Blood and the Lymphatic

System

Blood Plasma

• The human body contains 4 – 6 liters of blood

• 45% of blood consist of cells

• 55% consist of plasma, the straw colored fluid

Blood Cells - Red

• The most numerous cells in the blood are red blood cells

• Function: transport oxygen

• Hemoglobin is the iron-containing protein that binds to oxygen

• They are made in the red bone marrow and are used for ~120 days• They are destroyed in the liver and spleen

Blood Cells - White

• Like red blood cells, white blood cells are made in bone marrow

• Function: guard against infection, fight parasites and attack bacteria

• There are many types of white blood cells• Lymphocytes produce antibodies that are proteins the help destroy pathogens• White blood cells can leave the circulatory system to help fight infections

throughout the body• Your body can also increase the amount of white blood cells in your body if

there is an infection that needs to be destroyed

Blood Cells – Platelets and Blood Clotting• We need blood in order to survive so when we get injured blood can

slow or even stop us from bleeding• Blood clotting is made possible by plasma proteins and cell fragments

called platelets• Platelets are fragments of large cells found in bone marrow that break

apart and are enclosed by cell membrane.• when platelets come in contact with the edges of a broken blood

vessel they get very sticky and a cluster of platelets forms• They then release proteins that eventually form filament which form a clott

Blood Clotting Problems

• Hemophilia is a genetic disorder that results from a defective protein tin the clotting pathway

• People who have hemophilia cannot create clots strong enough to stop even minor cuts

The Lymphatic System

• The lymphatic system collects the fluid that is lost by the blood and returns it back to the circulatory system

• The fluid is known as lymph

• Lymph nodes acts as filters and trap bacteria and other microorganisms that cause disease