AP2

Transport O2, CO2, nutrients, hormones and wastes

Regulate pH, and body temperature

Protect against harmful microorganisms and toxins

Plasma: clear, staw-colored liquid portion of blood; 55% of blood volume

Formed elements: Solid cellular portion of blood; 45% of blood volume

Erythrocytes (red blood cells): transport O2 and some CO2: 99% of the formed elements

Luekocytes: Part of the body's defense system

Platelets (Thrombocytes): cellular fragments; help to control blood loss

Volume: varies with body size; approximately 8% of body weight; avg. adult has 5 liters.

Viscous: 3-4 times thicker than water

pH range: 7.35-7.45 slighlty alkaline (basic)

Test to seperate blood to obtain the percentage of RBC's

Normal: Adult female: 37-47% , Adult male: 40-54%

Biconcave disks

Centers are thinnner than their edges

1. Provides and increased surface area (allows for quicker diffusion)

2. Rouleaux: allows them to stack like dinner plates, so they can pass through a vessel not much larger than themselves.

3. Deformability: Quite elastic and flexible (allows them to bend and flex to enter small capillaries.

Accounts for 1/3 of the RBC by volume

Red due to the iron-containing pigment

Problem with hemoglobin synthesis would cause an increase in the area of Central Pallor (the inside of the red blood cell, hemoglobin is the red outer ring)

Adult female: 12-16 gm per 100 ml of whole blood

Adult male: 14-18 gm per 100 ml of whole blood

Hemoglobin is responsible for O2 and CO2 transport, due to O2 and CO2 loosely combining with it.

Oxyhemoglobin: compound formed when oxygen combines with hemoglobin: Bright red (arterial)

Doxyhemoglobin: hemoglobin that has released its O2: Appears bluish (cyanosis) (venous)

Mature red blood cells lack a nucleus

Unable to undergo mitosis

Also lacks mitochondria: relies on glycolysis for energy, thus all O2 makes it to its destination.

Adult female: 4.2-5.4 million cells per mm3

Adult male: 4.6-6.2 million cells per mm3

Broken down into Heme & Globin

Iron & Biliverdin

Iron is released back into the blood and combines with a plasma protein called transferrin: 80% of the iron is stored in hepatocytes (liver) in a protein-iron complex called Ferritin.

Biliverdin: Greenish pigment which is eventually converted to Bilirubin (orange pigment), excreted from the liver as Bile pigments (both green and orange).

Globin is the protein portion of hemoglobin

Degraded down to amino acids to be reused or catabolized

Red bone marrow (in adults)

Found in sternum, ribs, skull, scapulae, pelvis, vertebrae, and proximal bones of extremities

• Hemocytoblast (stem cell)
• Proerythroblast (committed stem cell)(large, loose, lacty chromatin)(clearly visible nucleoli, basophilic cytoplasm - blue)
• Erythroblast (hemoglobin shows pink in cytoplasm, synthesizes hemoglobin, nucleus becomes small to accomodate the hemoglobin)
• Normoblast (small nucleus, no basophilic cytoplasm is evident, appears pink in color)
• Reticulocyte (no nucleus, 80% of hemoglobin of mature RBC, hemoglobin synthesis continues do to polyribosomes)
• Erythrocyte (reticulocyte without polyribosomes & mitochondria, slighlty smaller with pink cytoplasm)

Controlled by a negative feeback system using Erythropoietin which is secreted mainly by the kidneys (manufactured by the liver to a lesser degree). Erythropoietin is released in repsonse to low O2. Circulates in the blood to bone marrow, causing the marrow to stimulate hemocytoblasts to differentiate. Levels of Erythropoetin will decrease as O2 rises.