Cardiovascular System: Cardiac Cycle and Blood Vessels

• Sequence of events in heart contraction and relaxation is the Cardiac Cycle.
• Heart sounds are normal sounds produced by heart valves closing.
• Heart murmurs are abnormal sounds indicating turbulent blood flow.
• Volume of blood pumped per heartbeat is Stroke Volume.
• Number of heartbeats per minute is Heart Rate.
• The Autonomic Nervous System regulates involuntary bodily functions, including heart rate.
• Arteries are blood vessels carrying blood away from the heart.
• Veins are blood vessels carrying blood toward the heart.
• Capillaries are the smallest blood vessels, which facilitate substance exchange.
• In Systemic Circulation arteries carry oxygenated blood.
• In Pulmonary Circulation veins carry oxygen-poor blood.
• The Tunica Interna is the inner layer of a blood vessel that reduces friction.
• The Tunica Media is the middle layer and controls vessel diameter and blood flow.
• The Tunica Externa is the outer layer, which protects and anchors blood vessels.
• Conducting Arteries are large arteries with elastin to manage pressure changes.
• Distributing Arteries are arteries delivering blood to specific organs.
• Arterioles are small arteries regulating blood flow to capillaries.
• Continuous Capillaries are common and allow fluid and small solute passage.
• The Blood-Brain Barrier are tight junctions in brain capillaries preventing substance passage.
• Fenestrated Capillaries are more permeable, aiding absorption and filtration.
• Vasoconstriction is the narrowing of blood vessels to reduce blood flow.
• Vasodilation is the widening of blood vessels to increase blood flow.
• Endothelium is a thin layer lining blood vessels, reducing friction.
• Elastic Lamina is a layer of elastin in blood vessel walls.
• Interstitial Fluids are fluid surrounding tissues, facilitating nutrient exchange.
• Red Blood Cells transport oxygen in the bloodstream.
• Pinocytic Vesicles aid in fluid absorption in capillaries.
• The Basement Membrane is a supportive layer beneath endothelial cells in vessels.
• The Nucleus of Endothelial Cells reside in the cell nucleus in the inner layer of blood vessels.
• Sinusoid capillaries are leaky capillaries, which allow large molecule passage.
• An incomplete basement membrane is a partial membrane supporting sinusoid capillaries.
• Intercellular clefts are spaces between endothelial cells in capillaries.
• The Nucleus of endothelial cells exist within blood vessel lining.
• Anastomosis is a connection between blood vessels supplying the same area.
• Arteriovenous anastomosis involves a direct connection between an artery and a vein.
• Metarterioles are small vessels connecting arterioles to capillaries.
• Precapillary sphincters are smooth muscle regulating blood flow into capillaries.
• The thoroughfare channel is a direct route for blood flow through capillary beds.
• Venules are small vessels formed from converging capillaries.
• A large lumen is a wide central space in veins for blood flow.
• Blood volume is the total amount of blood in circulation.
• Blood flow is the volume of blood passing through a vessel per minute.
• Blood pressure is the force exerted by blood against vessel walls.
• Resistance is friction between blood and vessel walls.
• Peripheral circulation is blood flow in vessels outside the heart.
• Peripheral resistance is the resistance affecting local blood flow significantly.
• Vasoconstriction is the narrowing of blood vessels, increasing resistance.
• Vasodilation is the widening of blood vessels, decreasing resistance.
• Blood pressure decreases as it moves from arteries to veins.
• Blood viscosity is the thickness of blood affecting flow resistance.
• Blood vessel length is the distance blood travels affecting flow resistance.
• Blood vessel diameter is the width of vessel influencing flow resistance.
• Capillary beds are networks of capillaries facilitating exchange.
• Veins are blood reservoirs storing approximately 65% of blood volume.
• Circulation routes are paths blood takes to reach tissues.
• Fluid exchange is the movement of fluids between blood and tissues.
• Systemic blood pressure is highest in the aorta and declines to 0 mmHg.
• 1 mmHg is the pressure of 1mm high mercury column.
• Arterial blood pressure is high due to compliance and ventricular systole.
• Systolic pressure is the peak pressure during left ventricle contraction.
• Diastolic pressure is the pressure during ventricular diastole, typically 70-80 mmHg.
• Pulse pressure is the difference between systolic and diastolic pressure.
• Mean arterial pressure (MAP) is diastolic pressure + ⅓ pulse pressure.
• Capillary blood pressure is low, 15-40 mmHg, which protects capillaries.
• Venous blood pressure is low and non-pulsatile, reflecting peripheral resistance.
• Hypertension is a sustained increase in systolic or diastolic pressure.
• Primary hypertension accounts for 90% of the cases and has no identifiable cause.
• Secondary hypertension accounts for 10% of cases and is due to identifiable causes.
• Hypotension is low blood pressure and concerns inadequate tissue flow.
• Circulatory shock is inadequate blood volume resulting in insufficient tissue blood flow.
• Hypovolemic shock is large-scale loss of blood volume.
• Vascular shock involves normal volume, extreme vasodilation, and low pressure.
• Transient vascular shock involves vasodilation due to prolonged heat exposure.
• Cardiogenic shock is heart inefficiency, often from myocardial damage.
• Blood vessel layers include three layers: tunica intima, media, and adventitia.
• Types of arteries include elastic, muscular, and arterioles with distinct functions.
• A capillary bed is a network for nutrient and gas exchange.
• Veins structure exhibit thinner walls, larger lumen than arteries.
• Vascular anastomoses are connections between blood vessels, which allow for redundancy.
• Blood flow is the volume of blood moving through vessels.
• Blood pressure is the force exerted by circulating blood on vessel walls.
• Resistance is the opposition to blood flow in vessels.
• Vasoconstriction is the narrowing of blood vessels leading to increased pressure.
• Vasodilation is the widening of blood vessels which leads to decreased pressure.
• Blood pressure differences vary in arteries, capillaries, and veins.
• Consequences of hypertension can lead to heart disease, stroke, and kidney damage.
• Forms of circulatory shock includes hypovolemic, vascular, and cardiogenic shock.

Explore the cardiac cycle, heart sounds, and blood circulation. Understand the roles of arteries, veins, capillaries, and the autonomic nervous system in regulating heart function. Differentiate between systemic and pulmonary circulation and finally blood vessel layers.