Flashcards in Chapter 15: Lung Structure and Function Deck (25):
Largest of the tubes that conduct air into and out of the lungs.
3) Terminal bronchioles
4) Respiratory bronchioles
What are the smallest bronchioles?
Small air sacs where O2 and CO2 exchange between the air
and pulmonary capillaries.
What two types of alveolar pneumocytes line alveoli?
1) Flat squamous cells
2) Larger secretory cells that produce surfactant
What secretion is produced by secretory cells in the alveoli?
Larger segments of the lungs
Smaller units (than lobes) of lungs
How many lung lobes are there?
5 (2 on L, 3 on R)
Structures deriving from a single terminal bronchiole.
A small group of terminal bronchioles and the respiratory units arising from them.
True or false: Alveoli contain macrophages that remove inhaled materials.
True; removes dust, pollen, etc.
What lines the respiratory passages?
Functional unit of the lung; formed by a cluster of respiratory bronchioles, alveolar ducts and sacs, and alveoli all derived from a single terminal bronchiole
What are the 2 functions of the respiratory system?
2) Gas exchange
What causes respiration?
Bellows action of ribs and diaphragm (lungs change in volume in response to changes in size of the thoracic cage
During inhalation, what happens to the ribs and diaphragm?
1) Diaphragm descends
2) Ribs more horizontal
What happens to the ribs and diaphragm during exhalation?
1) Diaphragm rises
2) Ribs more vertical
What causes gas diffusion between blood, tissues, and alveoli?
Differences in partial pressures
The part of total atmospheric pressure exerted by a gas
What are the requirements for efficient gas exchange?
1) Large capillary surface area in contact with alveolar membrane
2) Unimpeded diffusion across alveolar membrane
3) Normal pulmonary blood flow
4) Normal pulmonary alveoli
What condition can impede efficient gas exchange from the alveoli to the blood by decreasing the capillary surface areas in contact with alveolar membranes?
Emphysema (it destroys septa, making large alveoli with less capillary surface for diffusion
What conditions can impede diffusion across alveolar membranes?
1) fibrosis (septa thickened and scarred)
2) ARDS (thickened alveolar membrane)
3) PNA (alveoli filed with fluid and inflammatory exudate, so less air enters)
What conditions can impede normal pulmonary blood flow?
Pulmonary embolism (blocking large pulmonary artery or fat/foreign material blocking capillary network)