CHAPTER 14THE CARDIOVASCULAR SYSTEM: BLOOD

List the components and functions of blood components.

List the components and functions of blood plasma.

Describe the various mechanisms that prevent blood loss.

Understand blood typing and transfusions.

OBJECTIVES

TRANSPORTATION◦ Oxygen

From lungs to cells◦ Carbon Dioxide

Waste product of cellular respiration◦ Nutrients

From gastrointestinal tract to body cells◦ Heat and Waste

Away from cells◦ Hormones

From endocrine glands to other body cells

FUNCTIONS OF BLOOD

REGULATION◦ pH

Of body fluids◦ Body temperature

Heat-absorbing and coolant properties of water in blood plasma

Flow of water through skin for cooling◦ Water content of cells

Through blood osmotic pressure

FUNCTIONS OF BLOOD

PROTECTION◦ Prevents blood loss through clotting◦ Combats microbes and toxins through action of

certain phagocytic white blood cells or specialized plasma proteins

◦ Interferon and complements are proteins that help protect against disease

FUNCTIONS OF BLOOD

Viscosity (stickiness or thickness; resistance to flow) ◦ greater than that of water

Temperature range 38C or 100.4F. pH range between 7.35 and 7.45

◦ Is this alkaline or acidic? 8% of total body weight.

Volume in average-sized adult male body ◦ 5 to 6 liters or 1.5 gallons.

Volume in average-sized adult female body◦ 4 to 5 liters or 1.2 gallons.

COMPONENTS OF WHOLE BLOOD

Whole blood composed of two portions◦ 55% blood plasma

Liquid containing dissolved substances◦ 45% formed elements

Cells and cell fragments

Hematocrit: percentage of total blood volume occupied by red blood cells (99% of formed elements are red blood cells)

Buffy coat: thin layer of platelets and pale colorless white blood cells; less than 1% of blood volume

COMPONENTS OF WHOLE BLOOD

Straw-colored liquid left when formed elements removed from blood blood plasma

Composition:◦ 91.5 % water◦ 7% proteins◦ 1.5% solutes

Principle solutes include:◦ Proteins (Albumins, Globulins, and Fibrinogen)◦ Nutrients ◦ Hormones ◦ Respiratory gases◦ Electrolytes◦ Waste products

Blood Plasma

Red Blood Cells (RBCs) White Blood Cells (WBCs)

◦ Granular leukocytes Neutrophils Eosinophils Basophils

◦ Agranular leukocytes T and B lymphocytes and natural killer cells Monocytes

Platelets

Formed Elements

Hemopoiesis: process through which formed elements develop from pluripotent stem cells in red bone marrow

  Before birth hemopoiesis occurs in yolk sac of an

embryo Fetal hemopoiesis occurs in the liver, spleen,

thymus, and lymph nodes Hemopoiesis during the last three months before

birth occurs in red bone marrow and continues there throughout life

Formation of Blood Cells

Red bone marrow is derived from mesenchymal cells called pluripotent stem cells

Hormones stimulate pluripotent stem cells into two other types of stem cells:◦ Myeloid stem cells

Differentiate into red blood cells, platelets, eosinophils, basophils, neutrophils, and monocytes

◦ Lymphoid stem cells Differentiate into T and B lymphocytes

Formation of Blood Cells

Aka: ERYTHROCYTES

Hemoglobin oxygen-carrying pigment◦ Gives whole blood its red color

STRUCTURE OF RBCs:◦ Biconcave discs◦ 7-8µm in diameter (1µm = 1/25,000 of an inch)◦ No nuclei or other organelles◦ Cannot divide ◦ Do no carry on any extensive metabolic activity

Composed of : ◦ Selectively permeable plasma membrane◦ Cytosol◦ Hemoglobin

Healthy male has about 5.4 million RBCs/µL of blood Healthy female has about 4.8 million RBCs/µL of blood

Red Blood Cells(RBCs)

Live about 120 days◦ Wear and tear on plasma membrane squeezing

through capillaries necessitates replacement…

RBC LIFE CYCLE

(1) Macrophages in spleen, liver, and red bone marrow through the process of phagocytosis rupture worn-out red blood cells splitting apart the globin and heme portions of hemoglobin.

