Blood Vessels and Hemodynamics

Vocabulary flashcards related to blood vessels and hemodynamics.

Arteries

Carry blood away from the heart.

Capillaries

The site of nutrient, waste, and gas exchange in the cardiovascular system.

Veins

Carry blood towards the heart.

Systolic Blood Pressure

The higher pressure caused by ventricular systole (heart contraction).

Diastolic Blood Pressure

The lower pressure sustained by the blood itself.

Mean Arterial Pressure (MAP)

Calculated as 1/3 (systolic BP – diastolic BP) + diastolic BP; represents the average arterial pressure during a single cardiac cycle.

Blood Flow

The amount of blood per unit time reaching organs (tissues of the body).

Resistance

The sum of all factors which oppose the flow of blood.

Ohm's Law as applied to blood flow

Blood flow, blood pressure, and peripheral resistance are related; flow can be increased by increasing pressure or decreasing resistance.

Blood Viscosity

A factor that directly affects resistance to blood flow.

Blood Vessel Length

A factor that directly affects resistance to blood flow.

Blood Vessel Diameter

A factor that inversely affects resistance to blood flow; readily adjustable to control resistance.

Large Elastic Arteries

Arteries larger than 1 cm in diameter.

Medium Muscular Arteries

Arteries ranging from 0.1 to 10 mm in diameter.

Arterioles

Arteries smaller than 0.1 mm in diameter.

Venules

Small veins less than 0.1 mm in diameter.

Tunica Interna (Intima)

The innermost layer of a blood vessel, composed of epithelial tissue and a basement membrane.

Tunica Media

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

Tunica Externa

The outermost layer of a blood vessel, composed of elastic and fibrous connective tissue.

Elastic Arteries

Large arteries close to the heart with high levels of elastic tissue that store the energy of ventricular systole.

Muscular Arteries

Arteries with high levels of smooth muscle tissue that maintain blood pressure for more distal areas.

Anastomosis

A connection between blood vessels supplying blood to the same area, providing collateral circulation.

Arterioles

Control blood flow to capillaries; have the greatest drop in pressure.

Veins

Blood vessels with thinner walls, less muscle, lower pressure, and contain valves.

Venous Reserve

The large percentage of blood volume (about 64% at rest) contained in veins, functioning as a blood reservoir.

Venoconstriction

The constricting of veins to allow a greater volume of blood to flow to skeletal muscles.

Venous Return

The return of blood to the heart, aided by pressure, venous valves, skeletal muscle pump, and respiratory pump.

Autoregulation

Adjusting pressure and resistance to maintain adequate blood flow to vital organs, controlled through negative feedback loops and the ANS.

Baroreceptors

Sensory receptors located in the arch of the aorta and carotid sinus that detect changes in blood pressure.

Chemoreceptors

Sensory receptors that respond to hypoxia (low O2), hypercapnia (high CO2), or acidosis (high H+).

Renin-Angiotensin-Aldosterone System (RAAS)

An endocrine component of autoregulation that leads to the retaining of water, increasing blood pressure and volume.

Atrial Natriuretic Peptide (ANP)

A peptide released by cells of the cardiac atria that leads to loss of water to lower blood pressure.