Microanatomy Respiratory System

Week 8

What are the 8 functions of the respiratory system

1. Air conduction / gas exchange

2. Phonation / sound production

3. Olfaction

4. Heat regulation

5. Air temperature and moisture control

6. Protection

7. Acid-base regulation

8. Hormone conversion

How many functional divisions of respiratory system and what are they

3

1. Conductive system

2. Transitional system

3. Gas exchange system

What structures are in the conductive system

nasal cavity, pharynx, larynx, trachea, bronchi

what structures are in the transitional system

respiratory bronchioles

What structures are in the gas exchange system

respiratory bronchioles, alveoli

Air enters the respiratory system through the _________ system

conductive

How does the conductive system regulate the temperature of the air inhaled

blood in the venous plexuses in mucus membrane of the nasal cavity clean, moisten, and warm the incoming air

What structures in the nasal cavity trap particulate matter and what system of the respiratory system do they belong to

hair and secretions

Conductive system

What area is found between the ciliated conducting area and the alveolar gas exchange area

transitional system

Healthy bronchioles do or do not have more than just a few goblet cells

do not

The walls of the respiratory bronchioles possess outpocketings of _____ ________ tissue

gas exchange

What lines respiratory bronchioles

club cells

Non-ciliated secretory cells

A few ciliated cells

±/- a few goblet cells if healthy (if find more it is unhealthy)

Club cells used to be called

Clara cells

The pulmonary capillaries are a network enveloping

alveoli

What are alveoli lined by

Type I pneumocytes

Type II pneumocytes

Correct order of flow in respiratory system

nasal cavity → nasopharynx → larynx → trachea → bronchi → bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs → alveoli

What is the difference between between specific and non-specific defense mechanisms of the respiratory system

Specific defense mechanisms are immune-mediated

Non-specific defense mechanisms are not immune-mediated

which is not a specific defense mechanism of the respiratory system

antibody production

Cell-mediated immunity

Phagocytosis

Antibody-mediated phagocytosis

Phagocytosis

Mucous trapping, mucociliary clearance, phagocytosis, and air turbulence are examples of which type of defense mechanisms in the respiratory system

non-specific

Structures in the conductive system (nasal cavity, pharynx, larynx, trachea, bronchi) are lined mostly by _________

psuedostratified ciliated columnar epithelium with goblet cells and submucosa serous cells

T/F: psedustratified columnar epithelium does not fall under simple or stratified epithelia classificstions

false

It is simple, because cells are all attached to basal membrane

The lamina propria of the nasal cavity contains ________ glands, and what type are they

tubulo-alveolar glands

Mainly serous, smaller amounts of mucus and mixed glands

Function of Bowman’s glands

Olfaction

Contain odorant-binding proteins

What are the 3 regions of the nasal cavity

Vestibular region

Respiratory region

Olfactory region

What divides the nasal cavity into 2 halves

Nasal cartilaginous septum

T/F: the nasal cavity is divided into two halves and there is a vestibular, respiratory, and olfactory region in each half

True

Of the nasal cavity regions, which is outermost

Vestibular region

What type of epithelium lines the vestibular region of the nasal cavity

Stratified squamous keratinized epithelium

T/F: the vestibular region of the nasal cavity contains a cutaneous mucous membrane, haired skin and glands

True

What region of the nasal cavity is the largest

Respiratory region

What type of epithelium lines the respiratory region of the nasal cavity

Pseudostratified columnar ciliated epithelium w/ goblet cells

What is the mucociliary apparatus and what is its function

It is the combination of cells in the epithelium of the respiratory region of the nasal cavity

Function is clearance

What narrows the lumen of the respiratory region of the nasal cavity and increases the area of contact of inhaled air with the respiratory mucous membrane, and what is the overall effect of this function

Projections from the lateral wall conchae turbinates

Regulates the quality and quantity of inhaled air

What do goblet cells produce

Mucinogen granules

Function of cilia in mucociliary apparatus

Remove mucus with trapped airborne inhaled particles, like dust and microorganisms

Cleaning function

What 2 things in the mucociliary apparatus constitute a cleaning apparatus of the upper respiratory passages

Goblet cells and cilia

Goblet cells are present along the airways to the level of ____

Large bronchioles

What role does the goblet cell secretion play in particulate matter expulsion

It traps it

Then the cilia expels it

In smokers, there are increased numbers (hyperplasia) of what cells

Goblet cells

With metaplasia of goblet cells, what happens to the epithelium

Changes from ciliated pseudostratified to squamous stratified

What is immobile cilia syndrome / Kartagener’s syndrome

Dysfunction of the cilia where the dynein arms (‘claws’) are missing

T/F: cilia movement resembles a wave from cell to cell and they beat in succession to expel particles and mucus

False

They beat in unison, but their movement does resemble a wave from cell to cell

In the nasal cavity, how does the olfactory epithelium differ from the respiratory epithelium

The olfactory epithelium is thicker and lacks goblet cells

Where is olfactory epithelium located

in the olfactory region, in the dorsal part of the nasal cavity

What type of cells are present in the olfactory epithelium and what type of cells are notably not present

