Cardiovascular Physiology Lecture 1 Flashcards
Hematocrit Ratio:
Height of RBCs / Total Height
What is in Cell-free plasma and Packed RBCs (yellow and red part of blood)?
What is in the “Buffy coat”?
Plasma contains water / dissolved solutes, vitamins and minerals. Contains Platelets
Packed RBCs contain Formed Elements: Erythrocytes,
Buffy coat: WBCs: Granulocytes, Lymphocytes, Monocytes, platelets
Anemia, Polycythemia Hematocrit ratio
Anemia: smaller RBC ratio, Polycythemia, more RBCs
Pulmonary/Systemic Circulations. Direction of blood flow?
Systemic: Left Heart -> Aorta -> Arteries -> Arterioles -> capillaries, then returns to heart via venules -> veins
More blood in venous side (reservoir).
Resistance in series / parallel circuits
Parallel circuits reduce resistance.
Directly proportional to vessel length and blood viscosity.
Inversely proportional to radius of vessel to fourth power.
What does turbulent flow do and what are the factors that increase turbulence?
It is noisy, and can increase workload of the heart. Main problem is that it increases risk of clot formation.
Factors that increase turbulence:
Increased vessel diameter
High blood flow rate
Low Blood viscosity
Local decrease in vessel diameter
Low body temp (this decreases blood viscosity).
Systolic / Diastolic pressure
Systolic: when blood is being squeezed out of the heart. (Going to work)
Diastolic: Heart is at rest and blood is being returned to heart. (resting)
What are arterioles also known as, and why are they so important?
AKA Resistance vessels, because they are very subject to change diameter. Diameter of blood vessel is the most important factor in equation for blood flow.
Vascular compliance equation and facts
Compliance (C) = delta V / delta P
Veins are more compliant, meaning more likely to increase volume.
Transmural Pressure and Wall Tension
Transmural pressure is a distending force, it is opposed by wall tension. Wall tension is direc ctly proportional to transmural pressure and radius.
T = delta P x r.
T = wall tension.
Venous vessels have more elasticity.
Microcirculation
Lots of smooth muscle in arteriole, can change diameter moreso than any o9ther vessel because of this.
Microcirculation = capillaries, the change from arteriole side to venule. U see parallel circuits here, and precapillary sphincters. These are regions of increased smooth muscles that can change tension. Can regulate blood flow.
Filtration and absorption occurring here.
Forces that favor absorption / filtration in Capillaries.
Absorption: Plasma oncotic pressure and tissue hydrostatic pressure
Filtration: Capillary hydrostatic pressure and tissue oncotic pressure.
Oncotic: impact of protein.
Think of how water moves.
Net filtration = (CHP + TOP) - (POP + THP).
Starling’s law of the capillary: pressures are close to each other. If forces is not the same then there is problem.
Know what happens when you change one pressure? Just think hydrostatic pressure makes it go away. Oncotic going where it started.
Autoregulation found in where, what is it, possible factors causing it, and how do muscles affect this?
In Autoregulated blood vessels. Region of arterial pressure that is increasing but the blood flow stays the same. Mainly arterioles.
Possible factors: hypoxia, nutrient deficiency, myogenic response, toxin accumulation.
An increase in pressure can affect ion channels in muscle which change resistance and change blood flow.
Fast response action potentials, five phases defined.
a. Phase 0, the rapid upstroke, occurs as fast Na+ channels are activated and L type Ca2+ channels too.
b. Phase 1 defines early repolarization as fast Na+ channels and Ca2+ channels
are inactivated.
c. Phase 2 is the plateau caused by activation of slow Na+ channels and L-
channels. type Ca2+ channels. Potassium exits through delayed rectifier
d. Phase 3 is repolarization as slow Na+ channels and L-type Ca2+ channels
are inactivated and as K+ exits.
e. Phase 4 is when the resting membrane potential is restored and is stable
