D9-D10 Flashcards
What side of the heart pumps blood to the lungs?
Right side
The absorption of oxygen and the removal or co2 from the body as a whole
External respiration
The utilization of oxygen and production of co2 by cells and the gaseous exchange between the cells and their fluid medium
Internal respiration
The pressure exerted by one gas in a mixture of gases
partial pressure
How much oxygen is in the air at sea level?
20.98%
How much CO2 is in the air at sea level?
0.04%
How much Nitrogen is in the air at sea level?
78.06%
How much much pressure of CO2 is in the body?
about 40-45 mmHG
From the trachea to the alveoli, how many times do the airways divide?
23 times
How many generations of tubes form in the conducting zone?
16
The last 7 generations of tubes form where?
respiratory zone
What is the purpose of multiple divisions?
increases total cross-sectional area of airways
Which type of cells secrete surfactants?
Type II cells
Why is ventilation regulated?
to maintain concentration of CO2 (not O2)
What is the driving force for moving gases by diffusion?
Partial pressure
What do we convert the air to before it gets to the alveoli when we breathe?
BTPS (body temp pressure and saturation conditions)
2 zones for air movement
conducting, respiratory
What is airflow in the conducting zone governed by?
same laws as hemodynamics (poisuille’s law)
What will happen to the velocity of air flow when the cross sectional area increases?
velocity decreases
Where is the cross sectional area total high and the velocity low?
Respiratory zone
What do the trachea and bronchi have in their walls?
cartilage
What controls the size of the airways in the walls of the bronchioles?
smooth muscle
What receptors do the bronchial epithelium and smooth muscle contain?
b2-arenergic receptors
4 things that control pulmonary diameters?
- acetylcholine
- norepinephrine
- histamine
- CO2 levels
How does acetylcholine control pulmonary diameters?
cause contraction of the bronchial smooth muscle
How does norepinephrine control pulmonary diameters?
binds to b2 receptors and relaxes the bronchial muscle
How does histamine control pulmonary diameters?
can cause contraction of bronchial smooth muscle (sneezing, runny nose)
How does CO2 levels influence airway diameters?
Decreased CO2-constriction
Increased CO2-relaxation
What can be removed by macrophages that get to the alveoli?
small particles
What makes the lungs want to compress into a smaller structure?
elastic components
What keeps the lungs expanded and next to the thoracic cage and diaphragm
The pressure in the pleural cavity (pleura is tissue that surrounds the lungs)
What keeps the lungs expanded?
pressure in the pleural cavity is slightly less than atm pressure
What does increasing the volume in the lungs do to pressure in the lungs?
reduces the pressure
What helps with increasing the thoracic volume?
muscles of the neck
What plays the biggest role in moving air out rapidly?
abdominal muscle
What sends signals to the brain to contract the diaphragm?
phrenic nerve (C3-C5)
Do we want alveolar surface tension high or low?
low
What does the level of surface tension do?
- keep the alveoli from collapsing
- improves compliance (elasticity) of the lungs
When does surfactant develop in humans?
right when you’re born
Why are surfactants important?
keeps them from collapsing
What is the oxygen concentrations in the alveoli (inspired)?
158 mmHG
What is the typical oxygen concentration in the alveoli?
100 mmHG
Where are the gas concentrations different in the ventricles?
capillary beds of the lungs or tissues
What is effectiveness of ventilation determined by?
- tidal volume
- dead space
- frequency of breaths
How much O2 is in the blood?
1050 ml
How much O2 is used per min at rest?
250 ml
How much CO2 is eliminated per min?
200 ml
What dictates the amount of oxygen the hemoglobin can hold?
partial pressure of O2 in the plasma
What are 3 factors that affect the affinity of hemoglobin for oxygen?
1, the ph
2. the temp
3. BPG (2,3-biphosphoglycerate)
What does higher concentrations of BPG mean?
more oxygen is released for any PO2 level
3 forms CO2 is carried in the blood
- dissolved
- bound to amino acids (on hemoglobin)
- converted to carbonic acid by carbonic anhydrase and then converted to the bicarbonate ion and hydrogen ion
