Related Concept Videos

Structure of Blood Vessels01:15

Structure of Blood Vessels

Blood is circulated throughout the human body through a network of blood vessels called the circulatory system. This system includes arteries that transport blood from the heart to various body parts. These arterial pathways divide into smaller vessels until they reach the arterioles, which further split into capillaries. It is within these minuscule capillaries that the exchange of nutrients and waste products takes place. After this exchange, the blood is collected by venules, which fuse to...
Capillaries and Their Types01:20

Capillaries and Their Types

Capillaries, a crucial constituent of the circulatory system, are diminutive vessels with a diameter between 5–10 micrometers, accommodating perfusion to the tissues through the phenomenon known as microcirculation. Through their permeable walls, consisting of an endothelial layer ensconced by a basement membrane and sporadically dispersed smooth muscle fibers, the exchange of substances between the blood and the interstitial fluid becomes plausible. Variance in wall composition exists, with...
Veins as Blood Reservoirs01:10

Veins as Blood Reservoirs

Veins, while chiefly responsible for circulating blood back to the heart, also function as storage vessels for blood. They house approximately 64 percent of the body's total blood volume, a feat made possible by their high capacitance—the inherent ability to expand and accommodate large volumes of blood, even under low pressure. The large diameter and thin walls of veins augment their distensibility, significantly more so than arteries, due to their classification as capacitance vessels. When...
Esophagus01:24

Esophagus

The esophagus, a muscular conduit linking the pharynx and stomach, measures roughly 10 inches (25.4 cm) and sits behind the trachea. It remains collapsed when not swallowing. The esophagus follows a predominantly straight path through the thoracic mediastinum and enters the abdominal cavity through a diaphragmatic opening known as the esophageal hiatus.
The movement of edibles from the pharynx into the esophagus is facilitated by the upper esophageal sphincter, which is formed primarily by the...
Esophageal Varices-I: Introduction01:24

Esophageal Varices-I: Introduction

Esophageal varices are dilated, tortuous veins which are found mainly in the submucosa of the lower esophagus but which may also appear higher up or extend into the stomach. They develop due to increased pressure in the portal venous system, often as a result of liver cirrhosis. This condition scars and damages the liver, impeding normal blood flow through the portal vein. To compensate, blood seeks alternative pathways, forming fragile new vessels (varices) in the esophagus and stomach. These...
Diverticular Disease of the Colon01:27

Diverticular Disease of the Colon

Diverticular disease involves the formation of diverticula—small sac-like outpouchings of the colonic wall—and their complications. It most commonly affects the sigmoid colon due to higher intraluminal pressure and structural vulnerability. It results from structural weakness and increased pressure in the colon, producing pseudodiverticula that may remain silent or progress to inflammation and serious complications.Structure of DiverticulaIn diverticulosis, these outpouchings are...