Blood Review

Transport Functions of Blood

Blood transports oxygen, carbon dioxide, nutrients, hormones, and waste products.

Body Temperature Regulation by Blood

Blood helps maintain body temperature.

Blood pH Range

The normal pH range of blood is approximately 7.35 to 7.45.

Average Blood Volume in Adults

The average blood volume in adults is about 5-6 liters.

Percentage of Body Weight Contributed by Blood

Blood is approximately 7-8% of body weight.

Components of Blood

Plasma (55%), Red Blood Cells (45%), White Blood Cells (<1%), Buffy Coat (contains leukocytes and platelets).

Complete Cell in Blood

The only formed element of blood that is a complete cell is the White Blood Cell (WBC).

Formed Elements in the Buffy Coat

The formed elements that make up the buffy coat are Leukocytes and Platelets.

True Hematocrit

True hematocrit represents the proportion of blood volume occupied by red blood cells measured directly.

Clinical Hematocrit

Clinical hematocrit is often measured through centrifugation of whole blood samples.

Normal Male Erythrocyte Count

Normal erythrocyte counts for men are typically around 4.7 to 6.1 million cells per microliter.

Normal Female Erythrocyte Count

Normal erythrocyte counts for women are typically around 4.2 to 5.4 million cells per microliter.

Composition of Blood Plasma

Plasma is composed of 90% water, 7% proteins, and 3% other substances.

Albumin

A plasma protein that maintains osmotic pressure, produced in the liver.

Globulins

Plasma proteins involved in immune response, produced in the liver and lymphatic tissue.

Fibrinogen

A plasma protein essential for blood clotting, produced in the liver.

Role of Plasma Proteins

Plasma proteins maintain colloid osmotic pressure vital for proper fluid distribution in tissues.

Definition of Hemopoiesis

The process of blood cell formation from stem cells, primarily occurring in the bone marrow.

Significance of Hemocytoblasts

Hemocytoblasts are multipotent stem cells that can differentiate into all types of blood cells.

Multipotent Stem Cell Definition

A stem cell that can develop into multiple types of related cells.

Location of Hemopoiesis

Hemopoiesis mainly occurs in the red bone marrow of long bones, pelvis, and sternum.

Erythropoiesis

The process of producing red blood cells from stem cells, requiring erythropoietin (EPO).

Reticulocytes

Immature red blood cells that indicate the rate of erythropoiesis.

Leukopoiesis Process

The process of producing white blood cells.

Role of Lymphoid Stem Cells

Lymphoid stem cells produce lymphocytes.

Role of Myeloid Stem Cells

Myeloid stem cells produce other blood cells such as erythrocytes and platelets.

Thrombopoiesis Definition

The production of platelets from megakaryocytes.

Function of Megakaryocytes

Megakaryocytes are large bone marrow cells that fragment to release platelets.

Structure of Erythrocytes

Erythrocytes are biconcave disks that lack a nucleus.

Function of Erythrocytes

Erythrocytes transport oxygen from the lungs to tissues and carbon dioxide back to the lungs.

Biconcave Shape of Erythrocytes

The biconcave shape allows flexibility and maximizes oxygen-carrying capacity.

Hemoglobin Function

Hemoglobin binds oxygen in red blood cells.

Oxygen Binding in Hemoglobin

Oxygen binds to the iron in the heme portion of hemoglobin.

Function of Erythropoietin (EPO)

EPO stimulates the production of red blood cells in response to low oxygen levels.

Hormonal Negative Feedback in Erythropoiesis

As oxygen levels increase, the production of EPO decreases, regulating red blood cell production.

Fate of Erythrocyte Destruction

Components are recycled; iron is reused for new hemoglobin production.

Anemia Definition

A condition where there is a deficiency in red blood cells or hemoglobin.

Definition of Antigen

A molecule capable of inducing an immune response, found on the surface of red blood cells.

Role of Surface Antigens on RBCs

Surface antigens determine the blood group type (A, B, AB, O).

Antigen on Blood Type A

Type A blood has A antigens on RBCs and anti-B antibodies in plasma.

Blood Type A Compatibility

Can receive from A, O and can donate to A, AB.

Antigen on Blood Type B

Type B blood has B antigens on RBCs and anti-A antibodies in plasma.

