cardiovascular system: blood nestor t. hilvano m.d., m.p.h

Cardiovascular System: BLOOD

Nestor T. Hilvano M.D., M.P.H.

Learning Objectives 1. Describe the components and functions of blood.2. Identify the sites of blood collection.3. Describe the types of formed elements of blood as to

structures and functions.4. Describe the structure and functions of hemoglobin.5. Discuss the importance of blood typing and the basis for

ABO and RH incompatibilities.6. Discuss the mechanisms that control blood loss after an

injury. 7. Compare and contrast common abnormalities of blood

based on structure and function.

Introduction • Cardiovascular system consists of

1._____ - a pump

2._____ - conducting structures

3._____ - fluid medium • Blood collection for analysis

1.____ – superficial vein; commonly used

2.____ – arterial stick; blood gases a. Blood

b. Blood vessels

c. Heart

d. Arterial puncture

e. Venipuncture

Blood• Blood volume (7% of body wt.) = 4 -6 L • Main Components of blood are:

1. ____, liquid portion (50 – 60% of blood volume) in circulation.

2. ____, blood cells and cells fragments suspended.* _____- liquid in test tube after forming a blood clot

• General characteristics – temperature

38°C (100.4°F); high viscosity; sl. Alkaline(pH 7.35- 7.45) • Functions – transportation of gas/nutrient; protection;

regulation of pH/ions; stabilization of body temp.; restriction of fluid losses at injury sites

a. Formed elements b. Plasma c. Serum d. Lymph

Plasma composition • Plasma proteins

1. ____ - most abundant; contributes to viscosity and osmolarity.

2. ____ - provide immune system functions.3. ____ - precursor of fibrin threads that help form blood

clots.a. fibrinogen b. globulin c. albumin d. prothrombin

• Nitrogenous compounds (organic wastes)– Urea, uric acid, creatinine, bilirubin, ammonium ions

1.Nutrients - glucose, vitamins, fats, minerals, etc

2.O2 and CO2

3.Electrolytes - Na+ makes up 90% of plasma cations

Formed elements• RBC = erythrocytes• WBC = leucocytes

a) granular- neutrophils, eosinophils, basophils

b) agranular- lymphocytes, monocytes • Platelets = thrombocytes• _______ – process of producing formed

elements, from myeloid and lymphoid stem cells.

a. Hemopoiesis b. Hemolysis c. Erythropoiesis d. Granulopoiesis

Erythrocytes• biconcave shaped cell; 7.5 M diameter• What is the major function? • also produce carbonic anhydrase, important

role in pH balance• lifespan 120 days• 33% of cytoplasm is hemoglobin

Hemoglobin Structure• Globin - 4 protein chain• Heme groups - conjugate with each protein chain;

binds oxygen to ferrous ion (Fe2+)

• Function of Hgb - O2 delivery to ______ and CO2 transport to _____.

Erythrocytes and Hemoglobin

• RBC count and Hemoglobin concentration indicate amount of O2 blood can carry

– hematocrit (packed cell volume) - % of RBC in centrifuged whole blood

• men 40- 54% cells; women 37- 47% cells• after blood loss – hematocrit reduced

– hemoglobin - concentration of whole blood• men 14-18g/dL; women 12-16g/dL• Hgb – responsible to transport O2 and CO2

– RBC count • men 4.6-6.2 million/L; women 4-2-5.4 million/L

Erythrocyte Formation & Homeostasis• Negative feedback control

– drop in RBC count causes hypotension, stimulate liver and kidney to secrete ______; which in turn stimulates bone marrow for Erythropoiesis. .

– RBC count in 3 - 4 days

• Stimuli for erythropoiesis – low O2 level/reduced blood flow; exercise; emphysema

• ____ What is the youngest or immature RBC found in circulation?

