Respiratory System (5 Qs)

Boyle's Law

pressure & volume have an inverse relationship

(gas always fills its container: big contained = low pressure)

Tidal volume (TV)

amount of air moved in/out of lung with each breath

~500 mL

Inspiratory reserve volume (IRV)

amount of air that can be inspired forcefully beyond TV

~2100-3200 mL

Expiratory reserve volume (ERV)

amount of air that can be expired forcefully

~1000-1200 mL

Residual volume (RV)

Amount of air remaining in the lungs after a forced exhalation

Needed to keep alveoli open and prevent lung collapse

Inspiratory capacity (IC)

TV + IRV

Total amount that can be inspired after normal tidal expiration

Functional residual capacity (FRC)

RV + ERV

Air remaining in lungs after normal tidal expiration

Vital Capacity (VC)

TV + IRV + ERV

Total amount of exchangeable air

Total lung capacity (TLC)

TV + IRV + ERV + RV

sum of ALL lung volumes

Boyle's law

pressure and volume are inversely related (high volume = low pressure)

Henry's law

the amount of a gas that dissolves in a liquid is directly proportional to the partial pressure of that gas

(higher Pp --> more gas dissolves)

Dalton's law

total pressure exerted by a mixture of gases = the sum of the partial pressures

emphysema

walls of adjacent alveoli break down (reduces surface area)

perfusion

delivery of blood to a tissue

ventilation

exchange of gases

Po2 controls _____ by changing ____ diameter

perfusion ; arteriolar

Pco2 controls _____ by changing _____ diameter

ventilation ; bronchiolar

how many molecules of oxygen can each Hb carry?

4

saturation

the % of Hb that's bound to oxygen

factors that influence saturation

Po2

temperature

blood pH

Pco2

oxyhemoglobin dissociation curve

describes the relationship between O2 and Hb

how the body makes sure O2 is reserved for parts that need it

where is PO2 the highest and lowest?

highest in the lungs (pulmonary capillaries)

lowest in active tissues (because metabolic processes use O2 to make ATP)

what happens with Hb and O2 when there's low arterial PO2?

Hb releases O2 into tissues

what happens with Hb and O2 when theres high arterial PO2?

Hb binds O2

shifting the oxyhemoglobin disassociation curve to the RIGHT

lower saturation/affinity (Hb doesn't hold onto O2 as tightly)

increased temp, increased CO2, decreased pH

shifting the oxyhemoglobin curve to the LEFT

higher saturation/affinity (harder for blood to get into tissues ; Hb holds less tight)

decreased temp, decreased CO2, increased pH

Bohr effect

declining blood pH (acidosis) and increased Pco2 cause Hb-O2 bond to weaken

Haldane effect

amount of CO2 transported is affected by Po2

lower Po2 --> more CO2 can be carried in blood

anemic hypoxia

decreased oxygen carrying capacity of blood

ischemic hypoxia

blood isn't being delivered

ex) tourniquet

histotoxic hypoxia

mitochondrial dysfunction (can't use O2 properly)

hypoxemic hypoxia

low Po2 in blood (Hb has higher affinity for CO2 than O2)

carbon monoxide poisoning treatment

hyperbaric chamber

if ventilation is low and perfusion is high....

low levels of O2, high levels of CO2 -- pulmonary arteries constrict to reduce bloodflow

if ventilation is high and perfusion is low...

high levels of O2, low levels of CO2 -- pulmonary arteries dilate to increase bloodflow

where in the body is PO2 the highest and lowest?

highest in lungs (pulmonary capillaries) -- lowest in active tissues (bc metabolic processes to make ATP)