Splanchnic Circulation Overview

The splanchnic circulation consists of blood vessels supplying the digestive organs including the stomach, small intestine, colon, pancreas, liver, and spleen. These circulations are arranged in parallel, meaning they operate independently.

The three major arteries supplying the splanchnic organs are the celiac artery, superior mesenteric artery, and inferior mesenteric artery. These arteries branch out and connect extensively, forming a complex network.

The splanchnic circulation is influenced by factors outside (extrinsic) and inside (intrinsic) the digestive system. Extrinsic factors include systemic blood pressure, the autonomic nervous system, and circulating hormones. Intrinsic factors include the properties of blood vessels themselves, local chemicals, and local nerve signals.

The splanchnic circulation receives a significant portion of the heart's output, around 25-35%. This flow is regulated by autoregulation, neurogenic factors, and humoral factors.

Autoregulation ensures that blood flow in the splanchnic organs adjusts to their metabolic needs, meaning more blood flows when organs are actively digesting.

The pulmonary circulation carries deoxygenated blood from the heart to the lungs for oxygenation and then returns oxygenated blood to the heart. The bronchial circulation supplies blood to the airways and surrounding tissues.

In the pulmonary circulation, the pulmonary arteries branch alongside the bronchi, delivering deoxygenated blood to the capillaries in the lungs. The oxygenated blood is then returned to the heart through the pulmonary veins, which run between the bronchi.

The bronchial circulation arises from systemic arteries, supplying blood to the airways, pleura, and lymph nodes. The blood is drained back into the systemic circulation via bronchial veins, merging into the azygos vein.

A condition in which the heart is unable to pump blood effectively, leading to inadequate blood supply to the body.

A type of heart failure primarily affecting the right ventricle, often caused by lung conditions.

Damage to the heart muscle caused by conditions like infections, alcohol abuse, or drug abuse, contributing to heart failure.

A mechanism that compensates for reduced cardiac output in heart failure by activating the Renin-Angiotensin system and increasing aldosterone secretion to help retain fluids.

Fluid buildup in the tissues, particularly in the lower extremities, due to inadequate blood flow.

The failure of the left ventricle, causing increased pressure in the pulmonary veins and fluid buildup in the lungs.

A condition characterized by fluid buildup in the air spaces of the lungs due to increased pressure in the pulmonary veins, leading to shortness of breath and coughing.

The lymphatic system plays a key role in the lungs, with more lymphatic channels present compared to other organs. Lymph nodes are arranged along the bronchial tree, filtering lymph and facilitating unidirectional flow toward the subclavian veins.