Pearson's Comprehensive Medical Assisting Administrative and Clinical Competencies THIRD EDITION CHAPTER 27 The Cardiovascular System Lesson 2: Composition and Function of
Lesson Objectives Upon completion of this lesson, students should be able to: 1. Define and spell the terms to learn for this chapter. 2. List and describe the components of blood.
Lesson Objectives Upon completion of this lesson, students should be able to: 3. Discuss the importance of blood typing and cite which blood types are compatible. 4. State the difference between Rhpositive blood and Rh-negative blood.
Type of connective tissue composed of: cells Formed elements of blood Plasma Fluid portion of blood volume Amount of blood circulating in individual's body Average adult approximately 5 liters
Formation of blood cells (hematopoiesis) takes place primarily in bone marrow
Composition of Erythrocytes Red blood cells Leukocytes White blood cells Neutrophils Eosinophils Basophils Lymphocytes Monocytes
Composition of Platelets Thrombocytes
FIGURE 27-13 The formed elements of blood.
Red Cells (RBCs) Also known as erythrocytes Produced in red bone marrow Mature red blood cells do not contain nuclei but do contain hemoglobin
Red Cells (RBCs) Function of hemoglobin is to carry oxygen from lungs to cells throughout body RBC count Number of red blood cells in 1 cubic mm of blood (between 4 and 6.5 million)
White Cells Also known as leukocytes Larger than RBCs Have a nucleus Lack hemoglobin Translucent 5,000 to 11,000 per cubic mm of blood Fight infection Important contributors to homeostasis
White Cells Granulocytes have granules in cytoplasm Neutrophils Eosinophils Basophils Agranulocytes do not contain granules Monocytes Lymphocytes
Platelets Also known as thrombocytes Fragments of larger cells formed in red bone marrow Control loss of blood by coagulation 130,000 to 360,000 per cubic mm of blood
Plasma Liquid portion of blood 91 percent water 9 percent mixture of proteins, nutrients, gases, electrolytes, fats, hormones, enzymes, waste products
Plasma 55 percent of total volume of whole blood Albumin helps maintain fluid volume in blood, thereby controlling blood pressure
Functions of Transportation moves from heart to all tissues of body transports oxygen from lungs and nutrients from digestive tract Organs and tissues secrete hormones into blood; transports to other organs and tissues
Functions of Transportation picks up waste materials from cells later filtered and excreted
Functions of Regulation Helps to regulate body temperature Plays key role in maintaining body's water salt balance Helps body regulate the ph (acid/alkaline) balance of body
Functions of Defense Leukocytes defend body against pathogens such as bacteria and viruses Phagocytosis Neutrophils and monocytes engulf and destroy pathogens
Functions of Defense Lymphocytes secrete antibodies into blood When an injury occurs, platelets form a clot, thus preventing blood loss Hemostasis When bleeding has stopped
Types Determined by presence or absence of certain antigens and antibodies Agglutination (clumping) occurs when antigen on surface of RBCs binds to antibodies in plasma Presence of anti-a and anti-b antibodies in plasma requires blood be typed and cross-matched for transfusions
FIGURE 27-14 typing and cross-reactions. The blood type depends on the presence of surface antigens (agglutinogens) on RBC surfaces. (A) The plasma antibodies (agglutinins) that will react with foreign surface antigens; (B) in a cross-reaction, antibodies that encounter their target antigens lead to agglutination and hemolysis of the affected RBCs.
Types Type A Type A antigen on surface of red blood cells and anti-b antibody in plasma; people with Type A blood can only be given Type A blood Type B Type B antigen on surface of red blood cells and anti-a antibody in plasma; people with Type B blood can only be given Type B blood
Types Type AB Type AB has both antigens A and B on red blood cell surfaces and neither anti- A nor anti-b antibodies People with type AB blood considered universal recipients because majority can receive all ABO blood types because of lack of antibodies in their plasma
Types Type O Neither A nor B antigens are found on red blood cells; both anti-a and anti-b antibodies are in plasma People with type O blood considered universal donors because their blood can be administered to most people regardless of recipient's blood type
Types The Rh Factor Based on antigen discovered on RBCs of Rhesus monkey (hence name Rh) Rh-positive RBCs that contain Rh antigen
Types The Rh Factor Rh-negative Does not have Rh antigen If someone who is Rh-negative is given Rh-positive blood, the Rh-negative blood will form antibodies in response to exposure to Rh antigens
Types The Rh Factor If Rh-negative person is given Rhpositive blood on a second occasion, antibodies will bind to donor cells and agglutination will occur, precipitating a transfusion reaction
Types The Rh Factor Rh factor plays important role during pregnancy; vital a woman know her Rh type Erythroblastosis fetalis Baby born severely anemic; prevented by giving drug RhoGAM to Rh-negative mother
Questions?