the circulatory system: blood
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The circulatory system: Blood. Chapter 18 BSC 1086C Fall 2007. Functions of Circulatory System. _____________ O2, CO2, nutrients, wastes, hormones, and heat _____________ WBCs, antibodies, (immune system to fight infection) and platelets (blood clotting to prevent blood loss) - PowerPoint PPT PresentationTRANSCRIPT
The circulatory system:Blood
Chapter 18
BSC 1086C
Fall 2007
Functions of Circulatory System• _____________
– O2, CO2, nutrients, wastes, hormones, and heat
• _____________– WBCs, antibodies, (immune system to fight
infection) and platelets (blood clotting to prevent blood loss)
• _____________ – fluid regulation (water distribution) and buffering
(pH levels of body fluids)
Blood• Adults have 4-6 L of blood (~1.5 gallons)
– ___________: a clear extracellular fluid– ___________: blood cells and platelets
• Centrifuge blood to separate components
18.118.2
Plasma and Plasma Proteins• Plasma – non-living fluid matrix
– consists of water (92%), ions (electrolytes) and proteins
• 3 major categories of plasma proteins– _____________ - most abundant.
• solute transport and pH buffering– _____________ (antibodies)
• solute transport and immunity• alpha, beta, and gamma globulins
– _____________ • precursor of fibrin threads that help form blood clots
• Plasma proteins formed by ___________ – except globulins (produced by plasma cells)
Nonprotein Components of Plasma• ________________
– amino acids (from diet and tissue breakdown)– nitrogenous wastes (urea)
• toxic end products of catabolism• normally removed by the kidneys
• ________________ – glucose, vitamins, fats, minerals, etc
• ________ and ___________
• ________________– Na+ makes up 90% of plasma cations
Formed elements in blood• __________________
– Most abundant formed element– 200 billion made per day– no cell nucleus (and few other
organelles)– blood type determined by surface
glycoprotein and glycolipids
• Function– 1)– 2)
• Biconcave shape. Why??
RBCs and Gas Transport
• RBCs are packed full of ______________ (280 million/cell)
• O2 binds to non-protein ____________(Fe2+ an ionic form
of iron)
• each heme group binds to 1 O2, therefore 1 RBC can carry approximately 1 billion molecules of O2!
18.5
RBCs and Gas Transport
• RBCs also contain the enzyme carbonic anhydrase
• This enzyme catalyzes the reaction of CO2 with H2O
This serves 2 functions:
Erythrocytes and Hemoglobin
• RBC count and hemoglobin concentration indicate amount of O2 blood can carry– hematocrit (packed cell volume) - __________________
• men 42- 52% cells; women 37- 48% cells
– hemoglobin concentration of whole blood• men 13-18g/dL; women 12-16g/dL
– RBC count • men 4.6-6.2 million/L; women 4-2-5.4 million/L
• Values are lower in women…..why?– 1)– 2)
RBC production: Erythropoiesis
Stem cells that formALL formed elements
in bloodLocation:
EPO:________________A hormone that stimulatesECFU to transform into an erythroblast
Erythroblasts multiply and synthesize hemoglobin
Leave bonemarrow andenter bloodstream
Fig 18.6
RBC production rate ~ 2.5 million / second
Erythrocyte Homeostasis• Negative feedback control
– drop in RBC count causes _______________________
– EPO production stimulates bone marrow
– RBC count in 3 - 4 days
• Stimulus for erythropoiesis– low levels O2
– increase in exercise– loss of lung tissue in emphysema
18.7
Erythrocytes Recycle/Disposal• RBCs lyse in narrow
channels in ____________• Macrophages in _________
– digest membrane bits– separate heme from globin
• Globins converted to AAs
• iron removed from heme and recycled
Bile pigments
18.9
Blood typing: Antigens and Antibodies
• ___________– unique molecules on cell surface
• used to distinguish self from foreign• foreign antigens generate immune response
• ___________– secreted by plasma cells
• as part of immune response to foreign matter
• ___________ – antibody molecule binding to antigens– causes clumping
Blood Types• RBC antigens
– agglutinogens; A and B– on RBC surface
• Your ABO blood type is determined by presence or absence of antigens (agglutinogens) on RBCs– type A person has ____ antigens– type B person has ____ antigens– type AB has ________ antigens– type O has __________ antigen
• most common - type O
• rarest - type AB
18.12
Plasma antibodies• Antibodies (agglutinins); anti-A and -B• Appear 2-8 months after birth; at maximum
concentration at 10 yr.– Anti -A and/or -B (both or none) are in plasma
• you do not form antibodies against your antigens
• Therefore:– type A blood has _____________ antibodies– type B blood has _____________ antibodies– type O blood has _____________ antibodies– type AB blood has _____________antibodies
• Transfusion with wrong blood type = agglutination
Rh Group
• Rh (D) agglutinogens discovered in rhesus monkey in 1940– Rh+ blood type has D agglutinogens on RBCs– Rh frequencies vary among ethnic groups
• Anti-D agglutinins not normally present
Leukocytes (WBCs)
• 5,000 to 10,000 WBCs/L
• Conspicuous nucleus
• Travel in blood before migrating to connective tissue
• Function:_____________________
Granulocytes
- in bacterial infections
-phagocytosis of bacteria
-release antimicrobial chemicals
in parasitic infections-phagocytosis of antigen- antibody complexes, allergens and inflammatorychemicals
-release enzymes to destroy parasites
in chicken pox, sinusitis, diabetes
-secrete histamine (vasodilator)-secrete heparin(anticoagulant)
Agranulocytes
in diverse infections and immune responses
-destroy cells (cancer, foreign, and virally infected cells)-“present” antigens to activate other immune cells-coordinate actions of other immune cells-secrete antibodies and provide immune memory
in viral infections and inflammation
-differentiate into macrophages-phagocytize pathogens and debris-“present” antigens to activate other immune cells
Platelets• Small fragments of _____________ cytoplasm
– 2-4 m diameter; contain “granules”
– amoeboid movement and phagocytosis
• Normal Count - 130,000 to 400,000 platelets/L• Functions
– 1
– 2
– 3
– 4
18.20
Hemostasis: preventing blood loss
1) Vascular spasm
18.21
• Causes– 1– 2– 3
• Effects– prompt constriction of a
broken vessel• pain receptors - short
duration (minutes)• smooth muscle injury
- longer duration– provides time for other
two clotting pathways
Hemostasis: preventing blood loss
2) Platelet plug formation
18.21
• broken vessel exposes _____________
• platelet pseudopods stick to damaged vessel and other platelets - draw walls of vessel together forming a __________– Release 5-HT
(vasoconstictor), ADP, and thromboxane A2
• positive feedback cycle is active until break in vessel is sealed
Hemostasis: preventing blood loss
• Clotting - most effective defense against bleeding– conversion of plasma protein __________ into insoluble
_________ threads to form framework of clot– Extrinsic and intrinsic pathways converge on common
reaction cascade to produce fibrin
3) Coagulation18.21