Cardiovascular Pressures, Hemodynamics, and Regulation

Vocabulary flashcards covering intracardiac pressures, valvular dynamics, vascular mechanisms, oxygen saturations, and neurohormonal blood volume regulation.

Energy Gradients (Heart Valve Motion)

The transvalvular forces that entirely govern the opening and closing of heart valves, dictated by blood moving from high energy to low energy.

Atrioventricular (AV) Valves Opening Condition

The point in the cardiac cycle when atrial pressure exceeds ventricular pressure ($\text{atrium pressure} > \text{ventricular pressure}$).

Atrioventricular (AV) Valves Closing Condition

The point in the cardiac cycle when ventricular pressure exceeds atrial pressure ($\text{ventricular pressure} > \text{atrium pressure}$).

Semilunar Valves Opening Condition

The hemodynamic state achieved when ventricular pressure exceeds great artery pressure ($\text{ventricular pressure} > \text{great artery pressure}$).

Semilunar Valve Closure Deviation

The mechanism occurring halfway through systole where semilunar valves remain open despite great vessel pressure exceeding ventricular pressure, maintained because high forward kinetic energy keeps total ventricular energy higher than great vessel energy.

Total Energy (Hemodynamics)

The sum of pressure energy and kinetic energy ($\text{kinetic} + \text{pressure} = \text{total energy}$) that dictates fluid and valve movement in the heart.

Right Atrium (RA) Pressure

A right-sided chamber pressure that averages $3\,\text{mmHg}$.

Right Ventricle (RV) Pressure

A right-sided chamber pressure with an average systolic value of $25\,\text{mmHg}$ ($15\text{--}25\,\text{mmHg}$) and an average diastolic value of $3\,\text{mmHg}$ ($0\text{--}8\,\text{mmHg}$).

Pulmonary Artery (PA) Pressure

A right-sided vessel pressure with an average systolic value of $25\,\text{mmHg}$ ($15\text{--}25\,\text{mmHg}$) and an average diastolic value of $10\,\text{mmHg}$ ($8\text{--}15\,\text{mmHg}$).

Left Atrium (LA) Pressure

A left-sided chamber pressure that averages $10\,\text{mmHg}$.

Left Ventricle (LV) Pressure

A left-sided chamber pressure with an average systolic value of $120\,\text{mmHg}$ ($110\text{--}130\,\text{mmHg}$) and an average diastolic value of $10\,\text{mmHg}$ ($4\text{--}12\,\text{mmHg}$).

Aorta Pressure

A systemic arterial pressure with an average systolic value of $120\,\text{mmHg}$ ($110\text{--}130\,\text{mmHg}$) and an average diastolic value of $70\,\text{mmHg}$ ($70\text{--}80\,\text{mmHg}$).

Right Heart Oxygen Saturation

The normal blood oxygen saturation found in the right atrium, right ventricle, and pulmonary artery, measuring $75\%$.

Left Heart Oxygen Saturation

The normal blood oxygen saturation found in the left atrium, left ventricle, and ascending aorta, measuring $98\%$.

Coronary Sinus Oxygen Saturation

The blood oxygen saturation within the coronary sinus, measuring $60\%$ (lower than SVC/IVC saturation).

Cardiomyocytes

Specialized heart cells responsible for generating electrical impulses.

Ventricular Suction (Diastole)

A diastolic mechanism where expansion of the left ventricle pulls the mitral valve open and pulls the aortic valve closed.

Ventricular Squeeze (Systole)

A systolic mechanism where contraction of the left ventricle pushes against the valves to close the mitral valve and open the aortic valve.

Vasotone

The muscular expansion and contraction of arterial vessel walls used to regulate blood flow.

Mechanisms Used by the Arteries

Hemodynamic and structural mechanisms including pressure gradients, elastic and muscular vessel walls, capacitance of large arteries, vasotone, and parallel branching.

Mechanisms Used by the Capillaries

Microcirculatory physical mechanisms consisting of hydrostatic pressure and osmotic pressure.

Mechanisms Used by the Veins

Venous return mechanisms including pressure gradients, vessel wall stretch/capacitance, right atrial cardiac suction, skeletal and diaphragm muscle pumps, and backflow-preventing valves.

Baroreceptors

Pressure receptors that measure the stretch of blood vessel walls caused by circulating blood volume.

Chemoreceptors

Chemical receptors that monitor circulating $\text{O}_2$, $\text{CO}_2$, and $\text{H}^+$ levels to allow brain-mediated adjustments in respiration and circulation to prevent acidosis or hypoxia.

Epinephrine / Norepinephrine

Sympathetic nervous system hormones released in response to central feedback that directly affect heart rate.

Renin-Angiotensin-Aldosterone System (RAAS)

An endocrine pathway that acts directly on the kidney to regulate blood volume.

Antidiuretic Hormone (ADH)

A hormone secreted by the pituitary gland that acts on the kidneys to influence blood volume.

Atrial Natriuretic Peptide (ANP)

A hormone secreted by the atria that acts on the kidneys to alter blood volume.

BNP and ANP (Clinical Utility)

Natriuretic peptides (Brain Natriuretic Peptide and Atrial Natriuretic Peptide) utilized clinically as diagnostic biomarkers for the dilatation of the cardiac atria and ventricles.