Respiratory system Flashcards
What are the 7 functions of the respiratory system?
- provide oxygen
- eliminate C02
- Regulate blood pH
- Facilitate speech
- Provides microbial defense by means of epithelial secretions
- Activate and inactivate chemical messenger in blood
- Defend against blood clots (dissolve them in the narrow vessels of the lungs.
What are the 3 components of the respiratory system?
- lungs
- airways
- Mechanical aids (skeletal muslces)
What are the 3 regions of the Airways?
- Upper airway = structures outside of thoracic cavity (mouth/nose, pharynx, larynx, but not gas exchange occurs)
- Conducting zone = in thoracic cavity, but no gas exchange occurs here. (Trachea, primary bronchi, secondary bronchi, bronchioles and terminal bronchioles)
- Respiratory zone = structures where gas exchange takes place. (respiratory bronchioles, alveolar ducts and alveolar sacs)
What are the functions of the conducting zone?
- branching maintains airflow and lessens resistance to airflow
- Air is moistened and warmed
- Protects against microbes via goblet cells secretion and cilia that move mucus up towards pharynx where it can be swallowed.
________ is a disease that impairs the normal function of the conducting zone.
Cystic fibrosis = mutation in genetic code for Cl- channels reduces the amount of Na+ and Cl- secreted across the epithelium not the mucus = less water in mucus = mucus is thick and dry. *Infectious agents get trapped, but not expelled.
What are the functions of the respiratory zone?
- Bronchiolar smooth muscle regulate airflow.
- Alveoli well suited for optimizing gas exchange
- Microbial defense is provided by pulmonary macrophages
Describe the 3 cell types of the Alveoli…
Type 1 = epithelial; gas exchange surface
Type 2 = secret surfactant
Macrophages = immune cells
Alveolar sacs are around ___ in diameter.
0.5um
Distance between alveolar sacs is about ______.
0.2um
T or F, Respiratory gases are small, non-polar molecules that diffuse down a concentration gradient and diffuse easily through plasma membranes, yet less easily through body fluids.
True!
T or F, O2 and CO2 have the same diffusion rates.
False,they have different diffusion rates due to different solubilities. (Co2= 77 and O2 = 2.2)
What are the layers of the respiratory surface that gases must cross?
Air in alveolus –> across apical membrane of type 1 cell – through cytoplasm –> across the basal membrane of type 1 cell –> across basal lamina and underlying connective tissue –> across basal membrane of endothelial cell —-> through cytoplasm –> across apical membrane of endothelial cell —> into plasma!
Each lung is surrounded by a ______.
Pleural Sac
What are the 2 layers of the Pleural sac?
Parietal (outer) = pleura adheres to the underside of the thoracic wall and the top of the diaphragm.
Visceral (inner) pleura covers the outer surface of the lung.
*space between layers = intrapleural space filled with fluid that lubricates surfaces.
Is the Intrapleural space subject to pressure changes when thoracic cage expands or contracts?
Yes!
Airflow = ?
Airflow = Delta Pressure/Resistance
If P.alv is greater than P.atmosphere, what happens?
air flows out of lung (expiration)
If P.alv is less than P.atmosphere, what happens?
air flows into lung (inspiration)
What cause Alveolar pressure (P.alv) to change?
Changing of volume according to Boyle’s law. (P1 V1 = P2 V2)
What is atmospheric pressure?
760mm Hg at sea level = 1 atm
What 3 pressure readings relate to ventilation?
Intrapleural (P.ip) = pressure in the fluid of intraplerual space.
Alveolar (P.alv) = air pressure in the alveoli.
Transpulmonary (P.tp) = P.alv - P.ip
What are the activities of muscles during inspiration?
Diaphragm contracts –> lowers floor of cavity –> increases volume
external intercostals contract –> raise ribcage and increase volume.
What are the activities of Muscles during expiration?
diaphragm relaxes –> raises floor of cavity –> reduces volume
External intercostals relax –>lowers rib cage –> reduces volume
In between breaths, how does pressure change?
P.atm = 0 and P.alv = P.atm so no air is moving
During inspiration how does pressure change?
P.ip becomes more negative
P.tp increases so lung volume increase and air flows in until P.alv = P.atm
During expiration, how does pressure change?
P.ip becomes less negative
P.tp decreases so lung volume decreases and air flows out until P.alv = P.atm
What is a pneumothorax?
When plural sac gets punctured.
*Pressure difference no longer exists so lung collapses and chest wall will expand. (can happen to just one lung and other will remain inflated)
