Formed Elements

thrombocytes

Erythrocytes and leukocytes are cells, but these cells are cell

fragments, not complete cells.

Erythrocytes (RBCs)

Red, biconcave disks with no nucleus; 7.5 μm in diameter

Erythrocytes (RBCs)

Mainly, transport oxygen and carbon dioxide

neutrophils , basophils, and eosinophils

These types of leukocytes that has a different appearance and function,—contain small granules that differ in color when stained.

Granulocytes, Monocytes and lymphocyte

These leukocytes are agranulocytes— do not contain visible granules

Leukocytes (WBCs)

Spherical cells that must be stained to be seen

Leukocytes (WBCs)

These can move out of blood vessels into the tissues

Leukocytes (WBCs)

They are often in circulation only as a means of getting to the tissues where they perform their functions.

Leukocytes (WBCs)

These functions provide various defenses against foreign pathogens.

Neutrophils

These are the most common type of leukocyte that make up 40% to 70% of all white blood cells in circulation

neutrophils

Each of these has a lobed nucleus and faint granules in the cytoplasm that contain lysozymes used to destroy bacteria

These are the least common type of leukocyte.

These are the least common type of leukocyte that has an average of 0% to less than 2% of all the white blood cells in circulation

neutrophils

The number of these in circulation rises in response to bacterial infections

basophils

The number of these in circulation tends to increase with allergies

histamine and heparin

A basophil’s primary function is to release two chemicals for defense

Histamine

These are released from basophils causes vessels to dilate (expand). This brings

more blood to an area and causes blood vessel walls to become more permeable

Heparin

These are released from basophils is an anticoagulant, which means it prevents

clotting. This chemical allows other leukocytes to move more freely

Eosinophils

These make up 0% to 6% of the total circulating white blood cells.

Eosinophils

Their granules stain orange to bright red, making them easy to distinguish from other WBCs of the total circulating white blood cells.

Eosinophils

The numbers increase with parasitic infections and allergies. The chemicals they secrete can be effective against large parasites such as hookworms and tapeworms.

Monocytes

They make up 4% to 8% of the total circulating white blood cells

Monocytes

They are the largest of the WBCs, measuring two to three times the size of a red blood cell. They have a large, round, kidney-shaped or horseshoe-shaped nucleus surrounded by abundant cytoplasm.

Monocytes

They migrate to tissues where they become macrophages and function to phagocytize (eat) dead and dying tissue, microorganisms, and any other foreign matter or

debris.

Monocytes

The number of these in circulation increases with inflammation and viral infections.

Lymphocytes

They are fairly common in circulating blood, making up 20% to 50% of the total

Lymphocytes

This is important for the immune system that produces antibodies and other chemicals to fight foreign pathogens and is important for tumor control

Thrombocytes

These formed elements are commonly called platelets, that are not actually cells but cell fragments

Platelets

secrete vasoconstrictors (chemicals that reduce the size of broken blood vessels) to slow the flow of blood.

Platelets

They secrete clotting factors to promote the formation of blood clots

Platelets

form platelet plugs and destroy bacteria.

Platelets

They secrete chemicals to attract neutrophils and monocytes to sites of inflammation

Platelets

secrete growth factors to stimulate mitosis to repair vessel walls