7E The Lymphatic System

What is the lymphathic system?

The lymphatic system is a large network of vessels throughout the body through which lymph flows. It has two primary functions - to act as a transport system for antigen-presenting cells and pathogens and to serve as the location of clonal selection.

What does it do

transports fluid that seeps out blood vessels and returns to blood stream

Part of the system

Lymph - the fluid
Lymph vessels- transport lymph
Primary lymphoid tissue - bone marrow, thymus
Secondary Lymphoid tissue - lymph nodes, spleen, tonsils, adenoids, appendix

PLT Primary lymphoid tissue

Production and Maturation of lymphocyte

Lymphocyte

A type of white blood cell that make antibodies to fight off infections

SLT Secondary Lymphoid tissue

Maintenance of mature lymphocyte and activation of adaptative immune response

Lymph nodes

Area in tissue that filter fluid in body for harmful substances

The transport network

3 stages, where lymphatic capillaries collect interstitial fluid and the fluid passes through lymph nodes returning to the bloodstream

Lymphatic Drainages

Lymphatic drainage of an injured site. Fluid from tissues is drained through lymphatic capillaries into the lymphatic system for antigen surveillance.

Lymphatic Flow

Fluid only moves in one direction - away from tissue and to lymph sites

Lymphatic surveillance

Fluid, immune cells, pathogens, cellular fragments are collected in capillaries. Passes through lymph nodes. Lymphocytes detect antigens

What's in the Lymphatic System?

Lymph: A watery fluid that carries waste, germs, and special white blood cells called lymphocytes.
Lymph Vessels: Tiny tubes (like blood vessels) that carry the lymph all around your body.
Lymph Nodes: Small, bean-shaped filters that trap germs and help fight infections. You can feel them under your neck when you're sick!
Spleen: Helps clean your blood and fights germs.
Tonsils: In your throat—these trap germs too.
Thymus: Helps make special immune cells when you're a kid.

System for kids

The lymphatic system is like a clean-up crew for your body. It helps get rid of germs, waste, and extra fluid that your body doesn't need. It's also part of your immune system, which helps you stay healthy and fight off sickness.

Blood from heart

Releases 20L per day of water fluid O2

Blood to heart

take in 17L per day of water CO2 and wastes

How lymphatic system works with capillaries

The lymphatic system helps keep body fluids balanced and defends against infection.
Capillaries are tiny blood vessels where nutrients and waste are exchanged with body cells.
Some fluid leaks out of capillaries into nearby tissues — this is called interstitial fluid.
The lymphatic capillaries (very thin-walled vessels) absorb this fluid and turn it into lymph.
Lymph capillaries are one-way — they only take fluid in, not out.
Lymph is then moved through larger lymph vessels, filtered through lymph nodes, and eventually returned to the bloodstream.
This helps remove waste, fight germs, and prevent swelling (edema).

What are capillaries

Capillaries are tiny blood vessels where nutrients and waste are exchanged with body cells.

Interstitial fluid

Some fluid leaks out of capillaries into nearby tissues — this is called interstitial fluid.

3mL enters the lymphatic system by entering lymphatic capillaries

Role of lymphatic system in the adaptive immune response

Transport network for antigen presenting cells and antigens from the site of infection to the lymph nodes
Site of antigen recognition by B and T lymphocytes
Site of clonal selection of B and T lymphocytes