O2 & CO2 Flashcards by sophia cordova

why does O2 & CO2 matter to dentistry?

Understanding the basic fundamentals of gas exchange in the lungs and tissue is the foundation for understanding sedation

Dental anesthesia in toxic doses can cause respiratory depression: toxicity is more common in children (they weigh less)

The process of metabolism requires oxygen and creates CO2, therefore all tissues need oxygen and all tissues need to expel CO2

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the respiratory system is composed of:

naso- oro- and laryngo-pharync, trachea, bronchi, bronchioles, and lungs

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breathing in and out movement of the diaphragm

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sinuses do what?

warm and humidify the air that we breath
trap pathogens from the air

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where are the sinuses?

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in dentistry, what procedures can interact with sinuses?

extractions/implants
root canals
dentures

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epiglottis prevents ____ and ____ from getting into the respiratory system (aspiration/chocking)

food and drink

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vocal cords are located…

right at the top of trachea (below epiglottis)

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epiglottis is ____ when swallowing

depressed

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intubation tube is placed…

in trachea past the epiglottis

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alveoli is where _____ ________ happens

gas exchange

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flow of O2 of respiratory system

breathe in O2
oral cavity
trachea
bronchi
bronchiole
alveolar sacs
crosses alveolar membrane and capillary membrane
blood

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blood is our _____ ____ to transport gasses for and from metabolism

freeway system

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O2 goes ___ the blood while CO2 comes ______ the blood at the lungs

O2 into blood
CO2 out of blood
*at lungs

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O2 goes ___ the blood while CO2 comes ______ the blood at the tissues

O2 out of blood
CO2 into blood
*at tissues

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what does each letter represent?

D: rate of diffusion
delta P: change in partial pressure
A: surface area
S: solubility constant
d: distance of diffusion
MW: molecular weight

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limiting factors of diffusion of O2

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CO2 is ____ soluble in blood than O2

*readily allows exchange at the tissues that need O2

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oxygen delivery is the product of ___ ____

cardiac output

carries through Hb on RBCs
each RBC has many Hb molecules

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Hb has __ subunits containing ___ with ferrous iron atom

Hb has 4 subunits containing heme with a ferrous iron atom

Hb is a protein

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Hb: iron can reversibly bind to ___

O2
always diatomic oxygen (O2 not O)

“oxygenation”

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diatomic oxygen

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As O2 binds, the affinity for the other 3 subunits to bind ____

increases

“cooperative binding”
each binding increases affinity for binding more
aka peer pressure

hemoglobin/oxygen dissociation curve

hemoglobin/oxygen dissociation curve: small changes in pO2 at the beginning results in _____ changes in SaO2

large

affinity of Hb: 3 factors that change

1. pH 2. temperature 3. concentration of 2,3 - diphosphoglycerate

affinity of Hb: shifting right will ____ affinity

decrease affinity right = decrease affinity = release

affinity of Hb: shifting left will ____ affinity

increase left = increase affinity = bind

_____ in metabolic demand will decrease O2 in the blood

increase demand = decrease O2 blood

Bohr Effect

drop in pH causes a decrease in affinity (shift right) - high levels of CO2 causes decreased pH therefore need O2 to be released

what is 2,3 - diphosphoglycerate?

product of glycolysis increases 2,3-bip and the curve shifts right

increased metabolic load gives off more ____ into the blood

CO2

Haldane Effect

deoxygenated blood has a higher capacity to bind CO2 ie: venous blood caries more CO2 than arterial blood

CO2 is about __ x more soluble than O2 in the blood

20x more soluble

Hb can bind __ CO2

4 *like O2

vasodilation = _____ perfusion

increased

if no blood is perfusing the alveoli, then...

no gas exchange occurs

high levels of CO2 in the blood _____ pH

decreases more H+ acidic

bicarbonate buffer system

CO2 is converted to carbonic acid from carbonic anhydrase in RBs

how can kidneys assist in buffering blood when there is too much CO2?

H+ excretion by kidneys CO2 is discharged into alveoli and expired

Bohr effect vs Haldane effect

Bohr: acidic blood and lowers the affinity Haldane: deoxy RBsC have increased affinity for CO2

ph of arterial blood is

7.4

hypoxia

O2 deficiency at the level of the tissues

causes of hypoxia

* Decreased PO2 of arterial blood * Decreased amount of Hb to carry oxygen (anemia) * Low blood flow to a tissue (cutting off circulation) * Toxic product not allowing O2 to do its job (CO poisoning)

hypoxia symptoms

the brain is affected first causing confusion, headache, impaired judgment loss of consciousness death

respiratory complications

fluid in alveoli inflammation in any part of the respiratory tract ----asthma: bacterial, fungal, viral infections spasms of the muscles ----asthma and bronchospasm COPD ----emphysema and chronic bronchitis

Who do we monitor oxygen levels in?

Ways to measure safe oxygen levels in your patients:

capnography: measuring levels of CO2 expired, not an exact measure for dentistry pulse oximeters: measuring levels of O2 in blood respiratory rate: Make sure your pt is breathing

respiratory rate b/m (infant to adult

sleep apnea

A serious breathing condition where breathing is irregular and will stop for a period of time while asleep - obese - large tongue - skeletal class II (no prominent chin)

CO2 changes during CPR

CPR: rescue breaths is on ___-___% oxygen flow

16-17% O2 flow

gasses move ___ through the concentration gradient

downhill from high to low pressure

Hb _____ binds four O2 molecules through _____ binding to deliver O2 through the body to the tissues

Hb reversibly binds 4 O2 through Cooperative binding

what three factors impact the dissociation of O2 and Hb

1. pH 2. temperature 3. 2,3-biphosphoglycerate