Blood
anatomy
Components
• Formed elements: living blood cells are suspended in
the plasma (nonliving).
• Blood is connective tissue
• Buffy coat: the thin whitish layer between the RBCs
and the plasma.
– Leukocytes: white blood cells
– Platelets: cell fragments that function in the blood-clotting
process.
– Both of these are less than 1% of blood
• Hematocrit: erythrocytes that account for 45% of the
total volume of blood
• Plasma: makes up 55% of blood.
Physical characteristics and volume
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Sticky
Opaque
Metallic taste
Salty
Red
Heavier than water and 5 times thicker
Alkaline
pH 7.35-7.45
Temperature: 100.4 degrees F
8% of body weight
Healthy males have 5-6 quarts.
Plasma
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90% water
Most plasma proteins are made by the liver
Albumin: osmotic pressure of blood
Clotting proteins: help stem blood loss when a
vessel is injured.
• Antibodies: help protect the body from
pathogens
• Acidosis: too acidic
• Alkalosis: too basic
Formed elements
• Erythrocytes: Red blood cells, they ferry oxygen in
blood to all cells of the body.
• RBCs lack a nucleus.
• Hemoglobin: iron containing protein that transports
most of oxygen
– Lack of mitochondria and make ATP by anaerobic
mechanisms
• RBCs are normally 5 million cells per cubic millimeter
of blood.
• Blood contains 12-18 g hemoglobin per 100 mL blood.
– Higher in men than in women.
Formed elements cont.
• Leukocytes: white blood cells.
– Protects against diseases
– 4000-11,000 WBCs per cubic millimeter
– Can slip in and out of vessels. (diapedesis)
– Leukocytosis: a WBC count above 11,000
cells/mm3
– Leukopenia: abnormally low WBC
Other leukocytes
• Granulocytes: lobed nuclei, include neutrophils and
basophils
– Neutrophils: multiplied nucleus, avid phagocytes at sites of
acute infections
– Eosinophils: blue-red nucleus, increases rapidly during allergies
and infections by parasitic worms.
– Basophils: rarest of the WBCs, large histamine-containing
granules
• Agranulocytes: spherical nuclei, include lymphocytes, and
monocytes.
– Lymphocytes: large dark purple nucleus, in lymphatic tissue
– Monocytes: largest WBCs , change to macrophages with huge
appetites
Platelets
• Fragments of bizarre multinucleate cells called
megakaryocytes.
• Hemostasis: stoppage of blood flow
– Thrombus: a clot that develops and persists in an
unbroken blood vessel
– Embolus: if a thrombus breaks away from the vessel
wall and floats freely in the bloodstream
– Blood clots in 3-6 minutes
– Fibrin is a clot formed during hemostasis.
– Lack of Vitamin K in body causes undesirable clotting.
– Calcium is needed for clotting properly
Blood groups and transfusions
Losses of 15-30% lead to pallor and weakness
Losses of over 30% cause severe shock which
can be fatal
Blood can be stored for up to 35 days in a
refrigerator.
Human blood groups
• Antigens: body recognizes as foreign
• ABO blood groups: are based on the A or B a
person inherits.
• Absence of both is O blood group
• Rh blood groups: positive or negative
– Pregnant women who carry a positive baby in a
negative mother will have to have RhoGAM shots
to allow the baby to live.
Homeostatic Imbalances
• Anemia: a decrease in the oxygen carrying ability
of the blood
– 1. lower than normal number of RBCs
– 2. abnormal or deficient hemoglobin content in the
RBCs
– Lack of vitamin B12
– Lack of iron
– Genetic defect
– Hemorrhage
• Jaundice: yellowed tissue due to rapid break
down of hemoglobin.