Chapter 18: Blood
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Transcript Chapter 18: Blood
Transport
Protection
WBCs, antibodies, and platelets
Regulation
18-2
O2, CO2, nutrients, wastes, hormones, and heat
fluid regulation and buffering
You have about 11 pints of
blood (4 to 6 liters)
The plasma portion (fluid
portion) is mostly water
Cells float in the plasma
Red cells are also called
erythrocytes
White cells are also called
leukocytes
Platelets are pieces of cells
also called thrombocytes
Viscosity - resistance to flow
whole blood 5 times as viscous as water
Osmolarity
total molarity of dissolved particles
sodium ions, protein, and RBCs
high osmolarity
causes fluid absorption into blood, raises BP
low osmolarity
causes fluid to remain in tissues, may result in edema
18-4
18-5
Plasma – liquid portion of blood
serum remains after plasma clots
3 major categories of plasma proteins
albumins - most abundant
contributes to viscosity and osmolarity
globulins (antibodies)
provide immune system functions
alpha, beta and gamma globulins
fibrinogen
precursor of fibrin threads that help form blood clots
Plasma proteins formed by liver
18-6
except globulins (produced by plasma cells)
Nitrogenous compounds
amino acids
from dietary protein or tissue breakdown
nitrogenous wastes (urea)
toxic end products of catabolism
normally removed by the kidneys
Nutrients
O2 and CO2
Electrolytes
18-7
glucose, vitamins, fats, minerals, etc
Na+ makes up 90% of plasma cations
BUN
Creatinine
Iron
ferric (Fe3+) and ferrous (Fe2+)
stomach acid converts Fe3+ to absorbable Fe2+
gastroferritin binds Fe2+ and transports it to intestine
absorbed into blood and binds to transferrin for transport
bone marrow for hemoglobin, muscle for myoglobin and all
cells use for cytochromes in mitochondria
Vitamin B12 and folic acid
Vitamin C and copper
18-8
rapid cell division
cofactors for enzymes synthesizing RBCs
Disc-shaped cell with thick rim
18-9
7.5 M diameter and 2.0 m thick at rim
blood type determined by surface glycoprotein and
glycolipids
cytoskeletal proteins give membrane durability
18-10
Gas transport - major function
increased surface area/volume ratio
due to loss of organelles during maturation
increases diffusion rate of substances
33% of cytoplasm is hemoglobin (Hb)
O2 delivery to tissue and CO2 transport to lungs
Carbonic anhydrase (CAH)
produces carbonic acid from CO2 and water
important role in gas transport and pH balance
18-11
Are your red blood cells
Carry oxygen from the
lungs to your tissues
Contain hemoglobin, a
protein molecule that
actually carries the O2
Anemia is a low amount of hemoglobin in the blood,
sometimes caused by too few RBCs.
Symptoms:
Pallor
Weakness
Tiredness
Unable to
exercise
without getting
out of breath
RBC count and hemoglobin concentration
indicate amount of O2 blood can carry
hematocrit (packed cell volume) - % of blood
composed of cells
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
18-14
Adult produces 400 billion platelets, 200 billion RBCs
and 10 billion WBCs every day
Hemopoietic tissues produce blood cells
yolk sac produces stem cells
liver stops producing blood cells at birth
spleen remains involved with WBC production
red bone marrow
pluripotent stem cells
hemopoiesis produces RBCs, WBCs and platelets
18-17
Negative feedback control
drop in RBC count causes
kidney hypoxemia
EPO production stimulates
bone marrow
RBC count in 3 - 4 days
Stimulus for erythropoiesis
18-18
low levels O2
increase in exercise
loss of lung tissue in
emphysema
2.5 million RBCs/sec
Development takes 3-5 days
First committed cell - erythrocyte colony forming unit
has receptors for erythropoietin (EPO) from kidneys
Erythroblasts multiply and synthesize hemoglobin
Discard nucleus to form a reticulocyte
18-19
reduction in cell size, increase in cell number, synthesis of hemoglobin
and loss of nucleus
named for fine network of endoplasmic reticulum
0.5 to 1.5% of circulating RBCs
RBCs lyse (pop) in narrow channels in spleen
Macrophages in spleen
Globins hydrolyzed into
digest membrane bits
amino acids
separate heme from globin
18-20
Iron removed from heme and
converted (stepwise) into
bilirubin
Bilirubin
is released into blood
plasma (kidneys - yellow
urine)
liver secretes into bile
concentrated in gall
bladder: released into small
intestine; bacteria create
urobilinogen (brown feces)
18-21
Polycythemia - an excess of RBCs
primary polycythemia
myeloproliferative disorder
erythropoietic cell line in red bone marrow
hematocrit as high as 80%!!
