Basics Of Cardiovascular Physiology Flashcards
What is the “60/40/20” rule?
60% of the human body is comprised of fluids
40% of the human body is intracellular fluid
20% of the human body is extracellular fluid
What is the “60/40/20” rule?
60% of the human body is comprised of fluids
40% of the human body is intracellular fluid
20% of the human body is extracellular fluid
How much of the Extracellular fluid is interstitial fluid? How much of it is plasma?
80% of the extracellular fluid is interstitial fluid
20% of the extracellular fluid is plasma
How much of the total body water is intracellular fluid? How much of the total body water is extracellular?
Total body water is 60% of a person totalbody mass.
40% (2/3) of the total body water is intracellular fluid.
20% (1/3) of the total body water is extracellular fluid.
How are substances transported between organs?
Via Convection
What are the three main fluid compartments?
Interstitial
Intracellular
Plasma
What side of the heart/pulmonary circuit is low pressure, and low in oxygen and carbon dioxide gases?
The right side of the heart/pulmonary circuit.
What side of the heart/pulmonary circuit is high pressure, and high in oxygen and carbon dioxide gases?
The left side of the heart/pulmonary circuit
The cardiovascular system is a _______ loop where _________ valves direct flow.
Closed loop; one-way
True or False:
Venous return = Cardiac output
True, venous return should always be equal to the cardiac output!!
If it is not, this would result in edema.
What is the equation for calculating cardiac output?
CO = HR x SV
Where
CO = cardiac output (L/min)
HR = heart rate (beats per minute)
SV= stroke volume (the volume ejected per beat)
What is the average human cardiac output?
5 L/min
What separates intracellular fluid from interstitial fluid? What force is responsible for the fluid movement between these two compartments?
The cell membrane is the barrier between the intracellular fluid compartment & the interstitial fluid compartment.
Fluid moves between these two compartments along an osmotic gradient.
What separates interstitial fluid from the plasma? What force is responsible for the fluid movement between these two compartments?
The capillary membrane is the barrier between the plasma & the interstitial fluid.
The starling forces (hydrostatic & oncotic pressures/gradients) are responsible for fluid movement between these two compartments.
What role does lymphatics play in fluid movement?
The lymphatic system will move fluids from the interstitial fluid compartment to the plasma, bypassing the capillary membrane.
What side of the heart is referred to as the “boost pump”?
The right side
What side of the heart is referred to as the “main pump”?
The left side
Which side of the heart has a thicker muscle wall? Why?
The left side of the heart; This is because the left side is under high pressure
What are the 3 loops of extracellular fluid movement?
- Cardiovascular loop
- Transvascular loop
- Lymphatic loop
What two factors rate of blood flow?
- The pressure gradient across the vessel (driving force)
- The resistance encountered (impedance to flow)
What factors can influence resistance to blood flow?
- blood vessel radius
- blood vessel length
- blood viscosity
What is the equation for calculating flow rate?
Flow = Pressure difference / Resistance
Q = delta P / R
What is the unit of measurement used for pressure in blood flow?
Millimeters of mercury
mm Hg
What is the importance of the shape of the heart valves?
The shape of the valves help direct blood flow forward & prevent back flow
If cardiac output does not equal venous return, then what would happen?
Blood/fluids would accumulate on one side
What is the sequence of electrical impulse activation of the myocardium?
Sinoatrial node»_space; Atrioventricular node»_space; Bundle of His»_space; Right & left bundle branches»_space; Purkinje fibers
What is the sequence of events for a heartbeat?
- Blood from the superior & inferior vena cava fill the right atrium of the heart
- The tricuspid valve of the right opens and blood pours out of the right atrium, to fill the right ventricle.
- The pulmonary valve of the right ventricle opens and blood flows out of the pulmonary artery to the lungs to be oxygenated.
- Oxygenated blood then flows back from the lungs via the left & right pulmonary veins, and dumps into the left atrium.
- The mitral valve of the left atrium opens and blood pours into the left ventricle.
- The aortic valve of the left ventricle then opens and bloods flows out through the aorta to the rest of the body.
What is the sequence of events for a heartbeat?
- Blood from the superior & inferior vena cava fill the right atrium of the heart
- The tricuspid valve of the right opens and blood pours out of the right atrium, to fill the right ventricle.
- The pulmonary valve of the right ventricle opens and blood flows out of the pulmonary artery to the lungs to be oxygenated.
- Oxygenated blood then flows back from the lungs via the left & right pulmonary veins, and dumps into the left atrium.
- The mitral valve of the left atrium opens and blood pours into the left ventricle.
