Blood

Functions of Blood

1. Transportation – gas, nutrients, waste, hormones

2. Regulation –body temp., pH, fluid volume

3. Protection – immune response, blood clotting

Whole Blood Separation and Composition

• Plasma (55% of whole blood)

  • water 92% by weight

  • protein 7% by weight

  • other solutes 1% by weight

• Buffy Coat (<1% of whole blood)

  • white blood cells and platelets

• Erythrocytes (44% of whole blood)

  • red blood cells

Hematocrit

% formed elements (platelets, leukocytes, and erythrocytes)

• females 38%-46%

• males 42%-56%

Plasma Composition

• 92% water

• 1% electrolytes

• 7% plasma proteins

  • albumin (drives osmosis - movement of water)

  • Globulins (transport water-insoluble; antibodies)

  • Fibrinogen (fibrin → clots/stress or damage of tissue)

  • Regulatory (enzymes, hormones)

Hemopoiesis

production of formed elements

Hemopoiesis Formed Elements

1. Erythrocytes - Life span 120 days

2. Erythropoiesis - erythrocyte production; ~3 mil./sec

   1. –under the control of hormone erythropoietin

      (EPO)

3. Leukocytes - – life span 12 hours to years

   1. Leukopoiesis - leukocyte production

4. Platelets - life span 8- 10 days

   1. Thrombopoiesis – platelet

      production

Erythrocytes ( RBCs)

• Relatively small (7.5 μm in diameter, about the diameter of capillaries)

• Biconcave - indent

• Lacks nucleus

• Transports oxygen and carbon dioxide (hemoglobin)

Hemoglobin in Erythrocytes

protein made up of four polypeptide chains

• 2 alpha globin chains

• 2 beta globin chains

Heme

ringed molecule with iron ion [Fe2+] in center

• iron ions attract oxygen (O2) —> how oxygen is carried in hemoglobin

• Carbon dioxide attracted to globin chains

Each erythrocyte contains ~280 million molecules of

hemoglobin (red-pigmented protein ➔ why blood is red)

• Capable of reversibly transporting oxygen and carbon dioxide in the blood

Each hemoglobin molecule can bind a combination of ____ oxygen/carbon dioxide molecules.

four oxygen/carbon dioxide molecules.

Erythrocytes life cycle ~120 days

1. Erythrocytes from red bone marrow

2. Erythrocytes circulate in the bloodstream for 120 days (no nucleus)

3. aged Erythrocytes are phagocytized in the liver and spleen

4. Heme components are recycled back to bone marrow

Blood Type A

• Antigen A on erythrocytes

• Plasma: makes Anti-B antibodies

• A- 6% A+ 31%

Blood Type B

• surface antigen B

• Plasma: makes Anti-A anitbodies antibodies

• B- 2% B+ 9%

Blood Type AB

• Surface antigen A and B

• Plasma: Neither anti-A no anti-B antibodies

• AB- 1% AB+ 3%

Blood Type O

• Neither surface antigen A nor B

• both anti-A and anti-B antibodies

• O- 9% O+ 39%

“Universal Donor” ? (= can safely donate to anyone)

Type O - no antigen (no antibody agents)

“Universal Recipient” ? (= can safely receive blood from anyone)

Type AB

Erythrocyte Agglutination

• Occurs if someone receives an incompatible blood transfusion

  • Recipient’s antibodies bind to donor erythrocytes and clump them together

    • –Can block blood vessels

    • –Can cause hemolysis (rupture erythrocytes),

      organ damage

2. Leukocytes (“white blood cells”)

Immune response; defend against pathogens

• 1.5-3 Xs larger than erythrocytes

• Granulocytes

  • 1. Neutrophils 2. Eosinophils 3. Basophils

• Agranulocytes

  • 1. Lymphocytes 2. Monocytes

Granulocytes – Neutrophil

ca. 60% of leukocytes (most common)

• Multilobed nucleus w. pale granules

• Phagocytize bacteria (cell-eating harmful bacteria- infection)

  • function

Granulocytes – Eosinophil

ca. 3% of leukocytes

• Bilobed nucleus w. red

  granules

• Phagocytize allergens or antigen-antibody

Granulocytes – Basophil

ca. 1% of leukocytes

• Bilobed nucleus w. deep blue-violet granules

• Release histamine during inflation (classic allergy symptoms)

Agranulocytes – Lymphocyte

ca. 30% of leukocytes

• Round or slightly dented nucleus

  • May nearly fill the cell

• Produce antibodies (b-cells)

• attack antigens (T-cells)

• Attack abnormal/infected cells (NK cells)

Agranulocytes – Monocyte

• ca. 6% of leukocytes

• Kidney-shaped nucleus

• Abundant cytoplasm

• Exits blood vessels & becomes a macrophage - Phagocytizes pathogens cellular debris, dead cells, viruses

Never Let Monkeys Eat Bananas (descending abundance - most to least)

1. Neutrophil

2. Lymphocyte

3. Monocyte

4. Basophil

Platelets

• Megakaryocytes - cellular fragments

  • Megakaryocytes are about 15× larger than erythrocytes

• Platelets are about ¼ the size of erythrocytes

  • Platelets are involved in the clotting of blood

Coagulation: Blood Clotting

• signal when tissue damage —> change into fibrin (net)

• platelets —> stick together and hold fibrin in place (mesh network) —> hold erythrocytes back

  • platelets play a role in bloodclot