Respiratory System

Micro Exam 2

What does the conduction portion of the respiratory tract do? What about the respiratory portion?

Conduction: moves and preps air; Respiratory: gas exchange

Is the respiratory epithelium in the conduction or respiratory portion?

Conduction

Is the alveolar epithelium in the conduction or respiratory portion?

Respiratory

What are the functions of the conducting portion of the respiratory tract?

Clean, humidify and warm

How does the conduction portion of the respiratory tract clean the air?

Nasal cavity: Vibrissae (hairs) and mucus secretion; Airways: mucociliary transport

What are the functions of the nasal cavity and sinuses?

Clean, moisten, and warm incoming air, speech resonance and immune functions

What passes through the pharynx?

Food and air

What is the function of the larynx?

Sound and airway protection

How many secondary bronchi are on the right? Left?

Right = 3; Left = 2

List the structures of the bronchial tree in order:

Trachea - Primary Bronchi - Secondary (Lobar) Bronchi - Tertiary (Segmental) Bronchi - Smaller Bronchi - Bronchioles - Terminal Bronchioles - Respiratory Bronchioles - Alveolar Duct - Alveoli

What is the first sight of gas exchange?

the respiratory bronchioles

Describe the arrangement of the alveoli in the ducts vs sacs:

Ducts: scattered alveoli; Sacs: clusters of alveoli

What are the 5 layers of tissues of the conduction portion?

Epithelium, basement membrane, lamina propria, support layer and loose connective tissue

What are the supporting structures of the conducting system?

Cartilage and smooth muscle

What type of cartilage is in the conducting portion?

hyaline and elastic

As you move distal in the conducting portion the quantity of cartilage _____________, elastic fiber _____________ and smooth muscle _____________

decreases; increases; increases

Describe the lamina propria:

Contains seromucous glands, smooth muscle, and is highly vascularized

What is the benefit of the lamina propria being highly vascularized? What is the downside?

Benefit: warms the air; Downsides: allergies and colds

What are the 5 different cell types in the pseudostratified epithelium in the conducting portion?

Columnar, goblet, brush, small granule and basal cells

What cells are the primary releaser of mucus?

Goblet cells

What is the most abundant cell type in the conducting portion?

ciliated columnar

Cell height _____________ as we move down the bronchial tree

decreases

Describe brush cells:

Columnar with few short microvilli

What is the function of the chemosensory receptors on brush cells?

detect molecules from bacteria and general inflammation

Which cells in the conducting portion are local endocrine cells?

Small granule cell

Which cells in the conducting portion are stem and progenitor cells?

basal cells

Describe the stratified squamous moist epithelium:

Located in the oropharynx, epiglottis, and vocal folds; Non-keratinzed; in regions of direct airflow and/or trauma (food/speaking)

What is squamous cell metaplasia?

When epithelial regions go from columnar to squamous in response to unexpected forces

Is squamous cell metaplasia reversible? Is it cancerous?

Yes; No

What are the typical sites of squamous cell metaplasia?

Nasal turbinates, vocal folds, and epiglottis

What type of connective tissue is in the larger branches of the lamina propria? What other structures are there?

1) Loose CT with numerous elastic fibers; 2) serous and mucous glands; lymphocytes and lymphatic nodules

As the branches get smaller in the bronchial tree the thickness of the epithelial layer and the glands ________

reduce

True or false: The smaller bronchi have cartilage

False; they have no cartilage

Smooth muscle comprises ___% of the tissue in the smaller bronchi

20

Describe the epithelium in the trachea:

Ciliated pseudostratified columnar with goblet cells

The lamina propria in the trachea has __________ fibers and _________________ glands

elastic; seromucous

The hyaline cartilage in the trachea is ___-___ C-shaped structurs

16; 20

In the primary bronchi there is a gradual transition from pseudostratified columnar epithelium to what as you move to the bronchioles?

Simple ciliated columnar / cuboidal

Does the # of goblet cells decrease or increase as we transition from primary bronchi to bronchioles?

Decrease

How do the cells in the epithelium of the terminal bronchioles vary from the earlier parts of the conducting portion?

Ciliated cells predominate and there are few goblet cells

Are there glands and cartilage in the terminal bronchioles?

NO

The lamina propria in the terminal bronchioles is fibrous CT with prominent ____________ fibers and discrete bundles of _________ muscle

elastic; smooth

What is the end of the air conducting system?

