Blood Vessels Structure and Function (Part B)

These flashcards cover key terms and concepts from the physiology of circulation, focusing on blood flow, pressure, resistance, and regulatory mechanisms.

Blood flow

The volume of blood flowing through a vessel, organ, or entire circulation in a given period, measured in ml/min.

Blood pressure (BP)

The force per unit area exerted on the wall of a blood vessel by blood, expressed in mm Hg.

Resistance

Opposition to blood flow, measured by the friction blood encounters with vessel walls.

Blood viscosity

The thickness or 'stickiness' of blood due to formed elements and plasma proteins.

Total blood vessel length

Longer vessels create greater resistance to blood flow.

Blood vessel diameter

Has the greatest influence on resistance; changes can dramatically affect blood flow.

Systolic pressure

Pressure exerted in the aorta during ventricular contraction, averaging 120 mm Hg in a normal adult.

Diastolic pressure

The lowest level of aortic pressure when the heart is at rest.

Mean arterial pressure (MAP)

The pressure that propels blood to the tissues, calculated by diastolic pressure plus one-third of pulse pressure.

Capillary blood pressure

Ranges from 35 mm Hg at the beginning to 17 mm Hg at the end of the capillary bed.

Venous blood pressure

Changes little during the cardiac cycle with a small pressure gradient of about 15 mm Hg.

Muscular pump

The contraction of skeletal muscles that 'milks' blood back toward the heart.

Neural controls

Short-term regulation of blood pressure through reflex arcs that involve the cardiovascular center of the medulla.

Cardiac output (CO)

The volume of blood the heart pumps per minute, a factor regulating blood pressure.

Renal regulation

Long-term regulation of blood pressure through alterations in blood volume via the kidneys.

Angiotensin II

A potent vasoconstrictor that stabilizes arterial blood pressure.

Baroreceptor reflexes

Regulatory mechanisms that help maintain blood pressure homeostasis by detecting changes in arterial pressure.

Epinephrine

Hormone released by the adrenal glands that increases cardiac output and causes vasoconstriction.

Atrial natriuretic peptide

Hormone that decreases blood pressure by antagonizing aldosterone, causing decreased blood volume.