Blood
What do you know???
Why is it called the "river of
life"?
Function:
1. Transport: gases, nutrients, wastes
2. Transport of processed molecules:
-substances made in one part of body and transported to
another part of body
-ex. Vitamin D, Lactic acid
3. Transport of regulatory molecules
4. Regulation of pH & osmosis
pH 7.35-7.45
5. maintain body temperature
6. Protection against foreign substances
7. clot formation
Components:Plasma and formed
elements
Plasma:
-55% of blood
-made of: 90% water, salts, plasma proteins,
nutrients, hormones, wastes, gases
-plasma proteins (made by liver):
1. albumin - helps osmotic pressure of
blood
to keep blood in
bloodstream
2. Fibrinogen - clotting protein
3. globulins - antibodies for defense and
lipid
transport
proteins are not used by cells
plasma amount is regulated by body systems
1. if proteins too low - liver produces more
2. if blood too acid (acidosis) - or too basic
(alkalosis) - kidneys and lungs
help bring
pH back to normal (pH 7.357.45)
plasma also distributes body heat through body
Formed elements (cells)
-45% of blood
- include red blood cells (erythrocytes)
white blood cells (leukocytes)
platelets
(thrombocytes)
Red blood cells - erythrocytes
function - carry oxygen from lungs to cells and
carbon dioxide too
-are anucleate at maturity
-contain few organelles
-contain hemoglobin - (protein with iron)
-lack mitochondria
-make ATP by anaerobic fermentation - so don't
use oxygen they carry
-biconcave disk (think snow tube!)
-1000 RBCs to 1 WBC
-add thickness to blood
-1 cell = 250 million hemoglobin molecules
-5 million cells /cubic mm
-contains 12-18 g hemoglobin/100ml
Problems with RBCs:
1. anemia - decrease in oxygen carrying capacity
of blood
causes: low # of RBCs
RBCs don't have enough
hemoglobin
in them
Several types of anemia:
a. hemorrhagic anemia - due to blood loss
b. hemolytic anemia - bacteria lyse RBCs
c. pernicious anemia - lack of B12
d. aplastic anemia - bone marrow
destruction
e. iron deficiency anemia - low iron in diet
f.sickle cell anemia
cause: genetic defect - abnormal
hemoglobin
made (must have 2 copies)
mostly in people of African descent
RBC becomes sickle shaped
-become sickle shape when low oxygen - during
exercise, anxiety, stress
-dam up blood vessels
-low oxygen delivery to cells
-symptoms: pain, jaundice, tired, inability to fight
infection
-diagnosis: blood test
-treatment: folic acid -helps produce RBC, pain
meds
-prognosis: can live full life, some deaths
immune to malaria
2. polycythemia - increase in number of
RBCs
cause: bone marrow cancer
(polycythemia
vera), high altitudes
(secondary polycythemia)
increases blood viscosity, makes
circulation harder especially if clogged
arteries
Leukocytes- white blood cells (WBC)
function: fight off infection caused by bacteria, viruses, parasites,
tumor cells
-removes dead cells and debris
-4,000-11,000/mm3
-have nuclei (DNA)
-move in and out of blood vessels via diapedesis (amoeboid
movement)
-respond to chemicals released in body
-positive chemotaxis
-body can produce double amount in a few hours
Leukocytosis- Greater than 11,000 cells/mm3
-indicates an infection
Leukopenia - low white blood count
-caused by meds - corticosteroids, anticancer
agents
Mononucleosis
-cause Epstein Barr virus
-symptoms - sore throat, fever, tired, enlarged
spleen
-spread in saliva, mucus - "kissing disease"
-diagnosis - blood test, questions
-treatment-goes away on own
Leukemia- cancer of the blood cells
-body produces abnormal cells
-different types
acute leukemia - blood cells remain immature
(blasts)
chronic leukemia -some blasts present, progresses
more
slowly
-symptoms:-fever, chills, fatigue, frequent infections, swollen
lymph nodes, easy bruising/bleeding, bleeding gums,
joint
pain
-diagnosis:medical history, blood test, bone marrow biopsy,
lumbar puncture
-treatment:radiation therapy, chemotherapy, bone marrow
transplant
Leukocytes - two main groups of cells:
1. Granulocytes - have granules in cytoplasm
a. neutrophils - most common, alive for 10-12
hours
phagocytes, found in pus
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/Blood.html#neut
rophils
b. eosinophils - reduce chemicals to decrease
infection, rid body of parasitic worms, regulates
inflammatory response
http://www.funsci.com/fun3_en/blood/blood.ht
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c. basophils - release histamine to promote
inflammation, releases heparin - prevents clots
http://www.funsci.com/fun3_en/blood/blood.ht
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2. Agranulocytes- lack granules
a. lymphocytes- smallest white blood
cells
-produce antibodies
http://www.funsci.com/fun3_en/blood/blood.ht
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made in bone marrow:
B-lymphocytes - oversee immunity of bodies' humors
(fluids)
-mature in bone marrow
T-lymphocytes - arise from cells that migrate to thymus for
maturity (2-3 days) regulated by thymosin hormone
-circulate through body - go after pathogens infected
cells
both of these migrate via blood to lymph nodes, spleen and
other lymphoid tissues
b. monocytes - largest white blood cell
become macrophages - phagocytize bacteria, dead
cells
http://www.funsci.com/fun3_en/blood/blood.ht
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precursor to macrophage
Platelets
-fragments of large multinucleated cells (megakaryocytes)
-aka thrombocytes
-300,000/mm3
-produced in red bone marrow
-function - clotting of blood
Hematopoiesis
-blood cell formation