Terminal bronchioles

What do the terminal bronchioles secrete?

Surfactant, anti-microbial peptides and cytokines

Where are club cells found? What do they do?

Club cells are found in the terminal and respiratory bronchioles. They secrete proteins and enzymes which protect the epithelium of the airways as well as attack foreign invaders.

What is another name for alveolar cells?

Pneumocyte

What is the first site for gas exchange?

Respiratory bronchioles

How do the walls of the respiratory bronchioles compare to the terminal bronchioles?

Walls are identical with an addition of occasional alveoli

What is parenchyma?

tissue directly involved in gas exchange

What does parenchyma contain?

1) Type I and II alveolar cells; 2) Capillaries with RBCs; 3) Interstitial tissue (ECM) - collagen, elastin, PGs, and scattered fibroblasts

Describe type I alveolar cells:

1) extremely thin, squamous; 2) O2 and CO2 diffuse across

Describe type II alveolar cells:

1) Septal cells that are cuboidal; 2) Secrete pulmonary surfactant; 3) Stem cells for type I and II alveolar cells

What type of junctions are between alveolar cells?

Tight junctions

Describe the structure of the blood-air barrier:

1) Type I alveolar cell and capillary endothelium that is 4 lipid bilayers thick; 2) O2 and CO2 can diffuse across these bilayers; 3) tight junctions to prevent leakage

What produces pulmonary surfactant?

Type II alveolar cells

What is pulmonary surfactant a mixture of?

Phospholipids, cholesterol, and surfactant proteins

What are the functions of pulmonary surfactant?

1) Decrease surface tension; 2) Passively provide innate immunity

What is surfactant removed by?

Type I and II alveolar cells, macrophages and ciliary action

When does infant respiratory distress syndrome occur?

When premature babies do not have surfactant

What are interalveolar septa?

Septa WITHIN the parenchyma that separate neighboring alveoli and support capillary networks

What make up the interalveolar septa?

1) elastic and reticular fibers; 2) macrophages, fibroblasts, and various WBCs

What do alveolar pores do?

Connect each alveoli to a neighboring alveoli supplied by a different bronchiole

What is the purpose of alveolar pores?

Equalize air pressure and prevent collapse

What type of epithelium is the parietal and visceral pleura?

Simple squamous epithelium

What are the primary functions of pleural fluid?

Lubrication and surface tension

What produces the pleural fluid?

Parietal pleura

What makes up the pleural fluid?

Plasma, WBCs, and electrolytes

What is a pneumothorax?

Air in the pleural space typically caused by a hole in the chest wall

What is a hemothorax?

Blood in the pleural space

What is a hemopneumothorax?

Blood and air in pleural space

What typically causes a hemopneumothorax?

Stab or gunshot wound

What are the three main defense mechanisms of the respiratory tract?

1) Nasal passages; 2) Mucociliary transport; 3) Alveolar macrophages

What is a tracheostomy?

An artificial airway

Where is a tracheostomy located?

Between the 2nd and 3rd tracheal ring

What is the purpose of a tracheostomy?

1) Bypass airway blockages; 2) Prevent aspiration; 3) Long-term ventilator need

What is COPD a combination of?

Asthma, emphysema and chronic bronchitis

What occurs with chronic bronchitis?

1) Increased mucus production; 2) Decreased diameter of bronchioles; 3) Impaired bronchial cilia

What occurs with emphysema?

1) Destruction of lung parenchyma resulting in no support structure for alveolar cells or capillaries; 2) Air spaces distal to terminal bronchiole are enlarged

What is asthma?

Underlying airway inflammation

What cells are present in asthma?

Mast cells, eosinophils, lymphocytes, macrophages, T-cells; inflammatory cytokines

What happens to the smooth muscle of the airway due to chronic airway remodeling with chronic asthma?

Hperplasia and hypertrophy

Acute exacerbation of asthma consists of sudden contractions of ______________ _________ __________

bronchiolar smooth muscle

What causes acute exacerbation of asthma?

Mast cell degranulation (Ag interaction with IgE on mast cell membrane)

What can you treat acute exacerbation of asthma with?

Epinephrine or Albuterol

What is atelectasis?

Collapse of pulmonary lobules due to insufficient air in regions of the lung

What is cystic fibrosis?

Genetic mutation impacting a regulator of sweat and mucus production; thick mucus blocks airways

What can cause non-motile cilia (Kartagener syndrome)?

Congenital or due to smoking/vaping