Oxygen Carrying Oxygen Carrying CapacityCapacity

When oxygen diffuses into our blood it When oxygen diffuses into our blood it combines chemically with hemoglobincombines chemically with hemoglobin

Hemoglobin: (Hb)Hemoglobin: (Hb) a special globular protein with and a special globular protein with and

embedded heme component (iron) embedded heme component (iron) Found in red blood cellsFound in red blood cells When combined with OWhen combined with O22 it forms it forms

“oxyhemoglobin”“oxyhemoglobin” Each hemoglobin molecule carries 4 Each hemoglobin molecule carries 4

OO2 2 moleculesmolecules

At rest, under normal conditions:At rest, under normal conditions: 1 gram of Hb can hold 1.39 ml/g of 1 gram of Hb can hold 1.39 ml/g of

oxygenoxygen So in 100 ml of blood you can hold So in 100 ml of blood you can hold

15g/100ml X 1.39 ml/g of oxygen15g/100ml X 1.39 ml/g of oxygen

= 20.85 ml of oxygen/100 ml of blood= 20.85 ml of oxygen/100 ml of blood

The greater number of hemoglobin The greater number of hemoglobin you have, the greater amount of you have, the greater amount of oxygen you carryoxygen you carry

The amount of hemoglobin is a The amount of hemoglobin is a fixed fixed amountamount that varies little between that varies little between individualsindividuals

On average:On average: Adult males: 14-18 g/100 mlAdult males: 14-18 g/100 ml Adult women: 12-16 g/100 mlAdult women: 12-16 g/100 ml

During Exercise Your HB During Exercise Your HB concentration risesconcentration rises

But But hold on a second,hold on a second, you just said you just said Hb concentration was a fixed amount Hb concentration was a fixed amount

You have to ask yourself, You have to ask yourself, “ “ Hey self, how in the world, can we Hey self, how in the world, can we

add Hb to our blood during exercise?add Hb to our blood during exercise? I didn’t say we added HbI didn’t say we added Hb

I said the I said the concentration concentration rose.rose.

To understand this we must know To understand this we must know the composition of bloodthe composition of blood

Blood is made up of solids and liquidBlood is made up of solids and liquid The liquid portion of blood which The liquid portion of blood which

makes up about 55% of blood, is makes up about 55% of blood, is calledcalled PLASMA PLASMA

The solids in blood make up about The solids in blood make up about 45% of blood45% of blood

The solids are made up of Red Blood The solids are made up of Red Blood cells, White Blood cells and Plateletscells, White Blood cells and Platelets

How in the world can the How in the world can the concentration of Hb rise concentration of Hb rise

during exercise?during exercise?

During exercise some of the fluid During exercise some of the fluid portion of the blood shifts in the portion of the blood shifts in the muscle (causing it to swell)muscle (causing it to swell)

This leaves the same number of This leaves the same number of RBC’s in a lesser liquidRBC’s in a lesser liquid

Therefore a higher Therefore a higher CONCENTRATIONCONCENTRATION of Hb in the of Hb in the bloodblood

During exercise the Hb concentration During exercise the Hb concentration rises as high as 20.1 g/100 ml of bloodrises as high as 20.1 g/100 ml of blood

SoSo 20.1 X 1.39 ml/g20.1 X 1.39 ml/g

= 27.94 ml/g = 27.94 ml/g

(up from 20.85 ml at rest)(up from 20.85 ml at rest)

Not a huge growth but helps carry more Not a huge growth but helps carry more oxygenoxygen

HB SaturationHB Saturation

All the preceding information is only All the preceding information is only true if each Hb molecule hold 4 oxygen true if each Hb molecule hold 4 oxygen moleculesmolecules

OrOr

Is completely Is completely SATURATEDSATURATED with oxygen with oxygen

To find out if this is true use………..To find out if this is true use………..

THE OXYHEMOGLOBIN THE OXYHEMOGLOBIN DISASSOCIATION CURVEDISASSOCIATION CURVE

The curve relates Partial pressure of The curve relates Partial pressure of oxygen with the % saturation of oxygen with the % saturation of hemoglobin with oxygenhemoglobin with oxygen

At what POAt what PO2 2 is our HB 100% is our HB 100% saturated?saturated?

At 100mmHgAt 100mmHg Why is this an important number?Why is this an important number? When is our HB fully saturated?When is our HB fully saturated?

AllAll

The The

TimeTimeThe partial pressure in our alveoli is ALWAYS The partial pressure in our alveoli is ALWAYS

100mmHg100mmHg

When is the only time our When is the only time our Hb would not be full (fully Hb would not be full (fully

saturated)?saturated)? When the partial When the partial

pressure of oxygen pressure of oxygen is greater or less is greater or less than 100mm Hgthan 100mm Hg

At Altitude or At Altitude or under waterunder water

Our blood (or more specifically) our Our blood (or more specifically) our Hb is always full and cannot take Hb is always full and cannot take any moreany more

We do not “run out of oxygen” when We do not “run out of oxygen” when we exercisewe exercise

We are full and cannot carry any We are full and cannot carry any moremore

So…. What if we breath So…. What if we breath pure 100 % Oxygen, can pure 100 % Oxygen, can

carry more Ocarry more O22??NONOAccording to the Hb disassociation curve According to the Hb disassociation curve

at 100mmHg our Hb is 100% saturatedat 100mmHg our Hb is 100% saturated

(there are other minor benefits but NONE to (there are other minor benefits but NONE to oxygen carrying capacity) you will read oxygen carrying capacity) you will read about them in your text page 132about them in your text page 132

Make notes on the controversy over Make notes on the controversy over hyperbaric oxygen therapy and oxygen bars.hyperbaric oxygen therapy and oxygen bars.