ch.22 part. 2 Flashcards
minute ventilation
total air moved into and out of respiratory system each minute, tidal volume x respiratory rate
dead air
cannot exchange gases
alveolar ventilation rate
air that actually ventilates alveoli x respiratory rate
tidal volumes
air inhaled or exhaled in one quiet breath
500 ml
expiratory reserve volume
air in excess of tidal respiration that can be exhaled w/ max effort
inspiratory reserve volume
air in excess of tidal inspiration that can be inhaled w/ max effort
residual volume
air remaining in lungs after max. expiration
cannot measure w/ spirometer bc we can’t breathe it out
vital capacity
total amount of useable air
breathe in all you can and breathe out all you can
inspiratory capacity
max. amount of air that can be inhaled after a normal tidal expiration
functional residual capacity
amount of air in the lungs after a normal tidal expiration
total lung capacity
max. amount of air lungs can contain
What is the composition of air?
78.6 % of nitrogen
21% of oxygen
What factors affect gas exchange?
concentration gradients of gases
gas solubility
membrane thickness
membrane surface area
oxyhemoglobin disassociation curve
relationship between percent hemoglobin saturation and percent of oxygen is not linear
What is the normal tissue PO2?
40
What is the normal alveolar PO2?
100
How does ambient PO2 adjust to metabolic needs?
active tissue has less PO2, more O2 is released
how does temp. adjust to metabolic needs?
active tissue has increased temp, more O2 is released
how does pH and CO2 adjust to metabolic needs?
active tissue has increased CO2, which raises H+ and lowers pH and more O2 is released (Bohr effect)
How does biphosphoglycerate adjust to metabolic needs?
increases body temp
In what 3 ways is CO2 transported?
bicarbonate (90%)
carbaminohemoglobin (5%)
dissolved gas (5%)
systemic gas exchange
occurs in the capillary networks of the tissues
- CO2 loads into the blood and O2 unloads into the tissues
What is the role of hemoglobin in the systemic gas exchange?
buffer
carbonic anhydrase
located in the RBCs and catatlyzes systemic gas exchange reactions
alveolar gas exchange
movement of oxygen and CO2 across the respiratory membrane
- CO2 unloads and O2 loads
What occurs as hemoglobin loads O2 in alveolar gas exchange?
its affinity for H+ decreases and binds with HCO3-
chloride shift
keeps the systemic gas reaction proceeding and exchanges HCO3- for CL-
reverse chloride shift
HCO3- diffuses back into RBC for exchange for Cl-
dorsal group
integrates input from chemoreceptors and peripheral stretch
ventral group
rhythm generating and integrative center
apnea
cessation of breathing
hyperventilation
causes a decreases in blood PCO2 level,
What is the most powerful respiratory stimulus?
pH of the CSF
What are the peripheral chemoreceptors?
aortic and carotid bodies
What are the central chemoreceptors?
in the medulla oblongata and monitor the pH of CSF
respiratory acidosis
pH is less than 7.35, caused by a failure of pulmonary ventilation
How do you correct acidosis?
hyperventilate which causes hypocapnia
hypercapnia
PCO2 is greater than 43mmHg
alkalosis
pH is greater than 7.45(basic)
How do you correct alkalosis?
hypoventilate which causes hypercapnia
hypoventilation
causes an increase in blood PCO2 level
What is the normal systemic arterial blood gas value for PO2?
95mmHg
What is the normal systemic arterial blood value for PCO2?
40mmHg
