physiology exam 3 - respiratory volumes and capacities

Vital capacity (VC)

VC:
amount of air that can be exhaled with max effort after max inspiration

used to assess strength of thoracic muscles as well as pulmonary function

VC = ERV + TV + IRV
vital capacity = expiratory reserve volume + tidal volume + inspiratory reserve volume

inspiratory capacity (IC)

IC:
max amount of air that can be inhaled after a normal tidal expiration

IC = TV + IRV
inspiratory capacity = tidal volume + inspiratory reserve volume

functional residual capacity (FRC)

FRC:
amount of air remaining in the lungs after a normal tidal expiration

FRC = RV + ERV
functional residual capacity = residual volume + expiratory reserve volume

total lung capacity (TLC)

TLC:
max amount of air the lungs can contain

TLC = RV + VC
total lung capacity = residual volume + vital capacity

tidal volume (TV)

TV:
amount of air inhaled or exhaled in one breath

inspiratory reserve volume (IRV)

IRV:
amount of air in excess of tidal inspiration that can be inhaled with max effort (already did a normal breath in, its the amount of air that is left that can be inhaled)

expiratory reserve volume (ERV)

ERV:
amount of air in excess of tidal expiration that can be exhaled with mac effort (did a normal breath out, its the amount of air that you could still forcefully push out after a normal exhale)

residual volume (RV)

RV:
amount of air remaining in the lungs after max expiration; keeps alveoli inflated between breaths and mixes with fresh air on next inspiration
cannot be directly measured since it is located within the alveoli

total blood volume is...

5.5 L

"LUB"

AV valve closing

"DUB"

SL valve closing

stenotic valve

narrow valve causes whistling sound

insufficient valve

leaky valve causes gurgle sound

Flow equation

F = (delta P)/R

Delta P = pressure difference between 2 points
R = resistance to flow

Resistance equation

R = (8Ln) / (Pi r^4)

L = vessel length
n = viscosity
r = radius

pressure, resistance, flow equation

F = (delta P x Pi x r^4) / (8L n)

Stroke volume (SV)

amount of blood ejected from ventricles after each cardiac cycle

SV = EDV - ESV

Pulse pressure (PP)

the amplitude of the pressure wave from the highest systolic value to the lowest diastolic value. Difference in systolic and diastolic pressure. This is responsible for the throb that you feel in your pulse.

PP = systolic P - diastolic P

Mean Arterial Pressure (MAP)

tells us the average blood pressure in the arteries during a cardiac cycle or one heart beat (how well the blood is being pumped to the body)

MAP = DP + 1/3(PP)

Total peripheral resistance (TPR)

the resistance to the flow of blood through the entire systemic circulation

MAP = CO x TPR

cardiac output (CO)

amount of blood pumped by the heart per minutes.

CO = SV x HR

CO = MAP / TPR

transpulmonary pressure (Ptp)

pressure difference inside and outside of the lungs
usually positive value, it means that the lungs are being held open and are not collapsing (-Ptp or 0 = collapsing lungs)

Ptp = Palv - Pip
= pressure of alveoli - pressure of intrapleural

chest wall pressure (Pcw)

the pressure difference across the chest wall

Pcw = Pip - Patm
= intrapleural pressure - atmospheric pressure

boyle's law

P1V1 = P2V2

functional residual capacity (FRC)

the volume or air remaining in the lungs at the end of a quiet exhale when respiratory muscles are relaxed

FRC = RV + ERV
Residual volume + expiratory reserve volume

at FRC...
outward recoil of chest wall = inward recoil of the lung
alveolar pressure = atmospheric pressure (thus, no movement of air)
Patm = 0
Palv = 0
Pip = -4
Ptp = +4
Pcw = -4

Flow in terms of pressure

F = (Palv - Patm) / R

R = resistance

Forced expiratory volume in one second (FEV1)

a person takes a maximal inhalation and then exhales maximally as fast as possibly in one second

obstructive lung disease (COPD)

reduced airflow, obstructing the ability for air to go through the bronchi tree
the best test for this is the FEV1

restrictive lung disease

impair respiratory movement due to abnormalities in the lung tissues, the pleura, the chest wall,, etc. it effects the structure that allows you to expand the thoracic cavity. people with this cannot fully fill their lungs with air because their lungs, chest wall, and thoracic cavity are restricted from fully expanding.

FEV1 not a good test because there people have no problems forcefully and rapidly exhaling

PO2 in systemic arteries

Partial pressure of O2 at 100 mmHg (in systemic arteries), hemoglobin is 99-100% saturated

PO2 in systemic veins

partial pressure of O2 at 40 mmHg (in systemic veins), hemoglobin ~75% saturated

Atmospheric pressure of O2

atm P(O2) = 160 mmHg

alveolar pressure of O2

alv P(O2) = 105 mmHg

alveolar pressure of CO2

alv P(CO2) = 40 mmHg

atmospheric pressure of CO2

atm P(CO2) = 0.3 mmHg

pressure of O2 in pulmonary veins and systemic arteries

pulmonary/systemic arterial P(O2) = 100 mmHg

normal tidal volume

~500 mL

normal residual volume

~1200 mL

normal FEV1

~80% of air in lungs