respiratory system

the lungs are located in which cavities?

thoracic and pleural cavities

each lung is surrounded by what?

a serous (pleura) membrane

function of the respiratory system

provides gas exchange between air & circulating blood

Respiration involves:

ventilation

external respiration (gas exch blood ←→ lung air)

gas transport in blood

internal respiration (gas exch blood ← → cells)

conducting zone

movement of air through the respiratory passages, including the trachea and bronchi, that filters, humidifies, and warms the air before it reaches the lungs.

respiratory zone

origin of gas exchange in the lungs, including the alveoli and respiratory bronchioles, where oxygen diffuses into the blood and carbon dioxide diffuses out.

respiratory system structures

nose (nostrils), nasal cavity, pharynx epiglottis, larynx, trachea, 2 primary bronchi, lungs

nasal cavity consists of

nasal septum - divide

nasal conchae - structures (incr surface area)

nasal meatuses - passage ways

paranasal sinuses - open into cavity

pharynx

throat

divides into nasopharynx, oropharynx, and laryngopharynx, serving as a passageway for air and food.

nasopharynx

air passage with nasal cavity

oropharynx

passageway for both air and food

laryngopharynx

passage to esophagus (air and food)

larynx

“voice box” vocal cords

pitch = length

loudness = air force

speech = tounge, lips, nasal cavity, sinuses

lungs

3 lobes on the right, 2 lobes on the left, responsible for gas exchange.

branch into bronchial tree

smaller bronchi

bronchioles

alveolar sacs

alveoli

when the diaphragm contracts

the chest cavity expands, creating negative pressure that draws air into the lungs, pushing the diaphragm downward and allowing for inhalation.

when external intercostal muscles contract

the rib cage elevates, increasing the volume of the thoracic cavity and assisting in inhalation.

pleural membranes are attached by what?

serous (pleural) fluid

surfactants are located where?

in the alveoli of the lungs, reducing surface tension and preventing collapse.

pneunothorax

collapsed lung

air enters the pleural cavity

breaks the seal of pleural fluid that holds lungs to thoracic wall

causes - chest trauma/ deep stab wound or disease process

treatment involves surgically closing hole

exhalation/ respiration

driven by elastic recoil of the lungs and contraction of the diaphragm, allowing air to be expelled from the lungs.

diaphragm relaxes = moves upward

external intercostal muscles relax = rib cage lowers and volume decreases

no muscles on lungs, the diaphragm does the work

tidal volume

the amount of air inhaled or exhaled during normal breathing.

expiratory reserve volume (ERV)

the additional amount of air that can be forcibly exhaled after the expiration of a normal tidal volume.

residual volume (RV)

the amount of air remaining in the lungs after a maximal exhalation.

inspiratory reserve volume (IRV)

the additional amount of air that can be inhaled after a normal tidal volume.

vital capacity (VC)

the maximum amount of air that can be exhaled after a maximal inhalation, encompassing both tidal volume and reserves.

VC = ERV + TV + IRV

Vital capacity (VC) is a crucial measurement in assessing lung function, indicating the total volume of air that can be exchanged in a single breath.

should be at least 80% of predicted

males - 6.0 L females - 4.2 L

total lung capacity (TLC)

the maximum amount of air the lungs can hold, including vital capacity and residual volume.

TLC + VC + RV

gas exchange

occurs between the alveolar air & blood

follows henry’s law - the amt of a gas in a solution is directly proportional to the partial pressureof that gas.

in alveolus where PO2 is greater

O2 diffuses into capillary while CO2 diffuses into the alveolus.

hemoglobin is affected by

PO2 - directly, as it incr so does hemoglobin saturation with oxygen.

pH - directly, as it incr so does hemoglobin's saturation for oxygen.

temp - indirectly, as temp incr hemoglobin saturation decreases

carbonic acid

CO2 is converted by the enzyme carbonic anhydrase to carbonic acid inside RBC

hemoglobin saturation - 23% is bound to hb

dissolved in plasma - 7% CO2

Chronic Obstructive Pulmonary Disease COPD

air flow is difficult or obstructed

smoke paralyzes cilia

debris & mucus to pool in lower respiratory tract

emphysema

lung cancer

smoke contains over 4000 chemicals including 50 known carcinogens

nicotine is extremely addictive

1/3 of all cancer deaths

respiratory distress syndrome

affects infants born prematurely

lack of surfactant

alveoli collapse during exhalation & must be completely reinflated each inspiration

brbonchitis

inflammation of the bronchial tubes, causing coughing and mucus production, often due to smoking or infections.

acute - most common type, isially goes away in a few weeks

chronic - serious, can lead to COPD

Pneumonia

infection that inflames air sacs in one or both lungs, which may fill with fluid or pus, causing cough, fever, chills, and difficulty breathing.

6th most common cause of death because almost any severely ill person can develop it

asthma

a chronic condition characterized by inflammation and narrowing of the airways, leading to difficulty in breathing, wheezing, and coughing.

mast cells stimulate both bronchoconstriction & secretion of mucus