Chapter 13- The Respiratory System

What are the organs in the respiratory system?

nose, pharynx, larynx, trachea, bronchi, lungs

Where does gas exchange with blood occur?

alveoli

Upper Respiratory Tract

nose to larynx

Lower Respiratory Tract

trachea to alveoli

What is the only externally visible part of the respiratory system?

nose

Nose

air enters through nostrils (nares); interior is nasal cavity divided by midline nasal septum; olfactory receptors are in Mucosa in superior part of nasal cavity

Olfactory Receptors

sense of smell; in mucosa in the slit-like superior part of the nasal cavity; just beneath ethmoid bone

Respiratory Mucosa

mucosa lining the nasal cavity resting on rich network of thin-walled veins that warms the air as it flows; its sticky mucus moistens the air and traps bacteria and foreign debris and destroys through lysozyme enzyes

Ciliated cells of nasal mucosa

create gentle current to move mucus toward throat (pharynx) where it is digested by stomach juices; becomes sluggish in cold weather

Conchae

three mucosa-covered projections on lateral walls of nasal cavity; increase surface area of mucosa and air turbulence

What is the nasal cavity separated from the oral cavity by?

palate

Anteirorly supported palate

hard palate

Posterior unsupported palate

soft palate

Cleft Palate

genetic defect; failure of bones forming the palate to fuse medially; results in breathing difficulty and problems with oral cavity functions (speaking)

Paranasal sinuses

surrounds nasal cavity; located in frontal, sphenoid, ethmoid, and maxillary bones; lighten the skull and are resonance chambers for speech; produce mucus (blowing nose drains them)

Nasolacrimal ducts

drain tears from eyes; empties into nasal cavities

Rhinitis

inflammation of the nasal mucosa; causes nasal congestion and postnasal drip; from cold viruses and various allergens

Sinusitis

sinus inflammation; changes in voice quality; difficult to treat

Sinus Headache

passageways connecting the sinuses to nasal cavity are blocked with mucus or infectious matter so the air in the sinus cavities are absorbed; creases a partial vacuum over inflamed area

Pharynx

muscular passageway for food and air that is about 13 cm long; aka throat; continuous from nasal cavity to posterior nasal aperture

What are the three regions of the pharynx?

nasopharynx, oropharynx, laryngopharynx

Nasopharynx

supeiror portion; air enters from nasal cavity

Oropharynx

air/food from nasopharynx descends through this

Laryngopharynx

air/food from oropharynx

Epiglottis

a flap directs food into the esophagus

Pharyngotympanic tubes

drain the middle ears; open into the nasopharynx; mucosae are continuous so ear infections may follow a sore throat of other infections

Otitis media

a type of ear infection

Tonsils

clusters of lymphatic tissue found in the pharynx; protect the boy from infection

Paryngeal tonsil

single; adenoid; located his in the nasopharynx

Palatine Tonsils

two; in oropharynx at the end of the soft plate

lingual tonsil

lies at the base of the tongue

tubal tonsils

protect openings of the pharyngotympanic nubes in the nasopharynx

Tonsillitis

pharyngela tonsil becomes inflamed and swollen, obstructing the nasopharynx and forcing the person to breathe from the mouth; air is not properly moistened, warmed or filtered before reaching the lungs

Larynx

voice box; routes air and food into the proper channels and plays a role in speech; inferior to pharynx; formed by 8 hyaline cartilages and epiglottis

Epiglottis

spoon-shaped flap of elastic cartilage; protects the superior opening of the larynx; allows passage of air when breathing but tips, forming a lid over the larynx’s opening when swallowing

Thryoid cartilage

largest of the hyaline cartilages; shield-shaped protruding anteriorly; called Adam’s apple

Vocal Folds

aka true vocal cords; pair of folds in the mucous membrane of the larynx that vibrate with expelled air; vibration causes speech

glottis

slitlike passageway between the vocal folds

Trachea

windpipe; air enters it from the larynx and travels to the fifth thoracic vertebrae (about midchest)

Hyaline cartilage

C-shaped rings that reinforce trachea walls; have open parts about the esophagus which allow it to expand but the solid portions keep it patent (open)

