chapter 37 Flashcards
Partial pressure of gasses
pressure exerted by a gas in a mixture of gases or a liquid
Exchange of gasses in the lungs
takes place between alveolar air and blood flowing through lung capillaries
- The oxygen pressure gradient between alveolar air and blood
- The total functional surface area of the respiratory membrane
- The respiratory minute volume(volume going to alveoli per minute)
- Alveolar ventilation
Four factors determine the amount of oxygen that diffuses into blood
Hemoglobin (Hb)
Composed of four polypeptide chains (two alpha chains, two beta chains), each with an iron-containing heme group
CO2 can bind to amino acids in the chains, and oxygen can bind to iron in the heme groups
Exchange of gasses in tissues takes place
between arterial blood flowing through tissue capillaries and cells
CO2 exchange between tissues and blood takes place
in the opposite direction from oxygen exchange
Bohr effect:
increased PCO2 decreases the affinity between oxygen and Hb
Haldane effect:
increased CO2 loading caused by a decrease in PO2
glycolysis
cytosol
CAC and ETS=
in the mitochondrion
Respiratory control centers:
the main integrators controlling the nerves that affect the inspiratory and expiratory muscles are located in the brainstem
Medullary rhythmicity center:
generates the basic rhythm of the respiratory cycle
Factors that influence breathing
sensors from the nervous system provide feedback to the medullary rhythmicity center
PCO2 acts on central chemoreceptors in the medulla—if it increases, the result is
faster breathing; if it decreases, the result is slower breathing
a decrease in blood pH stimulates peripheral chemoreceptors in the carotid and aortic bodies and
stimulates the central chemoreceptors
