Lymphatic System Flashcards

Study Notes

Lymphatic System Overview

Comprises a network of vessels, ducts, nodes, and organs.
Essential for fluid balance and defense against infections.
Functions as a connective system supporting both the circulatory and immune systems.

Components of the Lymphatic System

Key parts include lymphatic vessels, lymph nodes, spleen, thymus, and tonsils.
Specialized structures, like lacteals, absorb fats from the small intestine.

Relation to Other Systems

The lymphatic system is crucial for the circulatory system and immune system function.
Serves as a complementary network, enhancing the effectiveness of the circulatory system.

Fluid Dynamics

Lymph consists of fluid derived from plasma, including lymphocytes and macrophages.
Moves in one direction, not circulating like blood.
Responsible for returning approximately 85% of leaked fluids and up to 15% via lymph capillaries.

Fluid Return Mechanism

Lymphatic system can return fluid equivalent to the total blood volume within 24 hours.
Blockage in the lymphatic system can lead to edema due to fluid retention.

Protein Transport

About 25-50% of blood proteins leak from capillaries daily.
These proteins are collected by lymphatic capillaries and returned to the bloodstream, preventing fluid imbalances.

Role in Fat Absorption

Specialized lymph vessels (lacteals) in the small intestine transport absorbed fats directly into the bloodstream.
Fat and fat-soluble vitamins bypass the liver, heading straight to adipose tissues.

Hemopoiesis and Immune Function

Hemopoiesis occurs in lymphatic tissues where specific white blood cells (lymphocytes, monocytes) are produced.
Monocytes can develop into dendritic cells, which help identify and mark antigens for lymphocyte targeting.

Defense Mechanism

Lymphoid tissue plays a critical role in the immune system, filtering body fluids and removing pathogens and damaged cells.

Composition of Lymph

Lymph is clear and watery, similar to blood plasma but with fewer proteins.
Its composition varies depending on the organs it drains.

Lymphatic System Capacity

Handles around 125 ml/hr, translating to approximately 2500-2800 ml of lymph daily.
The liver and small intestine contribute about half of this volume.

Structure of Lymphatic Vessels

Lymphatic capillaries are small and open-ended, effectively draining lymph from tissues.
Composed of a single layer of endothelial cells, they are more permeable than blood capillaries.

Function of Lymphatic Ducts

Lymphatic trunks combine to form two main vessels: the Right Lymphatic Duct and the Thoracic Duct.
These ducts function similarly to veins in the circulatory system, facilitating fluid flow back into circulation.

Specific Duct Functions

The Right Lymphatic Duct is short and collects lymph from the right side of the head, neck, upper right body, and right arm, emptying into the right subclavian vein.
The Thoracic Duct is larger and drains lymph from the remaining body portions.

Description

Test your knowledge of the lymphatic system with these flashcards. This quiz covers essential terms, parts, and functions related to the lymphatic system, a crucial component of the body's immune defense and fluid balance. Perfect for students of biology or healthcare.