secondary polycythemia
from dehydration, emphysema, high altitude, or physical
conditioning
Dangers of polycythemia
increased blood volume, pressure, viscosity
can lead to embolism, stroke or heart failure
18-22
Inadequate erythropoiesis or hemoglobin synthesis
inadequate vitamin B12 from poor nutrition or lack of
intrinsic factor (pernicious anemia)
Don’t make
iron-deficiency anemia
enough
kidney failure and insufficient erythropoietin
aplastic anemia - complete cessation
Hemorrhagic anemias
Hemolytic anemias
18-23
Lose cells
faster than
you can
make them
Tissue hypoxia and necrosis (short of breath and
lethargic)
Low blood osmolarity (tissue edema)
Low blood viscosity (heart races and pressure drops)
18-24
Hereditary Hb ‘defect’ of African Americans
recessive allele modifies hemoglobin structure
sickle-cell trait - heterozygous for HbS
individual has resistance to malaria
HbS indigestible to malaria parasites
sickle-cell disease - homozygous for HbS
individual has shortened life
18-25
in low O2 concentrations HbS causes cell elongation and sickle shape
cell stickiness causes agglutination and blocked vessels
intense pain; kidney and heart failure; paralysis; stroke
chronic hypoxemia reactivates hemopoietic tissue
enlarging spleen and bones of cranium
1 in 500 African
Americans have the
disease
1 in 1000 to 1400
Hispanic-Americans
18-26
Platelets (thrombocytes)
Fibrinogen
Small fragments of megakaryocyte cytoplasm
Functions
18-28
2-4 m diameter; contain “granules”
amoeboid movement and phagocytosis
secrete vasoconstrictors
stick together to form temporaryplatelet plugs
secrete clotting factors
initiate formation of clot-dissolving enzyme
phagocytize bacteria
chemically attract neutrophils and monocytes to sites of
inflammation
All 3 steps involve platelets
18-29
pain receptors
smooth muscle injury
platelets release serotonin (vasoconstrictor)
18-30
broken vessel exposes collagen
platelet pseudopods stick to damaged vessel and other
platelets
pseudopods contract and draw walls of vessel together
forming a platelet plug
18-31
Platelets degranulate releasing substances that initiate
fibrin clot
Fibrinogen (in plasma) is converted into fibrin threads
which form the clot
18-32
Most of the clotting factors are made in the liver
Liver diseases compromise clotting
Clot retraction occurs within 30 minutes
Platelet-derived growth factor secreted by platelets
and endothelial cells
Fibrinolysis (dissolution of a clot)
18-34
repair damaged vessel
plasmin, a fibrin-dissolving enzyme (clot buster)
Genetic lack of any clotting factor affects coagulation
Sex-linked recessive (on X chromosome)
hemophilia A missing factor VIII (83% of cases)
hemophilia B missing factor IX (15% of cases)
note: hemophilia C missing factor XI (autosomal)
Physical exertion causes bleeding and excruciating
pain
18-35
transfusion of plasma or purified clotting factors
factor VIII produced by transgenic bacteria
Embolism - clot traveling in a vessel
Thrombosis - abnormal clotting in unbroken vessel
most likely to occur in leg veins of inactive people
pulmonary embolism - clot may break free, travel from veins
to lungs
Infarction may occur if clot blocks blood supply to an
organ (MI or stroke)
18-36
650,000 Americans die annually of thromboembolism
18-38
Conspicuous nucleus
Travel in blood before migrating
to connective tissue
Protect against pathogens
Granulocytes
neutrophils (60-70%)
fine granules in cytoplasm; 3 to 5 lobed nucleus
eosinophils (2-4%)
large rosy-orange granules; bilobed nucleus
basophils (<1%)
large, abundant, violet granules (obscure a large S-shaped nucleus)
Agranulocytes
lymphocytes (25-33%)
variable amounts of bluish cytoplasm (scanty to abundant);
ovoid/round, uniform dark violet nucleus
monocytes (3-8%)
largest WBC; ovoid, kidney-, or horseshoe- shaped nucleus
18-39
Neutrophils ( in bacterial infections)
Eosinophils ( in parasitic infections or allergies)
phagocytosis of antigen-antibody complexes,
allergens and inflammatory chemicals
release enzymes to destroy parasites
Basophils ( in chicken pox, sinusitis, diabetes)
18-40
phagocytosis of bacteria
release antimicrobial chemicals
secrete histamine (vasodilator)
secrete heparin (anticoagulant)
Lymphocytes ( 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
Monocytes ( in viral infections and inflammation)
differentiate into macrophages
phagocytize pathogens and debris
“present” antigens to activate other immune cells
18-41
Hematocrit
Hemoglobin concentration
Total count for RBCs, reticulocytes, WBCs, and platelets
Differential WBC count
RBC size and hemoglobin concentration per RBC
18-42
Leukopoiesis
pluripotent stem cells – most WBCs develop in the bone
marrow
T lymphocytes complete development in thymus
Red bone marrow stores and releases granulocytes
and monocytes
Circulating WBCs do not stay in bloodstream
granulocytes leave in 8 hours and live 5 days longer
monocytes leave in 20 hours, transform into macrophages
and live for several years
WBCs provide long-term immunity (decades)
18-43
Fig. 18.18
18-44