Complete and in-depth Notes for PSL300 for EXAM prep. Kevin has combined notes from his peers and his own work to provide the most complete and comprehensive study guide for all types of students. He has achieved an overall cumulative GPA of 3.95 during his undergrad at the University of Toronto St...
Myocardial Infarction:
Symptoms include: dull ache in the chest, nausea, chest pain; family history of heart disease
can take aspiring, but need emergency medical technician
blood clot, effect/result, mechanisms, treatment, and outcome
Functions of Circulatory System
Transport and distribute essential moleculues/substances to the tissues
Remove metabolic byproducts ex. CO2
Adjustment of oxygen and nutrient supply in different physiologic states (sitting, standing)
Regulation of body temperature by regulating amount of blood to the surface
Humeral communication (cells to cells ~ hormones)
Overview: What is being transported and Where
Oxygen: from lungs to all cells
Nutrients and Water: from intestinal tract to all cells
Wastes: from some cells to liver for processing
Immune cells, antibodies, clotting proteins: from those in blood continuously to where needed
Hormones: from endocrine cells to target cells
Stored nutrients: liver and adipose tissue to all cells
Metabolic Wastes: from all cells to kidneys
Heat: from all cells to skin
Carbon Dioxide: from all cells to lungs
General Anatomy of Cardiovascular System – to be memorized
The cardiovascular system is a closed loop
The heart is a pump that circulates blood through the system. Arteries take blood away from
the heart, and veins carry blood back to the heart
Note: the hepatic artery to liver
Digestive tract’s blood goes to liver by Hepatic PORTAL vein
o Blood leaves liver via hepatic vein
Structure of the Heart
heart is composed mostly of myocardium (heart muscle)
Pericardium: fluid-filled sac the encases the heart
Has two sides, each with two chambers (atrium + ventricle)
The ventricles occupy the bulk of the heart
The arteries and veins all attach to the base of the heart
Coronary arteries provide oxygen to the heart muscles
Two large branches come directly out of aorta right to heart
Cardiac veins remove CO2 from the muscles
Atrioventricular Valves: occur between the atria and ventricles
Biscuspid/Mitral Valve: between right atrium and right ventricle
Tricuspid Valve: between the left atrium and left ventricle
, Valves are re-enforced by Chordae Tendinae attached to muscular projections within the
ventricles
Pulmonary valve: between right ventricle and pulmonary artery
Aortic valve: between left ventricle and aorta
During ventricular contraction, the AV valves remain closed to prevent blood flow backward into
the atria
During ventricular relaxation, the semilunar valves prevent blood that has entered the arteries from
flowing back into the ventricles
Passage of Blood Through the Heart (blood flow sequence)
à à à à à
Superior and inferior vena cava Right atrium Tricuspid valve Right ventricle Pulmonary semilunar valve
à à à à
pulmonary trunk and arteries to the lungs pulmonary veins leaving the lungs Left atrium Bicuspid valve Left
à à à
ventricle Aortic semilunar valve Aorta rest of body
General Terminology of Cardiovascular system flow
Coronary circulation: the circulation of blood WITHIN the heart
Pulmonary circulation: the flow of blood between the heart and LUNGS
Systemic circulation: the flow of blood between the heart and the cells of the body
Blood Pressure and the heart
blood pressure: greatest in the aorta
the wall of the left ventricle is thicker than that of the right ventricle, generating the greater force to
pump blood to the entire body
blood pressure then decreases as the cross-sectional area of arteries & arterioles increases
by the time the blood is in the vein, there’s almost no pressure
Hydrostatic pressure is the pressure exerted on the walls of any container, by the fluid within the
container.
o Hydrostatic pressure is proportional to the height of the water column
Once fluid begins to flow through the system, pressure falls with distance as energy is lost because of
friction. This is the situation in the cardiovascular system.
Pressure created by contracting muscles is transferred to blood vessels
Driving pressure is created by the ventricles
If blood vessels dilate/relax, BP decreases
If blood vessels constrict/tighten, BP increases
Volume changes affect blood pressure in cardiovascular system (eg. Dehydration)
Fluid Flow
flow is directly proportional to the pressure gradient
the higher the P gradient, the greater the fluid flow
fluid flows only if there is a positive pressure gradient (ie. High to low)
only the gradient (delta) matters, not the absolute pressure
flow through a tube is inversely proportional to resistance
resistance increase = flow decrease
resistance decrease = flow increase
R (proportional to) Ln/r^4
Resistance is proportional to length (L) of the tube (blood vessel)
Resistance increases as length increases
Resistance is proportional to viscosity (n), or thickness of the fluid (blood)
, Resistance increases as viscosity increases
Resistance is inversely proportional to tube radius to the fourth power
Resistance decreases as radius increases
As the radius of a tube decreases, the resistance to flow increases
and because resistance is inversely proportional to r^4, only a small change of radius
greatly affects resistance
and because flow is inversely proportional to resistance, change in resistance affects flow
ultimately, flow is proportional to radius
Small change in radius has an enormous effect on resistance to blood flow
Vasoconstriction: a decrease in blood vessel diameter/radius and decreased blood flow
Vasodilation: an increase in blood vessel diameter/radius and increased blood flow
In conclusion, Flow (proportional) to delta(P)/R = flow of blood in the cardiovascular system is
Directly proportional to the pressure gradient
Inversely proportional to the resistance to flow
Flow Rate NOT same as velocity of flow
Velocity refers to Flow rate / Cross-sectional Area
V = Q/A
Mean arterial pressure is proportional to cardiac output x peripheral resistance.
And can be affected by changes in vessel size, blood properties, and cardiac contractibility
Heart
in order to generate blood flow, need to generate a pressure difference.
Heart does this with a cardiac contraction
Heart is a simple pump with very small moving parts
myocardial muscle cells are branched, have a single nucleus, and are attached to each other by
specialized junctions known as “intercalated disks”
individual cells contain sarcomeres that does the actual contraction
the Actin Myosin interaction is calcium dependent
Like in skeletal muscles, cardiac muscles also have T tubules, sarcoplasmic reticulum, and
myofilaments
Excitation-Contraction Coupling
AP enters from adjacent cell
Voltage gated Ca+ channels open. Ca enters cell
Ca induces Ca release through Ryanodine Receptor Channels (RyR)
Local release causes Ca spark
Summed Ca sparks create a Ca signal
Ca ions bind to troponin to initiate contraction
Relaxation occurs when Ca unbinds from troponin
Ca is pumped back into sarcoplasmic reticulum for storage
Ca is exchanged with Na by the NCX antiporter
Na+ gradient is maintained by the Na/K ATPase
Cardiac Muscle vs. Skeletal Muscle
Smaller and have single nucleus per fiber
Have intercalated disks
Desmosomes allow force to be transferred
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