Blood Chapter 17
Composition of Blood
• Body’s only fluid tissue
• It is composed of liquid plasma (54%) and
formed elements (Cells) (46%)
• Erythrocytes, or red blood cells (RBCs)- 45%
• Leukocytes, or white blood cells (WBCs) and Platelets (1%)
Physical Characteristics and Volume
• The pH of blood is 7.35–7.45
• Temperature is 38C, slightly higher than “normal” body
temperature
• 5–6 L for males, and 4–5 L for females
Color depends on its oxygen content.
– Bright red when oxygenated (e.g., arterial blood)
– Dark red when deoxygenated (e.g., venous blood).
Without O2
With O2
Functions of Blood
• Distribution
– Gases, nutrients, signaling molecules, wastes, heat
• Regulation
– Body fluid volume
– Body fluid pH
– Body T°
– Electrolyte levels
• Protection from pathogens and fluid loss
Body Temperature Regulation
Notice how the distribution of
blood varies with temperature.
Under warm conditions, blood
is shunted to the surface so that
heat can radiate away. Under
cold conditions, blood (and thus
heat) are conserved within the
core of the body.
Plasma
• 55% of blood
• Mostly water
• Dissolved Solutes Contains:
– Proteins
– Electrolytes
– Gases
– Nutrients
– Wastes
– Signaling molecules
– Buffers
Some of the Plasma Proteins
– Albumin
• 60% of plasma proteins.
• Produced by the liver.
• Primary function is to maintain the osmotic pressure of the plasma. Also
involved in transport of certain substances (steroids, bilirubin).
– Globulins
• Some globulins are produced in the liver and are transport proteins for
lipids, metal ions, and fat-soluble vitamins.
• Other globulins are produced by plasma cells (a type of leukocyte) during
the immune response. These globulins are also known as antibodies.
– Clotting proteins
• Most produced in the liver.
• Two important examples are prothrombin and fibrinogen.
Erythrocytes (RBCs)
•
•
•
•
•
•
•
Small
Biconcave disks
Anucleate
No organelles
Stuffed with hemoglobin
Transport O2
4-6 million per μL of blood
Figure 16.3
Hemoglobin
• Note the 4 heme groups associated with the 4 polypeptide
chains of the hemoglobin protein. Each has an iron in its
center.
How many O2 molecules could a single hemoglobin carry?
Hemopoiesis
• Blood cell formation = hemopoiesis
• All blood cell production occurs in
the red bone marrow, which is found
in the:
– Axial skeleton
– Pelvic and pectoral girdles
– Proximal epiphyses of the humerus
and femurs.
• What must happen as a hemocytoblast
differentiates into an RBC?
•
- What must be lost?
•
- What must be made?
•
- What must change?
RBC Production
RBC Lifespan
Born in the red
marrow
Circulate for
120d
Swallowed by a macrophage
(usually in the spleen)
Hemoglobin
Heme
Globin
Iron
Bilirubin
Carried by albumin to
the liver
Carried by transferrin
to the liver
Secreted into the small
intestine as part of bile
Stored in the liver as
hemosiderin or ferritin
Converted to stercobilin and
urobilin and excreted in feces
Amino acids
Back into the plasma
for reuse/recycling
Red Blood Cells
An important measurement involving RBCs is the hematocrit.
The hematocrit is the % of whole blood occupied by RBCs. It’s
reflective of the body’s O2 carrying capacity.
What’s the hematocrit in the sample below?
Homeostatic Imbalance
Genetic
Thalassemias
• Missing a globin chain
• RBC fragile and ruputre easy
Homeostatic Imbalance
Sickle-cell anemia
-Results from a defective gene coding for an abnormal
hemoglobin called hemoglobin S (HbS)
- HbS has a single amino acid substitution (287)
- This defect causes RBCs to become sickle-shaped in low-oxygen
situations
Leukocytes (WBCs)
• Only blood components that are complete cells:
– 4000 – 11,000 WBC’s /mm3
– Make up 1% of the total blood volume
– Can leave capillaries via diapedesis
– Move through tissue spaces
– Most are found in lymphatic organs and loose
connective tissues.
Neutrophils
• Most numerous. 60% of circulating WBCs.
