HMX - First Half flashcards

Partial Pressure Percentages

PO2 = 0.21 (21%)

PN2 = 0.78 (78%)

Patm = PO2 + PN2 = 760mmHg at sea level

Hemoglobin

Proteins attached to RBC that act as binding sites for O2 to be carried throughout bloodstream

3 parts of cardiovascular system that O2 equilibrates in

Alveolus, Bloodstream, Hemoglobin

Oxygen content vs PO2 in blood

• Oxygen content in Blood: O2 dissolved in blood and O2 bound to hemoglobin

• PO2 in Blood: dissolved O2 in fluid of bloodstream only

3 major fluid compartments and ratio of fluid

• Intracellular, 2/3 H2O

• Interstitial, 2/9 H2O

• Intravascular, 1/9 H2O

Forces dictating intracellular fluid movement

Osmotic forces

water moves from low to high conc. fluid (moves toward greater solute ratio)

Forces dictating intravascular fluid movement

Starling forces (oncotic pressure and hydrostatic force)

water moves from high pressure to low pressure

Arterial vs venous end of capillary fluid movement

Arterial end favors filtration to push fluid and nutrients to surrounding tissue

Venous end favors reabsorption to pull fluid back into bloodstream

Bloodstream fluid movement summary

Hydrostatic pressure drives fluid out of capillary into surrounding tissue at arterial end. Remaining albumin (proteins) makes blood more concentrated and hydrostatic pressure drops as venous end is approached eventually leading to reabsorption. Outward hydrostatic pressure is greater than inward oncotic pull so net pressure drives filtration.

Kidney function

Organ that filters toxins resulting from metabolism and excess nutrient consumption

Nephron

component of kidney made up of glomerulus (filters waste products) and renal tubule (semi-permeable)

urea

particles at end of nephron that inc. concentration outside and drive water out of tubule

Nephron process

Waste is filtered at glomerulus. In beginning of tubule particles such as Na are reabsorbed driving movement of water to follow. Urea particles at end of tubule inc. concentration outside allowing for water to be reabsorbed while other solutes remain in tubule. urine becomes more concentrated and expels excess waste.

Ohms Law

change in P = Flow x Resistance

Flow is proportional to pressure change but inversely proportional to resistance

Passels law

R = 1/r^4

Resistance dramatically increases when radius decreases

ex. blood vessels restricting causes inc. resistance and drop in flow

Mean arterial pressure (MAP) vs venous pressure (VP)

• MAP: Pressure of blood coming out of heart

• VP: Pressure of blood returning to heart

Two types of flow through tubes

• Laminar flow: Molecules travel in same direction parallel to tube (change in P = change in flow)

• Turbulent flow: Molecules travel in different directions (change in P = change in flow²) more work required

Reynolds number

RN = velocity (density) / viscosity

A higher Reynolds number increases likelihood of turbulent flow

Tubes in series resistance

R = R1 + R2 + R3

Total resistance is greater than the individual resistance of each tube

Tubes in parallel resistance

1/Rtotal = 1/R1 + 1/R2

Total resistance is less than the individual tubes resistance making it easier to supply blood even when there are blockages

Compliance

Measure of objects stiffness

Change in P / change in V

High vs low compliance

High compliance means less pressure needed to change volume (Flexible)

Low compliance means more pressure needed to change volume (stiff)

Elastic forces

Restoring force exerted by an object when stretched or compressed

Surface tension

Forces at air-liquid interface that generate an inward vector force to minimize surface area

Laplces’s law

P = 2T/r

smaller radius will lead to greater inward force/internal pressure

Result of bubbles of different sizes and pressure differences

Bubbles of smaller radius have greater internal pressure and bubbles of larger radius have less pressure. fluid moves from high to low pressure which will drive it toward bigger bubble and expand it while smaller ones dissipate.

2 forces in alveoli

• elastic forces

• surface forces/tension

Different alveoli sizes in lungs

Larger alveoli are located at top and smaller ones are located toward bottom

How do lungs of different radius prevent fluid imbalances

Disrupting surface forces to keep pressure consistent across alveoli

Surfactant

Detergent body produces to disrupt forces in smaller alveoli to maintain consistent pressure in lungs. Higher the density surfactant the more forces disrupted.

Oxygen delivery

DO2 = O2 content x Q

Determined by O2 content of blood and flow of blood being delivered to tissue (cardiac output)

systemic circulation

P = MAP - VP

P = Q x SVR

can be determined by Pressure leaving heart - pressure returning to heart

or

Flow x systemic resistance

Fick principle

VO2 = Q(CaO2 - CvO2)

oxygen consumption is determined by O2 delivery to tissue - O2 delivery back to heart

Body compensate for lower DO2

If less oxygen is available to be delivered the body will maintain oxygen consumption by increasing oxygen extraction from lower volumes of blood.

Two types of metabolism

• Aerobic: uses O2 to produce H2O and CO2 and is where body wants to be

• Anaerobic: in absence of O2 makes lactic acid and is not favorable

negative of long term anaerobic metabolism

Production of lactic acid will increase [H+] conc. which will change environment pH to being more acidic.

coronary artery

Artery on epicardium of heart

penetrating artery

Artery that enters the endocardium of heart

Difference between flow to heart vs bodily vessels

Heart contraction blocks flow so flow only occurs during relaxation while other vessels have continuous flow.

BP and relation to flow

top number is systolic BP

bottom number is diastolic BP

if diastolic BP is lower than flow will also decrease