nutrients from digestive tract to body cells oxygen from lungs to body cells wastes from cells to...
TRANSCRIPT
Blood
Blood is a liquid connective tissue that transports various substances to body cells & helps to maintain homeostasis.
Nutrients from digestive tract to body cells
Oxygen from lungs to body cells Wastes from cells to respiratory and
excretory systems Hormones to target tissues Body temperature control – distributes
heat
Blood/Blood Cells
Volume Varies with body
size – usually between 4-6 liters
Solid portion – RBS, WBC, & platelets – Fig. 11-1
Liquid portion – plasma (55% of blood volume)
RBC’s – Erythrocytes - Fig. 11-2
Characteristics Biconcave disks; shape provides increased SA
& places cell membrane close to internal parts Contain hemoglobin – oxygen carrying protein Mature RBC’s lack nucleus, but contain
enzymes needed for energy releasing processes
Approx. 4-6 million/mm3
RBC’s (cont.)
Destruction of RBC’s (last about 120 days) Fragile & as they age they are damaged while
moving through capillaries Damaged cells are phagocytized by
macrophages in the liver & spleen Hb molecules are decomposed & the Fe they
contain is conserved
Macrophage engulfing two RBC’s
RBC’s (cont.) RBC production and its control (hematopoiesis)
During fetal development RBC’s are formed in yolk sac, liver & spleen; later produced by red bone marrow
Number remains relatively stable Rate of RBC production is controlled by a negative
feedback mechanism Kidney & liver tissues experience oxygen deficiency Tissues release erythropoietin Erythropoietin travels to red bone marrow stimulating
an increase in RBC production As RBC numbers increase the oxygen carrying capacity
of the blood rises Oxygen concentration in kidney & liver increase and the
release of erythropoietin decreases
WBC’s leukocytes – Table 11-1, Fig. 11-4 – Function to control disease conditions Types of WBC’s
Granulocytes – granules present in cytoplasm; include neutrophiles (phagocytize), eosinophi9ls, (defense against parasites), & basophils (inflammatory response)
Agranulocytes – monocytes & lymphocytes (humoral and cellular immune response)
Approx. 5,000 – 10,000/mm3; however the number of WBC’s may change as a result of infections, emotional disturbances or excessive loss of body fluids
Functions of WBC’s WBC’s may be stimulated by the
presence of chemicals (histamine) released by damaged cells & many move toward these chemicals
http://www.youtube.com/watch?v=y3bOgdvV-_M (body’s response to an allergen)
Neutrophils & monocytes phagocytize foreign particles
http://www.youtube.com/watch?v=7VQU28itVVw&feature=related (phagocytosis – fig. 11-5)
Functions of WBC’s Eosinophils kill parasites & help control
inflammation & allergic reactions Basophils release heparine – inhibits
blood clotting Lymphocytes produce antibodies that act
against specific foreign substances http://www.dnatube.com/video/194/Specif
ic-Adaptive-immunity-humoral-and-cell-mediated (immune response)
Platelets - thrombocytes
Fragments of giant cells that become detached & enter circulation
Help close breaks in blood vessels, Fig. 11-6
Approx. 130,000 – 360,000/mm3
Hemostasis – stoppage of bleeding http://www.youtube.com/watch?v=--bZUe
b83uU&feature=related (blood clotting)
Be familiar with the steps of blood clotting shown in the above link
Blood Clot
Blood Plasma
Liquid port of the blood that is composed of H2O and a mixture of organic & inorganic substances. It transports nutrients & gases, regulates fluid and electrolyte balance and helps maintain a stable pH.
Blood Types – blood can be typed on the basis of antigens displayed on the cell membranes of RBC’s
Antigens & antibodies Fig. 11-7 RBC membranes may contain antigens
(agglutinogens) and blood plasma may contain antibodies (agglutinins)
Blood typing involves identifying the antigens present on the red cell membranes
ABO Blood Groups
Type A blood Type A antigen; type B antibody
Type B blood Type B antigen; type A antibody
Type AB blood Type A & B antigens; no antibodies
Type O blood No antigens; A & B antibodies
ABO Blood Groups Adverse transfusion reactions are
avoided by preventing the mixing of blood that contain the antigen with plasma that contains the corresponding antibody
Adverse reactions involve agglutination (clumping) of the RBC’s
For example – if RBC’s with antigen A are added to blood containing antibody A….. The antibodies react with the antigens of the RBC’s and cause them to clump together
Agglutination
Rh Blood Group
Rh antigens are present in the RBC membranes of Rh+ blood; they are absent in Rh- blood
No antibodies are present in RH+ blood (do not develop spontaneously)
Mixing Rh+ RBC’s with plasma that contains anti-Rh antibodies results in agglutination of the + cells
Erythroblastosis fetalis – Fig. 11-8
Rh- woman becomes pregnant with her first Rh+ child
Pregnancy is uneventful, but at time of birth some Rh+ cells enter maternal circulation through damaged placental tissues
Maternal tissues produce anti-Rh antibodies Second Rh+ child is conceived Anti-Rh antibodies from the maternal
circulation pass through the placental membranes & enter the fetal blood
Fetal blood agglutinates because of reaction with the anti-Rh antibodies