Cardiovascular System

The journey of a blood drop from vena cava to aorta, including chambers and valves.

Cardiac muscle is striated, like skeletal muscle, but has intercalated discs and a branching, syncytial arrangement.

Structures that connect cardiac muscle cells, facilitating rapid ion diffusion and electrical conduction.

Prevent AV valve inversion during ventricular contraction by attaching to the valves via these structures.

Semilunar valves are stronger, handle higher velocities; AV valves are thin, require chordae tendinae.

Percent of blood flow at rest to various regions (brain, coronary, kidneys, GI tract, muscles, skin).

Constant volume (percentage decreases during exercise).

Increases proportionately during exercise (heart needs more blood).

Adjusts vascular resistance to regulate blood pressure.

Difference in cardiac muscle compared to skeletal muscle due to slow calcium channels.

Much faster than normal cardiac muscle conduction; spreads throughout heart quickly.

Heart cannot be stimulated to contract.

Heart can only react to very strong stimulation.

More crucial than in skeletal muscle for contraction because it's used directly from the extracellular space.

Higher heart rate leads to shorter action potentials and cardiac cycle durations.

Percentage of blood pumped out of ventricles with each contraction. (EDV-ESV)/EDV

Right ventricle pressure is approximately 1/6th of left ventricle pressure during systole.

End-diastolic pressure; tension in the heart before contraction. Reflects the filling conditions of the heart.

Resistance during ejection; aortic pressure.

Increased stretch in ventricles (increased blood volume) leads to increased contractile force and stroke volume.

Cells in the heart that automatically generate electrical impulses to initiate heartbeats (the SA node sets the rhythm).

Heart rate without autonomic nervous system influence (approximately 70–90 bpm).

Fast heart rate at rest. Not a designation for exercise.

Slow heart rate at rest.

Fluid inside cells, making up the largest fluid compartment in the body.

Fluid outside cells, further divided into vascular and interstitial compartments.

Fluid component of blood, primarily water with dissolved electrolytes and proteins.

Most abundant plasma protein, crucial for maintaining blood volume and transporting various substances.

Fluid found in the spaces between cells, primarily water and electrolytes.

Combination of proteoglycans and trapped interstitial fluid, creating a gel-like consistency.

Large molecules in the interstitial space that provide structure and interact with water to form a gel.

Swelling caused by excess fluid accumulation in the interstitial space.

Movement of fluid from the blood (capillaries) into the interstitial space.

Movement of fluid from the interstitial space back into the blood (capillaries).

Four forces that determine the movement of fluid between the vascular and interstitial compartments: hydrostatic pressure, interstitial fluid pressure, colloid osmotic pressure, and interstitial fluid colloid osmotic pressure.

Pressure of blood inside capillaries pushing fluid outward.

Pressure of fluid in the interstitial space pushing against capillaries.

Pressure exerted by plasma proteins pulling fluid inward.

Vessels that collect excess interstitial fluid and return it to the circulatory system.

Mechanisms that propel lymph through lymphatic vessels, including vessel wall contraction, external compression, and rhythmic compression.

Ability of a vessel to stretch and expand in response to changes in pressure.

Limited due to thicker smooth muscle layer, making arteries less expandable.

Greater than arterial due to thinner walls, making veins more expandable.

Veins hold a larger volume of blood due to their high distensibility.

Difference between systolic and diastolic arterial blood pressure.

A pulse with a high pulse pressure, indicating a large difference between systolic and diastolic pressure.

A pulse with a low pulse pressure, indicating a small difference between systolic and diastolic pressure.

Amount of blood ejected from the heart with each beat.

Ability of arteries to expand and contract in response to changes in blood volume.

Average pressure in the arteries during a cardiac cycle, not simply the average of systolic and diastolic pressure.

Pressure in the right atrium, normally low (approximately 0 mmHg).

A basic pathway for a reflex action, involving a sensory input (afferent), processing in the CNS, and a motor output (efferent).

The ability to consciously control a reflex response using higher brain centers.

Specialized sensory receptors that detect changes in blood pressure, primarily found in the carotid arteries and aortic arch.

Baroreceptors rapidly adjust blood pressure within seconds, primarily responsible for maintaining short-term homeostasis.

Baroreceptors located in areas with low blood pressure, such as the atria and pulmonary arteries, sensitive to small pressure changes.

A region in the brainstem responsible for regulating blood vessel tone, with three main areas: vasoconstrictor, vasodilator, and sensory.

The continual slight vasoconstriction caused by the sympathetic nervous system, maintaining a baseline level of vascular resistance.

These hormones bind to alpha and beta adrenergic receptors, causing vasoconstriction (alpha) or vasodilation (beta) depending on the receptor type.

Increases blood pressure by causing arteriolar and venous vasoconstriction, and increasing heart rate and stroke volume.

Increases blood pressure by raising heart rate through decreasing parasympathetic influence.

A feedback mechanism that regulates blood pressure by detecting changes in pressure and triggering sympathetic or parasympathetic responses.

When standing up, blood pressure drops in the head and upper body, activating baroreceptors and stimulating a sympathetic response to restore blood pressure.

Blood flows from areas of higher pressure to lower pressure, the greater the difference, the easier the flow.

The flow of blood from the periphery back to the heart, influenced by factors like blood pressure gradients and venous distensibility.