Blood Type B Compatibility

Can receive from B, O and can donate to B, AB.

Antigens on Blood Type AB

Type AB blood has A and B antigens on RBCs and no anti-A or anti-B antibodies.

Blood Type AB Compatibility

Can receive from A, B, AB, O and can donate to A, B, AB.

Antigens on Blood Type O

Type O blood has no antigens on RBCs and anti-A, anti-B antibodies in plasma.

Blood Type O Compatibility

Can receive O and can donate to A, B, AB, O.

Rh Antigen Presence

The presence of Rh antigen classifies blood as Rh positive; absence classifies it as Rh negative.

Rh Positive Blood Compatibility

Can receive from Rh+ and Rh- but can only donate to Rh+.

Rh Negative Blood Compatibility

Can only receive from Rh- but can donate to Rh+ and Rh-.

Anti-Rh Antibody Development

Develops only in Rh negative individuals following exposure to Rh positive blood.

Consequences of Incorrect Blood Transfusion

Can lead to agglutination and hemolytic reactions, which can be life-threatening.

Universal Donor Definition

Type O- (no A/B antigens, Rh negative) can donate to all blood types.

Universal Recipient Definition

Type AB+ (no antibodies against A, B, or Rh antigens) can receive from all blood types.

Erythroblastosis Fetalis Event

Occurs when an Rh- mother carries an Rh+ fetus, causing production of anti-Rh antibodies.

Common Characteristics of Leukocytes

Leukocytes have nuclei, lack hemoglobin, and are involved in immune responses.

Diapedesis Definition

The movement of leukocytes out of the bloodstream into tissues.

Chemotaxis Definition

Movement of cells towards sites of injury or infection guided by chemical signals.

Granulocytes Characteristics

Contain granules in their cytoplasm.

Agranulocytes Characteristics

Lack visible cytoplasmic granules.

Most Abundant Leukocyte

Neutrophils are the most abundant type of leukocyte.

Function of Neutrophils

Phagocytosis of bacteria.

Function of Lymphocytes

Adaptive immune response involving B and T cells.

Function of Monocytes

Phagocytosis and differentiation into macrophages.

Function of Eosinophils

Combat parasitic infections and allergic reactions.

Function of Basophils

Release histamine in allergic responses.

Function of T Lymphocytes

Cell-mediated immunity.

Function of B Lymphocytes

Antibody production.

Function of Natural Killer Cells

Attack virus-infected and tumor cells.

Leukemia Definition

A type of cancer characterized by excessive production of abnormal white blood cells.

Structure of Platelets

Platelets are fragments of megakaryocytes and not whole cells.

Function of Platelets

Essential for blood clotting and maintaining hemostasis.

Hemostasis Definition

The overall process to stop bleeding.

Coagulation Definition

The specific process of blood clotting involving protein cascades.

Vascular Phase of Hemostasis

Involves vascular spasm in response to endothelial cell injury.

Platelet Phase of Hemostasis

Involves platelet plug formation adhering to the injury site.

Coagulation Phase of Hemostasis

Fibrin clot formation through conversion of fibrinogen to fibrin.

Role of Endothelial Cells in Hemostasis

Release substances promoting vasoconstriction to reduce blood loss.

Steps in Platelet Plug Formation

Platelets adhere to collagen, become activated, and aggregate.

Formation of Fibrin Clot

Fibrinogen is converted to fibrin by thrombin to stabilize the platelet plug.

Intrinsic Clotting Mechanism

Triggered by damage to blood vessels; uses factors already in the blood.

Extrinsic Clotting Mechanism

Triggered by external tissue damage; involves tissue factor.

Common Pathway of Coagulation

Both intrinsic and extrinsic pathways converge at factor X.

Positive Feedback in Hemostasis

Platelets release substances to attract more platelets for enhanced clotting.

Role of Calcium Ions in Clotting Process

Calcium ions are essential for activating clotting factors.

Fibrinolysis Process

Involves the breakdown of fibrin in a clot by plasmin.

Importance of Fibrinolysis

Prevents excessive clotting and allows for tissue remodeling.

Definition of Thrombus

A stationary clot within a blood vessel.

Definition of Embolus

A clot that has broken loose and travels through the bloodstream.

Definition of Embolism

The obstruction of a blood vessel by an embolus.