-happens in red bone marrow
-stay in bone marrow until mature, then go to rest of body
hemocytoblast = stem cell that gives rise to all other blood cells
two types:
lymphoid stem cell - becomes lymphocytes
myeloid stem cells - all other cells
red blood cells live ~ 120 days
gotten rid of by phagocytes in spleen, liver and
other tissues
synthesize hemoglobin
young red blood cell - reticulocyte - still contains
ER
takes 5 days to mature from hemocytoblast
Erythrocyte production control
white blood cells and platelets is stimulated by hormones
(colony stimulating factors (CSFs) and interleukins)
stimulates bone marrow to produce leukocytes
exposure to bacterial toxins stimulates
macrophages/lymphocytes
to release CSFs and
interleukins
thrombopoietin - hormone that helps makes platelets
Hemostasis
-blood clotting process- results from break in blood vessel
Three major steps:
a. platelet plug
formation
b. vascular spasms
c. coagulation
1. Platelet plug formation:
-if blood vessels break - collagen fibers are exposed,
cause
platelets to get "sticky"
-anchored platelets release chemicals that attract more
platelets
to make platelet plug (white thrombus)
2. Vascular spasms:
-platelets release serotonin - causes blood vessels to
spasm
-narrows blood vessel, decreases blood loss, before
clotting
3. Coagulation events:
-thromoboplastin is released by injured tissues
-PF3 (phospholipid) coats platelets and reacts with
thromobplastin, other
clotting factors and calcium ions cause
clotting cascade
-prothrombin activator converts prothrombin in plasma
to
thrombin (enz)
-thrombin joins with fibrinogen to make long hairlike
fibers
called fibrin
-fibrin forms mesh network that traps other platelets and
RBCs
to form clot
-clot hardens to form scab
-serum = plasma minus clotting proteins - clear fluid that
seeps
from wounds
-takes 3-6 minutes to clot, once clotting cascade starts
-applying gauze and pressure speed up clotting
Hemostasis disorders:
1. thrombus = clot that develops and stays in unbroken blood
vessel
-if forms in heart vessels - causes heart attack
-if floats freely in blood stream = embolus
-no problem unless gets into small vessels it can't
get
through. cerebral
embolus = stroke
-anything that causes roughening of blood vessel can
cause
clotting
-severe burns, physical blows,
cholesterol build-up,
blood pooling
-treatment: anticoagulants - aspirin, heparin, coumadin
Bleeding disorders:
1. thrombocytopenia - insufficient # of platelets in blood
-normal movements causes bleeding from blood
vessels
-petechiae = purplish blotches
-cause- bone marrow cancer, radiation, drugs
2. Vit K deficiency - Vit K needed by liver to produce clotting
factors
3. Hemophilia - "bleeder's disease"
-lack of certain clotting factors
-factor VIII = 75% - most common
-sex linked trait
-use transfusions or injections of clotting factor
Blood Groups
-Karl Lansteiner (1900) discovered four different types
-due to specific presence or absence of agglutinogens (carbs,
glycoproteins or glycolipids) on surface of RBC
24 blood groups with 100 antigens
-rarest type MN
ABO blood groups based on type A and type B antigens
agglutinogens = antigens = substance that the body recognizes
as foreign
-stimulates the release of antibodies (agglutinins)for
defense
-we tolerate our own, get reaction if come in contact
with
different types of blood antigens
-antibodies "recognize" and attach to RBC antigen
causing
agglutination (clumping)
-can cause kidney failure
To figure out what blood type children would be: use Punnett
Squares
Type A blood = AA or AO
Type B blood = BB or BO
Type AB blood = AB
Type O blood = OO
so if parents are: AB and AO, children could be
A
B
A
AA
AB
O
AO
BO
Rh factor = another antigen on the surface of RBCs
can be Rh + (has antigen) or Rh- (no antigen)
-named after the Rhesus monkey where it was first
discovered
-normally not a problem unless mother is Rh- and baby is
Rh+
-first pregnancy - mother starts building
antibodies
against Rh factor
-second pregnancy - mother's body will try to
reject
baby
-baby can be born with hemolytic disease
-baby is anemic, hypoxic, brain damage if left
untreated
-treatment: transfusing the baby at birth
now injection of RhoGam (anti Rh gamma globulin)is all that is
needed to prevent mother from producing antibodies
Importance of blood typing:
-so no agglutination (clumping)
cross matching = testing to make sure donor blood is compatible
How is it done?
test blood with antiserum (Anti A and Anti B)
RBCs of type A will clump with anti A serum
RBCs of type B will clump with anti B serum
RBCs of type AB will clump with both anti A and Anti
B)
RBCs of type O will not clump with either anti A or Anti
B
Rh factor typing is same but with anti Rh
When is blood typing needed?
Blood tests:
1. red blood cell count
males - 4.6-6.2 million RBC/mm3
females 4.2-5.4 million RBC/mm3
2. Hemoglobin
14-18 gm/100ml - males
12-16 gm/100ml
3. Hematocrit = % of total blood volume composed of RBC
40-50% of total blood volume (male)
38-48% of total blood volume (female)
4. White blood cell count
total # of WBC in
blood
5000-9000/ml3
5. platelet count
250,000-400,000/ml3
Developmental aspects of blood
-embryo - liver and spleen also make blood cells
-by 7th month of development - red marrow does most production
-fetal hemoglobin (HbF) is different than mature hemoglobin has
more oxygen carrying capability
-after birth have hemoglobin (HbA) =typical
-jaundice happens in infants when liver can't process all of the
destroyed RBCs fast enough