- The aortic valve of the left ventricle then opens and bloods flows out through the aorta to the rest of the body.
What is the sequence of events for a heartbeat?
- Blood from the superior & inferior vena cava fill the right atrium of the heart
- The tricuspid valve of the right opens and blood pours out of the right atrium, to fill the right ventricle.
- The pulmonary valve of the right ventricle opens and blood flows out of the pulmonary artery to the lungs to be oxygenated.
- Oxygenated blood then flows back from the lungs via the left & right pulmonary veins, and dumps into the left atrium.
- The mitral valve of the left atrium opens and blood pours into the left ventricle.
- The aortic valve of the left ventricle then opens and bloods flows out through the aorta to the rest of the body.
Where is blood velocity the highest & the lowest?
Blood velocity is highest where the pressure is highest, which is typically on the left side.
Blood velocity is lowest where the pressure is the lowest, which is usually on the right side.
True or False:
Arteries are under the most pressure & thus contain stressed volume.
True
True or False:
Veins contain the most blood, as unstressed volume.
True
List the classes of blood vessels by size, smallest internal diameter to largest.
- Capillaries (smallest)
- Arterioles
- Venules
- Arteries
- Veins
- Aorta
- Vena Cavae
Which of the blood vessel classes has the largest cross-sectional area in the body?
Capillaries
What are the 3 layers of vascular walls?
Tunica Interna - endothelium, basement membrane, internal elastic lamina
Tunica Media - smooth muscle,external elastic lamina
Tunica Externa - fibrous tissue
What 4 tissue types compose the layers of vascular walls?
- Endothelium
- Elastic Tissue
- Smooth muscle cells
- Fibrous tissue
What kinds of tissue do arteries & veins contain?
All 4 tissue types; endothelium, elastic tissue, smooth muscle, & fibrous tissue.
What kinds of tissues do arterioles contain?
Endothelium & smooth muscle tissue
What kinds of tissues do venules contain?
Endothelium & fibrous tissue
What kinds of tissues do capillaries contain?
Endothelium tissue only
What is the typical blood distribution in the systemic blood vessels?
Systemic veins & venules hold 60% of the body’s blood.
Systemic arteries & arterioles hold 15%.
Pulmonary blood vessels hold 12%.
The heart holds 8%.
The capillaries hold 5%.
Which blood vessels’ main function is capacitance?
The veins & venules are considered the capacitors of the vascular system. Capacitance refers to their function in holding the largest volume of blood.
Which blood vessels are under the highest pressure?
Aorta, arteries & arterioles
What are the factors affecting the rate of diffusion through a cell membrane? How would each of these affect the rate of diffusion?
- lipid solubility
- molecular size
- cell membrane thickness
- concentration gradient
- membrane surface area
- composition of lipid layer (can increase or decrease membrane resistance)
What is the equation representing volume flow across a membrane?
The starling equation:
What are the two opposing starling forces?
Hydrostatic pressure (pushing water/fluid out) & osmotic/oncotic pressure (pulling water/fluid in)
Where is hydrostatic pressure highest? In arterioles or venules?
The hydrostatic pressure is the highest in the arterioles, and this allows filtration to dominate in the arterioles.
Where is oncotic pressure highest? In arterioles or venules?
Osmotic/Oncotic pressure is highest in the venules, & thus promotes fluid absorption to dominate in the venules.
What is the underlying physiology of pitting edema?
Edema occurs when there is a fluid imbalance occurring at the level of the capillaries.
The starling forces (hydrostatic pressure & osmotic/oncotic pressure) work in opposition of each other to keep the fluids balanced.
An imbalance where more fluid is being released into the interstitial space than is being reabsorbed, would cause edema.
Describe the condition & appearance of cells in isotonic, hypertonic, & hypotonic solution.
Isotonic solution - equal concentration of ions inside & outside of the cell; normal appearance
Hypertonic solution - higher concentration of ions outside of cell than inside; cells have shriveled appearance
Hypotonic solution - lower concentration of ions outside the cell than inside; cells have swelled appearance; lysis (bursting) can occur
What is the Nernst equation? What does is it represent?
The Nernst equation tells you the voltage across a membrane driven by a given ion at equilibrum (equilibrium potential). It tells you in which direction an ion will want to move to reach equilibrium (closer to 0 mV).
True or False:
The sodium/potassium pump is the determining factor of the resting membrane potential.
Fasle.
The electrogenic sodium/potassium pump sets up the ionic gradient, but only contributes little to the resting membrane potential.
Conductance pathways (leak channels) determine the membrane potential
