CARDIOVASCULAR SYSTEM

Blood

Blood – General Characteristics

Blood is C.T.Plasma = Liquid Matrix55% Plasma, 45% Formed Elements

(Cells)Hemopoiesis (Stem Cells in Bone Marrow

give rise to Cell types)

General Characteristics continued

Avg. Vol. = 4.5 to 5.5 literspH = 7.35 to 7.45Formed Elements:

- Erythrocytes (RBCs)

- Leukocytes (WBCs)

- Thrombocytes (Platelets)

Blood - Functions

Transports (Gases, Nutrients, Hormones)Regulates pH & Electrolyte Balance in

Interstitial FluidPrevents Fluid Loss from BleedingDefends against Pathogens & ToxinsAids in Body Temperature Regulation

Components - Plasma

Liquid Component of Blood92% Water7% Proteins:

- Albumins (Most Abundant, Osmotic Pressure)- Globulins (Antibodies, Transport Proteins,

Lipoproteins)- Fibrinogen (Clotting)

1- 2% Inorganic Salts, Carbohydrates, Lipids, Hormones, Gases, Wastes, etc.

Components - Erythrocytes

Red Blood Cells (RBCs)Most Abundant Blood CellBiconcave Discs (shaped like “LifeSaver”)Shape increases Surface Area/Volume

RatioAnucleate when matureLive 120 Days

Figure 17.3

Erythrocytes - continued

Hemoglobin (Hb)- Red Pigment- Contains 4 Heme Groups (Fe++)- Reversibly binds Oxygen

- In High [O2], Binds O2 OxyHb (Bright Red)

- In Low [O2 ], Releases O2 DeoxyHb (Darker)

Erythrocytes - continued

Hematocrit = % RBCs in BloodRBC Count = # RBCs/mm3

- Males: 4.6 – 6.2 X 106/mm3

- Females: 4.2 – 5.4 X 106/mm3

2 million produced/secondHumans have over a trillion RBCsBlood is 4X thicker than waterProduction with O2 or Blood Loss

Fate of ErythrocytesFate of Erythrocytes

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Unable to divide, grow, or synthesize proteins

Wear out in 100 to 120 days

Removed by phagocytes in the spleen or liver

New RBCs made by stem cells in bone marrow

Erythrocyte Disorders

Anemia (RBC or Hb Deficiency)- Hemorrhagic (Blood Loss)- Hemolytic (RBC Destruction)- Aplastic ( Bone Marrow Function)- Sickle Cell (Inherited Hb Mutation)

Polycythemia (Abnormal in RBCs) Viscosity & B.P. with O2 Delivery- Cyanosis, Blood Clots

Components - Leukocytes

White Blood Cells (WBCs)Defend Against MicrobesUse Blood for Transport, But Occur

Mostly Outside Circ. System in TissuesDiapedesis – Squeeze through Capillary

WallsAmeboid Motion to move once outside

bloodstream

Leukocytes - continued

Chemotaxis – Chemicals released from sites of damage or inflammation attract WBCs

Phagocytosis – ingestion of bacteria, debrisFive Types Based on:

- Size- Nuclear Shape- Cytoplasmic Granules- Affinity for Stain

Types of LeukocytesTypes of Leukocytes

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Leukocyte Types

Granulocytes- Cytoplasmic Granules - Differential Staining of Granules- Approx. 2X Size of RBC- 3 Types:

* Neutrophils65% of Circulating WBCsNucleus has 2-5 Lobes

Types of Leukocytes

L to R: lymphocyte, basophil, monocyte, neutrophil, eosinophil

Leukocyte Types - continued

Neutral Rxn to Stain (Light Pink to Purple)

Phagocytes in Bacterial Infections

* Eosinophils (Acidophil)1-3% of Circulating WBCsOrange/Red Granules (Acidic Rxn)Bilobed Nucleus

Types of Leukocytes

L to R: lymphocyte, basophil, monocyte, neutrophil, eosinophil

Leukocyte Types - continued

Active in Detoxifying Foreign Proteins in Allergies, Parasitic Infections

* Basophils½ - 1% of Circulating WBCsDark Blue/Black Granules (Basic Rxn)Granules Contain: Histamine, Heparin,

Seratonin

Types of Leukocytes

L to R: lymphocyte, basophil, monocyte, neutrophil, eosinophil

Leukocyte Types - continued

Agranulocytes- No Staining Granules- 2 Types:

* Monocytes3-9% in Circulating WBCsLargest WBCNucleus is Kidney-bean, oval in

shapeBecome Phagocytic Macrophages

Types of Leukocytes

L to R: lymphocyte, basophil, monocyte, neutrophil, eosinophil

Leukocyte Types - continued

* Lymphocytes30% Circulating WBCsSmallest WBCLarge, Spherical Nucleus, Little

CytoplasmProduce Antibodies

Leukocyte Disorders

Normal WBC Count 5,000 – 10,000/mm3

Leukemia – Uncontrolled Production of WBCs with Immature WBCs in Circulation- Myeloid ( Granulocytes from Myeloid

Stem Cells)- Lymphoid ( Lymphocytes from Lymphoid

Stem Cells)

HematopoiesisHematopoiesis

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Components - Thrombocytes

Cellular fragments (Megakaryocyte reside in bone marrow)

130,000 – 360,000/mm3

Active in Hemostasis (Stoppage of Bleeding)

Hematopoiesis (Hemopoiesis)

Process of Blood Cell FormationOccurs in Yolk Sac, Liver & Spleen

(fetus); Red Bone Marrow (adult)Involves Stem Cells (Hemocytoblasts) &

Series of StepsErythropoietin = Kidney Hormone,

RBCs

HematopoiesisHematopoiesis

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Hemostasis

Stoppage of BleedingRequires Vitamin K and Ca2+

3 Phases:- Vascular

* Blood Vessel Spasm* Direct Stimulus to Vessel or

Neurotransmitter from Platelets* Small Vessels

Hemostasis - continued

- Platelet* Platelet Plug Formation* Platelets Become Sticky & Adhere to

Endothelium, Collagen, & to One Another* Larger Vessels

- Coagulation (Blood Clotting)* Most Effective, But Delayed

Coagulation - continued

*Complex, Multi-substance, Multi-step Prothrombin Activator (PA or

thromboplastin) Released by Damaged Tissue & Platelets

PA (with Ca2+ & other factors) Converts Prothrombin into Thrombin

Thrombin Converts Fibrinogen into Fibrin (Insoluble)

Coagulation - continued

Fibrin Sticks to Damaged Edges, Forms Meshwork

Platelets, Blood Cells Stick to Meshwork, Clot Forms

Clot Later Retracts, Squeezes out Serum (plasma minus fibrinogen, & other clotting factors)

Abnormal Clot Formation

Thrombus – Clot Formed in Uninjured Vessel

Embolus – Thrombus, Broken Loose & Moved- Pulmonary Embolism (Lung Clot, Formed

Elsewhere)- Coronary Embolism (Clot in Coronary

Vessel, Formed Elsewhere)

Thrombus in Artery

Human Blood Types

InheritedInvolves Identifying Antigens on cell

membrane of RBCs (Agglutinogens)Must Avoid Agglutination (RBC Clumping

due to Antigen-Antibody Reaction)ABO and Rh Typing Significant in

Transfusions

ABO Typing - continued

ABO Typing Based on 2 Agglutinogens:- A Antigen & B Antigen- 4 Types:

* Type AA Antigen Only41% of US

* Type BB Antigen Only9% US

ABO Typing - continued

* Type ABBoth A & B Antigens3% USUniversal Recipient

* Type ONeither Antigen47% USUniversal Donor

ABO Typing - continued

Antibodies (Agglutinins)- In Plasma- Appear Spontaneously After Birth- Bind to Foreign Antigens- 2 Types:

* Anti-A (in Types B, O)

* Anti-B (in Types A, O)

ABO Typing - continued

Compatibility involves Matching RBCs of Donor (i.e.Antigens) & Immune System (Potential Antibodies) of Recipient

Type A can receive: Type A, Type OType B can receive: Type B, Type OType AB can receive: Types A, B, AB, OType O can Receive: Type O

Blood Typing

Human Blood Types - continued

Rh Typing Based on Factor Present on RBC

If Factor Present, Rh+If Factor Absent, Rh-Antibodies appear in Rh- persons only

after exposure. Subsequent exposure results in agglutination.

Rh Typing - continued

Erythroblastosis Fetalis (or HDN)- Occurs when Rh- Mom Pregnant with Rh+ Fetus

- Mixing of Maternal & Fetal Blood at Birth

- Mom then Starts to Produce Anti-Rh

- With 2nd Rh+ Fetus, Anti-Rh Passes from Mom to Fetus

- Fetal RBC Destruction

- Rhogam Prevents Mom from Producing Anti-Rh