Exam 2 - Respiratory System Flashcards
conducting portion function
delivers air to lungs - warms, moistens, and filters air
conduction portion contents
nose, nasopharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles
respiratory portion
structures within lungs where O2 is exchanged for CO2 in the blood
respiratory portion contents
respiratory bronchioles, alveolar duct, alveolar sac, alveolus
nasal cavity contents
vestibule, olfactory segment, respiratory segment
nares
nostril openings - outer portion is thin skin
vestibule
first internal nasal cavity with a vascular lamina propria containing seromucous glands
vestibule lining
nonkeratinized stratified squamous epithelium that changes to pseudostratified ciliated columnar epithelium posteriorly
vibrissae location and function
short hairs in vestibule that filter out large particles
olfactory epithelium
very small region of pseudostratified columnar epithelium containing olfactory cells, supporting/sustentacular cells, and basal cells
lamina propria of olfactory epithlium
has many veins, unmyelinated nerves, bowman’s glands
olfactory cells
bipolar nerve cells with a 30-60 day lifespan that contain bulbous apical projections (olfactory vesicles) with modified cilia
olfactory cilia
very long, nonmotile cilia that extend over the olfactory epithelium surface and function as odor receptors
olfactory cilia microtubule pattern
- prox 1/3: 9x2+2
- distal 2/3: 9x1+2
supporting/sustentacular cells
provide physical and metabolic support to olfactory cells
description of sustentacular cells appearance
apically located nuclei with many microvilli and a prominent terminal web
basal cells
stem cells for other cells in olfactory epithelium that are in contact w/ basal lamina, forming an incomplete cell layer that does not extend to the surface
bowman’s glands
exocrine glands that secrete thin, watery secretions to flush surface of olfactory epithelium and prepare the odor receptors to receive new stimuli
what detects odor?
olfactory cilia detect dissolved odorous substances
nasopharynx location
posterior continuation of nasal cavities that becomes the oropharynx at the level of the soft palate - contains lymphoid tissue (adenoids)
what is nasopharynx lined by?
respiratory epithelium
larynx
connects pharynx w/ trachea and contains striated muscle, CT, and glands w/i its walls
what supports wall of larynx?
hyaline cartilage and elastic cartilage
what in larynx is hyaline cartilage?
thyroid, cricoid, and lower part of arytenoid cartilages
what in larynx is elastic cartilage?
epiglottis, corniculate, and tips of arytenoids
vocal cords
consist of skeletal muscle (vocalis), vocal ligament (elastic fibers), and a covering of stratified squamous nonkeratinized epithelium
vestibular folds
folds of loose Ct containing glands, lymphoid aggregations, and fat cells
what lines vestibular folds?
stratified squamous nonkeratinized epithelium
location of vestibular folds
lie superior to vocal cords
trachea layers
mucosa (epithelium, lamina propria) + submucosa + cartilage + adventitia - lamina propria ends and submucosa begins w/ poorly defined elastic membrane
what supports walls of trachea?
C-shaped hyaline cartilages with trachealis (smooth muscle) extending b/w open ends of the cartilages
what lies b/w adjacent C-rings of the trachea? purpose?
dense fibroelastic CT - permits trachea elongation during inhalation
tracheal epithelium
ciliated, pseudostratified columnar epithelium
cell types in tracheal epithelium
ciliated cells, mucus cells, brush cells, small granule cells, and basal cells
brush cell
columnar receptor cell with blunt microvilli on surface - basal portion may be in contact w/ afferent nerve ending
small granule cell
bronchial cells of Kulchitsky that contain dense granules w/ catecholamine or other polypeptide hormones (members of diffuse endocrine system) - similar in size and location to basal cells
primary bronchi structure
structurally similar to trachea, but cartilage rings and spiral bands of smooth muscle completely encircle bronchi
in which bronchus are foreign objects more likely to lodge and why?
right - more vertical path
intrapulmonary bronchi
arise from subdivisions of primary bronchi and have irregular cartilage plates in walls, spiraling smooth muscle bundles that separate lamina propria from submocosa w/ seromucous glands
what are intrapulmonary bronchi lined by?
respiratory epithelium
layers of bronchi
- mucosa
- muscularis
- submucosa
- cartilage layer
- adventitia
primary bronchiole size
1 mm or less diameter
primary bronchiole walls
walls have smooth muscle instead of cartilage plates and lack glands in submucosa
primary bronchiole epithelium
larger airways: ciliated columnar w/ goblet cells
smaller airways: ciliated columnar w/ Clara cells
when do primary bronchioles divide?
