respiratory quiz #2 Flashcards
what does Dalton’s law of pressure state?
- that each gas in a mixture exerts its own pressure (called partial pressure)
- each gas diffuses independently of each other, moving from areas of high partial pressure to low partial pressure
what is the atmospheric composition of gases?
- 78% nitrogen
- 21% oxygen
- 0.03% carbon dioxide
where does external respiration occur?
in the lungs
what happens in external respiration?
- oxygen moves from alveoli to lung capillaries, carbon
- dioxide moves from capillaries to alveoli
why does oxygen diffuse from the alveoli to the capillaries?
because blood has a lower partial pressure
how much of oxygen is dissolved in plasma as a gas?
1%
how much of oxygen is carried in RBCs by hemoglobin?
99%
what is formed when hemoglobin picks up oxygen?
oxyhemoglobin
how much oxygen does the blood hold per 100mL of blood?
20mL/100mL
what is internal respiration?
gases exchanged between the blood in the capillaries and the surrounding tissues/cells
where does hemoglobin pick up oxygen?
in the lung capillaries
what happens as oxyhemoglobin circulates the body?
when is passes a tissue requiring oxygen, the oxygen will fall of the hemoglobin and will diffuse into the tissue
what happens if a tissue doesn’t need oxygen?
the hemoglobin will not drop the oxygen off
on average, how many hemoglobin still have their oxygens when heading back to the lungs?
~ 70%
in what direction does oxygen move during cell respiration?
from the lung capillaries to the red blood cells
in what direction does carbon dioxide move during cell respiration?
from cells to lung capillaries
through what process does cell respiration occur and why?
occurs through diffusion due to the partial pressures change
when will CO2 move from the tissues to the blood?
when there is a build up of CO2 in the tissue from cell respiration, the CO2 will move out of the tissue to the blood where there is a lower partial pressure
is oxygen soluble in blood?
no
is carbon dioxide soluble in blood?
yes
what are the three forms that CO2 can be transported as?
- carried by hemoglobin (carbaminohemoglobin) to the lungs
- carried in the plasma as a gas
- combines with water in the blood plasma to form carbonic acid (CO2 + H2O –> H2CO3)
how much CO2 is carried by hemoglobin?
~23%
how much CO2 is carried in the plasma as gas?
~7%
how much CO2 combines with water in the plasma to form carbonic acid?
~70%
what is the formula of the formation of carbonic acid?
CO2 + H2O –> H2CO3
how is CO2 forming carbonic acid beneficial?
it reduces the concentration of free CO2 in the blood, allowing diffusion to continue
how is H2CO3 broken down?
it breaks down into HCO3 and H+
how is H+ carried back to the lungs?
it binds to hemoglobin
how is HCO3 carried back to the lungs?
blood carries it back to the lungs
what happens when waste products reach the lungs?
the H+ is replaced by oxygen on the hemoglobin, the H+ reconnects with HCO3 to form H2CO3 which then breaks into CO2 and H2O in the alveoli and gets exhaled
what are chemoreceptors?
sensory receptors that detect chemical stimuli in the environment
what chemical stimuli do chemoreceptors detect?
oxygen and carbon dioxide
what happens when abnormal levels of O2 or CO2 are detected?
our breathing will either speed up or slow down
is breathing voluntary or involuntary?
involuntary
what 2 ways to do we regulate breathing?
- blood acidity
2. chemoreceptors
what is blood acidity caused by?
high blood acidity is caused by excess CO2
what happens when there is high acidity in our blood?
chemoreceptors stimulate a nerve in the brain to increase breathing which then expels more CO2
what happens when there is low acidity in our blood?
the chemoreceptors in the carotid artery will detect low levels of oxygen and send impulse to the brain, which increases breathing to get more oxygen in