• A.k.a. polymorphonuclear leukocytes b/c of their multilobed nucleus.
• Function primarily in killing bacteria.
• Contain pale, lilac colored granules
Eosinophils
•
•
•
•
3% of circulating WBCs.
Function primarily in killing parasitic worms.
Also help reduce the severity of allergy attacks.
Contain reddish/orangish granules
Basophils
• Least numerous. <1% of circulating WBCs.
• Involved in inflammation.
• Contain purplish granules that contain:
– Histamine – a vasodilator
– Heparin – an anticoagulant
Lymphocytes
• 25% of circulating WBCs.
• No granules. Large purple nucleus
dominates most of the cell.
• 2 main types:
– T lymphocytes
• Control/coordinate immune response
• Kill virus-infected and cancerous cells
– B lymphocytes
• Secrete antibodies (immunoglobulins)
Monocytes
•
•
•
•
6% of circulating WBCs.
No granules.
Large pale cells w/ U or kidney-shaped nucleus.
Travel in the blood. Become macrophages w/in the
tissue spaces.
In this picture, find: RBCs, 2 neutrophils, an eosinophil, a basophil, a monocyte, a
lymphocyte, and a platelet.
What can you find here?
Homeostatic Imbalance
Leukemias
• Cancerous bone marrow cell that send immature
white blood cells into blood stream
• Immune response lessen
Platelets
• Cell fragments of
megakaryocytes (giant
cells created from mitosis
w/o cytokinesis)
• Contain chemicals vital to
coagulation.
• A.k.a. thrombocytes.
Hemostasis
•
Designed for healing the vasculature and providing a
framework for tissue repair
Three phases
1. Vascular spasms – immediate vasoconstriction in
response to injury
2. Platelet plug formation
3. Coagulation (blood clotting)
Mosquito saliva contains an enzyme called
apyrase. Which of the following is it most
likely to do?
a.
b.
c.
d.
Inhibit fibrinolysis
Promote thrombin production
Inhibit platelet aggregation
Promote fibrin production
•
•
•
•
Antiprostaglandin Aspirin
Low dose helps reduce risk of heart attack
Reduces platelet aggregation and plug formation
Reduces risks to embolism  Heart attack and
stroke
Blood Groups
• Humans have 30 varieties of naturally occurring RBC antigens
• The antigens of the ABO and Rh blood groups cause vigorous
transfusion reactions with agglutination (cell clumping) and
severe consequences when they are improperly transfused
• RBC membranes have glycoprotein antigens on their external
surface
• These antigens are:
– Unique to the individual
– Recognized as foreign if transfused into another individual
• Presence/absence of these antigens are used to classify blood
groups
AB0 blood grouping system
= red blood cell
• Blood group A
– A antigens on the surface of their red
blood cells and B antibodies in their
blood plasma.
• Blood group B
– B antigens on the surface of their
RBCs and A antibodies
• Blood group AB
– A and B antigens on the surface of
their RBCs and no A or B antibodies at
all
• Blood group 0 (null)
– No antigens on the surface of their
RBCs but both A and B antibodies
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ABO Blood Groups
Universal donor Universal receiver -
Table 16.4
Blood Typing
http://nobelprize.org/medicine/educational/landsteiner/readmore.html
• When serum containing anti-A or anti-B
antibodies is added to blood, agglutination (cell
clumping) will occur between the antibody and
the corresponding antigens
• Positive reactions indicate agglutination (cell
clumping)
Blood typ e
being tested
RBC
agglutinog ens
AB
B
A
O
A and B
B
A
none
Serum
Reaction
Anti -A
Anti -B
+
+
–
+
+
–
–
–
Rh factor blood grouping system
Rh+
• Have Rh factor on RBCs
• Do not make Rh antibodies
Rh• Do not have Rh factor on RBCs
• Do not make Rh antibodies unless
exposed to Rh factor!!!
What will occur???
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Women and Pregnacy
• Rh- women with Rh+ babies
• Pregnancy okay, but mother builds Rh antibodies
• If next pregnancy is Rh+ again mothers antibodies
will kill fetus RBCs
• RhoGAM blocks the Rh+ affect and does not
allow mother to make antibodies