Chapter 22: Respiratory System

(1) provides an airway for respiration, (2) moistens and warms entering air, (3) filters and cleans inspired air, (4) serves as a resonating chamber for speech, and (5) houses the olfactory (smell) receptors

Nose

surface features of the external nose include:

root, bridge, and dorsum nasi

Nares

Nostrils

Also called choanae

Posterior Nasal apertures

What id the roof of the nasal cavity formed by?

The ethmoid and sphenoid bones.

What separates the nasal cavity from the oral cavity?

The palate

What is the nasal vestibule lined with?

Skin containing sebaceous/ sweat glands and hair follicles.

What are vibrissae?

Hair

What do vibrissae do?

Filter coarse particles from inspired air.

What is the nasal cavity lined with?

Olfactory mucosa and respiratory mucosa

What is lysozyme?

an antibacterial enzyme

What do lysozymes do?

Attacks and chemically destroys bacteria that mucus traps.

What are defensins?

Natural antibiotics that help kill invading microbes

What humidifies incoming air?

High water content in the mucus film

The epithelial cells of the respiratory mucosa secrete what?

Defensins and lysozymes

Whats an important action of the nasal cilia?

Creates a gentle current that moves contaminated mucus towards the throat.

What is the nasal mucosa richly supplied with?

Sensory nerve endings

What triggers a sneeze reflex?

Nerve endings making contact with irritating particles.

What warms incoming air as it flows across the mucosal surface?

Plexuses of capillaries and thin-walled veins under the nasal epithelium

When inspired air is cold what intensifies the air-heating process?

Vascular plexus becomes engorged with blood.

Why are nosebleeds common and often profuse?

Blood vessels are abundant and located superficially

What enhances air turbulence in the cavity?

curved conchae

Why is turbulence important in the cavity?

It allows for more nongaseous particles to get trapped onto the mucus.

How do the conchae and nasal mucosa function during inhalation?

Filter, heat and moisten air

How do the conchae and nasal mucosa function during exhaltion?

They reclaim heat and mositure

How do conchae reclaim heat and moisture during exhalation?

Cooled conchae precipitate moisture and extract heat from the humid air.

What do paranasal sinuses do?

Lighten the skull and may help warm and moisten air

Where are paranasal sinuses located?

In the frontal, sphenoid, ethmoid, and maxillary bones.

Where does the mucus that paranasal sinuses produce goes?

into the nasal cavity

What is rhinitis?

Inflammation of the nasal mucosa and excessive mucus production.

What is sinusitis?

Inflamed sinuses

What can a change in pressure result in?

A sinus headache

What is the pharynx also called?

The throat

What are the tree regions of the pharynx called?

Nasopharynx, oropharynx, and laryngopharynx

The nasopharynx only serves as what type of passageway?

Air pasageway

What closes off the nasopharynx and prevents food from entering the nasal cavity?

The soft palate and vulva moving superiorly

What does the pharyngeal tonsil do?

Traps and destroys pathogens entering the nasopharynx in air.

When the adenoids are chronically enlarged what may be disturbed?

Speech and sleep

What do the pharyngotympanic tubes do?

Drain the middle ear cavities and allow ear pressure to equalize with atmospheric pressure

What does the location of the tub tonsil do?

Heps protect the middle ear against infections likely to spread from the nasopharynx.

Swallowed food and inhaled air pass through what?

The oropharynx and the laryngopharynx

As the nasopharynx blends into the oropharynx, how does the epithelium change?

From pseudostratified columnar to stratified squamous epithelium.

Why does the epithelium change to squamous epithelium?

To accommodate the increased friction and chemical trauma accompanying food passage.

What is the laryngopharynx lined with?

Stratified squamous epithelium

Is the laryngopharynx continuous with the esophagus?

Yes

What happens to air and food when swallowing?

Food has the right of way and air passage temporarily stops.

What does the lower respiratory system consist of?

Larynx, trachea, bronchi, and lungs

What are the two zones of the respiratory system?

The respiratory zone and conducting zone

What is the respiratory zone?

The site of gas exchange

What is the conducting zone?

All respiratory passageways that provide conduits for air to reach sites of gas exchange

What do the conducting zone organs do?

cleans, humidifies, and warms incoming air

What are the characteristics of air reaching the lungs?

Have fewer irritants, is warm and damp.

What are the three functions of the larynx?