(2) Globin broken down into amino acids (to be used in protein synthesis).(3) Iron removed from heme portion associates with plasma protein called

transferrrin.(4) Iron-transferrin complex goes to red bone marrow for RBC precursor cells

to use in hemoglobin synthesis. IRON NEEDED FOR HEME PORTION OF HEMOGLOBIN, AMINO ACID NEEDED FOR GLOBIN.

◦ Also needed: Vitamin B12_ and Intrinsic factor. Intrinsic Factor protein produced in stomach lining

(5) Erythropoiesis is the process in red bone marrow that results in production of new red blood cells.

(6) Iron removed from heme, non-iron portion converted to hiliverdin, a green pigment, and then into bilirubin, a yellow-orange pigment. Bilirubin enters blood and is transported to the liver, where it is secreted into bile. Bile goes to small intestine then large intestine.(7) Bacteria in large intestine converts bilirubin into urobilinogen, which is absorbed back into the blood, and converted to a yellow pigment called urobilin, which is excreted in urine. Urobilinogen is eliminated in feces in the form of a brown pigment called stercobilin.

Erythropoiesis formation of only RBCs in the red bone marrow of adults

RBC PRODUCTION

Hypoxia DEFICIENCY OF OXYGEN

RBC PRODUCTION

Also called: leukocytes

Have nuclei but do not contain hemoglobin

Classified as granular or agranular depending on whether or not they contain granules.

Granular leukocytes include: ◦ Neutrophils◦ Eosinophils◦ Basophils

Agranular leukocytes include: ◦ Monocytes◦ Lymphocytes

B cells T cells Natural Killer Cells

WBC STRUCTURE AND TYPESSOME REVIEW…

Main function: Combat inflammation and infection

Through processes of :◦ Phagocytosis◦ Antibody production

WBC FUNCTIONS

Natural Killer Cells…FYI

Life span = few hours to a few days Normal blood contains 5000 to 10,000

WBCs per µL

WBC LIFE SPAN

Developed in red bone marrow leukocytes

Monocytes and granular leukocytes develop from myeloid stem cells

T and B cells develop from lymphoid stem cells

WBC PRODUCTION

Are derived from: ◦ Pluripotent stem cells

Structure:◦ Disk-shaped fragment◦ Lack a nucleus

Normal blood contains 250,000 to 400,000 platelets/µL

Platelets

Hemostasis sequence of responses that stops bleeding when blood vessels are injured

Three mechanisms that reduce blood loss:◦ Vascular Spasm

◦ Platelet Plug Formation

◦ Blood Clotting (Coagulation)

Hemostasis averts hemorrhage in smaller blood vessels

HEMOSTASIS

Complete notes for ‘Vascular Spasm’, ‘Platelet Plug Formation’, and ‘Blood Clotting’

BUT first…let’s watch this

http://www.mhhe.com/biosci/esp/2002_general/Esp/folder_structure/tr/m1/s7/trm1s7_3.htm

Read pages 387-388

Blood vessel damaged Its smooth muscle wall contracts immediately

◦ Initiated by pain receptors◦ Reduces blood loss

Few minutes to several hours Then other hemostatic mechanisms begin to

operate

Vasoconstriction narrowing of blood vessel; platelets accumulate at damage site-release chemicals to maintain vascular spasm

Vascular Spasm

Plugs form when platelets come into contact with parts of a damaged blood vessel

Platelet Plug Formation process:◦ Platelet Adhesion

Platelets contact and stick to damaged blood vessel (collagen fibers of connective tissue underlying damaged endothelial cells)

◦ Platelet Release Reaction Result of adhesion = platelets activated; characteristics change;

extend projections to connect and interact; interaction triggers release of chemicals from their vesicles; chemicals activate nearby platelets to sustain vascular spasm= decreased blood flow through injured vessel

◦ Platelet Aggregation Chemicals made platelets sticky so they stick together and gather

(aggregation); eventually enough to form a mass called platelet plug; completely covers hole in damaged vessel; blood loss ceases

