Chapter 23: The Respiratory System Flashcards
What is the major function of the respiratory system?
to supply the body with O2 and get rid of CO2
What are the 2 division of the respiratory system?
- The conducting portion -include everything from the nostrils to bronchioles (it is the pathway that conducts air)
- The respiratory portion - include alveoli for gas exchange
How many lobes are in each lung?
Right lung - 3 lobes
Left lung - 2 lobes
(Right lung bigger since it is closer to the heart)
What makes up the respiratory zone?
- Bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli
What makes up the respiratory membrane? What makes this membrane significant?
- type 1 alveolar cells
- basement membrane
- endothelial cells of pulmonary capillaries
The respiratory membrane is the site of gas exchange
What is the difference between type 1 and type 2 alveolar cells?
Type 1 - line the alveoli
Type 2 - secrete fluid to keep the surface of the alveoli moist. It also contains surfactant which helps decrease friction while lungs expand
What is respiratory distress syndrome?
A breathing disorder of premature newborns in which the alveoli do not remain open due to lack of surfactant.
What is chronic obstructive pulmonary disease?
A respiratory disorder involving a chronic obstruction of airflow
What is emphysema?
The destruction of the walls in the alveoli, causing abnormally large air spaces that remain filled with air during exhalation.
Causes less surface area for gas exchange
What is chronic bronchitis?
Excessive secretion of bronchial mucus, along with a bad cough.
Many mucus- making goblet cells may obstruct the airflow passage, and the thick mucus narrows the airway
What is asthma?
Chronic airway inflammation
Symptoms include coughing, wheezing, and general difficulty breathing
What are the 3 respiratory pressures?
- Atmospheric - pressure exerted by air on the surface of the body (≈760mmHg)
- Intrapleural - pressure within the pleural cavity (≈756mmHg)
- Alveolar - pressure within the alveoli
What is Boyle’s gas law?
States that: under constant temperature, the pressure exerted by a gas varies inversely with volume.
i.e. if volume increases pressure decreases (inhale), is volume decreases pressure increases (exhale)
What gases is air made of?
- Nitrogen (78.6%)
- Oxygen (20.9%)
- Carbon dioxide (0.04%)
Rest is other gases and water vapour
Define pulmonary ventilation
Gas exchange between atmospheric air and the alveoli of the lungs
Define external respiration
The gas exchange between alveoli and the blood of pulmonary capillaries
i.e. O2 moves from alveoli to blood, CO2 moves from blood to alveoli
Internal respiration
Involves gas exchange between the blood of capillaries and tissue cells
i.e. O2 moves from capillary to tissue, CO2 moves from tissue to capillary
Why is carbon monoxide (CO) so dangerous?
CO binds to hemoglobin just like O2 does, except the bind is 200x stronger than O2 so it is hard to unload it.
This reduces the oxygen carry capacity of hemoglobin and very little oxygen can be transported to tissues
How is oxygen transported in the body?
98% of oxygen is transported by binding to hemoglobin (heme portion)
2% is transported by dissolving in plasma
How is carbon dioxide transported in the body?
70% of CO2 is transported as bicarbonate ions
23% is transported by hemoglobin (globin portion)
7% is transported by dissolving in plasma
How can we sustain life 4-5 minutes after you stop breathing?
This is because hemoglobin only unloads about 25% of the O2 that it carries at a time, and is still saturated with 75% of the O2
What are the 2 respiratory centers in the brain?
- Medulla oblongata
a) dorsal respiratory group (DRG)
b) ventral respiratory group (VRG) - Pons
What is the dorsal respiratory group (DRG) responsible for?
The DRG is responsible for maintaining a basic breathing rhythm.
DRG will send impulses to stimulate the diaphragm to contract for inhalation, then the DRG will be inactive for exhalation
What is the ventral respiratory group (VRG) responsible for?
Forced breathing
