Chapter 10 Blood Flashcards
Functions of blood
transport nutrients, oxygen, carbon dioxide, waste products, hormones
distributes heat
hemeostasis
Blood components
only fluid tissue in body
living cells: formed elements
non-living cells: plasma
composition of blood
erytrocytes (RBC) 45%
buffy coat: leukcytes (WBC) and platelets less than 1%
Plasma 55%
characteristics of blood
oxygen rich-scarlet red
oxygen poor-dull red
ph 7.35-7.45
temp 100.4
volume 6 qts
Blood Plasma
90% water
dissolved substances: nutrients, salts (electrolytes), respiratory gases, hormones, plasma proteins, waste products
Plasma proteins
most abundant solutes in plasman 7%
most made by liver
albumin
clotting proteins
globulins
albumin
60% of plasma proteins
regulates osmotic pressure
made by liver
clotting proteins
4% of plasma
plays role in blood coagulation
made by liver
Globulins
36% of plasma
Alpha and Beta globulins
transport proteins
made by liver
Gamma globulins
(antibodies)
help protect the body from pathagens
made my lymphocytes
Formed elements
erythrocytes (RBC)
leukocytes (WBC)
platelets-thrombocytes
Erythrocytes
RBC
carry oxygen
biconcave disks
bags of hemoglobin
no nucleus
very few organelles
5 million per mm^3
Hemoglobin
iron containing protein
binds strongly but reversibly to oxygen
each hemoglobin molecule has 4 O2 binding sites
RBC has 250 million hemoglobin molecules
normal blood 12-18 g per 100ml of blood
Hemoatopoiesis
Erytrhocyte production
kidneys produce most erythropoietin in response to reduced O2 levels in blood
erythroprotein stimulates RBC formatoin in red marrow
homeostasis is maintaind via negative feedback from blood O2 levels
Old RBC
unable to divide, grow or synthesize proteins
wear out in 100-120 days
when worn out RBC is eliminated by phagocytes in teh spleen or liver
Leukocytes
WBC
protect body against pathogens
4000-11,000 WBC per mm^3
differential WBC count lists % of each type of WBC, may change with disease status
Platelets
Thrombocytes
fragments of megakaryocytes
form platelet plug to help seal damaged blood vessels
initiates formatoin of blood clot
normal cound 300,000 per mm^3
Hemostasis
stoppage of bleeding resulting from breaking in a blood vessel
phases of hemostasis
vascular spasm
platelet plug formation
coagulation (blood clotting)
Vascular spasms
occurs immediatly if a vessel is cut or broken
spasm narrows the vessel decreasing blood loss
platelet plug formation
collagen fibers are exposed by break in vessel
platelets become “sticky” and cling to fibers
anchored platelets release chemicals to attract more platelets
platelets pile up to for a plug
Coagulation
blood clotting
most effective homeostatic mechanism
final step conversion of fibrogen into insoluable fibrin threads
Thrombin: enzyme that converts fibrinogen into fibrin
fibrin forms meshwork that traps RBC
blood usually clots in 3-6 min
clot remains as endothelium regenerates
clot is broken down after tissue repair
Blood loss
loss of 15-30% causes weakness
loss of over 30% causes shock which can be fatal
Blood Transfusion
transfusions are the only way to replace blood quickly
transfused blood must be of the same blood group
Blood group genetic proteins
antigens: proteins found on surface of RBC
antibodies: clumping of RBC due to interaction of antigens and antibodies
Blood groups
grouped based on presence or absence of 2 major protein antigens on the RBC membrane
4 ypes: A, B, AB and O
2-8 mos after birth the body may synthesize certain antibodies
Antibodies A or B
found within plasma
Type AB blood
Antigens: both A and B
Antibodies: neither A or B
Type A blood
Antigens: A is present
Antibodies: B is present
Type B blood
Antigens: B is present
Antibodies: A is present
Type O blood
Antigens: lack A and B
Antibodies: A and B are present
AB transfusion
can receive A, B, AB or O blood
Universal recipient
A transfusion
can receive A and O blood
B transfusion
can receive B and O blood
O transfusion
can receive O blood
universal donor
RH blood groups
presence or absence of antigen D
Rh negative: RBC lasck Rh antigen
Rh positive: RBC has antigen
person with rh neg blood does not make anti Rh unless exposed to Rh positive blood
Rh Sensitization
person with negative blood receives transfusion of positive blood
initial is not problme but anti body cells begin synthesizing anti-Rh antibodies
person is now sensitized to Rh-positive blood
next exposure wo Rh positive blood will cause recipients blood to agglutinate with donors RBC
Rh pregnance dangers
when mother is Rh- and father is Rh+
Erythroblastosis Fetalis
Erythroblastosis Fetalis
Rh- mother carrying Rh+ baby
first child no problem
after mother is sensitized to Rh+ and will produce anti Rh antibodies
2nd pregnancy will attack Rh+ blood of fetus
RhoGAM shot
shot to prevent buildup of anti Rh+ antibodies in mothers blood
Blood Typing
blood type is determinede by finding which antigens are present on RBC membrane
blood is typed by using antibodies that will cause blood with certain antigens to clump
ABO and Rh typing are done in similar manner
Cross matching
testing for agglutination of donors RBC by the recipients serum and vice versa
Agglutination testing
expose sample to anti A antibodies and anti B antibodies
look for clumping (agglutination)]
if clumping present the antigen is present on the RBC
Blood Transfusions
always best to give person their own blood
Transfusion reaction
agglutination of donor RBC because recipients plasma contains antibodies against the antigens on donor RBC
