Blood and Lymphatics

Agranulocyte

granules are NOT present in their cytoplasm

Basophil

Bi-lobed dark purple nucleus with dark purple granules in cytoplasm.

Dark staining, grainy nucleus (lots of visible granules). Multilobed nucleus, can be difficult to see because of granules.

Granulocytes.

0-1% frequency in the blood

Eosinophil

Bi-lobed dark purple nucleus with red-orange granules in cytoplasm.

Red staining, grainy cytoplasm (visible granules). Bilobed nucleus.

Granulocytes.

Erythrocyte / red blood cell

The most plentiful formed element, these cells appear pinkish-red on the outside and pale in the center. Functions to transport oxygen and carbon dioxide throughout the body. The normal count for people living at sea level is 4 - 6 million per cubic millimeter of blood.

Formed elements

red blood cells, white blood cells, platelets

Granulocyte

have granules in cytoplasm

Leukocyte / white blood cell

The five different types of cells are grouped by the presence or absence of granules in their cytoplasm. These cells are important in fighting infections and diseases. A normal count is 4,000 - 11,000 cells per cubic millimeter of blood.

Lymphocyte

The round dark purple nucleus takes up almost all of the cell. Only a slight "halo" of cytoplasm is visible.

Small 'crescent' of light cytoplasm. Large, round nucleus. About the same size as surrounding RBCs.

Agranulocytes.

20-45% frequency in the blood

Monocyte

The largest of the white blood cells, this cell has a washed-out appearance with a large cytoplasm and kidney bean-shaped nucleus.

Large amount of light cytoplasm. Large irregular nucleus. MUCH larger than surrounding RBCs.

Agranulocytes.

4-8% frequency in the blood

Neutrophil

Multi-lobed dark purple nucleus with light purple granules in cytoplasm.

Light cytoplasm (granules don't stain well). 3-5 lobed nucleus.

Granulocytes.

40-70% frequency in the blood

Plasma

The liquid portion of the blood. 90% water. Protein and electrolytes. Important for transport.

Thrombocyte / platelet

These fragments of megakaryocytes appear as small purple bits scattered among the red blood cells. They are important in the process of hemostasis (blood clotting). A normal count is 250,000 - 500,000 per cubic millimeter of blood.

Hematocrit

The percentage by volume of red blood cells in blood.

Hemopoiesis

the formation of blood cells and components

Hemostasis

blood clotting

Differential white blood cell count

Determines the percentage of each blood cell type in a person.

A blood smear is stained, and the percent of the different WBC types in a person's blood are determined. This is important in diagnosing clinical conditions where one type of white blood cell is elevated. For example, patients with an increased percentage of eosinophils may be having an allergic reaction to something.

Lymphatic system

Lymphoid organs

Consists of different organs, vessels, and tissues that make up a major portion of the immune system.

Lingual tonsil

A mass of lymphoid tissue located at the base of the tongue.

Lymph node [histology]

Lymph moves through these.

Acts as a filter to remove microorganisms and other foreign substances from the lymph.

capsule

connective tissue surrounding the lymph node

outer layer

cortex

outer region of lymph node

germinal center

central region of nodule, an area of rapid lymphocyte division

hilum

depressed, concave side of lymph node where efferent lymphatic vessels exit

Lymph nodule

(Follicles). Clusters of lymphocytes.

medulla

inner region of lymph node

medullary cord

dark staining area in medulla, consists of lymphocytes and other cells

medullary sinus

major pathway through which lymph fluid flows through node

light staining portion of medulla

trabecula (pl. trabeculae)

inward extensions of capsule

Palatine tonsil

two masses of lymphoid tissue located at the back of the throat, one on each side

Pharyngeal tonsil

posterior wall of nasopharynx

Red bone marrow [histology]

The site of blood cell production.

Adipocyte

These cells are numerous as the bone marrow is a location for energy storage.

Fat storage cells in. In histology, they appear round and white.

Hemocytoblast

Stem cells from which all blood cells and cells fragments are made. Note: A stem cell is a cell capable of producing daughter cells that can differentiate into different cell types.

Small stem cells forming bone cells.

Megakaryocyte

Giant pink-stained cells that fragment to form many smaller platelets.

Large cell with cytoplasmic extensions (like the arms of an octopus) that stick into sinusoids. As blood flows through the sinusoids, bits break off. These are platelets.

Sinusoid

Small vessels through which blood cells enter the bloodstream.

Blood vessels in bone marrow where blood cells enter bloodstream. In histology, they appear as white spaces with a rust color, which is the red blood cells of the blood contained in them.

Spleen

A part of the lymphatic system and blood systems, is located just above the stomach, below the diaphragm, and inside the left rib cage. This small organ filters blood, removing cellular debris, microorganisms, and old or damaged blood cells. Stores blood cells and helps to fight infection by making lymphocytes. You can live without it, but you may be at a greater risk for certain types of blood infection. The degree of risk depends on your age and if you have other diseases.

Thymus gland

A small gland located behind the sternum and anterior and superior to the heart. Lymphocytes travel from the bone marrow to the here where they mature and become specialized T-cells. These T-cells are released from the here into the bloodstream after they have matured and are essential to fight infection and disease.

2 major components of blood

plasma and formed elements