A&P 2: Respiration

Structures of the upper respiratory tract

nose, pharynx

Structures of the lower respiratory tract

larynx, trachea, bronchi, lungs

What structures does the path of air pass through?

1. nasal cavity

2. pharynx

3. larynx

4. trachea

5. primary bronchi

6. secondary bronchi

7. tertiary bronchi

8. bronchioles

9. alveoli

Pharynx (+ location, function)

- hollow tube that starts posterior to internal nares and runs to opening of larynx in neck

function: passageway for air and food and houses tonsils

Function and types of tonsils

function: houses lymphocytes and traps bacteria entering through nose/mouth

types: pharyngeal (adenoids), palatine, lingual, tubal

Location and function of nasopharynx

location: behind internal nares

function: contains pharyngeal tonsils (adenoids) and the opening of auditory tubes and acts as an airway

Location and function of oropharynx

location: behind mouth

function: respiratory and digestive functions and houses the palatine and lingual tonsils

Which tonsils are removed during a tonsilectomy?

Palatine tonsils

Location and function of laryngopharynx

location: inferiorly and opens into larynx and esophagus

function: respiratory and digestive functions

What are the 3 regions of the pharynx?

1. Nasopharynx

2. Oropharynx

3. Laryngopharynx

What two cartilages are used as a landmark for making cricothyrotomy?

Thyroid cartilage and cricoid cartilage

What is the purpose of a cricothyrotomy?

Emergency airway

Ventricular folds

false vocal cords external to the true vocal cords surrounding the glottic opening

What structures form the rima glottidis?

The true vocal cords or vocal folds

Epiglottis (+ location, function)

- flap of elastic cartilage covered with mucous membrane

location: attached to roof of tongue

function:

breathing- held anteriorly

swallowing- pulled backward to close off the glottic opening and divert food away from trachea and into esophagus

What type of cells is the respiratory tract made of?

Ciliated pseudostratified columnar epithelium

How does the cilia of the respiratory tract move in the upper vs. lower respiratory tracts?

Upper: cilia move mucous and trapped particles down toward pharynx

Lower: cilia move mucous and trapped particles up toward larynx

Trachea (+ length, location)

- semi-rigid pipe made of semi-circular cartilaginous rings

location: anterior to esophagus extending into mediastinum where it divides into left/right primary bronchi

length: 12 cm long

Carina (+ function)

- internal ridge located at the junction of the two main stem bronchi

function: sensitive trigger for coughing reflex

Location and function of trachealis muscle

location: posterior trachea directly adjacent to the esophagus

function: contract the trachea to increase airflow velocity and enhance the expulsion of mucous and foreign particles during coughing

What structural changes occur as bronchi branch into bronchioles?

- mucous membrane changes then disappears

- cartilaginous rings become more sparse and eventually disappear

- as cartilage decreases, smooth muscle increases

Effect of sympathetic stimulation on smooth muscle of bronchi/bronchioles

airway dilation

Effect of parasympathetic stimulation on smooth muscle of bronchi/bronchioles

airway constriction

Alveoli (+ function, how many cells thick, type of epithelium)

- cup-shaped outpouchings for gas exchange

function: gas exchange

- one cell thick

-simple squamous epithelium

Function of alveolar ducts

connect terminal bronchioles to alveolar sacs

Alveolar sacs

clusters of alveoli

How is the right lung divided?

into 3 lobes (superior, middle, and inferior) by the oblique and horizontal fissure

How is the left lung divided?

into 2 lobes (superior and inferior) by the oblique fissure

Apex of lungs

superior and extends slightly above the clavicles

Base of lungs

flat bottom sitting on diaphragm

Cardiac notch

the indention for the heart in the left lung (makes the left lung 10% smaller than right)

What are the thoracic muscles for inhalation?

1. sternocleidomastoid

2. scalenes

3. external intercostals

4. diaphragm

What are the thoracic muscles for exhalation?

1. internal intercostals

2. external oblique

3. internal oblique

4. tranversus abdominis

5. rectus abdominis

6. diaphragm

Functions of the nose

• provides airway for respiration

• moistens/warms entering air

• filters/cleans air

• resonating chamber for speech

• houses olfactory receptors

What is the external nose composed of?

the nasal bone and several cartilages

Types of mucosas in the nasal cavity

olfactory and respiratory mucosa

Location and type of epithelium of olfactory mucosa

located in the superior region of the nasal cavity and contains olfactory epithelium

Location of respiratory mucosa

location:

• lines most of the nasal cavity

• nasopharynx

• larynx (except vocal cords)

• trachea

• bronchial tree (down to bronchioles)

Location and function of nasal conchae

• protrude medially from the lateral walls of the nasal cavity

• their shape increases mucosal area exposed to air and enhances turbulent flow

• during inhalation they filter, heat, and moisten air and then reclaim most of the heat/moisture during exhalation

What bones are the paranasal sinuses located in?

frontal, sphenoid, ethmoid, maxillary

paranasal sinuses and functions

spaces in the skull that connect the nasal cavity

• lighten the skull

• secrete mucus

Label each paranasal sinus

frontal sinus - on forehead

ethmoid sinus - on sides of bridge of nose

maxillary sinus - on cheeks beside nose

sphenoid sinus - behind eyes

What happens during swallowing that prevents food from going into the nasopharynx?

The uvula and soft pallete move superiorly to block nasopharynx during swallowing

What covers the opening of the auditory tubes in the nasopharynx?

tubal tonsils

Isthmus of Fauces

archway between oropharynx and oral cavity

What type of epithelium is in the laryngopharynx?

stratified squamous epithelium

If swallowing, which has right of way, air or food?

food has right of way so airflow temporarily stops

Label each blank

Red - pharyngeal tonsil

Green - tubal tonsil

Blue - palatine tonsil

Purple - lingual tonsil

Respiratory zone + structures

sites for gas exchange

• respiratory bronchioles

• alveolar ducts

• alveoli

Conducting zone + functions

all other airways from nose to bronchioles

• transport air to/from sites of gas exchange

• cleanse, warm, and humidify incoming air

What vertebrae does the larynx span from?

