ANATOMY #3: CH. 23 - Respiratory

Structural Divisions

• Upper Respiratory System

• Lower Respiratory System

Upper Respiratory System

• Nose

• Pharynx

Lower Respiratory System

• Larynx

• Trachea

• Bronchi

• Lungs

Functional Divisions

• Conducting Zone

• Respiratory Zone

Conducting Zone

Filters, warms, moistens air

• Nose

• Pharynx, larynx, trachea, bronchi, bronchioles

Respiratory Zone

Gas exchange

• Respiratory bronchioles

• Alveolar ducts

• Alveoli

External Nose

• Extension of bone and cartilage with an internal dividing wall

• Cartilaginous framework (hyaline cartilage)

Internal Nose

• ~3/4 of nose

• Bony and cartilaginous framework keeps space patent

  • Respiratory Region

  • Olfactory Region

Respiratory Region of Internal Nose

• Lined with mucous membrane

• Includes nasal conchae

Olfactory Region

• Lined with olfactory epithelium

Pharynx

• Posterior to nasal and oral cavities

• Skeletal muscle lined with mucous membrane

  • Nasopharynx

  • Oropharynx

  • Hypopharynx

Nasopharynx

• 2 openings to auditory tubes

• Lining: Pseudostratified ciliated columnar epithelium, one layer

• Receives air and mucus from nasal cavity

• Moves mucus towards esophagus

Oropharynx

• Both respiratory and digestive functions

• Lining: Nonkeratinized stratified squamous epithelium

Hypopharynx

• aka. Laryngopharynx

• Lining: Nonkeratinized stratified squamous epithelium

• Split point for food and drink OR air

9 Pieces of Cartilage

• Thyroid Cartilage

• Epiglottis

• Cricoid Cartilage

• Arytenoid Cartilage x2

• Corniculate Cartilage x2

• Cuneiform Cartilage x2

  • Label on image in slides!

  • If not located on midline, are in pairs

Thyroid Cartilage

• Laryngeal prominence

• AKA Adam’s Apple

Epiglottis

• Relatively flexible

• Epiglottis folds over opening to larynx

Cricoid Cartilage

Connected by cricothyroid and cricotracheal ligament

Arytenoid Cartilage

• x2

• Allows us to modify noises from vocal system

Corniculate Cartilage

• x2

• Elastic

Cuneiform Cartilage

• x2

• Tablet-shaped

• Allows for good seal, so that we don’t get wrong things in airway

Epithelial Lining of the Larynx

• Above Vocal Folds

• Below Vocal Folds

Above Vocal Folds

• Nonkeratinized squamous epithelium

• Food and drink could pass through

Below vocal folds

• Pseudostratified ciliated columnar epithelium

• Purely respiratory in function

Voice production

2 pairs of folds in larynx

• Vestibular folds

• Vocal folds

• Intrinsic muscles

Vestibular Folds

• Hold breath against pressure in thoracic cavity

• Prevent loss of air

Vocal Folds

• Principal structures in voice production

• Bands of elastic

  • Ligaments deep to folds stretch between laryngeal cartilages

Intrinsic Muscles

• Between laryngeal cartilages manipulate vocal folds

• Contraction - pulls folds into airway

• Passing air produces vibrations, which produces sound waves

• More tension, pitch goes up

• Less tension, pitch goes down

• Thicker, lower

• Thinner, higher

• Connective tissue is impacted by testosterone

Trachea Wall Structure

• Mucosa

• Submucosa

• Fibromusculocartilaginous Layer

• Adventitia

Mucosa

Pseudostratified ciliated columnar epithelium + lamina propria

Submucosa

• Areolar CT

• Contains seromucous glands

  • Produce mi of serous fluid and mucus

Fibromusculocartilaginous Layer

• 16-20 incomplete rings of hyaline cartilage

• Open end of ring faces posteriorly

• Spanned by fibromuscular membrane, aka trachealis (smooth muscle)

• Ensures trachea stays patent

Adventitia

• Areolar CT, connects trachea to surroundings

• If something touches the ridge, in the bottom of trachea, cough reflex is initiated