Platelet Plug Formation

Serum: plasma minus clotting proteins◦ Clots are composed of a network of insoluble fibers (fibrin) filled with trapped

formed elements

Coagulation: formation of fibrin threads in a series of chemical reactions

Thrombosis: if blood clots too easily may result in a clot in an unbroken blood vessel

Hemorrhage: if blood takes too long to clot = uncontrolled bleeding Three stages of the clotting process:

◦ Prothrombinase formed◦ It is then converted to prothrombin (plasma protein formed in liver with help

of Vitamin K); then converted to thrombin◦ Thrombin converts soluble fibrinogen (plasma protein formed by liver) into

soluble fibrin; fibrin forms threads of clot

CLOTTING FACTORS: Calcium ions, enzymes, and molecules associated with platelets or damaged tissues activate each other throughout the clotting process

Clotting

Clot Retraction: consolidation or tightening of fibrin to reduce further damage

Blood Vessel Repair: fibrin threads attached to damaged surfaces of blood vessels gradually contract as platelets pull them in; as clot retracts it pulls edges of vessel closer together = decreasing risk of further injury

Clear Retraction and Blood Vessel Repair

Small, inappropriate clots dissolve through the process of fibrinolysis

What is the relationship between plasminogen and plasmin? PLASMINOGEN IS AN INACTIVE PLASMA ENZYME; IS

INCORPAORATED INTO A CLOT. PLASMINOGEN IS ACTIVATED TO PLASMIN BY CERTAIN

SUBSTANCES FOUND IN BOTH BODY TISSUES AND BLOOD. PLASMIN IS AN ACTIVE PLASMA ENZYME, WHEN PLASMA IS

FORMED IT CAN DISSOLVE CLOTS BY DIGESTING FIBRIN THREADS.

Heparin _Anticoagulant; prevents blood clots

Warfarin (Coumadin) Antagonist to Vitamin K thus blocking synthesis of 4 clotting factors; also prevents clotting

Hemostatic Control Mechanisms

Atherosclerosis accumulation of fatty substances on arterial walls; result = roughening of endothelial surfaces of blood vessels; now possibility to blood clots forming when blood flows too slowly (allows clotting factors to accumulate)

Pulmonary Embolism embolism in the lungs; blood clot, bubble of air, fat from broken bones, or piece of debris are causes

Clotting in Blood Vessels

RBC surfaces are marked by genetically determined glycolipids and glycoproteins called isoantigens or agglutinogens.◦ distinguishes at least 24 different blood groups

i.e. ABO, Rh, etc.

BLOOD GROUPS AND BLOOD TYPES

Based on two glycolipid isoantigens called A and B found on surface of RBCs.

If RBCs display only antigen A blood type Adisplay only antigen B blood type Bdisplay both antigens A & B blood type ABdisplay neither antigen blood type O

Plasma contains isoantibodies or agglutinins to the A or B antigens not found in your blood

anti-A antibody reacts with antigen A anti-B antibody reacts with antigen B

ABO Blood Group

Rh Blood Group Antigen was discovered in blood of Rhesus

monkey

People with Rh isoantigens on RBC surface are Rh+. 

People with no Rh isoantigens on RBC surface are Rh-. ◦ Normal plasma contains no anti-Rh antibodies.

Rh negative mom and Rh+ fetus will have mixing of blood at birth thus the Mom's body creates Rh antibodies unless she receives a RhoGam shot soon after first delivery, miscarriage or abortion. In 2nd child, hemolytic disease of the newborn may develop causing hemolysis of the fetal RBCs

RISK ASSOCIATED WITH Rh- MOTHERS

Universal Donors and Recipients: People with type AB blood called “UNIVERSAL

RECIEPIENT” since have no antibodies in plasma.

People with type O blood cell called “UNIVERSAL DONOR” since have no antigens on their cells theoretically can be given to anyone.

Transfusion transfer of whole blood or blood components (RBCs only or plasma only) into the bloodstream

Transfusions

  A B AB O

ANTIGEN A B A and B NEITHER

ANTIBODY B A NEITHER A and B

MAY RECEIVE FROM

A and O B and O ALL O

MAY DONATE TO

A and AB B and AB AB ALL

Transfusion chart