What are the 3 separate functions of respiration?
- ventilation
- gas exchange
- O2 utlilization
T/F. Ventilation is the same as breathing. O2 utilization is cellular respiration.
Both statements are true.
Gas exchange is between air and capillaries in the ___ and between systemic capillaries and tissues of the ___.
lungs; body
___ is the mechanical process that moves air in and out of the lungs. [O2] of air is ___ (lower/higher) in the lungs than in the blood. O2 diffuses from ___ to ___.
Ventilation; higher; air; blood
___ moves from the blood to the air by diffusing down its concentration gradient.
CO2
T/F. Gas exchanges occurs entirely by diffusion.
True
Which alveolar cells are structural and which secrete surfactant?
type 1 - structural
type 2 - secrete surfactant
Which zone is a region of gas exchange between air and blood that includes respiratory bronchioles, alveolar sacs and must contain alveoli?
respiratory zone
Describe the conducting zone.
All the structures air passes through before reaching the respiratory zone.
- Warms and humidifies inspired air.
- Filters and cleans:
Mucus secreted to trap particles in the inspired air.
Mucus moved by cilia to be expectorated.
T/F. Elasticity is distensibility (stretchability). or the ease with which the lungs can expand. It is reduced by factors that produce resistance to distension.
False, both statements refer to compliance
Elasticity is the tendency to return to initial size after distension.
___ ___ is the force exerted by fluid in alveoli to resist distension.
surface tension
H2O molecules at the surface are attracted to other H2O molecules by ___ forces.
attractive
the force is directed inward, raising the pressure in alveoli.
Law of Laplace states the pressure in alveoli is directly proportional to ___ ___ and inversely proportional to ___ of alveoli. Therefore, pressure in ____ (smaller/larger) alveoli is greater.
surface tension; radius; smaller
P= (2 x T) / r
How does surfactant lower surface tension?
reduces attractive forces of hydrogen bonding by becoming interspersed between H2O molecules
T/F. As alveoli radius decreases, surfactant’s ability to lower surface tension increases.
True
___ law states that changes in intrapulmonary pressure occur as a result of changes in lung volume.
Boyle’s
pressure of gas is inversely proportional to its volume.
Which way does air flow?
- Increase in lung volume decreases intrapulmonary pressure.
- decrease in lung volume, raises intrapulmonary pressure above atmosphere.
- air goes in
2. air goes out
What is the intra-alveolar pressure (pressure in the alveoli)?
intrapulmonary pressure
T/F. Intrapleural pressure is postive due to lack of air in the intrapleural space.
False, pressure is NEGATIVE.
What is the pressure difference across the wall of the lung?
transpulmonary pressure
What pressure is the intrapulmonary pressure - intrapleural pressure?
transpulmonary pressure.
it keeps the lungs against the chest wall.
Describe the active process of quiet inspiration.
Contraction of diaphragm, increases thoracic volume vertically.
Contraction of parasternal and internal intercostals, increases thoracic volume laterally.
Increase in lung volume decreases pressure in alveoli, and air rushes in.
Match the pressure changes during INSPIRATION.
- alveolar
- intrapleural
- transpulmonary
A. = +3 mm Hg
B. -4 to -6 mm Hg
C. 0 to -3 mm Hg
- C
- B
- A
Match the pressure changes during EXPIRATION.
- alveolar
- intrapleural
- transpulmonary
A. = -3 to +3 mm Hg
B. +6 mm Hg
C. -6 to -3 mm Hg
- A
- C
- B
T/F. Quiet expiration is a passive process.
True
What is the atmospheric and intrapulmonary pressures at rest?
760 mm Hg
The ___ ___ space is when not all of the inspired aire reached the alveoli. Fresh air is inhaled and mixed with air this space.
Anatomic dead space
conducting zone and alveoli where [O2] is lower than normal and [CO2] is higher than normal.
F x (TV-DS) =
alveolar ventilation
F= frequency (breaths/min) TV = tidal volume DS = dead space
What are the two disorders of COPD?
asthma and emphysema
What disorder has a normal structure of lungs disrupted by accumulation of fibrous connective tissue proteins?
pulmonary fibrosis
P(ATM) = P(N2) + P(02) + P(C02) + P(H20)= ??? mm Hg.
760
O2 is humidified to ??? mm Hg?
105
H2O (water vapor pressure) contributes to partial pressure ???
47 mm Hg
What is the PO2 at sea level?
150 mm Hg
What is the PCO2?
40 mm Hg
What is the normal PO2 in arterial blood and systemic veins?
arterial blood = 100mm Hg
systemic veins = 40 mm Hg
What is the PCO2 in systemic veins?
46 mm Hg
T/F. The rate of blood flow through the pulmonary circulation is equal to the flow rate through the systemic circulation.
True.
The driving pressure is about 10 mm Hg
T/F. The pulmonary vascular resistance is high.
False, it is low. Low pressure pathway produces less net filtration than produced in the systemic capillaries.
What constricts when alveolar PO2 decreases? What is this called?
pulmonary arterioles
autoregulation
T/F. Alveoli at the apex are underventilated (overperfused).
False,
Alveoli at apex are underperfused (overventilated).
Alveoli at the base are underventilated (overperfused).
___ neurons located primarily in dorsal respiratory group (DRG) regulate activity of phrenic nerve.
___ neurons located in ventral respiratory group (VRG) passive process.
Activity of ___ neurons inhibit ___ neurons.
I; E; E; I
Medullary rhythmicity center influenced by ___. ___ center promotes inspiration by stimulating the I neurons in the medulla. ___ center antagonizes the apneustic center and inhibits inspiration.
pons; Apneustic; Pneumotaxic
T/F. Chemoreceptors monitor changes in blood PC02, P02, and pH.
True.
Which receptors are more sensitive to changes in arterial PCO2?
central chemoreceptors
T/F. H+ can cross the blood brain barrier.
False, it cannot cross the BBB.
___ can cross the BBB and will form H2CO3, which lowers the ___ of CSF and directly stimulates ___ chemoreceptors.
CO2; pH; central
Which chemoreceptors are not stimulated directly by changes in arterial PCO2?
peripheral chemoreceptors
They are stimulated by rise in [H+] of arterial blood.
This lacks electrons and cannot bind with O2.
methemoglobin
Its bond with carbon dioxide is 210 times stronger than the bond with oxygen, thereby impairing the transport of O2.
carboxyhemoglobin
What does the loading and unloading of hemoglobin depend on?
- PO2 of environment
2. affinity between hemoglobin and O2
What conditions cause a shift of the oxyhemoglobin dissociation curve to the right?
Decreased pH, increased temperature, and increased 2,3 DPG:
Affinity of hemoglobin for 02 decreases.
Greater unloading of 02
What 3 ways is CO2 transported in the blood?
- HCO3- (70%)
- Dissolved CO2 (10%)
- Cabaminohemoglobin (20%)