Lymphatic System Chapter 37 Section 2 CERVICAL NODES THYMUS LYMPH VESSELS SPLEEN INGUINAL NODES LYMPH VESSELS LYMPH VESSELS AXILLARY NODES DIAPHRAGM Notes

Keys Lecture Outline – Lymphatic System PowerPoint Notes textbook questions

Crucial in helping the body ward off disease and heal from injury Advanced infection from poor circulation

Function 1. Collects fluid lost from the blood and returns it to the circulatory system –More than three liters of fluid leave the capillaries each day –This continually bathes the cells –There is twice as much lymph in the body as blood –Lymph is dumped back into the circulatory system thru the superior vena cava

Functions cont’d 2. Filters fluid to rid it of bacteria and other pathogens Lymph Capillaries in the Tissue Spaces Tissue cells Tissue spaces Venule Lymphatic vessel Lymph capillary Arteriole Tissue fluid

More Functions 3. Collects fat from the small intestine and delivers it to the circulatory system 4. Generates and stores WBC’s called lymphocytes that fight infection Notice the location of the nodes

Components of the Lymphatic System A. Lymph – fluid collected in lymph vessels Clear straw colored fluid – same basic component as plasma

B. Lymph vessels – structures that collect lymph and deliver it back to the circulatory system –Valves within keep the lymph moving in one direction Wall of lymphatic capillary Opening into lymph vessel Tissue cellTissue fluid

C. Lymph nodes = series of cleaning filters Lymph moves slowly through the nodes WBC’s attack and engulf bacteria and pathogens in nodes

Location of vessels and nodes

The lymphatic system is closely linked to several other systems But especially to the Circulatory System

Nodes swell when large numbers of pathogens are trapped The swelling can cause pain – like a sore throat Have you ever had tonsillitis? Did it look like this?

Edema Swelling of tissues due to excess fluid accumulation Swelling of tissues due to excess fluid accumulation Caused by disease or injury Caused by disease or injury

Elephantiasis –a–a–a–a condition of extreme edema that occurs when lymph vessels become blocked by filarial worms.