Anatomy and Physiology - Blood Vessels and Circulation

Vocabulary flashcards covering key terms, anatomical concepts, and circulatory mechanisms from Chapter 20 (Blood Vessels and Circulation).

Systemic Blood Pressure Gradient

The pressure pattern where blood pressure is highest in large systemic arteries near the heart and progressively decreases through the circulation to its lowest levels in the veins near the right atrium.

Circulatory Pulsations

Pressure waves traveling through elastic arteries caused by the intermittent ejection of blood from the ventricles during systole.

Capillary Plasma Proteins

Proteins remaining in blood capillaries that maintain blood colloid osmotic pressure, drawing water into capillaries and opposing filtration into tissues.

Capillary Hydrostatic Pressure Gradient

The capillary pressure condition that is always greater at the arterial end than at the venous end of a capillary bed, falling as blood moves through.

Left Common Carotid Artery

The third vessel to branch from the aortic arch when counting major branches sequentially after the brachiocephalic trunk and before the left subclavian artery.

Baroreceptor Reflex Response to Hypotension

A compensatory reflex triggered when arterial blood pressure falls markedly, increasing sympathetic activity to boost heart rate, contractility, and systemic vasoconstriction.

Hepatic Blood Flow

The combined hepatic arterial and portal flow that allows the liver to receive the greatest total blood flow share among individual resting organs.

Arterial Wall Structure

Thick, muscular, and elastic walls adapted to high pressure, characteristic of vessels carrying blood away from the heart.

Vein Capacitance

The high compliance property of veins resulting from thinner walls and larger lumens, allowing them to stretch and store large volumes of blood at low pressure.

Capillaries

Microscopic exchange vessels made primarily of a single endothelial cell layer and a basement membrane, lacking thick muscular walls.

Sequence of Vessels Away from Heart

The directional pathway of blood movement: arteries $\rightarrow$ arterioles $\rightarrow$ capillaries, returning via venules $\rightarrow$ veins $\rightarrow$ heart.

Tunica Media

The middle layer of blood vessel walls containing large quantities of elastic fibers and smooth muscle, especially prominent in the aorta and major arteries.

Pulmonary Capillary Hydrostatic Pressure

The low blood pressure within pulmonary capillaries, averaging approximately $10\,mmHg$, which helps keep alveolar and interstitial spaces dry.

Arterioles

The primary resistance vessels that best regulate systemic blood pressure and vascular resistance via vasoconstriction and vasodilation.

Capillary Net Filtration Pressure Calculation

Determined by $NFP = (60\,mmHg + 1\,mmHg) - (25\,mmHg + 15\,mmHg) = +21\,mmHg$, indicating net fluid movement out of the capillary into the interstitial space.

Ductus Arteriosus

A fetal blood vessel connecting the pulmonary trunk to the aorta, allowing fetal blood to bypass nonfunctioning lungs.

Tissue Fluid

Fluid found in the interstitial spaces between tissue cells, also known as interstitial fluid.

Phlebotomy

The procedure of drawing or removing blood from a vein.

Hepatic Portal Circulation

A vascular system carrying nutrient-rich blood from digestive organ capillaries and spleen through the hepatic portal vein to liver sinusoids before returning to systemic circulation.

Superior Mesenteric to IVC Route

The blood pathway sequence: superior mesenteric artery $\rightarrow$ intestinal arterioles/capillaries $\rightarrow$ superior mesenteric vein $\rightarrow$ hepatic portal vein $\rightarrow$ liver sinusoids $\rightarrow$ hepatic veins $\rightarrow$ inferior vena cava.

Edema

Tissue swelling resulting from excess filtration or inadequate removal of interstitial fluid, caused by increased capillary hydrostatic pressure, decreased plasma osmotic pressure, increased capillary permeability, or impaired lymphatic drainage.

Prothrombin Activator

Also called prothrombinase; an enzyme whose available quantity directly determines the rate of thrombin formation from prothrombin in the presence of calcium ions.

Endocardium

The innermost layer lining all heart chambers, consisting of simple squamous endothelium supported by a thin connective tissue layer.

Arterial Structural Layers

The layers of an arterial wall listed from outermost to innermost: tunica externa $\rightarrow$ tunica media $\rightarrow$ tunica intima.

Diastolic Pressure

The arterial blood pressure maintained between ventricular contractions, generated largely by the elastic rebound of arterial walls.

Vascular Hemodynamics Rule

The physical relationship where blood flow through a vessel equals the pressure gradient divided by vascular resistance ($\text{Flow} = \frac{\Delta P}{R}$).

Venous Return Factors

Mechanisms that promote blood return to the heart during exercise, including the skeletal muscle pump, respiratory pump, sympathetic venoconstriction, and venous valves.

Orthostatic Postural Reflex

The rapid response upon standing where falling blood pressure decreases baroreceptor firing, triggering sympathetic activation to elevate heart rate, contractility, and vasoconstriction.

Tunica Intima

The innermost layer of a blood vessel wall, microscopically composed of simple squamous epithelium underlain by a sparse connective tissue layer.