium (composed of type I pnuemocytes) - Have a thin layer of surfactant that cover the Alveola Epithelium 2. Capilary endothelium (endothelial cells) 3. Fused basal laminae of the two cells Have a thin layer of surfactnat that covers the apical side of the Type 1 Pnumocytes

Answer 23

Blood Air barrier Type I pneumocytes form a simple squamous epithelium lining the majorty of the surface area of the alveoli Capilaies - single layer endothelium IMage - aveolar wall -- see Type 1 Pnumocytes form stromas epithelum lining air spaces see pulminary capilzaries inside alveolar wall

Answer 24

The cytoplasm of the Type I pnumocytes and the endothelial cells is HIGHLY attenuated + The two cells types share a fused basement mmebrane --> BOTH factors minimize the barrier = increase gas exchnage efficiencey

Answer 25

Cytoplasm of Type 1 and Capilary endothelial cells is attentuated (dcereased) - thickness of the cytoplas is 0.5-15 um ALSO twi cells share a fused babsement memberane= air can difuse more easily = increases gas exhnage efficiencey NOTE - air does not go through nucei 0 air goes across the cytoplpas

Answer 26

O2 in teh Alveoli --> O2 goes to the cytoplasm of the Type 1 Pneumocyte --> O2 goes across the basement memebrane --> O2 goes to the cytoplasm of the endothelial cell --> O2 goes to the Blood CO2 does the same but it goes in the opposite direction

Answer 27

1. Malignent Mesothelioma 2. Chronic Brinchitus 3. Respitory Distress Syndrome

Answer 28

Overall - cancerous growth of the mesothlium (Arrow in image) Occurs in simply epitheliam cells derived from the mesoderm Could occur in simple epithilial cells in teh Serous memebranes (serosa) of Pericardium (heart) + Pleura (Lungs) + Peritenium (GI system) + Tunica Vaginalis (Testicles) - Occurs in the serous meembranes of all of these linings 80% of cases is due to Asbestos exposres

Answer 29

Rare - only 4,000 cases per year Majority of cases in men 50-70 YO (because industrial occupations + disease takes 20 years to develop) Agressive cancer (almost always fatal = poor prognosis) - With treatment - survival is <10% at 5 years Pleural form is most common ; paritenial is the second most common Symptons: 1. Diffuculty breathing 2. Painful cough 3. Unitended weight loss Image - see different forms _ subtypes

Answer 30

Still an open question - some posisblities: 1. Driven by negative plural pressire + inflimantion from fbers + increasing permability of epithelial layer of aveoli ---> fibers can go to pleural cavity 2. Cells are peirced by the fibers 3. Aveolar macrophages phagocytose the fibers and then travel to the plural space (controversial hypothesis)

Answer 31

Drainage of the plueral fluid occurs predominatley thrugh the parietal side through stoma - Fibers are bigger than the stoma = can clog the stoma on parietal sde = cancer usually forms on the parietal pleura (NOT visceral) - Asbestos fobers = very durable Image: Left - black arrounds show plueral fluid turnover

Answer 32

Asbestos can't be effectivley dgeraded Size can prevent phagocytosis

Answer 33

Asbests fibers are tracked to the pleura --> Asbestos fibers cause frustrated phagocytosis --> Mutagenic envirnment on the pareital mesothelum results in cancerous transfermation Asbestos fibers = very durable Phagocytosis = makes a mutigenic envirnmenta due to ROS and inflmation = causes cancer

Answer 34

Overall - severe long term inflamation of the bronchi Diagnosis - chronic cough for a least 3 month over the course of 2 years Chronic bonrchitus = a form of Chronic obsturctuve pulminary disease (COPD) Caused by cigarette smoking or noxious polutants - Noxious pollutants = second hand smoke or occupational polutants or pollustion --> al risk factors) Image - shows healthy (open passage of air) vs chronic bornchitus (have inflamation + Mucous)

Answer 35

1. Chronic bronchitus 2. Emphyzema Emphyzmea + chronic bronchitus = often co-occur

Answer 36

Symptoms: 1. Coughing and Wheezing - Cough out a lot of flem 2. Cyanosis (blue colro in skin - espeically in the extremities because reduced oxygen) 3. Shortness of breath 4. Lungs appear hyper inflated 5. Barrel shape chest --> because not exhaling air properly Diagnosis - do pulminary function spirometry tests - Test - have patient take a deep breath - measure FEV and the FVC - FEC = meausre volume of air that you ca forcfully exhale - Diagnose if have a decline in FEV/FVC) --> have less air leaving the lungs - Lower FEV/FVC ratio in obstruvtive disease = redced in chronic bronchitus - Can also do CT Imaging - Can also do pulse oximertry (monitor O2 in blood)

