Blood Chapter 17 Bio 125

Polycythemia

(many blood cells) is an abnormal excess of erythrocytes that increases blood viscosity, causing it to sludge, or flow sluggishly (impairing circulation).

Distribution Functions of Blood (3)

1. Delivering oxygen from the lungs and nutrients from the digestive tract to all body cells. 2. Transporting metabolic waste products from cells to elimination sites ( lungs to eliminate CO2 and kidneys to dispose of nitrogenous wastes in urine) 3. Transporting hormones from the endocrine organs to their target hormones

Life Cycle of Red Blood Cells (5)

1. Low O2 levels in blood stimulate kidneys to produce erythropoietin 2. Erythropoietin levels rise in blood. 3. Erythropoietin and necessary raw materials in blood promote erythropoiesis in red bone marrow. 4. New erythrocytes enter blood stream, function about 120 days. 5. Aged and damaged red blood cells are engulfed by macrophages of spleen, liver, and bone marrow; the hemoglobin is broken down.

Regulation Functions of Blood (3)

1. Maintaining appropriate body temperature by absorbing and distributing heat throughout the body and to the skin surface to encourage heat loss. 2. Maintaining normal pH in body tissues. Many blood proteins and other blood borne solutes act as buffers to prevent excessive or abrupt changes in blood pH that could jeopardize normal cell activities. Blood acts as a reservoir for the body's alkaline reserve of bicarbonate ions. 3. Maintaining adequate fluid volume in the blood vessels remains ample to support efficient blood circulation to all parts of the body.

Protection Functions of Blood (2)

1. Preventing blood loss. When damaged, platelets and plasma proteins initiate clot formation, halting blood loss. 2. Preventing infection. Drifting along in blood are antibodies, complement proteins, and WBC's, all help defend body against foreign invaders.

Functions of Erythrocyte

1. Transporting respiratory gases (O2 and CO2)

Three (3) Major steps of Hemostasis

1. Vascular spasm 2. Platelet Plug formation 3. Blood coagulation

Events of hemostasis (3)

1. Vascular spasm- smooth muscle contracts, causing vasoconstriction. 2. Platelet plug formation- Injury to lining of vessel exposes collagen fibers; platelets adhere. a) Platelets release chemicals that make nearby platelets sticky; platelet plug forms. 3. Coagulation- Fibrin forms a mesh that traps red blood cells and platelets, forming the clot.

Thrombopoietin

A hormone that regulates the formation of platelets.

ABO Blood Groups

A person with neither the A nor the B antigen possesses both anti-A and anti-B antibodies, also called a and b agglutinins respectively. Those with group A blood have anti-B antibodies, while those with group B have anti-A antibodies. AB individuals have neither antibody.

Buffy Coat

A thin whitish layer, present at the erythrocyte plasma junction, this layer contains leukocytes

Leukocytosis

A white blood cell count of over 11,000. This condition is a normal homeostasis response to an infection in the body.

Platelet

150,000-400,000 (cells/uL) small, no nucleus granules adhere to site of injury release chemicals to help control blood loss

Antigens or Agglutinogens

Anything the body perceives as foreign and that generates an immune response. Glycoprotein and glycolipid markers.

Hematopoiesis

Blood Cell formation which occurs in red bone marrow

Carbaminohemoglobin

CO2 bound to Hb

Extrinsic Pathways (4)

Called extrinsic because the tissue factor it requires is outside of the blood. Triggered by exposing blood to a factor found in tissues underneath the damaged endothelium. The factor is called tissue factor or factor III. Faster because it bypasses several steps of the intrinsic pathways. In severe tissue trauma, it can for a clot in 15 seconds.

Intrinsic Pathways (3)

Called intrinsic because the factors needed for clotting are present within the blood Triggered by negatively charged surfaces such as activated platelets, collagen, or glass. Slower because it has many intermediate steps.

Platelet

Cell fragment found in blood ; involved in blood clotting

Two Pathways to Prothrombin Activator (2)

Coagulation may be initiated by either the intrinsic or the extrinsic pathway. In the body, the same tissue-damaging events usually trigger both pathways. Outside the body (test tube) only the intrinsic pathway initiates blood clotting.

Platelet

Cytoplasmic fragments of extraordinarily large cells called megakaryocytes.

