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Compendium Notes Chapter 6 Cardiovascular System; Blood

6.1 Blood an Overview (Mader p. 106 107)

Functions of Blood:

(1) Blood is primary transport medium.(2) Defends against invasion by pathogens.

(3) Blood has regulatory functions (temp and pH).

Composition of Blood:

-Blood is a tissue that contains cells and cell fragments.

-Collectively called formed elements.

-Cell and cell fragments suspended in liquid called plasma.-Formed elements: Red Blood Cells, White Blood Cells, Platelets

-All produced in red bone marrow.

-Contains stem cells.

-Red blood cells-2 to 3 times smaller than white

-Many more of them than white-Plasma

-Liquid medium for carrying various substances in blood (and distributes heat)

-91% of plasma is water

-Remaining 9% is various salts (ions) and organic molecules.-Salt part of buffer to help maintain pH of blood

-Small org. molecules like glucose and amino acids are nutrients for cells

-Urea is nitrogenous waste product on way to kidneys for excretion-Most abundant org. molecules in blood are plasma proteins.

-Liver produces plasma proteins. They help maintain homeostasis. Able to take upand release hydrogen ions and help keep blood pH around 7.4-Too large to pass through capillary walls and remain in blood. They establish

osmotic gradient (force that prevents excessive loss of plasma from capillaries

into tissue fluid).

(Mader p. 106)

Types of plasma proteins:

(1) Albumins

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a. Most abundant and contribute to osmotic pressure. Help transport other

org. molecules

(2) Globulinsa. Alpha, beta and gamma. Alpha and beta combine with and help transport

substance in blood such as hormones, cholesterol and iron. Gamma

produced by white blood cells and help fight disease.(3) Fibrinogen

a. Active in formation of blood clots.

6.2 Red Blood Cells and Transport of Oxygen (Mader p. 108 109)

-RBCs also called erythrocytes

-Biconcave disks that lack nucleus.-Hemoglobin: Lack nucleus and instead have this.

-Globin is a protein that contains four highly folded polypeptide chains.

-Heme contains iron group in the center of each polypeptide chain.

-*Iron combines (reversible) with oxygen (accepts O2 in lungs and lets go intissues).

-280 million hemoglobin molecules in one RBC-When O2 binds with heme its called Oxyhemoglobin.

-Deoxyhemoglobin: When heme gives up O2 in tissue and resumes former shape.

Disorders:-Anemia: RBCs do not have enough hemoglobin.

-Hemolysis: Rupturing of RBCs.

-Sickle-Cell Disease: Hereditary condition where individual has sick-shaped RBCs thattend to rupture as they pass through narrow capillaries.

-Hemolytic Disease of the Newborn: Type of hemolytic anemia.

(Mader p. 108)

6.3 White Blood Cells and Defense Against Disease (Mader p. 110 111)

-White blood cells are larger than RBCs

-Production of each type of white blood cell is regulated by protein called colony-

stimulating factor (CSF)

-Phagocytosis: Cell surrounds a pathogen and engulfs it. Some whites are good at this.-Vesicle moves toward and fuses with a lysosome (enzymes digest pathogen).

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-Other white blood cells produce antibodies, proteins that combine with antigens (foreign

proteins).

Types of White Blood Cells:

(1) Granular Leukocytes

a. Neutrophils account for 50 70% of whites. Have multilobed nucleus.First responders to bacterial infection, with intense phagocytic activity.

They are vacuum cleaners. Their death in large numbers results in pus.

b. Basophils have U-shaped or lobed nucleus. In connective tissue, theyrelease histamine associated with allergic reactions.

(2) Agranular Leukocytes

a. Lymphocytes account for 25 35% of whites. Responsible for specific

immunity to ppathogens and toxins.i. *Accountable for B Cells and T Cells that protect by producing

antiobodies proteins that cobine with target and mark for

destruction.

ii. *Some T Cells (cytotoxic T cells) directly destroy pathogens.b. Monocytes: Largest of white blood cells. Also vacuum cleaners.

Disorder w/ White Blood Cells

-Severe Combined Immunodeficiency Disease (SCID): Stem cells of white blood cells

lack enzyme and the body cannot fight infections at ALL.-Leukemia: Means, white blood; uncontrolled white blood cell growth, but immature

and incapable of normal defense.

6.4 Platelets and Blood Clotting (Mader p. 113)

-Platelets also called Thrombocytes-*Result from fragmentation of large cells called Megakaryocytes (in red bone

marrow).

-Involved in clotting-Also involved are proteins thrombin and fibrinogen (manufactured in liver and

put in blood).

Clotting:-Initiated when platelets and damaged tissue release prothrombin activator

-Converts prothrombin to thrombin.

-Thrombin acts as enzyme that severs two short amino acid chains from fibrinogenmolecules.

-Activated fragments join end to end, forming long thread of fibrin.

-Fibrin threads wind around platelet plug in damaged area of blood vessel and provideframe work for clot. RBCs trapped also.

-As soon as blood vessel repair is initiated, enzyme called plasmin destroys fibrin

network and restores fluidity of plasma.

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-Serum: yellowish fluid that escapes from clot that contains all components of plasma

except fibrinogen and prothrombin.

6.5 Blood Typing and Transfusions (Mader p. 114 115)

-Blood transfusions are safely done to avoid agglutination (clumping of RBCs).-Blood typing involves determinding the ABO blood group and whether the individual is

Rh- or Rh+.

-Plasma membranes of RBCs carry glycoproteins that can be antigens to otherpeople.

-*ABO blood typing is based presence or absence of two possible antigens: A antigen and

B antigen.

*See Mader p. 114 for pictures of blood typing.