Histology Flashcards
Conducting portion of respiratory system
Nasal cavities
Pharynx and larynx
Trachea
Bronchi and bronchioles
Respiratory portion of respiratory system
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli
Embryological Origin of Respiratory System
evagination of Respiratory diverticulum from the foregut
Epithelium is of endodermal origin
Cartilage, smooth muscle, and CT–thoracic mesenchymal
What makes up the mucosa and submucosa
Mucosa–
respiratory epithelium (most conducting positions)
Respiratory portions–simple cuboidal and squamous epithelium
Laminapropria (CT)
Glands
Submucosa
–cartilage and smooth muscle
Tubular so there will be an adventitia
What prevents collapse in extrapulmonary and intrapulmonary parts
Extrapulmonary–cartilage
Intrapulmonary–negative pressure
Chambers of the nasal cavities
Vestibule
Respiratory segment
Olfactory segment
Vestibule
outside of bone
Stratified squamous epithelium (in contact with outside environment)
Vibrissae (hair)
Sebaceous glands to moisten air
Respiratory segment
Warms, moistens and filters air
Blood vessels set parallel
Turbinates/conchae to increase SA and created turbulence
Psudeostratified ciliated columnar epithelium with goblet cells
Mucosa of the respiratory segment
Respiratory epithelium -ciliated cells Goblet Brush (micro villi) Small granule cells (endocrine, para cringe secretion) Basal cells (progenitor cells)
Lamina Propria --loose connective tissue -diffuse lymphatic system Large blood vessels Mixed mucous/serous glands
Glands and connective tissue of Lamina propria
Loose connective tissue
Mixed mucous/serous glands
Lies on periostium of turbinate bones
What is the dark line of the respiratory mucosa (respiratory epithelium)
Basal Bodies connecting cilia to apical membrane
Difference in nuclei between seromucous glands
Serous– rounded (thinner fluid)
Mucous–flattened (thicker)
Location of basal cells in respiratory mucosa
Close to the bottom, progenitor cells
How do you identify respiratory mucosa
Mixed seromucous glands (Lamina propria) Goblet cells (clear) Ciliated cells Rounded, dark nucleated progenitor cells (basal cells) Basal body anchoring cilia Parallel blood vessels with blood running perpendicular to air flow Loose CT Look for bones of turbinates/conchae
Function of ciliated cells and crush cells
Ciliated–movement of mucous towards pharynx
Brush–small microvilli to transmit sensory signals via trigeminal nerve/ sneeze reflex
Cilia structure
9 pairs of microtubule doublets surrounding two central pairs of microtubule so that anchor to apical surface by basal bodies
Cells attached together via zonula occludens and macula adherens
Move toward pharynx–microvilli art escalator
Sol made/function
Made my serous glands, allow cilia to beat freely
Gel–made/function
Goblet cell made, traps particles. Moved by cilia
Cystic fibrosis/mucoviscidosis
Defect in Cl-channel protein making mucous more viscous
Malfunction in mucociliary escalator–dehydration
Autosomal recessive, chronic pulmonary obstructive disease
Too much water absorbed by cells (follows Na)
Allergic Rhinitis
Swollen blood vessels as a result of a histamine immune response in the Lamina propria of the respiratory segment of nasal cavity
Nasal Cavity Mucosa–olfactory segment
Olfactory epithelium–psudeostratified columnar
NO GOBLET CELLS (don’t want too much viscosity to trap receptors)
Olfactory cells (bipolar, axons innervate olfactory bulb)
Supporting/sustentacular cells
Basal cells
Brush cells (trigeminal nerve)
Lamina propria olfactory segment
Bowman’s glands (serous)
Directly adjacent to periosteum of overlying bone
Function of sustentacular cells and location
Support for bipolar olfactory cells
Near apical part of cell
Elongated, darker, apical (don’t get confused with neurons which have prominent nucleoli)
Ciliated in olfactory segment of nasal cavity
Bipolar neurons modified to express receptors for various order ants
Every olfactory receptor cell expresses one and only one odorant receptor
Receptor cells carrying the same type of receptor converge their processes into the same glomerulus
Non-motile
Synapse on olfactory glomerulus
Axons of olfactory cells
Unmeylenated nerve bundles in Lamina propria of olfactory segment in nasal cavity
Bowman’s glands
Lamina propria of olfactory segment of nasal cavity
Serous only
Large, bright red nucleus
Flush olfactory epithelium so stimuli are washed away
Functions of Respiratory System
Exchange O2 in the air with CO2 in the blood Filtration Thermoregulation Humidification (Air conditioning) Immune Response Olfaction Phonation Water Balance
Pharynx layers
Epithelium–respiratory (nasopharynx)
—-stratified squamous in oropharynx and laryngopharynx (need tougher, orally ingested materials)
Lamina Propria
Muscle layer–skeletal
Adventitia–connective tissue
Lamina propria of pharynx
Seromucous glands in nasopharynx (still part of mucociliary escalator)
Mucous glands in oropharynx and laryngopharynx
Chronic inflammation of pharyngeal tonsil
Adenoids
Roof of nasopharynx (respiratory epithelium)
Lymphatic tissue
Block eustactian tubes
Epiglottis
Elastic cartilage core
CT (elastic)
Stratified squamous epithelium (from food)
Respiratory epithelium with mucoserous glands
Muscle in true vocal folds
Vocalis muscle (skeletal muscle) Covered by stratified squamous nonkeritizined epithelium
Lamina propria–elastic fibers
