chapter 22: the respiratory system

refers to ventilation of the lungs (breathing)

respiration

oxygen and carbon dioxide exchanged between blood and air. 2 types: external and internal respiration

gas exchange

exchange of gases between air and blood (alveoli)

external (pulmonary) respiration

blood and tissue fluid (systemic and gas exhange)

internal tissue respiration

principal organs of the respiratory system

nose, pharynx, larynx, trachea, bronchi, & lungs

what are conducting zones?

passages that serve only for airflow (no gas exchange happens, just moving air)

where is the conducting zone?

nostrils through the major bronchioles

what are respiratory zones?

regions that participate in gas exchange

what structures participate in the respiratory zone?

terminal ends of bronchi (alveoli) & nearby structures

airway from nose through larynx

upper respiratory tract

regions from trachea through lungs

lower respiratory tract

what is the job of the nose/nasal cavities

warms, cleans, and humidifies inhaled air, detects odor, and serves as a resonating chamber that amplifies the voice

what 2 major structure are located in the nose?

olfactory nerve/mucosa & ethmoid bone

what does charles law state?

the volume of gas is directly proportional to its absolute temp, for example, warm air has more volume

on a cool day (60 degrees), by how much will air temperature increase during inspiration?

39 degrees

if 500 mL of air inhaled, what will the volume expand to? (remember, warm air=more volume)

536 mL

(throat) muscular funnel extending from nose to larynx, assist in swallowing and speech

pharynx

responsible for airflow: it receives auditory tubes & mucosa traps airborne pathogens near the pharyngeal tonsil

nasopharynx

responsible for airflow and digestion: its the space between soft palate and epiglottis & contains palatine and lingual tonsils

oropharynx

responsible for airflow and digestion: it is posterior to larynx, from epiglottis to cricoid cartilage, its also where the esophagus begins

laryngopharynx

keeps food and drink out of the airway. the superior opening is guarded by the epiglottis and gives the voice box sound

larynx

directs food to the esophagus

epiglottis

supportive plate in epiglottis (elastic cartilage)

Epiglottic cartilage

shield-shaped, largest laryngeal cartilage; contains laryngeal prominence (Adam’s apple)

Thyroid cartilage

what stimulates the growth of the adams apple? (this is why its more prominent in men)

testosterone

ring-like shape; connects larynx to trachea

cricoid cartilage

make the voice box

thyroid and cricoid

holds up the larynx

hyoid bone

if the muscles of the larynx are tighter, it gives off a __ pitch

higher

if the muscles of the larynx are looser, it gives off a __ pitch

low

posterior to thyroid cartilage

Arytenoid cartilages

attached to arytenoid cartilages like a pair of little horns

Corniculate cartilages

these 2 cartilages are important for speech and the muscles that move cartilage attach at these points

Arytenoid and Corniculate

adduction v. abduction of the vocal chords

closed v. open

the “windpipe.” a rigid tube supported by 16-20 C shaped rings of hyaline cartilage to prevent collapse during inhalation

trachea

lowermost tracheal cartilage where the trachea splits into the left & right bronchi

carina

what is the trachea lined with?

pseudostratified ciliated columnar epithelium with goblet cells

mechanism for debris removal to prevent pathogens

mucociliary escalator

how does the mucociliary escalator work?

Mucus traps inhaled particles, upward beating cilia moves mucus to pharynx to be swallowed

to make a temporary opening in the trachea & insert a tube to allow airflow

tracheotomy

benefits of a tracheotomy

prevents asphyxiation

potential problems of a tracheotomy

air is not humidified & will dry out mucous membranes, resulting in it becoming crusty & interfering with clearance of mucus from the tract, thereby promoting infection

when a patient is on a ventilator, air is introduced directly into the trachea (through nose or mouth)

intubation

has 3 bronchi lobes, is wider and more vertical. aspiration typically occurs in this bronchus

right main bronchus

3 lobes of the right lung

superior, middle, & inferior

2 lobes of the left lung

superior & inferior

why is the right lung shorter?

the liver takes up space below it

why is the left lobe narrower?

the heart tilts into the left lung

the tertiary bronchi supply the _______ segment of the lungs

bronchopulmonary

continuations of airway that lack supportive cartilage and are 1 mm or less in diameter

bronchioles

portion of lung ventilated by one bronchiole

pulmonary lobule

each bronchiole divides into terminal bronchioles, how many of these are there?

