Microcirculation, Capillary Exchange, and Lymphatics Flashcards

Vocabulary practice flashcards covering microcirculation, capillary fluid dynamics, vessel structure, the lymphatic system, and regulatory mechanisms from the lecture.

Arterioles

Small blood vessels wrapped in smooth muscle that regulate blood flow into capillary beds and control systemic vascular resistance by dilating or constricting.

Capillaries

Very thin, single-file red blood cell vessels designed for the rapid exchange of gases, nutrients, and wastes between blood and local tissues.

Venules

Stretchy blood vessels lacking organized smooth muscle that receive blood from capillaries and serve as a primary reservoir for blood volume.

Continuous Capillaries

The most common capillary type in the body, characterized by endothelial walls without gaps.

Fenestrated Capillaries

Specialized capillaries containing small pores found in the kidney glomerulus that function primarily as filters.

Sinusoidal Capillaries

Highly permeable capillaries located mainly in the liver that allow rapid passage and processing of large molecules and cellular components.

Pericytes

Cells with contractile activity that hold capillaries in place, support the basement membrane, and communicate with neighboring endothelial cells.

Venoconstriction

The squeezing of venules that pushes stored blood volume back toward the heart to increase preload and stroke volume without creating resistance on capillaries.

Lymphatic System

A low-pressure vessel network acting as the body's overflow system that collects excess interstitial fluid and proteins and returns them to the venous circulation.

Elephantiasis

A condition caused by a parasitic infection that blocks the lymphatic ducts, resulting in severe, unmanaged fluid accumulation and tissue swelling.

Hydrostatic Pressure

The pushing force of blood inside a capillary that drives fluid out into the interstitial space, steadily dropping from the arterial end to the venous end.

Oncotic Pressure

The pulling force exerted by plasma proteins, such as albumin, that draws fluid from the interstitial space back into the capillary.

Edema

The abnormal accumulation of fluid in the interstitial space caused by increased capillary leak, venous obstruction, decreased plasma proteins, or lymphatic blockage.

Tinting of the Skin

A physical finding where pinched skin fails to quickly snap back to its normal position, indicating tissue dehydration.

Pitting Edema

A type of tissue swelling common in heart failure where pressing on the affected area leaves a temporary indentation.

Ascites

An abnormal accumulation of fluid within the abdominal cavity, often associated with liver failure, cirrhosis, or reduced plasma protein levels.

Alpha-1 Receptors

The main sympathetic receptors on arteriolar smooth muscle that regulate blood vessel diameter by promoting constriction when firing rates increase.