5D- Gas Transport and Oxyhemoglobin Saturation Curve/ internal and external respiration

percentage wise- how does oxygen move through the blood

• dissolved in plasma- 1.5%

• hemoglobin (HbO2)- 98.5%

how is hemoglobin saturated

• there are 4 binding sites- with competition for them

• saturation level is an indicated of whether a binding site is occupied with oxygen

  • ex. 1 site bound = 25% saturation

what controls the level of saturation

• pO2

  • proportional to pO2

  • as pO2 increases so does saturation - and vice versa

which gases compete for Hb binding sites - and what determines if they get them

• CO2

• CO

  • exception to the rule, binds even if it is not most present

• H+

• O2

• whichever is most present is typically what wins the binding site

what is the typical O2 and Hb content in the blood

• 1 g Hb= 1.34 mL O2

• 15g Hb / 100mL blood

• 20 mL O2 / 100mL blood

how much O2 is typically in 100mL of arterial/venous blood- and what is the a-vO2 difference AT REST

• arterial

  • 20mL O2 / 100mL blood

• venous

  • 15mL O2 / 100mL blood

• a-vO2 difference

  • 5mL O2 / 100mL blood

what what pO2 does the blood become fully saturated

• 60mm Hg

• is why people are okay even at high altitudes or if they are sick

at what pO2s are large amounts of O2 released to areas of need

• between 40 and 20mm Hg

• like contracting muscles

• area where a small pO2 change makes a big difference on sat

what is the effect of pH on the oxygen-hemoglobin dissociation curve

• lowered blood pH = more acidic = more H+ ions

• this causes the curve to shift to the right and saturation to decrease

  • this is due to the increased concentration of H+ kicking some of the O2 out of the Hb binding sites

• this frees up some O2 to be dropped off at tissues in need

  • which is why this commonly happens during exercise

• opposite pH change will have opposite effect (shift curve to the left)

what effect does temperature have on the oxygen-hemoglobin dissociation curve

• increased temp = increased metabolic activity - shifting the curve to the right

• this increases the concentration of H+ ions

  • decreases saturation due to H+ kicking O2 out of binding sites

• frees up O2 to go to needed tissues

  • why we heat up during exercise

• lower temp has opposite effect- shifts curve left

percentage wise- how does CO2 travel through the body

• dissolved in plasma- 7%

• on RBC forming carbaminohemoglobin = 23%

• bicarbonate ions (HCO3) = 70%

what is the formula for bicarbonate ions (HCO3)

CO2+H2O ←→ H2CO3 ←→ HCO3+H

• Moves right when theres lots of CO2

• Moves left when theres lots of H+

what is carbaminohemoglobin

• Hb + CO2 ←→ Hb-CO2

• amount CO2 transported depends on percent saturation of Hb with O2

• Haldane effect

what is the Haldane effect

lower Hb-O2 = greater CO2 carrying capacity

why is carbon monoxide so dangerous and what is the treatment

• binds to Hb heme group more successfully than O2

• treated by administering pure O2 to kick some CO off of the binding sites

how does pCO2 and oxygen release effect the oxygen-hemoglobin dissociation curve

• increased pCO2 = increased O2 released = shift to the right

• happens during exercise

• decreases sat as the pCO2 increases CO2 takes over some of the Hb binding sites

  • this kicks off some of the oxygen, freeing it to be released

what things increase O2 dissociation

• decreased pH

• increased pCO2

• increased temp

what are the purposes of the respiratory system

• gas exchange

• regulation of blood pH, sensory receptors, air filtration, and vocal sounds

what are the key processes of the respiratory system

• pulmonary ventilation

  • movement of air in and out of lungs

• alveolar (external) respiration

  • movement of gases from the lungs to the blood

• tissue (internal) respiration

  • movement of gases from the blood to the tissue cells (diffusion)

what are the two divisions of the lung

• conducting zone

  • branches 0-16

  • moves, filters, warms, and humidifies air

• respiratory zone

  • branches 17-23

  • gas exchange

  • site of respiration

  • 8,388,608 air way segments

  • 300 million alveoli

which zone of the lung has more space devoted to it and why

the respiratory zone because it allows more space for gas exchange to happen

what are the different gas laws

• volume is inverse to temp

• volume is 1/pressure (boyles law)

• gases move from high to low pressure

how do we use pressure to move air into the and out of the lungs

to move air in we increase the volume of our lungs, which drops pressure and allows air in. we do the opposite to move air out

how do how do we breathe at rest

• a change in pressure gradient

• inspiration

  • active process

  • diaphragm contracts to increase lung volume

  • decrease alveolar pressure to 758 to allow air in

  • thorax volume increases

• expiration

  • passive process

  • diaphragm relaxes to decrease lung volume

  • increases alveolar pressure to 762 go force air out

• 500ml of air moves with each breath (TV) (normal sized adult)

what is labored breathing

• TV increases to 2-3L

• forced expiration

  • abdominal muscles force diaphragm up

  • internal intercostals depress ribs

• forced inspiration

  • sternocleidomastoid, scalenes, and pectoralis minor lift chest upwards as you gasp for air increase volume

what are the typical values for minute ventilation

• VE= 6 L/min

• TV= 500 mL/br

• fB= 12 br/min

what is the dead space

• conducting airways (no respiration)

  • does not take part in gas exchange

  • equal to your weight in pounds

what is alveolar ventilation

• volume of air per minute that reaches to alveoli and respiratory areas

  • takes part in gas exchange

  • 4.2 L/min for 150lb person

what does a spirometry test do

assess lung volumes

what is the inspiratory reserve and its typical value

• how much air can you bring in above your normal breath

• 3.1L

what is expiratory reserve volume and what is its typical value

• how much air you can breath out below your normal breath

• 1.2L

what is your residual volume and what is its normal value

• how much air is left behind in your lungs after your expiratory reserve

• keeps your lungs inflated

• is estimate, we cannot actually measure

• 1.2 L