Provides a patent airway, acts as a switching mechanism to route air and food, and voice production

Except of the epiglottis all laryngeal cartilages are what kind of cartilage?

Hyaline cartilage

What are the three small cartilages that form part of the lateral and posterior walls of the larynx?

Arytenoid, cuneiform, and corniculate cartilages

Which cartilage anchors the vocal folds?

The arytenoid cartilges

What is the epiglottis covered in?

taste bud-containing mucosa

What has the epiglottis been called?

the guardian of the airways

How are the larynx and epiglottis positioned during airflow?

The larynx is wide open and the edge if the epiglottis projects upwards

How are the larynx and epiglottis positioned during swallowing?

The larynx is pulled superiorly and the epiglottis tips to cover the laryngeal inlet.

What initiates the cough reflex?

Anything other than air entering the larynx

What do true vocal cords lack?

blood vessels

What are glottis?

Opening between the vocal cords in the larynx

What lines the superior portion of the larynx?

Squamous epithelium

What does the pseudostratified ciliated columnar type do?

Filters dust

What does the power stroke of the cilia od pseudostratified ciliated columnar type do?

Directs upwards towards the pharynx to move mucus away from the lungs.

What does speech involve?

The intermittent release of expired air as the glottis opens and closes

What does good enunciation depend on?

Muscles in the pharynx, tongue, soft palate, and lips

What is laryngitis?

Inflammation of the vocal folds.

What causes vocal folds to swell and interfere with their vibration?

Laryngitis

What does the Valsalva maneuver do?

helps empty the rectum and can also splint the body trunk when lifting a heavy load.

What is the Valsalva maneuver?

The glottis closes to prevent exhalation and the abdominal muscles contract causing the intra-abdominal pressure to rise.

What is the trachea also called?

The windpipe

What layers does the tracheal wall consist of?

mucosa, submucosa, and adventitia

What does the cilia continually do?

Propel debris-laden mucus toward the pharynx

What does the submucosa contain?

Seromucous glands that help produce sheets of mucus in the trachea.

What is the adventitia?

the outermost layer or covering of some organs

What prevents the trachea from collapsing and keeps the airway patent?

The cartilage rings

What causes expired air to rush upward from the lungs?

Contraction of the trachealis which decreases the tracheas diameter

What happens when the mucosa of the carina makes contact with a foreign object?

Violent coughing is triggered

What do conducting zone structures give way to?

Respiratory zone structures

Where does the trachea divide to form the right and left primary bronchi?

Level T7

Which bronchus is more common for an inhaled foreign object to get stuck in?

The right main bronchus

Which main bronchus is wider, shorter, and more vertical?

The right main bronchus

What structural changes occur as the conducting tubes become smaller?

Support structures change, epithelium type changes, amount of smooth muscle increases

What support structure changes when conducting tubes become smaller?

irregular patches of cartilage replace the cartilage rings and when the bronchioles are reached theres no more supportive cartilage

What epithelium type changes happen when conducting tubes become smaller?

the mucosal epithelium thins as it changes from pseudostratified columnar to simple columnar and then to simple cuboidal.

How does the amount of smooth muscle change as conducting tubes become smaller?

The smooth muscle in the tube walls increase

What are alveoli?

Thin-walled air sacs

What accounts for most of our lung volume and provides lots of surface area for gas exchange?

gas filled alveoli

What are the walls of the alveoli composed primarily of?

A single layer of squamous epithelial cells(type 1 alveolar cells)

What forms the respiratory membrane?

capillary and alveolar walls and their fused basement membrane

Where does gas exchange occur readily?

By simple diffusion across the respiratory membrane

What are the 3 major types of cells found in alveoli?

Type 1 alveolar cells, Type 2 alveolar cells, Alveolar macrophages

What do type 2 alveolar cells do?

they secrete fluid containing surfactant along with antimicrobial proteins.

What do alveolar macrophages do?

crawl freely along the internal alveolar surfaces consuming bacteria, dust, and other debris

What are two other significant features of alveoli?

Are surrounded by fine elastic fibers and open alveolar pores that connect adjacent alveoli that allows air pressure throughout the lung to be equalized.

How are alveolar surfaces usually sterile?

Most macrophages are swept up by the ciliary current of superior regions

What is the hilum?

The indented region of an organ from which blood and/or lymphatic vessels and nerves enter and exit.

How many bronchopulmonary segments does the right lung have?

10