The Lymphatic System

Published on 6th June 2018

FUNCTION

Drains tissue spaces of escaped protein and fluid and returns to cardio-vascular system

Transports fats from intestines to blood
Produces Lymphocytes to protect body from foreign bodies, and disease
Acts as a filter to prevent spread of pathogens from blood stream

Two types of Lymphocytes:

T-Cells – destroy foreign cells/viruses/cancer cells
B-Cells – secrete anti-bodies against foreign substances

ANATOMY

Lymph (fluid derived from plasma)
Lymph Vessels/Capillaries
- Have valves. Run alongside arteries and veins
- Very thin permeable walls that large particles including bacteria can permeate
- Some contain involuntary muscles
- Found throughout body except C-N-S, cartilage, teeth
Lymph Nodes
- Bean shaped 1-25mm in length
- Produce lymphocytes in outer cortex
- Filter lymph
- Found around major arteries

Lymphatic Tissue

Found in mucous membranes of gastro-intestinal tract, respiratory passageways, urinary tract, reproductive tract, and organs of body

Tonsils

Collection of lymphatic tissue in a mucous membrane
Protect against invasion of foreign substances

Spleen 12cm

Largest mass of lymphatic tissue
Stores and releases blood in emergency
Produces activated lymphocytes
Ingests bacteria and worn out erythrocytes and thrombocytes

Peyer’s Patches

A collection of lymphatic tissue found in the small intestines, mainly in the ileum

Thymus Gland between lungs

Conspicuous in Infant
Atrophied but still functional in adult
Activates T Cells and distributes to other lymphoid tissue around the body

Thoracic duct and right lymphatic duct

Collects lymph from all lymph vessels
Drains into left and right jugular veins

LYMPHATIC SYSTEM QUIZ

1. What is the lymphatic system?

a. A network of tubes throughout the body that drains fluid from tissues and returns it to the bloodstream
b. A transport system for carrying nutrients around the body
c. A series of glands that secrete chemicals called hormones into the blood

2. What are the main functions of the lymphatic system?
a. Managing fluid levels in the body, making hormones that regulate metabolism, and filtering out bacteria
b. Managing fluid levels, maintaining the sense of balance, and housing types of white blood cells
c. Managing fluid levels, filtering out bacteria, and housing types of white blood cells

3. What are lymph nodes?
a. Glands made of lymph tissue that are found at various sites around the body
b. Abnormal scar tissue that prevents the free flow of lymph through the vessels
c. Special clusters of nerve cells that allow the lymphatic system to communicate directly with the brain.

4. Which organs belong to the lymphatic system?
a. The spleen and thymus
b. The pancreas and the liver
c. The kidneys and bladder

5. What happens to the excess fluid that the lymphatic system removes from the tissues?
a. Fluid that the body needs is returned to the bloodstream but excess fluid is piped directly to the bladder for excretion
b. Fluid that the body needs is returned to the bloodstream but excess fluid is directed to the mouth to aid in saliva production
c. All collected fluid is returned to the bloodstream

6. What is oedema?
a. A type of cancer that affects the lymphatic system
b. Temporary swelling of certain parts of the body
c. The collective name for the largest lymph vessels