Chapter 10: Circulation Flashcards

This set of vocabulary flashcards covers the hemodynamics, determinants of blood pressure and cardiac output, blood vessel structures, and microcirculation principles discussed in the lecture.

Pulmonary circulation

The circuit of blood flow between the heart and the lungs.

Systemic circulation

The circuit of blood flow between the heart and the organ systems of the body.

Poiseuille’s Equation

An equation describing blood flow rate as proportional to the pressure gradient ($\Delta P$) and vessel radius ($r^4$), and inversely proportional to viscosity ($\eta$) and vessel length ($l$): $Flow = \frac{\pi \times \Delta P \times r^4}{8 \times \eta \times l}$.

Systolic Blood Pressure (SBP)

The arterial pressure resulting from the heart ejecting blood into the arteries and the lack of compliance of those vessels.

Diastolic Blood Pressure (DBP)

The arterial pressure resulting from the elastic recoil of the aorta pushing blood to distal arteries during heart relaxation.

Pulse pressure (PP)

The difference between systolic and diastolic blood pressure, calculated as $SBP - DBP$.

Systole

The phase of the cardiac cycle characterized by heart contraction.

Diastole

The phase of the cardiac cycle characterized by heart relaxation.

Mean Arterial Pressure (MAP)

The average blood pressure throughout the cardiac cycle, calculated as $MAP = \frac{SBP + (2 \times DBP)}{3}$ because the heart spends twice as much time in diastole.

Cardiac Output (CO)

The volume of blood ejected by each ventricle per minute, calculated as $HR \times SV$.

Stroke Volume (SV)

The volume of blood ejected by each ventricle during a single contraction.

Preload

The amount of blood filling the heart before each contraction, also known as the end-diastolic volume (EDV).

Contractility

The amount of force the myocardium generates to eject blood from the ventricles, representing the extrinsic control of stroke volume.

Frank-Starling Law of the Heart

The principle of intrinsic control stating that the heart normally pumps out the volume of blood returned to it (increased venous return leads to increased stroke volume).

Skeletal Muscle Pump

The process where the contraction of skeletal muscles surrounding veins aids in the one-way flow of blood back toward the heart.

Baroreceptors

Pressure sensors located in the carotid sinus and aortic arch that provide neural signals to the cardiovascular control center in the medulla oblongata to regulate blood pressure.

Tunica interna

The innermost endothelial layer of a blood vessel.

Tunica media

The middle layer of a blood vessel, composed of smooth muscle.

Tunica externa

The outermost structural layer of a blood vessel.

Capillaries

Narrow, numerous blood vessels consisting of a single layer of endothelial cells that facilitate molecule exchange between blood and tissues.

Precapillary sphincters

Smooth muscles that regulate the flow of blood from arterioles into the capillaries.

Edema

A condition caused by an excess of fluid in the tissues, often occurring when net filtration exceeds lymphatic removal.

Starling Equation

An equation used to calculate net fluid movement ($Jv$) across capillary membranes: $Jv = Kf [(Pc - Pi) - (\Pi c - \Pi i)]$.

Adenosine

A substance released by heart muscle to vasodilate coronary vessels, allowing blood flow to keep pace with cardiac oxygen needs.