C3 to C6

Functions of the larynx

provides open airway, routes air/food into proper channels, and voice production

What are the structures of hyaline cartilage and elastic cartilage in the larynx?

Hyaline:

• thyroid cartilage

• cricoid cartilage

• arytenoid cartilage

• cuneiform cartilage

• corniculate cartilage

Elastic:

• epiglottis

Laryngeal prominence

“adam’s apple” anterior midline ridge on the thyroid cartilage

What are the 3 pairs of small cartilages in the larynx?

1. arytenoid cartilage

2. cuneiform cartilage

3. corniculate cartilage

Epiglottis + function

elastic cartilage covered in taste bud containing mucosa

• covers laryngeal inlet during swallowing as larynx is pulled superiorly

Vocal folds (synonym, function, formed by…)

• also called “true vocal cords”

• mucosal folds that vibrate to produce sound as air passes through during expiration

• formed by vocal ligaments

Vocal ligaments (location + function)

lie deep to mucosa and attach thyroid cartilage to arytenoid cartilage and form true vocal cords

Vestibular folds

• also called “false vocal cords”

• no sound production but helps close glottis during swallowing

Speech

intermittent release of expired air during opening/closing of glottis

How is pitch determined?

by length and tension of vocal folds (tenser folds vibrate faster to produce higher pitch)

How is loudness determined?

depends on force of airflow vibrating folds

What structure muscles shape speech into language?

pharynx, tongue, soft palate, and lips

Laryngitis, causes, and consequences

inflammation of vocal cords

• caused by viral infections, overuse of voice, dry air, tumors of vocal cords, inhalation of irritating chemicals

• can result in hoarseness and in severe cases, speaking limited to a whisper

3 layers of the trachea wall from inside to outside

1. mucosa

2. submucosa

3. adventitia

Mucosa layer of the trachea wall

respiratory epithelium

Submucosa layer of the trachea wall

CT with seromucous glands supported by 16-20 cartilage rings to prevent airway collapse

How does smoking affect breathing?

Smoking inhibits and destroys cilia, which causes coughing because it is the only way to prevent mucus accumulation

Does cilia return several weeks after quitting smoking?

Yes

Heimlich maneuver

procedure where air in a victim’s lungs is used to expel an obstructing piece of food

How many generations of branching do airways undergo?

23

Hilum

place on lung where primary bronchi enter

Why are secondary bronchi also called “lobar bronchi”?

Because each lobe of the lungs gets one secondary bronchi

What are the differences structurally between bronchi and bronchioles?

• bronchi have cartilage rings and bronchioles have smooth muscle

• bronchioles have cuboidal epithelium while bronchi have respiratory epithelium

How thick is the respiratory membrane and what is it composed of?

about 0.5 um thick and made of the alveolar wall, capillary wall, and a shared basement membrane

Types of cells in the alveolar wall

1. type I alveolar cells

2. type II alveolar cells

3. mobile alveolar macrophages

Type I alveolar cells

simple squamous epithelium

Type II alveolar cells (+ function)

scattered cuboidal cells that secrete surfactant and antimicrobial proteins along inner surface

Function of alveolar macrophages

keep inner surface clean and consume bacteria and debris

Function of alveolar pores

connect adjacent alveoli, equalize air pressure throughout lungs, and provide alternate routes in case of airway blockages

Atmospheric air is…

21% oxygen, 0.04% CO2, and 78% nitrogen

type of epithelium of respiratory mucosa

contains respiratory epithelium with goblet cells resting on a basement membrane with seromucos glands.

What is the function of surfactant and what secretes it?

function: reduces attraction/cohesiveness between water molecules to prevent alveolar collapse and reduce work of lung inflation

• secreted by type II alveolar cells

lobule (+ shape, separated by…)

smallest subdivision of lung visible to the naked eye

• hexagonal in shape

• separated by CT

What does the connective tissue that connects lobules look like in smokers?

Blackened with carbon

Lung tissue composition

alveoli within a stroma

Stroma

“bed” of mostly elastic connective tissue which reduces work of breathing

What are the two divisions of lung circulation?

Pulmonary and bronchial

Function of pulmonary arteries

• carry systemic venous blood from heart to lungs for oxygenation

• branch and lead into pulmonary capillary networks that surround alveoli

Which division of lung circulation is low/high pressure and low/high volume?

Pulmonary: low pressure, high volume

Bronchial: high pressure, low volume

Function of pulmonary veins

carry oxygenated blood from alveoli back to heart (left atria)

Where are enzymes that act on blood housed?

Capillary epithelium of pulmonary capillary networks

Bronchial arteries (function, place of origin, and place of insertion)

• provide oxygenated blood to lung tissue (except alveoli)

• arise from aorta

• enter lungs at hilum

What are the three parts of innervating the lungs?

1. parasympathetic fibers

2. sympathetic fibers

3. visceral sensory fibers

What causes bronchoconstriction?

parasympathetic stimulation

What causes bronchodilation?

sympathetic stimulation

Where do parasympathetic and sympathetic fibers enter into the lungs and then go?

The pulmonary plexus on lung root and run along bronchial tree and blood vessels

Pleurae

double-layered serous membrane that divides thoracic cavity into two pleural compartments and mediastinum

Parietal pleurae

lines inner surface of thoracic wall, superior face of diaphragm, and lateral walls of mediastinum

Visceral pleurae

lines external surface of lungs and dips into fissures