Trachealis

muscle that lies next to the esophagus and complete the wall of the trachea posteriorly

Heimlich maneuver

producde where ethe air in a person’s lungs is used to expel an obstructing pice of food; save people from chocking

Tracheostomy

surgical opening of the trachea; alternate route for air to reach the lungs

What is the trachea lined with?

ciliated mucosa that beat continuously in a superior direction

Cilia

surrounded by goblet cells that produce mucus (collects dust particles) that they propel away from the lungs to the throat

What does smoking do to the cilia?

it inhibits and destroys it; cough a lot to prevent mucus from accumulating in lungs so should avoid medications that inhibit cough reflex

Why is nose breathing preferable to mouth breathing?

the mucosa in the nose traps bacteria and other foreign debris and they are destroyed by lysozyme enzymes so the air has few irritants

What is the specific protective function of cilia in the trachea?

propel mucus that is loaded with dust particles and other debris away from the lungs to the throat where it can be swallowed or spat out

Main (primary) bronchi

formed by division of trachea; runs obliquely before plunges into medial depression (hilum) of the lung

What is the difference between the left and right main bronchus?

the right is wider, shorter, straighter & more common site for an inhaled foreign object to become lodged

Lungs

fairly large organs; occupy the entire thoracic cavity except for mediastinum (the heart, blood vessels, bronchi, esophagus)

Apex

narrow superior portion of each lung; deep to clavicle

Base of lung

broad lung area resting on diaphragm

What does fissures divide the lung into?

lobes; left- 2 lobes; right- 3 lobes

Pulmonary pleura

aka visceral pleura; visceral Serosa that covers the surface of each lung

Parietal pleura

lines walls of the thoracic cavity

Pleural membranes

produce pleural fluid (slippery serous fluid) that allows the lungs to glide easily over the thoracic wall during breathing and cause the two layers to cling together (easily to slide but hard to pull apart)

Pleura space

potential space not actually since lungs are held tightly to thorax wall

Pleurisy

inflammation of the pleural; could be from insufficient secretion of pleural fluid; pleural surfaces become dry and rough, causing friction and stabbing pain with each breath; or could have excessive amounts of fluid, exerting pressure on lungs and hinders breathing movements

Bronchioles

smallest of the conducting passageways

Alveoli

terminal bronchioles led to respiratory zone structures that terminate into these; air sacs; single, thin layer of simple squamous epithelial cells

Respiratory Zone

respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli; site of gas exchange; other parts in respiratory system are conducting zone structures

Stoma

lung tissue; elastic connective tissue that allows the lungs to stretch and recoil when breathing

Respiratory Membrane

air-blood barrier; alveolar and capillary walls, fused basement membranes, and occasional elastic fibers; gas (air) glowing past on one side and blood on the other; gas exchange occurs through simple dissusion

Alveolar macrophages

“dust cells” in alveoli; final line of defense for respiratory system

Surfactant

lipid molecule; coats gas-exposed alveolar surfaces and helps with lung function

Name the order of the following parts of the human respiratory system from the site where air enters the nostrils to the site where air reaches the end passages of the lungs- bronchi, larynx, nasal cavity, alveoli, trachea, pharynx, bronchioles.

Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli

Which main bronchus is most likely site for an inhaled object to become lodged? Why?

the right main bronchi; it is wider, shorter, and straighter

The lungs are mostly passageways and elastic tissue. What is the role of the passageways? Of the elastic tissue?

conduct air; the lungs to stretch and recoil passively when exhaling which saves energy

Name the four structures that make up the respiratory zone.

