pulmonary ventilation through the bronchial tree

bronchial tree

trachea splits into right and left main bronchi; continued splitting leads to progressively smaller tubes

bronchioles

smaller tubes that are < 1 mm in diameter

bronchiole walls

do not contain cartilage but have a thick layer of smooth muscle; controls bronchoconstriction and bronchodilation

terminal bronchioles

final segment of conducting pathways

alveoli

small; saccular outpocketings; site of gas diffuse between pulmonary capillary blood and air in the lungs

alveolar wall

formed from 2 types of cells: type I and type II

alveolar type I cell

simple squamous epithelial; rapid gas diffusion

alveolar type II cell

almost cuboidal; produce pulmonary surfactant

pulmonary surfactant

decrease surface tension within alveolus and prevents its collapse

surfactant-producing cells in premature babies

underdeveloped cells; causes alveoli to collapse, causing Infant Respiratory Distress Syndrome

respiratory membrane

thin wall between alveolar lumen and the blood across which gases diffuse

costal surface of lungs

anterior, lateral, and posterior surfaces of the lungs

mediastinal surface of lungs

medial surface of lungs

hilum

concave ares where everything is entering/leaving the lung in the mediastinal surface

left lung

slightly smaller to accommodate heart; contains cardiac notch; contains oblique fissure

oblique fissure

divides the lung into superior and inferior lobes

right lung

contains oblique and horizontal fissures that divide the lung into superior, middle, and inferior lobes

bronchopulmonary segments

10 in right lung; 8-10 in left lung; supplied by its own tertiary bronchus and branch of a pulmonary artery and vein; each is surrounded by and isolated from other segments by CT

pulmonary ventilation

“breathing”; the movement of air into and out of the respiratory system structures

external respiration

exchanges gases between atmosphere and blood

internal respiration

exchanges gases between blood and body’s cells

mechanics of breathing

follows Boyle’s law: volume and pressure are inversely related

inhalation

increase in thoracic cavity volume, decrease intrapulmonary pressure, air flows into the lungs

exhalation

decrease in thoracic cavity volume, increase in intrapulmonary pressure, air flows out of the lungs

vertical changes in thoracic cavity

result of diaphragm movement

lateral changes in thoracic cavity

result of rib cage elevation/depression

anterior/posterior changes in thoracic cavity

result of sternum moving anteriorly or posteriorly

quiet breathing

normal inhalation and exhalation

forced inhalation

allows deeper inspirations by increasing thoracic cavity expansion when they contract

forced exhalation

contract during hard exhalation and work to decrease thoracic volume

eupnea

resting breathing; costal breathing and diaphragmatic breathing

costal breathing

more shallow, more movements in ribs

diaphragmatic breathing

deeper breaths, more movement in diaphragm

syphymometer

used to measure respiratory function and lung capacity

tidal volume (TV)

volume of air in and out of lungs in 1 resting breath

vital capacity (VC)

volume of air in and out of lungs in 1 maximal breath (biggest breath possible)

inspiratory reserve volume (IRV)

volume of air that can be inhaled beyond a tidal inhale

expiratory reserve volume (ERV)

volume of air that can be exhaled beyond a tidal expiration

residual volume (RV)

volume of air remaining in lungs after a maximal exhalation

smoking

irritates mucous covering the epithelium of respiratory system, destroys macrophages; causes lung cancer; not spongy lungs

common cold

caused by a virus that enters the cells of the upper respiratory tract; spreads by mucous droplets; nasal stuffiness, scratchy throat, headache, sneezing, and coughing; usually occurs in winter because people are confined and in close contact

pneumonia

can be bacterial or viral; fluid builds up in the alveoli

bronchitis

can be bacterial or viral; acute - usually bacterial, responds to antibiotics; heavy mucous discharge, persistent cough; chronic - caused by infection of environment

asthma

compromised airflow during “attacks” sue to inflammation, mucous secretion, and bronchoconstriction; wheezing, shortness of breath; caused by exercise or allergens

emphysema

disease characterized by the alveoli becoming brittle and eventually rupturing

pulmonary fibrosis

contaminants are inhaled; caused by asbestos, silica, coal dust; causes cells in the lungs to form fibrous CT, making the lungs less elastic and less efficient