• Erythropoitin c. nromoblasts • Reticulocytes d. erythroblasts

Erythrocyte Disorders• _______ - an excess of RBCs

– increased blood volume, pressure, viscosity • can lead to embolism, stroke or heart

failure• _______ - inadequate erythropoiesis or

hemoglobin synthesis

- causes: iron deficiency, decrease B12 or intrinsic factor, hemolysis or hemorrhage

• Sickle cell anemia– mutation in amino acid sequence of beta chains of Hgb; RBC stiff and curved

a. anemia b. polycythemia

Blood Type• Blood type is determined by presence or absence

of surface antigen on RBCs– type A person has A antigens, anti-B (antibody)– type B person has B antigens, anti A– type AB has A & B antigens, no anti-A & no anti-B– type O has no antigens, with anti-A & anti-B

• Most common blood type: ___• Rarest blood type: ____• Universal donor: _____• Universal recipient: ____

Rh Group• Rh (D) agglutinogen (surface antigen)

– Rh+ blood type has D (Rh) antigen on RBCs

• Anti-D agglutinin (antibody) not normally present– form in Rh- individuals exposed to Rh+ blood

• Rh- woman with an Rh+ fetus or transfusion of Rh+ blood

• no problems with first transfusion or pregnancy due to low titer

• Hemolytic disease of newborn also called erythroblastosis fetalis.

Blood Typing

Identify the blood types in doing a cross match:

___ 1. + RBC clumps (agglutination) in anti-A and anti-D

___ 2. + RBC clumps in anti-B and anti-D

___ 3. + RBC clumps in anti-A, anti-B, and anti-D

___ 4. negative clumps in anti-A, anti-B, and anti-D

a.O-

b.AB+

c.B+

d.A+

Leukocytes (WBC)• Normal count = _________ WBCs/L• Granulocytes - neutrophils (60-70%), eosinophils (2-4%),

basophils (<1%); Agranulocytes - lymphocytes (25-33%); monocytes (3-8%)

• What type of WBC is elevated in:

___ - acute bacterial infection?

___ - viral, cancer, and chronic infections?

___ - allergy and parasitism?

___ - anaphylaxis and bronchial asthma? a. Basophils

b. Eosinophils

c. Lymphocytes

d. Neutrophils

Leukopoiesis

• Pluripotent stem cells• Committed stem cells

- Myeloblasts

- Monoblasts

- Lymphoblasts

• Leukocytes disorders

- leukopenia

- leukocytosis

- leukemia

Platelets (Thrombocytes)• Formed from fragmentation of _______• Normal Count - 150,000 to 500,000 platelets/L• biconvex shape• Thrombocytopenia• Thrombocytosis • Functions

– Secrete clotting factors– Temporary patch in walls of damaged b.v. – Contract after clot has formed

Hemostasis• Stop bleeding• Mechanisms

1. Vascular phase

2. Platelet phase

3. Coagulation phase

a. Involve coagulation factors, forming insoluble, blood clot in a vessel

b. Platelets adherence and formed platelet plug in a vessel

c. Smooth muscle contraction in the vessel wall

Coagulation Phase

• Most effective defense against bleeding– conversion of fibrinogen into insoluble

________ threads to form a _______. • Involves procoagulants (clotting factors) present

in plasma, extrinsic pathway (damaged tissues), and intrinsic pathway (factors found in blood)

• Completion of coagulation: – Activation of Factor X leads to production of

prothrombin activator– Prothrombin activator converts prothrombin to

______– Thrombin converts fibrinogen into _______

Fate of Blood Clots• Clot retraction = occurs within 30 minutes

reducing bleeding and reduces size of damaged area to complete repair.

• Fibrinolysis = dissolution of a clot– activation of plasminogen into plasmin, a fibrin-

dissolving enzyme

• Coagulation disorders

___________ - abnormal clotting within a vessel

___________ - clot traveling in a vessel

Infarction/ stroke may occur if clot blocks blood supply to an organ.

a. embolus b. thrombus c. aneurysm d. hemorrhage

Homework (Self-Review) 1. Define the following terms: - plasma, serum, anemia,

polycythemia, hematocrit, hemoglobin, hemolytic disease of newborn, surface antigens, leukocytosis, leukopenia, embolus, thrombus, and hemostasis.

2. Discuss the coagulation phase to stop bleeding.

3. Describe briefly plasma and formed elements of blood.

4. Identify the blood cell types elevated in: acute bacterial infection, anaphylaxis (B. asthma), viral infection (chronic diseases and cancer) and, parasitism and allergy.

5. What blood type can be safely transfused into a person with Type A, Type B, Type AB, and Type O blood?

6. Differentiate venipuncture and arterial puncture of blood withdrawal.