80

each terminal bronchiole gives off 2 or more smaller respiratory bronchioles, each with a ___

alveoli

beginning of the respiratory zone (gas exchange)

alveoli

rapid gas exchange with blood

simple squamous alveolar cell layer

secret phospholipids and proteins to prevent collapse of alveoli

great alveolar cells

remove debris (wandering cells)

macrophages

how is gas exchanged across the alveolar membrane?

simple diffusion

two-membrane, fluid filled sac surrounding the lungs

pleura

covers the inside of the lungs

visceral pleura

outer layer (connected to diaphragm and ribs)

parietal pleura

space between membranes that reduces friction breathing

pleural cavity

breathing is a repetitive cycle of ___ and ___

inhalation and exhalation

one complete breath, inspiration and expiration

respiratory cycle

requires a difference between air pressure within the lungs and the external air pressure

ventilation

major muscles involved in creating difference in pressure gradients

diaphragm (2/3 or airflow) & intercostal muscles (1/3 of airflow)

what happens when the diaphragm relaxes? (boyles law)

relieves pressure on organs and the lungs move up

what happens when the diaphragm contracts (boyles law)

it pushes abdominal organs down so the lungs can expand

exhale v. inhale pressure

positive v. negative pressure

what is the primary function of intercostal muscles?

stiffen thoracic cage and prevent collapsing when diaphragm decends and 1/3 of airflow

contract during inhaling to widen thoracic cavity (intercostal muscles)

external muscles

contract during exhaling to narrow thoracic cavity (intercostal muscles)

internal muscles

scalenes of the neck fix ribs 1 & 2 while external intercostals pull the ribs upward and forwards (quiet respiration)

quiet inhalation

the energy-saving passive process achieved by the elasticity of the lungs and thoracic cage. as muscles relax, structures recoil to og shape and original (smaller) size of thoracic cavity (quiet respiration)

quiet expiration

breathing while at rest; effortless and automatic

quiet respiration

deep or rapid breathing, such as during exercise or playing an instrument

forced respiration

what happens during forced inspiration?

erector spinae arches the back & upper ribs are elevated

what happens during forced expiration

increases abdominal pressure and pushes viscera up against diaphragm, increasing thoracic pressure & forcing air out. pelvic muscles move down

breathing technique used to help expel contents of certain abdominal organs

valsalva maneuver

how does the valsalva manuever work?

breathing hard against a closed airway for 15 seconds to increase pressure in the abdomen and slow the heart

what is the purpose of the valsalva maneuvar?

diagnoses heart conditions, problems with ANS, and clears ear tubes

what are the 2 words for a collapsed lung?

atelectasis and pneumothorax

caused by obstruction of an airway or pressure on the outside the lung

atelectasis

thoracic wall is punctured, with inspiration sucking air into the pleural cavity. causes a build up of pressure in the lungs

pneumothorax

Does your chest expand because your lungs inflate or do your lungs inflate because your chest expands?

your lungs inflate because your chest expands

When the diaphragm contracts, do you inhale or exhale?

inhale

When inferior accessory muscles contract, do you inhale or exhale?

exhale

When superior thoracic muscles contract, do you inhale or exhale?

inhale

which medulla respiratory center is the primary generator of the respiratory rhythm, reverberating circuits of inspiratory neurons and expiratory neurons?

ventral respiratory group (VRG)

which medulla respiratory center modified the rate and depth of breathing and receives influences from external sources?

dorsal respiratory group (DRG)

which medulla respiratory center modifies rhythm of VRG by outputs to both VRG & DRG, adapting breathing to special circumstances such as sleep, exercises, vocalization and emotional responses?

pontine respiratory group (PRG)

detects changes in pH of cerebrospinal fluid (CO2 levels increases, pH decreases) and brainstem neurons

central chemoreceptors

detect changes in oxygen and carbon dioxide content, pH of blood, carotid (glossopharyngeal nerve) & aortic (vagus nerve) bodies

peripheral chemoreceptors

what do stretch receptors do?

respond to inflation of the lungs (smooth muscles of bronchi/bronchioles & visceral pleura)

what do irritant receptors do? (nerve endings between the epithelial cells of the airway

respond to irritants like smoke, dust, pollen, cold air, chemical fumes, and excess mucus and trigger reflexes such as bronchoconstriction, shallower breathing, breath-holding (apnea), or couching

what does the motor cortex of the frontal lobe of the cerebrum do?

voluntary control of breathing, sends impulses down corticospinal tracts to respiratory neurons in the spinal cord (bypasses brainstem), and breaking point

when carbon oxide levels rise to a point where automatic controls override one’s voluntary will

breaking point

what is spirometry?

measuring pulmonary ventilation

what is spirometry used for?

assess severity of a disease, monitor improvement or deterioration

a device used to make measurements; recaptures expired breath and records variables such as rate and depth of breathing, speed of expiration and rate of oxygen consumption

spirometer