Histo: Respiratory System Flashcards
How is elastic fiber concentration related to diameter?
Inversely related
Which way do elastic fibers in the lamina propria run? What about elastic fibers in smooth muscle?
Longitudinally; circular
Two functions of the respiratory system
- provides conduit to transfer air
2. conditions the air (cleans, moistens, warms)
Most predominate respiratory epithelium. Continues until respiratory portion.
Ciliated columnar cells
This cell type has mainly serous secretion
Columar cell
These cells synthesize mucinogen, and hydrate it to turn it into mucous. They trap and remove bacteria and particles, and continue until terminal bronchiole.
Mucous goblet cells
This cell type has no cilia, but many microvilli
Brush cell
Two types of brush cells
- one acts like a goblet cell and releases mucinogen
2. one has nerve endings on basal surface
This cell may be responsible for the sneeze reflex
Brush cell
These cells are thought to control mucous and seromucous secretion. May control vessel diameter.
Small granule cells
These cells rest on the basement membrane and do not reach the lumen. In this way, they are considered pseudostratified. They are stem cells!
Basal cells or immature cells
abnormal transformation of adult cells in a tissue
to a form which is not normal for that tissue. This
can be in response to a disease process, a physical,
or chemical event
Metaplasia
2 changes in respiratory epithelium of a smoker
- increase in goblet cells due to pollutants
2. decrease in cilia due to CO2
Anterior portion of the nasal cavity
Vestibule
2 types of mucosa in the nasal cavity
- respiratory
2. olfactory
Venous plexus in lamina propria that enlarge alternately on two sides of nasal cavity (about every 30 minutes) giving mucosa on occluded side time to recover from desiccation and help to direct air to the olfactory epithelium
Swell bodies
What 2 things do plasma cells release in the lamina propria?
IgA and IgE
Discuss what happens with IgE
IgE binds to its receptors on mast cells and basophils, and causes the release of inflammation mediators of the mast cells and basophils
T/F: Nasal cavity provides a site for drug delivery since there is a convenient access to a superficial venous plexus beneath the nasal cavity mucosa
True
Where are olfactory epithelium located?
On the roof of the nasal cavity and on the superior nasal conchae
bipolar neurons whose apical surfaces are modified to form the olfactory vesicle and olfactory cilia
Olfactory cell
These cells are stem cells for ALL olfactory epithelium
Basal cells
Where are Bowman’s glands located? What is significant that occurs in these glands?
Located in the lamina propria; synthesis of an odorant binding protein (ODP)
Why is serous secretion important in Bowman’s glands?
Dissolves odors and cleans the surface
Air spaces within cranial bone lined with respiratory epithelium
Paranasal sinuses
What are the cartilagenous plates of the larynx made up of?
Elastic (smaller) and hyaline (larger) cartilage
This structure connects the trachea with the pharynx
Larynx
Two functions of the larynx
- responsible for phonation (producing sounds) via the vocal cords
- prevents entry of food and fluids into the respiratory system
Do false vocal cords have glands and/or muscle?
They have glands and NO muscle
The false vocal cords are covered with (blank)
respiratory epithelium
What is the epiglottis made up of?
Two types of epithelium and elastic cartilage
What happens during swallowing in regards to the epiglottis?
During swallowing, the backward motion of the tongue forces the epiglottis over the laryngeal opening and closes the larynx to direct food into the esophagus
What covers the true vocal cords?
Stratified squamous epithelium
Do the true vocal cords have glands?
No
What type of muscle is the vocalis muscle? What type of fibers make up the vocal ligament?
Skeletal; elastic fibers
Which primary bronchi is more vertical?
Right
What type of epithelium makes up the trachea?
Respiratory epithelium or ciliated and pseudostratified columnar!
What is significant about the respiratory epithelium of the tracheae?
Thick basement membrane
Two significant features of the lamina propria of the trachea.
- seromucous glands that can extend into the submucosa
2. collagen and elastic fibers
What is significant about the adventitia of the trachea?
C-shaped hyaline cartilage rings, closed off by trachealis muscle posteriorly
Cells found in the epithelial lining of the trachea?
- columnar ciliated cell
- goblet cell
- basal cell
Which are more rigid? Extra or intrapulmonary bronchi?
Extrapulmonary
Which extrapulmonary bronchi is straighter and trifurcates? Which bifurcates?
Right; left bifurcates
Which intrapulmonary bronchi go to lobes? Which go to the bronchopulmonary segments?