Answer 37

cellular chanages = lungs trying to defend against harmful stimuli - Have inflmation Get Goble cell hyperplasia (increase in number of goblet cells) --> get excess mucous production --> get luminal occulsion Have squamous cell metaplasia Cilia is damaged (clipped short) --> mucous accumilates - Pateints need to cough to get mucous out (because cilia is not moving it) Immunosupression of alveolar macophages by tobacco smoke = immunosupresive envirnment Have predisposition to lower respitory tract infection because the mucous acts as a bacterial growth medium

Answer 38

Chronic bronchitus --> get squamous cell metaplasia Metaplasia = chnage from one type of epithelial cell to another (tyically occurs in response to an irritatiion) In bronchitus - have Psudostratified cillitaed columnar cells --> tranistions to squamous epitheliam - Lung = normaly psudeostratified columnar epithelium --> metaplasia occurs as an immune respinse to iritant (from exposure to toxin) --> epithelum chnages to squamous - Get increase in number of layers of cells If irritants are adressed the process can be revered Metaplasia can be part of larger process to neoplastic chnages Image - shows chnage in epithelial cells - left - see cialia and columnar formation --> right have squamous layer

Answer 39

Chronic bronchitus --> can lead to goblet cell hyperplasia - Goblet cell hyperplasia + squamous cell metaplasia usually occur together Have proliferation of goblet cells Increase numver of goblet cells --> get increased production of mucus --> leads to narrower airways Image - Have non-smoker = have small amount of goblet cells --> see more goblet cells in COPD

Answer 40

Damage is irreversible so treatments usually try and stop progression Goal = stop progression and manage symptoms - Stop porgression by stopping smoking Can give bronchodialtors to relax airways and increase airflow (Beta-2 agonists + antocholinergenics + theopylline) - Ca be short or long acting Give inhaled steroids to rduce inflamation Give Suplemental O2

Answer 41

Lack of surfactant in the lungs --> have Aveoli collapse --> leads to wax build up around lungs --> abstructs gas exhchange Kown as Hyaline memebrane disease - Cell debris accuminaltes in the airway 60-80% of infants born before 28 weeks (common in pre mature infants) - 90% survival rate - Prevelane decreases with gesttional age Symptims: 1. Diffuculty breathuing 2. Cyanosis (blue color from poor oxygen exchnage 3. Rib muscles pulling inwards on inhale 4. CO2 --> leads to Acidosis --> causes dysfunction Diagnosis: 1. CT Scans 2. Blood tests for acidosis

Answer 42

Overall: Dirven by Type II Pnumocytes Normally type II pnuemocytes (alveolar cells) secrete surfactant - Surfactant secretion starts around 28 weeks = premature babies do not have surfactant production Surfactant - contains phospholipids + prteins + glycosaminoglycans - Surfacant covers alveolar epitheluum - Surfacatant reduces surface tension in aveoli + barrier between airspace and water space of inner lungs - When inhale surfactnat facilitates Aveolar expansion and orevents aveolar collapse during exhale If lack surfactant = have problems inhaling and aveoli collapse (issues expanding and keeping lungs open)

Answer 43

Upper left - healthy lung - aveoli are open and have thin walls Lower left - aveoli are smaller and walls are thicker/inflamed Right - white aveoli spaces - Black arrows show hylin memebrane (around aveolei - impede gas exhnage by acting as a membrane)

Answer 44

CPAP - continous positive airway pressue --> pushes air into the lungs to inflate the aveoli Surfactant replacement - implant synthetc surfactant through endotracheal tube Mechanical ventilaion - Only in severe cases - Can cause airway or lung injury Glucocotricoids --> given to the mother before premature delivery - Stimulates lung maturation + surfactant productionin baby

Answer 45

Results from a viral infcetion in lugs --> have inflmatory cells --> get nuertophil relased inflmaatry molcules --> leads to damage of aveolar papailary memebrane --> causes pulmenary adema + increase in permeability Inflmation in lungs from COVID19 or sepsis or flu - Pnumocytes - releases inflamatory cytokines - Nuertophils - release proteases + ROS - Occurs in adults Injury to alveolrar capilary memebrane = more permable Pulminary edmea --> washes away surfactant --> leads to aveoli collapse 40% moretality (high mortaility rate ; have few treatments)