Download - The cardiovascular system: blood
THE CARDIOVASCULAR SYSTEM: BLOODChapter 11: Hematology
THE FUNCTIONS OF BLOOD1. Transportation: of dissolved gases, nutrients,
hormones, and metabolic wastes.2. Regulation: of
1. pH, 2. blood clotting, 3. body temperature, and 4. renal control.
3. Protection: against harmful toxins and pathogens
ANATOMY OF BLOODBlood is a fluid connective tissue that contains:Plasma (55%)
Dissolved proteinsDenser than water
Formed elements (45%)Blood cellsPlatelets (cell fragments)
MEASURING BLOODWhen we take blood, there are 3 characteristics we look at:
1. Temperature (100.4°F)2. Viscosity (5x Water’s)3. pH (7.35-7.45), Slightly Alkaline
PLASMAWater takes up 92% of plasma volume8% Electrolytes, Proteins, Nutrients
Proteins: Albumins (60%): of plasma proteins, produced in the liver, maintain osmotic balance (via water retention)
Globulins (35%): Immunoglobulins: attack foreign proteins and pathogens; antibodiesTransport (escort) Proteins: carry compounds that are not water soluble (i.e. lipids)
Fibrinogens: function in blood clotting when converted to fibrin.*Liver synthesizes many of these proteins.
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FORMED ELEMENTSProduced via hemopoiesis (hematopoiesis)Composition: (Hematocrit)
99.9 % Red Blood Cells (Erythrocytes)<.1% White Blood Cells (Leukocytes)
~ 1 to every 1000 RBCs<.1% Platelets
RED BLOOD CELLSShape: Biconcave discsMature RBCs lack nuclei and other organs (Erythropoiesis)
Life cycle: ~120 days; 1% replaced each day (3 million new cells each second!)
Hemoglobin: made of two globular proteins; contains heme pigment which holds an iron ion that binds with oxygen
HEMOGLOBIN – IRON IN THE BLOOD
hemoglobin
heme a
heme b
close up of Fe
Cause: genetic mutation that affects the globular protein of hemoglobin
Sickled cells can easily clot and cause oxygen starvation of tissues
CLINICAL NOTE: SICKLE CELL ANEMIA
ANTIGENS – CAN TRIGGER AN IMMUNE RESPONSE Antibody generator Four Blood Types:
Type A: surface antigen A, plasma Anti-B Antibodies Type B: surface antigen B, plasma Anti-A Antibodies Type AB: surface antigen A & B, no anti-A or B antibodies Type O: no surface antigens A or B, plasma Anti-A & Anti-B Antibodies (+/-): Determined by presence or absence of Rh antigens on RBCs
Cross-reactions: mixing of blood types can cause agglutination (clumping) of RBCs and eventual hemolysis (RBC destruction)
Anti-Rh antibodies are not normally present in plasma, unless exposure sensitizes an individual.
PLATELETS – THROMBOCYTESCell fragments that function in blood clotting
Formed from megakaryocytes
“Stick” together at injury sites to stop bleeding (hemostasis)
WHITE BLOOD CELLS – LEUKOCYTESLarger than RBCs, have nuclei, lack hemoglobinFunction: defense against pathogens, toxins, wastes and abnormal/damaged cells
Two groups: granulocytes & agranulocytesAmoeboid movementMigration out of the blood streamSome capable of phagocytosis
Granulocytes Neutrophils Eosinophils Basophils
Agranulocytes Monocytes Lymphocytes
NEUTROPHILS70% of WBSsFirst to arrive at an injury site
Active phagocytes (esp. bacteria)
Produced in bone marrow10-hour lifespanDeath recruits other WBCs and forms pus
EOSINOPHILS2-4% of WBSsTwo-lobed and dyed red by eosin
Attack anti-body labeled materials by exocytosis (secretion) of toxins
Produced in bone marrow
BASOPHILS<1% of WBSsDeep purple/blue with many granules
Migrate to injury sites and stimulates inflammation (via histamine) and prevents blood clotting (heparin)
Stimulated basophils release chemicals to attract other basophils and eosinophils
Produced in bone marrow
MONOCYTES2-8% of WBSsAbout twice as big as a RBCLarge free or fixed macrophages
Aggressive phagocytesActive monocytes release chemicals to attract and stimulate other neutrophils, monocytes, phagocytes, and draw fibroblasts to the region.
Produced in bone marrow
LYMPHOCYTES20-30% of WBCsLarge nucleus with “halo” of cytoplasm
Integrates with lymphatic system
Do not rely on phagocytosis
Produced in bone marrow and lymphoid tissues
ABNORMAL AMOUNTS OF LEUKOCYTESToo few: leukopeniaToo many: leukocytosisExtreme leukocytosis: leukemia
Cancer of blood-forming tissues.
HEMOSTASISHemo “blood” + stasis “halt”: stops bleeding1. Vascular Phase: constriction of damaged blood vessels
(~30mins); blood vessel spasm2. Platelet Phase: “sticky” platelets form a platelet plug3. Coagulation Phase: conversion of fibrinogen to fibrin
ABNORMAL HEMOSTASISExcessive coagulation
Thrombus: blood clot attached to wall
Embolus: moving blood clot i.e. strokes, pulmonary embolism: immobile embolus within a blood vessel.
Inadequate coagulationHemophilia
Missing clotting factor Symptoms including excessive bleeding (external and internal)