Types of Bronchi

• Main Primary

• Kobar Secondary

• Segmental Teritiary

Main Primary Bronchi

• Left main bronchus is slightly different shape

• Takes to entire lung

Kobar Secondary Bronchi

• Takes to lobe of lung

• Right lung has THREE lobes

• Left lung has TWO lobes

Segmental Tertiary Bronchi

• Broncho pulmonary segment

• Takes to segment in lobe

• 10 

Bronchioles

• Mucous Membrane

• Cartilage

• Smooth Muscle

Mucous Membrane

• Pseudostratified ciliated columnar epithelium

• Simple ciliated columnar

• Simple ciliated cuboidal

• Simple cuboidal

Where is pseudostratified ciliated columnar epithelium found?

• Main Bronchi

• Secondary Bronchi

• Tertiary Bronchi

Where is simple ciliated columnar epithelium found?

Larger bronchioles

Where is simple ciliated cuboidal found?

Smaller bronchioles

When is simple cuboidal found?

Terminal bronchioles

What is the formation of the mucus layers in the bronchioles?

Slowly gradually thinning layers down, getting shorter and shorter

• Allows easier exit of foreign substances

Cartilage in Bronchioles

• Incomplete rings replaced with plates of hyaline cartilage; cartilage disappears in distal bronchioles

• There to help keep airways open

• As amount of cartilage declines, amount of smooth muscle increases

Smooth Muscles in Bronchioles

• As cartilage decreases, smooth muscle increases to maintain patency without cartilage

• As part of f/f response, release epi/norepi, dilates passages, helps power through emergency situation

Base of Lungs

Broadest section

Apex of Lungs

• Top tip

• All the way to shoulder

• Most of space in thoracic cavity

Cardiac notch

• Notch on left lung

• Space where heart occupies

Hilum/Hilus

• An indent, serves as entry and exit point

  • Where primary or main bronchus enters lungs

  • Pulmonary artery bringing blood into lung

  • Pulmonary vein taking blood out of lung

Oblique fissure

• Crossing down on both right and left lung

• Only fissure on left lung

Horizontal fissure

• On right lung

• Above oblique

Superior Lobe

• On right and left lung

• Portion that includes apex

Inferior Lobe

• On right and left lung

• Includes the base

Middle Lobe

• On right lung only

• Between two fissures

Second/Lobar Bronchi

Each lobe gets one of these

Bronchopulmonary Segments

10 in each lung, supplied by segmental (tertiary) bronchi

Lobules

• Little comportments within each segment

• Wrapped in elastic CT

• Contains lymphatic vessel, arteriole, venule and branch of terminal bronchiole

Alveoli/Alveolus

• Cup-shaped pouch lined with simple squamous epithelium and thin basement membrane

• Branch off of alveolar ducts

Alveolar Sac

• 2 or more alveoli that share one opening

• Gives more opportunities for gas exchange

  • Type I Cells

  • Type II Cells

  • Alveolar Macrophages

Type I Alveolar Cells

• Simple squamous epithelial cells

• Lots of surface area, not a lot of thickness

• Produce a nearly continuous lining of alveolar wall

• Main site of gas exchange

Type II Alveolar Cells

• Cuboidal epithelial cells with microvilli, aka septal cells

• Help absorb extra fluid on alveoli, controls amount of liquid

• Secrete surfactant, decreases surface tension of alveolar fluid, helps keep alveoli open (Surface acting agent)

• Fewer in number than Type 1

• Neonates have less, Can wind up in respiratory distress, May deliver androgynous surfactant, until type 2 develop and they can make their own

Alveolar Macrophages

• Not part of the wall

• Aka dust cells

• Wandering phagocytic cells

• Help keep space within alveoli clear

Walls of Alveoli

• Spaces, where air would be

• Thin walls of alveoli separating spaces

• Exchange of O2 and CO2 happens by diffusion across respiratory membrane

• Type 1 alveolar cells, alveolar basement membrane, capillary basement membrane, capillary endothelial cells (In order)

• Very thin membrane = very quick diffusion

• O2 and CO2 diffuse down gradients