Gas Exchange System

what is the main function of the respiratory system

respiration- supplying oxygen to the body and removing carbon dioxide

what additional roles does the respiratory system serve

olfaction (smell) and speech

what are the four main processes of respiration

• pulmonary ventilation (breathing)

• external respiration

• transport of gases in blood

• internal respiration

what is cellular respiration

the energy-releasing process in cells

what are the major organs of the respiratory system

nose, nasal cavity, sinuses, pharynx, larynx, trachea, bronchi and branches, lungs, alveoli

what are the functions of the nose

airway, moistens/warms/filters air, speech resonance, houses olfactory receptors

what bones form the roff and floor of the nasal cavity

roof: ethmoid and sphenoid bones

floor: hard and soft palates

what are the two types of nasal mucosa

olfactory mucosa and respiratory mucosa

what type of epithelium lines the nasal cavity

pseudostratified cilated columnar epithelium

what is the function of cilia and mucus in the nasal cavity

trap and move contaminants to the throat

what is the function of cilia and mucus in the nasal cavity

trap and move contaminants to the throat

what are nasal conchae and their function

superior, middle, and inferior projections that increase surface area and air turbulence

what is a nasal meatus

a groove beneath each nasal concha

what are the three regions of the pharynx

nasopharynx, oropharynx, and laryngopharynx

what is the pharynx made of

skeletal muscle

what is the nasopharynx’s function

air passageway behind the nasal cavity

what important structures are in the nasopharynx

pharyngeal tonsil and pharyngotympanic tubes

what is the function of the oropharynx

common passageway for food and air

what is the function of the laryngopharynx

passageway for food and air; connects to the esophagus

what are the three main functions of the larynx

airway, switch between food/air, voice production

what cartilage forms the Adam’s apple

thyroid cartilage

what type of cartilage is the epiglottis

elastic cartilage

what are true vocal cords

vocal folds that vibrate to produce sound

what are vestibular folds

false vocal cords that help close the glottis when swallowing

what determines pitch

length and tension of vocal cords

what determines loudness

force of air through the glottis

what is the trachea also called

the windpipe

what supports the trachea structurally

C-shaped rings of hyaline cartilage

what are the layers of the trachea wall

mucosa, submucosa, adventitia

how many branches does the bronchial tree have

about 23 orders of branching

what is the pathway from the trachea to alveoli

trachea → main bronchi → lobar bronchi → segmental bronchi → bronchioles → terminal bronchioles

What are terminal bronchioles

The smallest conducting zone branches

what changes occur in bronchi as they branch

• cartilage decreases, replaced by elastic tissue

• epithelium changes to cuboidal

• smooth muscle increases

what structures form the respiratory zone

respiratory bronchioles → alveolar ducts → alveolar sacs

what is the primary site of gas exchange

alveoli

what forms the respiratory membrane

alveolar wall + capillary wall + fused basement membrane

what is the function of type II alveolar cells

secrete surfactant and antimicrobial proteins

what are alveolar pores

openings that equalize air pressure between alveoli

what keeps alveoli sterile

alveolar macrophages

how many lobes does each lung have

right: 3 (superior, middle, inferior)

left: 2 (superior, inferior)

what are bronchopulmonary segments

functionally independent regions of the lungs

what delivers deoxygenated blood to the lungs

pulmonary arteries

what returns oxygenated blood to the heart

pulmonary veins

what supplies oxygenated blood to lung tissues (except alveoli)

bronchial arteries (from aorta)

what are the two pleural layers

parietal pleura, lines thoracic wall

visceral pleura, covers lungs

what is the function of pleural fluid

reduces friction and helps lungs expand and recoilw

what happens during expiration

• diaphragm relaxes

• thoracic volume decreases

• intrapulmonary pressure rises

• air flows out

what is the nature of pulmonary circulation

low pressure, high volume

what do pulmonary arteries do

deliver deoxygenated blood from the heart to the lungs

what do pulmonary veins do

Carry oxygenated blood from the lungs back to the heart

what role does lung capillary endothelium play in blood chemsitry

contains enzymes like ACE (angiotensin-converting enzyme), which activates blood pressure hormones

what is the function of bronchial arteries

provide oxygenated blood to lung tissue (except alveoli)

where do bronchial arteries arise from

the aorta

what do bronchial veins connect with

they anastomose with pulmonary veins

What is the function of pleural fluid

lubricates and reduces friction during breathing

what separates the lungs

mediastinum

what happens during inspiration

• diaphragm contracts and flattens

• external intercostals lift rib cage

• thoracic volume increases

• intrapulmonary pressure drops

• air flows into the lungs

what muscles assist forced expiration

abdominal wall muscles and internal intercostals

where does the greatest airway resistance occur

medium-sized bronchi

what is the effect of resistance on breathing

Increased resistance makes breathing more difficult

what causes surface tension in alveoli

attraction between liquid molecules lining alveoli

what reduces surface tension

Surfactant secreted by Type II alveolar cells

what is lung compliance

The ease with which lungs expand

what can decrease lung compliance

scar tissue, low surfactant, decreased thoracic mobility

what is tidal volume (TV)

amount of air inhaled or exhaled with each breath

what is inspiratory reserve volume (IRV)

extra air that can be inhaled after a normal inhalation

what is expiratory reserve volume (ERV)

extra air that can be exhaled after a normal exhalation

what is residual volume (RV)

air remaining in lungs after forced exhalation

what is vital capacity (VC)

TV + IRV + ERV — the maximum amount of air that can be exhaled after a deep breath

what is total lung capacity (TLC)

TV + IRV + ERV + RV — the total volume in lungs after maximum inspiration

what is anatomical dead space

air in conducting zone that doesnt participate in gas exchange

what is alveolar dead space

non-functional alveoli due to collapse or obstruction

what is Boyle’s law

P1V1 = P2V2

what is Dalton’s law

total pressure of a gas mixture is the sum of the partial pressures of each gas

what is Henry’s Law

Gas solubility depends on its partial pressure and solubility in the liquid

alveolar gas vs atmospheric gas

aleveolar gas has more CO2 and water vapor, less O2

how is O2 carried in blood

98.5% bound to hemoglobin

1.5% dissolved in plasma

what is oxyhemoglobin

Hb bound to oxygen

what brain regions control breathing

medullary respiratory centers and pontine centers

what do the medullary centers control

ventral and dorsal respiratory rhythms

how is co2 transported in blood

70% as bicarbonate ions, 20% bound to hemoglobin, 7-10% dissolved in plasma