Download The Human Body in Health and Illness

Human Body
in Health and Illness
The
Barbara Herlihy
Chapter 15:
Blood
What Blood Does
• Three general functions:
– Transportation: oxygen, carbon dioxide, nutrients,
hormones
– Regulation: body temperature, fluid and electrolyte
balance
– Protection: WBCs and platelets
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Composition of Blood
• Characteristics:
–
–
–
–
Type of connective tissue
Color varies with oxygenation
pH between 7.35 to 7.45
Viscosity: thickness or stickiness compared to water
(more viscious)
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Composition of Blood
(cont’d.)
• Two Parts:
– Plasma: pale, yellow
fluid composed mostly
of water
– Blood cells (formed
elements):
• Red blood cells (RBCs)
• White blood cells
(WBCs)
• Platelets
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Hemopoiesis
• Process of blood cell
formation
• Hemopoietic tissue:
– Red bone marrow:
found in the end of
long bones, flat and
irregular bones
– Lymphatic tissue:
spleen, lymph nodes
and thymus
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Myelosuppression
• Condition in which bone marrow cannot produce
enough blood cells
• Myelosuppression can result in:
– Aplastic anemia: RBC deficiency
– Leukopenia: WBC deficiency
– Thrombocytopenia: Platelet deficiency
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Polycythemia Vera
• Bone marrow overactivity leads to excess RBC
production
• Caused by a gene mutation
• Excess thickened blood:
– Burdens the heart
– Overwhelms clotting system
– Causes beet-red face
• Treatment: drugs to suppress bone marrow
and/or phlebotomy
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Red Blood Cells
• Red blood cells (RBCs):
– Also called erythrocytes
– Most numerous of the blood cells
– Primarily responsible for the transport of oxygen and
carbon dioxide
– Large, disc-shaped, thick outer rim, thin center,
bendable
– Filled with hemoglobin (iron containing protein)
– Color changes from bright red to blue-red
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Sickle cell disease
• Genetic disorder
characterized by RBCs
that form an
abnormal, rigid, Cshape.
• Blocks blood flow and
restricts tissue of
oxygen.
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Hemoglobin
• Iron containing protein
in RBCs that transports
oxygen and carbon
dioxide
• Heme: iron containing
substance (O²
attaches)
• Globin: protein (CO²
attaches)
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Regulation of RBC Production
1. Low O²
2. Kidneys release
erythropoietin (EPO)
(hormone)
3. Stimulates bone
marrow to produce
RBCs
4. O² levels increase
5. EPO no longer released
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Recycle!
• Worn out RBCs are
broken down into:
– Heme: iron (used
later) and bile
(excreted)
– Globin: amino acids
(used later for
proteins)
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White Blood Cells
• White blood cells (WBCs):
– Large, round cells that contain
nucleus
– Also called leukocytes
– Function to protect the body
– Can leave the blood vessels
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White Blood Cells
(cont’d.)
Type of WBC
Granulocytes
Neutrophils
Eosinophils
Function of Cell
Basophils
Inflammatory responses; release of
heparin
Phagocytosis
Inflammatory responses; allergies
Agranulocytes
Lymphocytes
Immunity
Monocytes
Phagocytosis
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White Blood Cells
(cont’d.)
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Platelets
• Platelets:
–
–
–
–
–
Tiniest blood cells
Produced in red bone marrow
Also called thrombocytes
Life span is 5 to 9 days
Function to prevent blood loss
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Blood Diagnostic Tests
• Differential white blood cell count: indicates the
percentage of each type of white blood cell
• Complete blood count (CBC): lists the normal
ranges of the numbers of RBCs, WBCs, and
platelets in blood
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Hemostasis: process that stops
bleeding
• Vascular spasm: decreases
the diameter of the blood
vessel
• Platelet plug: platelets stick
together and adhering to the
lining of the injured vessel
• Coagulation: clotting of blood
to seal off the opening in an
injured blood vessel (caused
by a series of chemical
changes in blood)
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Blood Types: ABO Grouping
• ABO grouping:
– Four blood types: A, B, AB, O
• Agglutination: clumping together of RBCs;
causes hemolysis (bursting of RBCs)
• Compatible blood groups: blood types that mix
without undergoing agglutination reactions
• Universal donor: type O blood
• Universal recipient: type AB blood
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Blood Types: Rh Factor
• Rh factor: an
antigen located on
the surface of the
RBC
• About 85% of
people are Rhpositive (+)
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