Vascular System, Fluid Dynamics and Labs. Flashcards
What is the function and anatomy of the arteries ?
Carry oxygenated blood from the heart to the other tissues within the body.
Experience the highest BP of any vessels and thus have the thickest walls.
Very elastic walls to expand and accommodate the high BP.
Large amounts of smooth muscle (for vasodilation and vasoconstriction) and a narrow lumen.
What is the function and anatomy of the capillaries ?
One cell thick and have very narrow walls to allow easier transfer of nutrients and gases between the blood and the tissue.
Adapted for CO2 and O2 transfer specifically.
What is the function and anatomy of the veins ?
Carries blood away from the tissue to the heart.
Thin muscular layer due to low BP and therefore don’t maintain shape.
Contain valves to ensure one directional flow.
Goes to the kidney first to remove waste before pumping to the heart.
What is the flow path of blood starting from and returning to the heart?
Heart –> Arteries –> Capillaries –> Veins –> Kidney –> Veins –> Heart –> Arteries –> Lungs –> Veins –> Heart
What are the functions of microcirculation and what is the main microcirculatory vessel ?
Capillaries are the main microcirculatory vessel.
Occurs due to combination of heart beat and vessel regulation
Ensures adequate oxygen delivery to the tissues.
Pass and relay nutrients and energy between cells.
Transports harmful bi-products of metabolism such as Lactic acid or CO2 out of the body.
How big are microcirculatory vessels and what is their human body importance ?
The smallest are 2 microns (micrometres) and the largest are 100 microns.
Can cause ulcers or skin, lung or kidney diseases if not functioning properly/ congested.
What biomechanical factors are important to understand for biofluids ?
velocity distribution, pressure, flow rate ratio, flow behaviours , velocity gradients and stress.
Useful in only liquids or gaseous solids.
What is cohesion and adhesion in fluid mechanics and an example of where they are used in anatomy ?
cohesion - attraction between like molecules
liquid surface tension of mucus lined sacs of the alveoli just before expiration.
adhesion - attraction between unlike molecules.
between liquid on the outer lung surface and inner chest surface during inspiration.
What is an ideal fluid and a real fluid and which one is blood ?
Blood is a real fluid.
Ideal fluids are assumed to have 0 viscosity whereas real fluids have some viscosity.
What equations are used for mass and weight density and what are the uses of density in a medical setting ?
Mass p = mass (kg) / volume (m^3)
weight p = weight (N) / volume (m^3)
Relative density is the ratio of the density compared to the density of water at 4C its maximum p . This is used in hydrotherapy to calculate buoyancy or stability of a patient in a pool.
Human body relative p = between 0.86 and 0.97.
What equations are used for pressure and what is the SI unit ?
Force acting normal to the surface (N) / Surface Area (m^2) = Pressure (Pa).
What is Pascals principle of transmission of enclosed pressure and what medical application may this have ?
Only for enclosed ideal fluids at rest.
“Any change in pressure at any point will be transmitted to without loss to all other points of the fluid. “
Fluid filled beds/ cushions are examples of systems which use this principle as well as hydraulic jacks in a patient hoist.
What is hydrostatic pressure, its mathematical equation and its uses in the human body?
Pressure exerted on a fluid at rest as a result of gravity.
In the vascular system, this is influenced by the weight of the liquid and the depth of the point below the liquid surface.
P = p. g .h (density x gravity x depth below the surface) .
Typically measured as BP in mmHg.
What is the relationship between gravity and blood pressure and what examples can you think of in the human body?
Can compare the human body to a liquid column.
Horizontal lying has constant pressure across the “column”. (Head = Heart = Feet)
Vertical standing position means hydrostatic pressure increases with depth, (Head < Heart < Feet)
Swelling in the legs can be cause due to this pressure gradient when in the standing position. Hydrotherapy can reduce this swelling which will shift the pressure to a lower pressure area such as the abdomen.
What is Archimedes principle ?
The vertical buoyancy force when an object is immersed in water is equal to the hydrostatic force of the weight of the liquid displaced.
This upward force occurs through the centre of buoyancy which is the centre of gravity of the immersed liquid.
