Download Chapter 7: Blood

Chapter 7: Blood
I. Components and Functions
Functions: transportation of nutrients, wastes, hormones; regulation of body temperature, pH, and
fluid volume; and defense via white blood cell activity.
An adult male has approximately 5-6 liters and a female 4-5 liters of blood.
(A) Plasma: comprises approximately 55% of blood volume. It consists mostly of water,
with proteins, hormones and various solutes. Plasma proteins are responsible for osmotic balance
by attracting water, transport (hormones and drugs), antibodies and for clotting. Some plasma
proteins are incorporated in HDLs (high density lipoproteins) which contain “good “ cholesterol and
LDLs, which contain “bad” cholesterol.
(B) RBCs – Red Blood Cells = erythrocytes.
No nucleus or organelles. Packed with hemoglobin, which binds O2 to Fe (iron) groups. Also
binds some CO2. Hematocrit = % blood volume of RBCs. When high, elevates BP and creates
viscous blood; when low = anemia.
RBCs short-lived (max = 120 days), old ones removed by liver and spleen. Iron and
amino acids recycled, bile created from the remains. RBCs produced from stem cells in red bone
marrow, stimulated by hormone erythropoietin.
(C) White Blood Cells – WBCs = leukocytes.
These comprise less than 1% of healthy blood volume. They are involved in body defense.
Granular WBCs – neutrophils, eosinophils and basophils. Agranular WBCs – lymphocytes
and monocytes.
Some WBCs produce antibodies, there are other specialized functions. Most capable of
phagocytosis, may leave bloodstream. Also produced in red marrow.
(D) Platelets - involved in clotting, a form of hemostasis: maintenance of blood volume.
Platelets are cell fragments.
II. Hemostasis
Vessel injury results in vascular spasms. If that doesn’t seal leak, a platelet plug might.
Otherwise, clot formation occurs:
This involves a series of chemical reactions which require clotting factors and Vitamin K., resulting
in a tangled clot of the protein fibrin. Hemophiliacs lack clotting factors. Drugs can also interfere
with clotting, e.g. aspirin.
III. Blood Types
Based on the fact that cells have surface markers called antigens. Antibodies are produced in
response to foreign antigens. RBCs can have up to three important antigens: A, B, and Rh.
Antibody action results in clumping, called agglutination.
In HDN (Hemolytic Disease of the Newborn) an Rh- woman has been pre-sensitized to the
Rh factor (antigen). Her anti-Rh antibodies pass the placenta, creating severe anemia in an Rh+
fetus. There is preventative treatment, an injection of Rhogam prevents sensitization of the woman,
IV. Pathology
(A) Carbon Monoxide poisoning CO competes with O2 for hemoglobin binding.
(B) Anemias: iron deficiency, aplastic (RBC destruction), hemorrhagic, pernicious (Vitamin
B12 deficiency), Sickle Cell (genetically malformed hemoglobin).
(C) Leukemias – WBC cancers.
(D) Mononucleosis – viral infection of lymphocytes.