BLOOD

Physical Characteristics  Color depends on oxygen content  8% of body weight  L in females, L in males  pH – slightly alkaline (7.35 – 7.45)  About 100.4° F With O 2 Without O 2

What Is It?

 55% plasma  Plasma is 90% water – solvent, heat absorber  Plasma proteins Albumin – osmotic balance, pH buffering Fibrinogen – blood clotting Globulins – defense (antibodies), lipid transport  Salts (electrolytes) – osmotic balance, pH buffering

What Is It?  45% formed elements (living cells)  Buffy coat = less than 1% Leukocytes (white blood cells) Platelets  Erythrocytes (red blood cells) More than 99% Percentage of total blood volume = hematocrit

Erythrocytes  Transport oxygen to cells  Tiny million /mm 3 of blood  Produced in bone marrow  Life span is days  Biconcave (Why?)  Anucleate  No organelles (How do they get energy?)

Erythrocytes  97% of solid material is hemoglobin  Anemia – reduced oxygen levels low # of erythrocytes low amounts of hemoglobin  Sickle-cell anemia Mutation in hemoglobin gene Reduced malaria risk

Normal vs. Iron Deficiency Anemia

Normal vs. Sickle Cell Anemia

Leukocytes  Defend against disease  Produced in bone marrow  Perform diapedesis

Types of Leukocytes  Granulocytes – contain granules  Neutrophils Most numerous WBC (~60%) Multi-lobed nucleus & pale granules Kill bacteria  Eosinophils Bi-lobed nucleus, reddish granules Kill parasitic worms  Basophils Bluish granules Inflammatory response

Types of Leukocytes  Agranulocytes – lack granules  Lymphocytes About 30% WBC One large nucleus  2 Types T-Lymphocytes (T-Cells) – control immune response B-Lymphocytes (B-Cells) – secrete antibodies  Monocytes  Largest WBC with pale U-shaped nucleus  Become macrophages – “cell eaters”

Normal vs. Leukemia

Platelets  Small cell fragments  Responsible for blood clotting

Sketch & Label

Hemostasis – 3 Phases  Phase One: Platelet plug formation Damage to a blood vessel Exposes collagen fibers Platelets stick to collagen and release chemicals Chemicals attract more platelets

Hemostasis – 3 Phases  Phase Two: Vascular spasms  Platelets release serotonin, causing the blood vessel to spasm and narrow. How is this helpful?

Hemostasis – 3 Phases  Phase Three: Coagulation A “clotting cascade” is triggered:  Damaged tissues release TF (tissue factor)  TF combines with vitamins, ions and clotting factors in the plasma and platelet plug to form prothrombin activator  Prothrombin activator converts prothrombin in plasma to thrombin  Thrombin joins together soluble fibrinogen proteins into long insoluble molecules of fibrin

Tissue Damage (TF) Platelet Plug (PF 3 ) Factors in blood (clotting proteins, Vitamin K, calcium) Prothrombin Activator Prothrombin Thrombin Fibrinogen (soluble) Fibrin (insoluble)

Clotting Cascade (continued)  Fibrin traps red blood cells & contracts, squeezing out plasma & sealing blood vessels

Question to consider…  When you have an open wound, why should you apply gauze and pressure?

Disorders of Hemostasis  Hemophilia

Disorders of Hemostasis  Thrombus  Embolus

Blood Typing - Antigens

Blood Typing - Antibodies

To clarify…

Blood Typing - Agglutination

Blood Typing

Hematopoiesis  Blood cell formation  In red bone marrow  Axial skeleton  Pelvic and pectoral girdles  Humerus & femur

Hemocytoblasts  Stem cells that make all formed elements

Erythropoiesis  Red blood cell production  3 phases: 1. Ribosome synthesis – used to produce hemoglobin 2. Hemoglobin accumulates 3. Nucleus and organelles are ejected

Erythropoietin  Hormone that stimulates erythropoiesis; increases RBC production  Produced by the kidneys  Release controlled by negative feedback The balance between RBC production and destruction is very important!! Why?

Events causing release of erythropoietin… 1. Decreased RBC count 2. Decreased availability of oxygen 3. Increased tissue demands for oxygen What is the variable that is being monitored?

The Spleen  Graveyard for RBC’s  Dying erythrocytes are engulfed and destroyed by macrophages  Hemoglobin gets reused Why do erythrocytes die of old age?

Questions for thought…  How would spending time on the upper slopes of K2 (at right) affect your body’s erythropoietin levels?  How would it affect your blood viscosity?

Questions for thought…  What changes would you expect to see in an athlete who trains at high altitudes? Do you think these are a benefit or detriment to sea- level performance?

Questions for thought…  Blood-Doping  Blood-Doping – illegally boosting the number of RBCs in circulation in order to enhance athletic performance Do you think this should be illegal? How does it differ from high altitude training?