chapter 22 Flashcards
Respiratory system
What are the 4 processes involved in respiration
- pulmonary ventilation
- external respiration
- gas transport
- internal respiration
What does the respiratory system and circulatory system do
Together they carry out four processes that supply the body with oxygen and rid the body of carbon dioxide
Describe Dalton’s law of partial pressure
- Total pressure exerted by a mixture of gases is the some of the pressure exerted by each gas
- partial pressure of each gas is directly proportional to its percentage in the mixture
Describe Henry’s law for gas exchange
- when a mixture of gases is in contact with a liquid each gas will dissolve in the liquid in proportion to its partial pressure
- the amount of gas that will dissolve in a liquid also depends upon its solubility. (i.e. CO2 is 20x more soluble than O2 when in water)
What does a spirometer do
It measures respiratory volumes and capacities
Describe lung compliance (EXAM)
It’s the ability of the lung to respond to changes in transpulmonary pressure
- the higher the compliance unless the effort needed to breathe
- it’s normally high because of distensibility of the lung tissue and surface tension within the pleural cavity
- lung compliance can be diminished by nonelastic scar tissue, reduced production of surfactant, decreased flexibility of the thoracic cage, or blockage of smaller respiratory passages
Describe respiratory volumes and total lung capacity
- Tidal Volume (TV) - average air moved in/out in single breathe (500mL)
- Inspiratory reserve volume (IRV) - the maximum amount that can be inhaled in addition to TV. (~2400mL)
- Expiratory reserve volume (ERV) - the maximum amount that can be forcefully expired out after TV. (~1000mL)
- Residual Volume (RV) - Volume left in the lungs after a forceful expiration (which prevents collapse of airways and lungs) (~1100mL)
TOTAL LUNG CAPACITY(TLC) = TV + IRV + ERV + RV = 5000mL
VITAL LUNG CAPACITY(VLC) - volume moved in/out with as deep a breath as possible = TV + IRV + ERV = ~80%TLC or 4000mL
Describe external respiration
- between the inhaled air and the blood in the alveoli
- o2 and CO2 are exchanged across the respiratory membrane by simple diffusion
- direction of diffusion depends on the partial pressure, or concentration, gradients of the gases
- there must be equal ventilation perfusion coupling. The amount of gas reaching the alveoli must equal the amount of blood reaching the Alveoli
Describe ventilation perfusion coupling
- the amount of gas reaching the alveoli must equal the amount of blood reaching the Alveoli
- Changes in Po2 in the alveoli cause diameter of arterioles to change. o2 high = dilate, to increase blood flow
- changes is Pco2 in the alveoli cause the diameters of the bronchioles to change. high co2 = dilate, increases air flow
Describe internal respiration
- gas exchange in body tissues between blood and tissue cells
- partial pressures and diffusion gradients are reversed compared to external respiration
- oxygen is normally used at the same rate that CO2 is produced
Describe the influence of Po2 on hemoglobin saturation
- binding and releasing of o2 is influenced by the Po2 of the blood
- Hemoglobin hangs onto oxygen in areas where the oxygen concentration is high and releases it where oxygen concentrations are very low. This ensures that all tissues get enough oxygen and this a large VENOUS RESERVE that can be used if needed. blood leaving tissue is STILL 75% saturated with o2
Describe the four homeo static imbalances of oxygen transport: HYPOXIA - shortage of o2 to tissues leads to cyanosis
- anemic hypoxia is insufficient red blood cells
- Ischemic hypoxia, is blocked blood supply to tissues
- histotoxic hypoxia, cells cannot utilize oxygen (i.e. cyanide)
- Hypoxemic oxygen is not getting to RBC’s (CO poisoning)
List the three forms in which CO2 is transported in the blood
- 7-10% dissolved in the plasma
- 20% bound to glob in of the Hb as carbaminohemoglobin
- 70% is carried as bicarbonate ion (HCO-) in plasma
Compare contrast the Bohr effect and Haldane effect
As carbon dioxide enters the bloodstream it causes more oxygen to disassociate from hemoglobin (Bohr effect), which in turn allows more carbon dioxide to combine with hemoglobin and more bicarbonate ions to be formed (haldane effect)
describe the influence of CO2 on blood pH
HCO3 bicarbonate in plasma is the alkaline reserve of the carbonic acid-bicarbonate buffer system. Essentially, if pH changes the H+ is either removed by combining with the HCO3 (if + H+) OR (if - H+) drops then H2CO3 dissociates releasing H+, which returns pH to normal levels.
name the blood circuit that delivers o2 to the lungs tissues themselves
bronchial circuit
alveolar cells that produce surfactant
Type II - cuboidal cells
alveolar cells that perform gas exchange
Type I - squamous
filling and emptying of the lungs is called this
ventilation
process by which gases move from the alveolar air into the blood
simple diffusion
what do you call a lung collapse caused by injury to the chest
Pneumothorax, which leads to Atelectasis (lung collapse)
irritants entering this area trigger sneezing
nasal cavity
the cavity in the left lung that accommodates the heart
cardiac notch
name given to the amount of air moved in and out of the lungs during quiet breathing
tidal volume