Transition of epithelium in larynx for vocal folds
Non-keratinized stratified squamous epithelium covering vocal folds to respiratory epithelium below true vocal folds
Stratified columnar epithelium can be found in the transition from stratified squamous to respiratory epithelium
Lymph nodules and elastic fibers–present in Lamina propria
Distinguishing vocal fold vs ventricular fold
Vocal fold–you will see vocalalis muscle
No muscle in ventricular fold
Vocal fold–dense bright red elastic fibers
Trachea layers
Epithelium–respiratory
Lamina propria-thick basement membrane, abundant elastic fibers, diffuse lymphatic system
Submucosa–mixed seromucus (more particles from lungs)
Cartilage layers–c shaped
Adventitia–CT, blood vessels, nerves
Mucosa of Trachea
Respiratory epithelium
Basal bodies of cilia
Goblet cells above triangle nucleus
Lamina propria
Collagen, thick basement membrane. (Thickens with smoking)
Elastic fibers
Diffuse lymphatic system
Glands in submucosa of trachea
Mixed seromucus
Cartilage layer of trachea
C-shaped that prevents collapse along with the tracheal is muscle –flexibility at esophagus
Divisions of left and right bronchi
Right-3 lobar, 10 segmental
Left-2 lobar, 8 segmental
Layers of Bronchi
Epithelium–respiratory
Lamina propria–basement membrane decreases in thickness
Muscularis–smooth muscle
Submucosa-mixed seromucus
Cartilage-discontinuous
Adventitia-connective tissue, blood vessels, nerves
Lamina propria of bronchi
Decreases in thickness
Abundant elastic fibers
Diffuse lymphatic system
Part of the folded mucosa-due to contracted smooth muscle
Blood supply to bronchus
Pulmonary and systemic supply
Pulmonary arteries do not supply tissue, feed alveolar capillaries at respiratory bronchioles
Bronchial arteries from aorta and supply the intersitium to respiratory bronchioles, anastomoses with pulmonary capillaries
Pulmonary arteries
Thin tunica media
Size of bronchioles
Distinguishing features of Bronchioles
No glands, no cartilage (different than bronchus which has seromucus)
Goblet cells only in largest bronchioles
Epithelium has cilia
Abundant smooth muscle (decreases with the diameter of the bronchioles)
Bronchioles in asthma
Extreme contraction of the smooth muscles surrounding causing restriction of flow to the alveoli
Divisions in respiratory bronchiole
Alveolar duct–in a line
Atrium
Alveolar sac–culdesak
Respiratory portion of the respiratory system
Respiratory bronchioles, alveolar ducts, sacs, and alveoli
Large respiratory bronchiole epithelium
Psudeostratified ciliated columnar epithelium
Transition of epithelium in respiratory bronchioles
Psudeostratified ciliated columnar to simple ciliated columnar to simple cuboidal epithelium with ciliated and Clara cells
Clara cells
Divides and differentiate to form ciliated an non-ciliated epithelial cells
Secrete lipoprotein CC160–lung damage marker
ER of Clara cells
Rough ER (and apical secretory granules) and have smooth ER–detox gases
Lung capillary volume, area
Alveolar volume, area
LCV–250 mL
LCA-125 square meters
AV-4000 mL (airspace)
AA-140 square meters
Cell types in alveoli
Pneumocytes (I and II)
Macrophage–phagocytic, wandering black lung, stain dark
Endothelial cells–angiotensin I converting enzyme (ACE)
Brush cells–General sensation
Fibroblasts–produce collagen, elastic, and reticular fibers
Blood cells–erythrocytes in capillaries; leukocytes in capillaries and septa
Type 1 vs type 2 alveolar cells
Type 1–squamous, joined by zonula occuludens, 95% of area
Type 2-cuboidal, 5% surface area, lamellar bodies, produce surfactant
Contents of Alveolar Septum
Surfactant Pneumocytes Basal lamina of Pneumocytes Connective tissue and cells (thicker portion) Basal Lamina of endothelial cell Endothelial cell
How can you tell the difference between type I vs epithelial cell?
Type I–nucleus bulges into air space
Epithelial cell–nucleus bulges into capillary
F(X) of macrophages in heart failure
Damaged RBCs are degraded after accumulation in lungs
F(X) of Type II
Secrete phospholipids, neutral lipids, and proteins that form surfactant
Progenitor cells for type 1 cells.
Hyperplasia of type II is a marker for alveolar injury
Make up of surfactant
Proteins (A-D)–organize surfactant layers and modulate immune responses
DPPC–most surface tension reducing properties
Only occurs after 35 weeks gestation
Lack of surfactant–RDS
Components of Pluera
Mesothelial sheet with layer of connective tissue rich in elastic fibers, lymphatics in visceral pleura drain towards the hilum
Respiratory changes due to smoking
larger basement membrane (decrease elasticity)
Increase in goblet cells (stickier, more mucus)
Loss of synchronous beating patter of cilia, loss of cilia (decrease function of cilia)
Loss of olfactory neurons
CIlia replaced with stratified squamous cells (increased stress, abrasion)–metaplasia
Increase lung cancer
COPD
Increase macrophages and increased neutrophils, larger alveolar spaces, decrease in surface area in contact with lungs/Ari
Destruction to inter alveolar septa
Loss of tissue elasticity
Elastase is major mechanics in the destruction of alveolar morphology and function
Respiratory vs Olfactory epithelium lab differentiation
Respiratory–goblet cells, mixed seromucus, blood vessels
Olfactory–no goblet cells, serous glands (bowman’s) and nerve bundles
Olfactory Receptor cells
Bipolar neurons that span entire thickness of epithelial layer of olfactory epithelium