Secondary goes to lobes; tertiary goes to segments
What type of epithelium make up the intrapulmonary bronchi?
Respiratory
3 features os the lamina propria and submucosa of the intrapulmonary bronchi
- rich elastic fibers
- spiral smooth muscle
- seromucous glands between cartilage plates and smooth muscle
Layers of the bronchus
- mucosa
- muscularis
- submucosa
- cartilage layer
- adventitia
Bronchioles lack these two things
seromucous glands and cartilage
Describe the changes that occur in the epithelium as you move along the bronchioles.
Ciliated columnar with goblet cells to a ciliated columnar/cuboidal with clara cells. Goblet cells decrease, clara cells increase.
Do clara cells have microvilli or cilia?
Short microvilli
Three functions of clara cells
- secrete glycoprotein that protects the mucosa
- degrade airborne toxins by sER 450 cytochromes
- divide to regenerate the bronchiole epithelium
What two things primarily make up the lamina propria of the bronchioles? What two things are NOT present?
smooth muscle fibers and elastic fibers; NO cartilage or seromucous glands
Parasympathetic innervation to the bronchioles causes (blank), while sympathetic innervation causes (blank)
constriction; dilation
A widespread constriction of smooth muscle in the bronchioles causing a decrease in diameter.
Asthma
Which two features persist from the conducting system all the way until the respiratory system?
Epithelium and elastic fibers
What is the epithelium found in the respiratory bronchiole?
Simple ciliated cuboidal with Clara cells
Describe the lamina propria of the respiratory portion?
Very thin smooth muscle and elastic fibers at alveolar openings
A bronchiole with alveolar cells?
Respiratory bronchiole
What kind of epithelium are alveolar ducts lined with?
Squamous epithelium (primarily Type I pneumocytes)
Describe the lamina propria of the alveolar ducts
Smooth muscle
Lots of elastic fibers
What percentage of alveoli develop after birth?
85%
Interalveolar wall or septum is lined by what type of epithelium?
Type I and II pneumocytes
These connect adjacent alveoli; responsible for collateral respiration when blockage of a small bronchiole occurs.
Pores of Kohn
Smooth muscle fibers in the bronchioles are oriented (blank), while elastic fibers are oriented (blank)
concentrically (circular); longitudinally
Two components of the interalveolar septum
Type I and type II pneumocytes
This type of pneumocyte makes up 95% of the alveolar surface, is very attenuated, can NOT regenerate, and made up of simple squamous epithelium.
Type I
This type of pneumocyte makes up 5% of the alveolar surface, CAN regenerate the entire surface, and made up of cuboidal epithelium.
Type II
What keeps type I and type II pneumocytes together?
Occluding junctions
List a function of type II pneumocytes and a feature that distinguishes them histologically.
Type II pneumocytes produce surfactant, which reduces surface tension. It is stored in lamellar bodies, and is present at 26-28 weeks in the amniotic fluid.
What is respiratory distress syndrome? What can you give the mother to help?
When an infant lacks sufficient surfactant and the alveoli collapse. Give mother glucocorticoids to induce synthesis of surfactant.
4 components of the blood-gas barrier in the thin portion of the interalveolar septum
- surfactant layer
- cytoplasm of type I pneumocytes
- fused basal lamina between type I and capillary endothelium
- cytoplasm of capillary endothelium
3 things found in the interalveolar septum
- type I and type II pneumocytes
- elastic and reticular fibers
- continuous capillaries
Things that make up the thick portion of the IA septum
continuous capillaries
elastic, collagen, reticular fibers
fibroblasts, macrophages, mast cells
Where do lymphatic stop in the lungs?
No lymphatics from the alveolar air sacs distally
IA septum is responsible for removing liquid from a closed space. How does it do this?
A wicking action
2 types of macrophages (dust cells) in the interalveolar septum
Fixed: associated with alveolar wall
Free: produce elastase
Heart failure cells are alveolar macrophages that have digested (blank) and stain positive for Fe in the RBCs.
erythrocytes
When do the Pores of Kohn develop? What is their main role?
Develop at 3-4 years. Equilibrate pressure from alveoli to alveoli, allow free macrophages to pass through, allow collateral ventilation in case of bronchiole obstruction
Destruction of interalveolar wall causing decreased elasticity in the lungs and the inability to recoil.
Emphysema (4th leading cause of death)
This substance protects the lungs from the action of elastase. Inhibited by cigarette smoke.
Alpha1-antitrypsin
Purpose of the thick portion of the interalveolar septum?
To “drain” lymphatics