Respiratory bronchioles, alveolar ducts, alveolar sacs, individual alveoli

Respiration

four distinct events to supply the body with oxygen and to dispose of carbon dioxide

Pulmonary ventilation

air moves into and out of the lungs to continuously refresh the alveoli’s gases; aka breathing; depends on volume changes in thoracic cavity

External Respiration

gas exchanges (oxygen loading and carbon dioxide unloading) between the pulmonary blood and alveoli; between blood and body exterior

Respiratory Gas Transport

oxygen and carbon dioxide are transported to and from the lungs and tissue cells of the body via the bloodstream

Internal Respiration

gas exchange occurs between the blood and cells (capillaries) inside the body; oxygen is unloaded and carbon dioxide is loaded

Cellular Respiration

use of oxygen to produce ATP and carbon dioxide

Inspiration

aka inhalation; air flowing into the lungs; diaphragm and external intercostals contract, increasing intrapulmonary volume and decreasing gas pressure which produces a partial vacuum causing air to flow into the lungs; pressure in the lungs is less than atmospheric pressure, gas flows down gradient until pressures equal

Expiration

aka exhalation; air leaves the lungs; inspiratory muscles relax, intrapulmonary volume decreases and gas pressure increases; gas pressure is higher than atmospheric pressure, so air passively flows out to equalize the pressure

Inspiratory Muscles

diaphragm and external intercostals

When can expiration become active process?

respiratory passageways are narrowed by spasms of the bronchioles (asthma) or clogged with mucus or fluid (chronic bronchitis or pneumonia); forced expiration (internal intercostal muscles and abdominal muscles contract to force air out)

What major factor prevents lung collapse?

intrapleural pressure (in the pleural space) is always negative, or lower than pressure inside the lungs; if they become equal, lungs collapse

Atelectasis

aka lung collapse; air enters the pleural space through chest wound or rupture of visceral pleura; pneumothorax (air within intrapleural space) pushes in on the lung, disrupting fluid bond between pleural; reversed by drawing air out of intrapleural space with chest tube

What is the most basic function of respiration?

supplying the body with oxygen and disposing of carbon dioxide

What causes air to flow out of the lungs during expiration?

increased air pressure in the lungs as they recoil

What factors affect respiratory capacity?

size, sex, age, physical condition

Tidal Volume

normal quiet breathing moving air into and out fo the lungs with each breath; usually around 500 mL

Inspiratory Reserve Volume (IRV)

amount of air that can be taken in forcibly; around 3,100 mL

Expiratory reserve volume (ERV)

amount of air that can be forcibly exhaled; around 1,200 mL

Residual volume

air still in lungs and cannot be voluntarly expelled; around 1,200 mL; allows gas exchange to go on continuously even between breaths and keeps alveoli inflated

Vital Capacity (VC)

total amount of exchangeable air; sun of tidal volume + inspiratory and expiratory reserve volumes; men- 4,800 mL; females- 3,100 mL

Dead Space Volume

some of the air that enters the respiratory tract remains in the conducting zone passageways and never reaches the alveoli; about 150 mL

What are respiratory capacities measured with?

spirometer; evaluates losses in respiratory function

Nonrespiratory air movements

• Cough- clears lower respiratory passagways of debris or collected mucus by forcing air superiorly from lungs against glottis so it opens suddenly and blast of air rushes upward

• Sneeze- clears upper respiratory passageways of debris or collected mucus; expelled air is directed through nasal cavities instead fo oral cavity by uvula closes oral cavity off to pharynx, redirecting air through nose

• Crying & laughing- inspiration followed by release of air in short expirations; emotionally induced

• Hiccups- sudden inspirations from spasms of diaphragm; initiated by irritation of diaphragm or phrenic nerves; sound occurs when inspired air hits vocal folds of closed glottis

• Yawn- very deep inspiration with jaws wide open; ventilates all alveoli

Bronchil sounds

produced by air rushing through large respiratory passageways (trachea and bronchi)

Vesicular breathing sounds

air fills the alveoli; soft murmurs that resembly a muffled breeze

Crackle (bubbling sound), Wheezing (whistling sound), Rales are produced by what?

diseased respiratory tissue, mucus or pus; abnormal bronchial sounds from presence of mucus in lungs passages or thickening of bronchial walls

Which is the largest respiratory volume- ERV, IRV, TV, or VC? Which is the smallest?

VC; TV

Dead space volume accounts for about 150 mL of tidal volume. How much tidal breath actually reaches the alveoli?

350 mL

Jimmy broke a left rib when he fell from his bike. The rib punctured the chest wall. What happened to his left lung? Why?

left lung collapses because pressure in the intrapleural space became equal to the atmospheric pressure

What does gas exchange obey?

laws of diffusion, movement from high concentration to low concentration