Functions of Blood

Distribution, Regulation, and Protection

Erythropoiesis

Formation of red blood cells

Two Categories of Leukocytes

Granulocytes~ contain obvious membrane bound cytoplasmic granules Neutrophils (50-70%) Eosinophils (2-4%) Bas0phils (0.5-1%) Agranulocytes ~lack obvious granules Lymphocytes (25-45%) Monocytes (3-8%)

Reduced Hb

H+ binds to hemoglobin (pH buffer)

Eosinophils

Kill parasitic worms, complex role in allergy and asthma account for 2-4% of WBC population and are around same size as neutrophil. They lead the counterattack against parasitic worms that are too large to be phagocytize., as well as play a role in allergies and asthma. They lack enzymes that specifically digest bacteria. Bilobed nucleus, red cytoplasmic granules

Normal Values for Hemoglobin

Male Adult ~ 13-18 (g/100ml) Female Adult~ 12-16(g/100ml)

Normal Hematocrit Values

Males: 47% Females: 42%

Albumin

Most abundant plasma protein. Accounts for 60% of plasma proteins and acts as a carrier to shuttle certain molecules through circulation, is an important blood buffer and is the major blood protein contributing to the plasma osmotic pressure

Lymphocytes

Mount immune response by direct cell attack or via antibodies. account for 25% or more of WBC population are the second most numerous leukocyte in the blood relatively few found in bloodstream are closely associated with lymphoid tissues (lymph nodes, spleen) where they play a crucial role in immunity T Cells fucntion in the immune response by acting directly against virus infected cells and tumor cells B Cells give rise to plasma cells, which produce antibodies that are released to the blood Large spherical nucleus, thin rim of pale blue cytoplasm

Erythrocyte Structural Characteristics

No nuclei or organelles, biconcave flattened discs with depressed center. Spectrin allows erythrocyte to change shape as necessary 1. Its small and biconcave shape provide a huge surface area relative to volume suitable for gas exchange 2. Discounting water content, erythrocyte is over 97% hemoglobin ( molecule that binds to and transports respiratory gases 3. B/C erythrocyte lack mitochondria and generate ATP by aerobic mechanisms they do not consume O2 Very efficient O2 transporters

Plasma

Nonliving fluid component of blood within which formed elements and various solutes are suspended and circulated. Straw colored, sticky fluid, mostly water 90%

Oxyhemoglobin

O2 bound to Hb (bright red)

Deoxyhemoglobin

O2 dissociates from Hb (dark red)

Leukemia

Over production of abnormal white blood cells

Neutrophils

Phagocytize bacteria the most numerous white blood cell ( 50-70%) they are about twice as large as erythrocytes. Neutrophils are our body's bacteria flyers. They are chemically attracted to sites of inflammation and are active phagocytes. Multi-lobed nucleus, pale red and blue cytoplasmic granules

Monocytes

Phagocytosis, develop into macrophages in the tissues. account for 3-8% of WBC population they are the largest leukocyte U or kidney shaped abundant pale-blue cytoplasm purple nucleus They differentiate into highly mobile macrophages with prodigious appetites. Crucial in the body's defense against viruses.

Major Components of Whole Blood

Plasma ~55% of whole blood, least dense component Buffy Coat (Formed Elements) ~ <1% of whole blood, Leukocytes and platelets Erythrocytes (Formed Elements) ~45% of whole blood ( hematocrit), most dense component

Leukopoiesis

Production of White Blood Cells, stimulated by chemical messengers (paracrine or hormones). ~is directed by colony-stimulating factors and interleukins released by supporting cells of the red bone marrow and mature WBCs.

Hemoglobin

Protein that makes red blood cells red, binds easily and reversibly with oxygen and most O2 carried in blood is bound to hemoglobin.

Two Pathways Phase II

Prothrombin activator catalyzes the conversion of a plasma protein called prothrombin into the active enzyme thrombin.

Diapedesis

RBCs are confined to the bloodstream but white blood cells are able to slip out of the capillary blood vessels which is a process called.....

Erythrocytes

Red Blood Cells (RBCs), sacs of hemoglobin molecules that transport the bulk of oxygen carried in the blood and a small percentage of carbon dioxide

Hemoglobin Consists OF:

Red Heme pigment bound to the protein globin Globin consists of four polypeptide chains ( two alpha and two beta)and four heme groups A hemoglobin molecule can transport four molecules of oxygen because each iron atom can combine reversibly with one molecule of oxygen.

Production of Erythrocytes

Red blood cells begin as hematopoietic stem cells and, through erythropoiesis, proceed from the pro erythroblast (committed cell) stage to the basophilic, polychromatic, and orthochromatic erythroblast and reticulocyte stages. During this process, hemoglobin accumulates and the organelles and nucleus are extruded. Differentiation of reticulocytes is completed in blood stream.

