respiration 4 Flashcards
Rhythmical breathing is controlled by ___________
skeletal muscles
what does inspiration require?
inspiration requires action potentials in motor neurons
expiration occurs due to what? (think muscles)
due to cessation of motor neuron activity and lung recoil
rhythmic contraction of the breathing muscles is controlled by what?
controlled by pacemaker neurons
how can the pacemaker neurons for respiration be modulated
- activity of pulmonary stretch receptors
- drugs
- partial pressures of respiratory gases and [H+]
- peripheral chemoreceptors being stimulated
- central chemoreceptors being stimulated
what stimulates peripheral chemoreceptor for respiration?
stimulated by:
↑ [H+]
or ↓ PO2
what stimulates central chemoreceptors for respiration?
↑ [H+] in extracellular fluid in brain
ventilation rate increases below PO2 of about ____ mm Hg
60
at PO2 = 60, Hb is ___% saturated
90%
ventilation rate is much more sensitive to ______ than to PO2
PCO2
rate increases above PCO2 of about _____ mm Hg
40
anemia does not change ventilation….why not?
Hb content is reduced, but PO2 is normal
carbon monoxide poisoning does not change ventilation…why not?
HbO2 is reduced, but PO2 is normal
_____ poisoning symptoms depend on level of toxicity
CO2
Ventilation rate can be modified by what non-respiratory sources of H+?
metabolic acidosis, e.g. excess lactic acid
metabolic alkalosis, e.g. severe vomiting
T/F: during exercise, arterial O2 decreases, but not venous
FALSE
venous O2 decreases, but not arterial
with severe exercise, arterial PCO2 will ________
decreases
hypoxia is a deficiency of O2 at the ___________
tissue level
________ hypoxia is caused by blood flow to tissues being too low
Ischemic
what causes Histotoxic hypoxia?
cells being unable to utilize O2
what are the causes of hypoxia?
1) Hypoventilation
2) Diffusion impairment
3) Shunt
4) Ventilation-perfusion inequality (COPD)
what are the immediate effects of altitude hypoxia?
stimulate ventilation & increase anaerobic glycolysis
what are the delayed responses for altitude hypoxia?
- increase RBC synthesis
- increase 2,3 DPG synthesis
- increase synthesis of other components of O2 delivery and consumption
___________ is used by athletes to artificially increase RBC count
Erythropoietin
