Composition of Blood

Plasma (Percentage of Blood)

55% of blood

Formed Elements (Percentage of Blood)

45% of blood

Hematocrit (definition)

Percentage of blood volume consisting of RBCs

Hematocrit in Males

42-52% (lab says 41-51%)

Hematocrit in Females

37-47%

Plasma is made up of

• Water

• Proteins

• Electrolytes, blood gases, nutrients, enzymes, waste products, ions (Na+), hormones, antibodies

Formed Elements

• Erythrocytes

• Buffy Coat (Leukocytes + Platelets)

Blood Plasma consists of ___% water

90% water

Plasma Proteins

Albumin, Globulin, Fibrinogen

Albumin

60-80% of plasma proteins; Produced by the liver; Provide the osmotic pressure needed to draw water from the surrounding tissue fluid into the capillaries (or out of bloodstream into extracellular matrix of tissues); Blood Pressure and Blood Volume

Globulin

Produced by the liver; Function in transporting lipids and fat-soluble vitamins (alpha/beta); Function in immunity (gamma)

Fibrinogen

Important clotting factor produced by the liver. Forms fibrin threads essential in blood hemostasis

Serum

The fluid from clotted blood

…achieves a blood clot

Fibrinogen is converted by thrombin into fibrin, which…

Alpha Globulin

Transports lipids and fat soluble vitamins

Gamma Globulins

Antibodies produced by lymphocytes, function in immunity

RBC Structural Characteristics

• Lack nuclei and organelles (no mitochondria!)

• Biconcave discs

• Hemoglobin

• 100-120 day lifespan (can be altered by “shear effect”)

Erythropoietin (EPO)

maintains balance between production and destruction of RBCs

Do runners have RBCs with high or low lifespans?

RBC shorter lifespan in these people

Leukocytes can be classified as

Granulocytes and Agranulocytes

Granulocytes

Basophils, Eosinophils, Neutrophils

Leukocyte Characteristics

• Move in amoeboid fashion via cytoplasmic extensions

• Squeeze through intracellular junctions between capillary walls via diapedesis or extravasation

Amoeboid fashion

How leukocytes move. Project cytoplasm in front then rest of self follows.

Diapedesis/Extravasation

How WBCs move through intracellular junctions between capillary walls

Agranulocytes

Lymphocytes, Monocytes

Lymphocyte

• 20-45% of WBCs (second most abundant)

• Most important cells of the immune system

• Agranulocyte

• Nucleus stains dark purple

• Effective in fighting infectious organisms

• Act against a specific foreign molecule (antigen)

• Smallest leukocyte

• Not much cytoplasm, no granules visible

• Two classes (T & B)

T cell

Type of lymphocyte. Attacks foreign cells directly. E.g. attacks virus-infected cells and tumor cells.

B cell

Type of lymphocyte. Multiplies to become plasma cells. Secretes antibodies.

Monocytes

• 4-8% of WBCs

• Biggest leukocyte

• Agranulocyte

• Phagocytic

• Dark-staining, kidney-shaped nucleus

• Transform into macrophages

• Abundant cytoplasm, no granules visible

Neutrophils

• Most abundant WBC

• Granulocyte

• Phagocytic

• Helps us respond to bacterial infection

• Dark purple multi-lobed nucleus

Eosinophils

• Granulocyte

• Prominent, large bright-red granules

• Large dark purple bi-lobed nucleus

• Phagocytic

• Turn off allergic responses, kill parasites

Basophils

• Play major role in allergic response

• Release histamines during allergic reaction

• Least abundant WBC

• Granulocyte

• Dark purple-blue granules

• Nucleus (also purple) often hidden by granules

Platelets/Thrombocytes

• Blood clotting (releases serotonin, which stimulates constriction of the blood vessels, reducing the flow of blood to the injured area)

• Secrete growth factors (autocrine regulators)