Basophils

Release histamine and other mediators of inflammation, contain heparin, an anti coagulant. are the rarest of white blood cells accounting for only 0.5-1% of the leukocyte population, Histamine is an inflammatory chemical that acts as a vasodilator (makes blood vessels dilate) and attracts other WBCs to the inflamed site. Bilobed nucleus, purplish-black cytoplasmic granules

Blood

Special connective tissue in which living blood cells, called the formed elements, are suspended in a non living fluid matrix called plasma.

How long does it take to form red blood cells?

The entire process from hematopoietic stem cell to reticulocyte takes about 15 days.

Hematocrit

The percentage(45%) of total blood volume occupied by erythrocytes

Rh Blood Groups

There are 53 named Rh agglutinogens, each of which is called an Rh factor. Only three of these, the C, D, and E antigens are fairly common. The Rh blood typing system is so named because one Rh antigen (agglutinogen D). About 85% of Americans are Rh+ ( Rh positive), meaning that their RBCs carry the D antigen.

Antibodies or Agglutinins

Unique to the ABO blood groups is the presence in the plasma of preformed antibodies, the agglutinins act against RBCs carrying ABO antigens that are not present on a persons own red blood cells.

Intrinsic Pathway Phase I

Vessel endothelium ruptures, exposing underlying tissues (ex, collagen) Platelets cling and their surfaces provide sites for mobilization of factors.

Composition of Plasma

Water: 90% Solvent for carrying other substances; absorbs heat Solutes: Salts :Most abundance solutes by number Electrolytes : Osmotic Balance, pH buffering Sodium, Potassium, Calcium, Magnesium, Chloride, Bicarbonate, Osmotic balance Plasma Proteins: 8% Albumin ~60% of plasma proteins osmotic balance Fibrinogen ~ 4% of plasma proteins~clotting of blood Globulins~36% of plasma proteins~ defense(antibodies) and lipid transport Substances transported by blood Nutrients~ glucose, fatty acids, amino acids, vitamins, cholesterol Waste products of metabolism(Nonprotein nitrogenous substances)~ urea, uric acid,creatine, and ammonium salts Respiratory gases O2 and CO2 Hormones

Erythropoietin (EPO)

a glycoprotein hormone, stimulates the formation of erythrocytes.

Citrate

added to blood when donated or for tests binds to calcium unavailable for clotting

ABO blood groups

are based on the presence or absence of two agglutinogens, Type A and Type B. Depending on which of these a person inherits, the ABO blood group will be one of the following: A, B, AB, or O. The O blood group, which has neither agglutinogen, is the most common ABO group. AB, with both antigens, is least prevalent. The presence of either the A or the B agglutinogen results in group A or B.

Platelets

are fragments of large megakaryocytic formed in red marrow. When a blood vessel is damaged, platelets form to plug to help prevent blood loss and play a central role in the clotting cascade.

Leukocytes (WBCs) White Blood Cells

are the only formed elements that are complete cells, which nuclei and the usual organelles, they are crucial to our defense against disease.

Formed elements of blood

cellular portion of blood erythrocytes, leukocytes, and platelets

Type A

contains agglutinogen A, agglutinates with anti-A

Type B

contains agglutinogen B, agglutinates with anti-B

Type AB

contains agglutinogens A and B, agglutinates with both sera

Type O

contains no agglutinogens, does not agglutinate with either serum

Warfarin (Coumadin)

disrupts vitamin K activity

Hemocytoblast

gives rise to all blood cells

Sickle Cell Anemia

havoc caused by the abnormal hemoglobin (Hbs), results from a change in just one of the 146 amino acids in a beta chain of the globin molecule, leaving victims gasping for air and in extreme pain.

Infectious Mononucleosis

highly contagious viral diseases, excessive number of agranulocytes.

Granulocytes

include neutrophils, eosinophils, and basophils are all roughly spherical in shape. They are larger and much shorter lived than erythrocytes. They have lobed nuclei, functionally all granulocytes are phagocytes to some degree

Heparin

inhibits thrombin formation

Two Pathways to Prothrombin Activator

intrinsic extrinsic

Essential for production of hemoglobin

iron, vitamin B12, and folic acid.

Anemia

is a condition in which the bloods oxygen carrying capacity is too low to support normal metabolism. Individuals are fatigued, often pale, short of breath and chilled.

Blood doping

is artificially inducing polycythemia, RBCs are stored and after few days rein fused, the additional infusion should increase O2 carrying capacity due to a higher hematocrit, hence greater speed and endurance.

Hemostatsis

is prevention of blood loss.

Aspirin

keeps platelets from sticking together + prevents their release of clotting substances

ABO Blood Typing

system of blood classification based on the presence of specific glycoproteins on the outer surface of the RBC plasma membrane.