Present: olfactory neurons, supporting cells (sustenacular cells), basal cells

Not present: goblet cells

The lamina prop ría of the olfactory region of the nasal cavity contains what type of glands and bundles of ____

Serous glands

Nerve bundle with non-myelinated axons of olfactory neurons

What are venous plexuses, and where are they found in the nasal cavity

Expanded vessels known as swell bodies that are distended with blood

Found in olfactory and respiratory regions of the nasal cavity

The vomeronasal organ is a ____receptor organ that detects _______ and is located higher or lower in the nasal canal

Chemoreceptor organ

Detects pheromones

Located higher up in nasal canal

T/F: vomeronasal organ is associated with social behavior

False

Sexual behavior

Cartilage, vocal folds, and skeletal muscle are all included in ___ of the respiratory system

Larynx

What type of epithelium lines the larynx

Initial part - stratified squamous epithelium

After vocal cords, lining changes to pseudostratified ciliated columnar epithelium

What type of epithelium lines the trachea

Ciliated pseudostratified columnar epithelium with goblet cells

What type of glands are in the lamina propia and su mucosa of the trachea

Serous glands

T/F: the lamina propia and submucosa are clearly demarcated in the trachea

False

Not clearly demarcated

In the trachea, the rings of cartilage are incomplete dorsally, except in which species, which have complete rings

Birds have complete rings

What completes the incomplete cartilage rings in the trachea in mammals

Connective tissue adventitia

What type of cartilage is the tracheal cartilage rings made of

Hyaline cartilage

What does the trachea branch into

2 bronchi

Bronchus has plates of __ cartilage

Hyaline

Bronchi are lined by

Ciliated pseudostratified columnar epithelium

Smooth muscle surrounds the lamina propria and separates it from the submucosa in _____

Bronchi

The connective tissue external to the muscularis mucosa of the bronchi contains what type of glands and what type of cartilage plates

Mixed bronchial glands (seromucous)

Hyaline cartilage plates

What do the mixed seromucous glands of the bronchi secrete

Mucin, lactoferrin, and lysozyme (bacteriostatic/bacteriocidal)

What do the bronchi branch into

Bronchioles

Bronchioles lack:

Cartilage

Glands

T/F: after the bronchi, the terminal bronchioles do not contain a muscularis mucosa

False

They have muscularis mucosa

What lines the terminal bronchioles

Ciliated cuboidal or columnar cells with 0 to few goblet cells

Where are club cells located

Terminal bronchioles and respiratory bronchioles

Bronchioles exocrine cells are also called

Club cells

Club cells metabolize:

Airborne toxins

Club cells have a secretory function, producing:

Surfactant-like substance that helps maintain patency of airway

T/F: club cells metabolize airborne toxins and may have immune function

True

What is the function of respiratory bronchioles

Conduction and gas exchange

What type of epithelium lines the respiratory bronchioles

Ciliated cuboidal epithelium, becomes flattened distall

What do respiratory bronchioles subdivide into

Alveolar ducts

Histolologically, what is the difference between terminal bronchioles and respiratory bronchioles

The epithelium of respiratory bronchioles is interrupted by alveoli

T/F: the muscularis mucosa of respiratory bronchioles is incomplete

True

Alveolar ducts empty into:

Alveolar sacs and alveoli

What are the walls of alveolar ducts composed of

Alveoli, lined with simple squamous epithelial cells

The edge surrounding the opening of each alveoli of an alveolar duct contains:

Smooth muscle

What gives alveoli a knob-like appearance on sections

Smooth muscle

In contrast to the alveoli, alveolar sacs lack:

Smooth muscle

What lines alveoli

Type I pneumocytes and Type II pneumocytes

Type I pneumocytes comprise how much of the alveolar surface area

95%

Type I pneumocytes are ____ on appearance while type II pneumocytes are ____

Type I are thin

Type II are round

What is the function of type I pneumocytes

Gas permeability

In Type I pneumocytes, organelles are grouped around:

Nucleus

Function of type II pneumocytes

Secretion

What produces surfactant in a type II pneumocyte

Lamellar bodies

Which type of pneumocyte is mitotic and what cells does it produce

Type II is mitotic

Produces type I and type II pneumocytes

Type II pneumocytes account for how much of the alveolar surface area

5%

Type II pneumocytes can be granular pneumocytes, which are also called

Great alveolar cells

Granular pneumocytes contain ______ granules that contain recently synthesized ________

Lamellar granules

Surfactant

Surfactant is a mono-molecular layer of

Phospholipoprotein

Function of surfactant

Reduce surface tension

Reduce effort needed to inflate alveoli, thus preventing alveolar collapse (atelectasis)

T/F: surfactant only produced by type II pneumocytes when needed

False

Produced constantly by type II pneumocytes

What stimulates the production of surfactant in the fetus just prior to parturition

Cortisol

What is hyaline membrane disease

The absence of surfactant in newborns

What are the 4 components of the blood-air barrier

Cytoplasm of type I pneumocyte

Basement membrane of type I pneumocyte

Basement membrane of the endothelial cell

Vascular endothelium

T/F: in the blood-air barrier, the basal laminae of the alveolar epithelium and the capillary endothelium are fused

True