Respiratory System Flashcards
What is the difference between external and internal respiration?
External: O2 and CO2 exchange between lungs and atmosphere, alveoli and blood, blood transport, and between blood and cells
Internal: O2 utilization by mitochondria to regenerate ATP and form CO2
What are the primary functions of the respiratory system?
- Respiration
- Homeostatic regulation of body pH
- Defence against microbes
- Modifies arterial concentration of chemical messengers
- Vocalization
- Sense of smell
What is the pleural sac?
double layered serous membrane that surrounds the heart. includes inner visceral pleura and outer parietal pleura with thin layer of fluid to hold the layers together and lubricate them.
What is the difference between the inner visceral pleura and the outer parietal pleura?
visceral: attached to lung by connective tissue
parietal: attatched to thoracic wall and diaphragm
How many generations of branches are there in the respiratory tract?
around 23 generations of branches, each one narrower, thinner and shorter than the last. Divided into conducting zone and respiratory zone.
What is the conducting zone?
Area of 150mL anatomical dead space where gases are warmed, humidified and transported down pressure gradients. (generation 1-16)
What is the bronchial wall made of?
Smooth muscle, elastic tissue and cartilage and lined by mucus-secreting, ciliated epithelium
What is the respiratory zone?
Area of respiratory tract that holds the post inspiration volume (3,000 mL) where gases move internally by bulk flow and diffusion. (generation 16-alveoli)
What is the structure of the respiratory zone?
Huge, thin surface area for gas exchange richly supplied with capillaries. Lacks cartilage and smooth muscle to allow less hindrance to diffusion, but has elastin fibers.
Why are macrophages in the respiratory zone?
Foreign matter entering the respiratory zone is engulfed and destroyed.
What are the pores of Kohn?
Small openings in the walls of the alveoli in the lungs. They are filled with fluid and connect adjacent alveoli to allow accessibility for exchange
What are alveoli shaped like?
- Polyhedral in shape, 0.25mm diameter.
- Composed of a single layer of flat type 1 cells and interspersed with cuboidal type II cells.
- Connected by elastin fibres
- Attached to capillaries via basement membrane.
What is the difference between type I and type II alveolar cells?
Type I: squamous, where most gas exchange occurs, on top of basement membrane
Type II: secrete surfactant, reabsorb Na+ and H2O
What is tidal volume?
volume of air that moves in and out of lungs per breath (500-4,600 mL)
what is inspiratory reserve volume?
maximal air volume that can be inspired FOLLOWING normal inspiration (3,000 mL)
what is expiratory reserve volume?
maximal amount of air that can be expired following a normal expiration (1,000 mL)
What is residual volume?
volume of air in the lungs following a maciximal expiration (1,200 mL)
What is vital capacity?
Maximal volume of air that can be exchanged per breath. Inspiratory reserve - expiratory reserve. (4,600 mL)
What is the difference between minute ventilation and alveolar ventilation?
Minute: volume of air inhaled/exhaled per minute = tidal volume x respiratory rate
Alveolar: volume of air that enters the alveoli per minute = (tidal volume - dead space) x respiratory rate
What is atmospheric pressure?
Pressure of the outside air (760mmHg at sea level)
What is intra-alveolar pressure (Palv)
Pressure within the alveoli (-1 to +1 mmHg at rest)
