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Cardiovascular system anatomy and physiology
Lymphatic system anatomy and physiology
Abnormal heart sounds
Normal heart sounds
Changes in pressure-volume loops
Cardiac and vascular function curves
Altering cardiac and vascular function curves
Law of Laplace
Measuring cardiac output (Fick principle)
Stroke volume, ejection fraction, and cardiac output
Physiological changes during exercise
Cardiovascular changes during hemorrhage
Cardiovascular changes during postural change
Cardiac conduction velocity
Electrical conduction in the heart
ECG normal sinus rhythm
ECG QRS transition
ECG rate and rhythm
ECG cardiac infarction and ischemia
ECG cardiac hypertrophy and enlargement
Control of blood flow circulation
Microcirculation and Starling forces
Blood pressure, blood flow, and resistance
Compliance of blood vessels
Laminar flow and Reynolds number
Pressures in the cardiovascular system
Resistance to blood flow
Action potentials in myocytes
Action potentials in pacemaker cells
Cardiac excitation-contraction coupling
Excitability and refractory periods
With microcirculation and Starling forces, microcirculation refers to the blood that flows through the smallest vessels in the circulatory system called capillaries.
And Starling forces, named after British physiologist Ernest Starling, sometimes called Starling pressures, are the forces that drive the exchange of fluid through the walls of the capillaries.
The capillaries have a single layer of endothelial cells lining their walls with clefts between these cells.
Normally, blood flows into smaller and smaller arteries, eventually reaching the arterioles, the metarterioles, and then the capillaries. In the capillary bed, due to the capillary’s thin walls and clefts, substances like nutrients or waste products can move from the blood into surrounding tissues and vice-versa.
After the capillaries, blood moves into venules, and then finally into veins. Intertwined with these capillaries are the lymphatic capillaries, which return interstitial fluid and proteins to the vascular system.
Lymphatic capillaries can also empty into larger lymphatic vessels and eventually into the thoracic duct, which empties lymphatic fluid directly into the large veins.
So, arterioles, metarterioles, capillaries, venules, and lymphatic vessels together make up the microcirculation.
Now, the arterioles that come before the capillaries act as floodgates, regulating blood flow into the capillaries.
The microcirculation refers to the network of small blood vessels that deliver oxygen and nutrients to individual cells and remove waste products. Starling forces are the physical forces that determine the movement of fluid between capillaries and tissue fluid.
The two major starling forces are hydrostatic pressure and oncotic pressure. Hydrostatic pressure is the force exerted by blood inside the capillary or in the interstitial space. It is generated by the contraction of the heart muscle, which squeezes blood through the arteries and pushes it into the capillaries. On the other hand, the oncotic pressure is created by proteins (mainly albumin) in the blood, which pulls water out of tissue fluid into capillaries.
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