Lymphatic

5.1

Lymph

fluid of the lymphatic system

Contains white blood cells, fats, water, proteins, salts and many other substances

Drains through the lymphatic system into the blood stream

Flow

lymphatic capillaries > larger lymphatic vessels > venous blood of the cardiovascular system

Lymphatic vessels

Take up excess tissue fluid from the cardiovascular capillaries and return it to the bloodstream

extend throughout most sections of the body

one way flow

smaller vessels merger to larger and larger ones

All lymphatic vessels enter venous circulation at the

Thoracic duct (left lymphatic duct)

right lymphatic duct

Thoracic duct

drains to left subclavian vein

larger than right lymphatic duct

Right lymphatic duct

drains to right subclavian vein

smaller

Lymphatic system

helps with immunity to defend the body

Lymphatic capillaries

absorbs fats and transport them into the bloodstream

Areas drained by thoracic duct

both lower extremities

abdomen

left arm

left head and neck

Areas drained by right lymphatic duct

right arm

right side of the head and neck

right thoracic region

Lymph nodes

hundreds of lymph nodes, found at the junctions of lymphatic vessels

encapsulated in fibrous connective tissue

many incoming vessels and fewer outgoing vessels

Flow of lymph nodes

afferent vessels (incoming)

lymph flows through network of sinuses that contain cells

lymph flows out through efferent vessel

Lymph node interior

divided into open spaces called nodules

contain lymphocytes and macrophages

filtering center

Lymph node locations

Tend to be grouped in regions of the body

Higher concentrations

• groin

• axilla

Spleen

extracts old or defective blood cells and platelets

removes debris, foreign matter, pathogens, and toxins from the blood as it moves through it

Spleen blood flow

Incoming: splenic artery

outgoing: splenic vein

vein flows into the hepatic portal vein

Hepatic portal system carries blood drained from the veins of spleen, intestines, stomach, pancreas, liver

Blood then transported into the liver

• detoxified and cleaned before returning to general circulation via the right atrium

Thymus

secretes thymosin and thymopoietin

enable t cells to mature and function as part of the immune system

mature t cells help attack cancerous or infected body cells

prominent in newborns, becomes larger in childhood and shrinks by old age

Tonsils

group of small lymphoid organs

gather and destroy bacteria inhaled in air or food

Crypts

• channels in tonsils

• trap bacteria and foreign matter

bacteria are destroyed in lymphoid tissue