Blood Type of connective tissue The only fluid tissue in the human body 38 degrees celsius or 100.4 degrees farenheit Slightly alkaline, pH 7.35-7.45 About 5x’s thicker than water 5.3 Q average adult More blood in males than females Account for approximately 8% of body weight

Functions: Transport, Regulation and Protection The transport functions include: carrying oxygen and nutrients to the cells. transporting carbon dioxide to the lungs (for removal) transporting nitrogenous wastes to the kidneys (for removal) carrying hormones from the endocrine glands to the target tissues. The regulation functions include: removing heat from active areas, such as skeletal muscles, and transporting it to other regions or to the skin where it can be dissipated (maintaining body temp) pH regulation through the action of buffers in the blood. The protection functions include: preventing fluid loss by forming clots protect the body against microorganisms that cause disease

2 Parts of Blood Cells (formed elements) living component 45% of total blood formed in red bone marrow of long bones Plasma (matrix) non-living component 55% of total blood mainly water (90%) over 100 dissolved substances ex. nutrients, salts (electrolytes), gases, hormones, proteins, carbs, amino acids, vitamins, carbon dioxide, urea, ammonia

Separating Blood Components A Centrifuge can be used to separate blood components

Separating Blood Components Blood samples are spun at high speeds in the centrifuge This force causes layers to form.

Separating Blood Components Layers are based on density Plasma rises to the top Thin white middle layer: Buffy coat: contains white blood cells (leukocytes) and platelets) Red Blood Cells: Erythrocytes: sink to the bottom (known as the hematocrit) Red Blood Cells

Blood Plasma Plasma proteins Most abundant solutes in plasma Most are made by the liver Ex. Albumin—regulates osmotic pressure Clotting proteins—help to stem blood loss when a blood vessel is injured Antibodies—help protect the body from pathogens

Formed Elements (Blood Cells) Erythrocytes Red blood cells (RBCs) Leukocytes White blood cells (WBCs) Platelets Cell fragments and not whole cells, used in blood clotting

HEMATOCRIT Hematocrit is a percentage of red blood cells, by volume, found in whole blood. Normal : Males: 41 - 50% Females: 36 - 44%. Low hematocrit might be due to anemia, blood loss, bone marrow failure, destruction of red blood cells, leukemia, dietary deficiencies, or other causes.

1. Erythrocytes Commonly known as red blood cells or RBCs Main function is to carry oxygen Anatomy of circulating erythrocytes Biconcave disks Essentially bags of hemoglobin Anucleate (no nucleus) Contain very few organelles *4-6 million RBCs per cubic millimeter of blood

Formation of Erythrocytes Unable to divide, grow, or synthesize proteins Wear out in 100 to 120 days RBCs are eliminated by phagocytes in the spleen or liver Lost cells are replaced by division of hemocytoblasts (blood stem cells) in the red bone marrow

Hemoglobin Iron-containing protein Binds strongly, but reversibly, to oxygen Each hemoglobin molecule has four oxygen binding sites Each erythrocyte has 250 million hemoglobin molecules *Normal blood contains 12–18 g of hemoglobin per 100 mL blood

Carbon monoxide poisoning When carbon monoxide binds to hemoglobin, less oxygen gets transported to body tissues. The bond between carbon monoxide and hemoglobin is approximately 250 times stronger than the bond between oxygen and hemoglobin. You essentially suffocate to death.

2. Leukocytes commonly known as white blood cells or WBCs Crucial in the body’s defense against disease These are complete cells, with a nucleus and organelles Able to move into and out of blood vessels Respond to chemicals released by damaged tissues Many types of WBC’s some are macrophages and some produce antibodies or histamine *4,000 to 11,000 WBC per cubic millimeter of blood

Types of Leukocytes

Antibodies B cells are antibodies that bind to specific invaders. T cells are helper cells – important in fighting off infections – stimulates the production of other immune cells

3. Platelets - thrombocytes Derived from ruptured multinucleate cells (megakaryocytes) Needed for the clotting process Normal platelet count = 300,000/mm3

Hemostasis: Blood Clot Formation 3 phases 1. Vascular spasms 2. Platelet plug formation 3. Coagulation (blood clotting)

1. Vascular spasms Vasoconstriction causes blood vessel to spasm Spasms narrow the blood vessel, decreasing blood loss Step 1: Vascular Spasms

2. Platelet plug formation Collagen fibers are exposed by a break in a blood vessel Platelets become “sticky” and cling to fibers Injury to lining of vessel exposes collagen fibers; platelets adhere Collagen fibers Step 1: Vascular Spasms Step 2: Platelet Plug Formation

Anchored platelets release chemicals to attract more platelets Injury to lining of vessel exposes collagen fibers; platelets adhere Platelet plug forms Collagen fibers Platelets Step 1: Vascular Spasms Step 2: Platelet Plug Formation Anchored platelets release chemicals to attract more platelets Platelets pile up to form a platelet plug Figure 10.6, step 3

3. Coagulation Prothrombin in the plasma becomes thrombin (an enzyme) Formation of prothrombin activator Prothrombin Fibrinogen (soluble) Fibrin (insoluble) Thrombin Phases of coagulation (clotting cascade) 3. Coagulation Prothrombin in the plasma becomes thrombin (an enzyme) Fibrinogen (also found in plasma) becomes insoluable fibrogen (a web-like network) RBCs are trapped in the fibrogen Figure 10.6, step 7

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