after entering pulmonary lobules
terminal bronchiole size
less than 0.5 mm diameter
terminal bronchiole walls
smooth muscle, no cartilage, lack glands in submucosa
terminal bronchiole epithelium
simple cuboidal epithelium containing mostly Clara cells, some ciliated cells, NO goblet cells
Clara cells function
secrete GAGs to protect bronchiolar lining and metabolize airborne toxins w/ cyt P450 enzymes in sER
Clara cell appearance
dome-shaped apical surface w/ NO cilia
respiratory bronchiole epithelium
simple cuboidal lining: prox - clara cells and ciliated cells; dist - mostly clara cells; occasional brush and dense-core granule cells
how do you differentiate terminal bronchioles from respiratory bronchioles?
respiratory bronchiole walls are interrupted by alveoli
alveolar duct walls
adjacent alveoli separated from one another by an inter alveolar septum
what is the most distal portion of the respiratory system to contain smooth muscle?
alveolar ducts - present in walls at openings of adjacent alveoli
alveolar duct lining
simple squamous epithelium consisting of type I and II pneumocytes
alveolar sacs
outpouchings of numerous alveoli located at distal end of the alveolar duct
alveoli
pouch-like evaginations in respiratory bronchiole walls, alveolar ducts, and alveolar sacs
alveoli function
site of O2 and CO2 diffusion b/w air and blood
how are alveoli separated from each other?
inter alveolar septa that may contain 1 or more alveolar pores for pressure equalization b/w alveoli
what types of fibers do alveoli have?
elastic fibers at openings and many reticular fibers in the walls
alveoli lining
simple squamous epithelium of type I and II pneumocytes
type I pneumocyte fxn
form tight junctions with adjacent cells
what type of pneumocyte covers 95% of alveolar surface?
type I
can type I pneumocytes divide?
no
type II pneumocyte alternative names
type II alveolar cells, great alveolar cells, granular pneumocytes, septal cells
type II pneumocyte description
cuboidal cells usually found near septal intersections that hae apical cytoplasm w/ short microvilli
type II pneumocyte fxn
contain cytoplasmic lamellar bodies that store pulmonary surfactant
can type II pneumocytes divide?
yes - can divide and regenerate both types of alveolar pneymocytes
interalveolar septum
partition b/w two adjacent alveoli that contains continuous capillaries in the central/interior region
interalveolar septum fxn
accomodates blood-gas barrier, which separates the alveolar airspace from the capillary lumen
blood-gas barrier
type I pneumocyte + surfactant layer 0.2 um or less thick with fused basal lamina of pneumocytes and capillary endothelial cells and endothelium of continuous capillaries
pulmonary surfactant composition
4 proteins (SP-A, SP-B, SP-C, SP-D) and a phospholipid called DPPC (dipalmitoyl-phospholipidcholine)
lung macrophages
cells found in airways and interstitial septal CT that clean up debris, bacteria, etc. and can move from septa to alveoli and back
what percent of the cells in airways are alveolar macrophages normally?
70-85%
how do inflammatory conditions affect macrophages in lungs?
increase in number and activation of both types of macrophage
Hyaline membrane disease
neonatal RSD - not enough surfactant, causing labored breathing due to difficulty expanding alveoli
what cells make surfactant and when?
type II pneumocytes after 25th week of gestation
can HMD be treated?
if detected before birth - treat with glucocorticoids
glucocorticoids
induce surfactant synthesis
what type of emphysema gives you destruction of just respiratory bronchioles?
in smokers
what type of emphysema gives you destruction of respiratory bronchioles, alveolar ducts, and alveolar walls?
emphysema w/ alpha 1-antitrypsin deficiency
emphysema
formation of cyst like sacs that reduce gas exchange SA, causing decreased lung elasticity - can’t recoil adequately during expiration
what is barrel chest a symptom of?
emphysema - lungs eventually expand and enlarge thoracic cavity
alpha 1-antitrypsin
protein that protects lungs from elastase produced by neutrophils
pulmonary edema
when fluid leaks into interstitial tissue and alveoli
what cardiogenic dysfunction causes pulmonary edema?
LV dysfunction that causes dilation of pulmonary capillaries and increase in hydrostatic pressure
what endothelial issue causes pulmonary edema?
destruction of endothelial lining by bacteria (endotoxin), trauma, or other agents (water - near drowning, chemical agents)
asthma
constriction of bronchiolar smooth muscle associated w/ difficult air expiration, mucus accumulation in airways, and inflammatory cell infiltration that is often progressive and associated w/ allergic rxn
asthma treatment
epinephrine and isoproterenol or other bronchiolar smooth muscle relaxants
effects of allergens
cause mast cell degranulation, releasing histamine and other inflammatory substances
cystic fibrosis
defect in Cl channel that causes thick mucus build up in lungs
lung pleura
consists of thin mesothelial layer attached to lung that seals the lung
what lies under mesothelium of lung pleura?
CT layer w/ blood vessels, lymphatics, nerves
hydrothorax
fluid in pleural cavity
pneumothorax
air in pleural cavity
