Transcript Blood - Lancaster High School

Blood
Blood
• Connective tissue
• Formed elements suspended in intercellular matrix
(plasma)
– Cells
– Cell fragments
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Only liquid tissue
4-5L female
5-6L male
8% of total body weight
slightly alkaline pH 7.35 – 7.45
• 3 main functions
– transportation
• carries O2 and nutrients to cells
• CO2 and nitrogenous wastes from tissues to lungs
and kidneys
• Carries hormones from the endocrine glands to
target tissues
– Regulation
• Regulate body temp.
– Removes heat from areas and transporting to other regions
(skin)
– Fluid and electrolyte balance
– pH reg.
– Protection
• Clotting prevents fluid loss
• Phaogcytic WBC’s destroy microorganisms
• Antibodies help protect against disease
Composition of Blood
• Plasma – 55%
– Liquid portion
– 90% H2Ocontains >100 different organic and inorganic
solutes
• Plasma Proteins
– Most abundant
– Normally not used for energy
– 3 major classes
• Albumins – 60% ~ Help maintain fluid balance
• Globulins – 36% ~ Lipid transport and immune support
• Fibrinogens – 4% ~ Blood clotting
Composition of Blood
• Nitrogen-Containing Molecules
– Amino Acids – transported to cells that need
– Urea – excreted
– Uric Acid – excreted
• Nutrients and Gases
– Glucose, fatty acids
– O2 and CO2
• Electrolytes
– Na+, K+, Ca++, Cl-, HCO3-, PO4-3
• Formed Elements – 45% (hematocrit) –
packed cell volume (PCV)
– Cells and cell fragments
– Hematopoiesis
• Production of blood cells
• After birth, occurs in red bone marrow and
lymphoid tissue
• Hemocytoblast
– Stem cell that is the precursor to all formed elements
– Erythrocytes (RBC) 4.5-6million/mm3
• Most numerous
• Biconcave disks
– Thin in middle, thick around periphery
– Allows for flexibility and maximum surface area
• Anucleate – What does this mean?
– Cannot undergo mitosis –why?
– How do we make new RBC’S?
• Function
– Transport O2 and CO2
– Uses hemoglobin
• Lifecycle Fig. 11-3
– Production regulated by erythropoietin (hormone
from liver)
• Activated by renal erythropoietic factor
(REF) from kidneys
• Iron, vitamin B12 , folic acid are essential to
RBC production
• Live for about 120 days
– Age  membrane elasticity and becomes
fragile -> similar to our skin as we age
– Macrophages (phagocytic) remove cells from
circulation
• 2 million destroyed and replaced every
second!
– Hemoglobin is separated into
• Heme - Iron- recycled
• Bilirubin – becomes part of bile & carried
to sm. intestine
– Leukocytes (WBC’s) 5,000 – 9,000/ mm3
• Larger and fewer than RBC’s
• Derived from hemocytoblast stem cells
– Do not lose nucleus
– Do not have hemoglobin (appear white)
• Most of the work takes place in tissues
– Diapedesis
• Process by which WBC’s move through
capillary walls into tissue spaces
• 2 main groups
– Granulocytes
• Cells that develop granuoles in cytoplasm
• 3 types
– Neutrophils – granules stain pink
• Most common – 60-70%
• First to respond to tissue damage
• Engulf bacteria by phagocytosis
•  # in acute infections – what is that?
– Eosinophils – granules stain red
• 2-4%
• neutralize histamine
• # during allergic reactions
• destroy parasitic worms
– Basophils – granules stain blue
• <1%
• those that enter tissue are called mast cells
• secretes histamine - dilates blood vessels
• secretes heparin - inhibits blood clot formation
– Agranulocytes
• Cells that do not have granules
• 2 types
– Lymphocytes
• 20-25%
• help fight against disease
• T-cells –attack bacteria & viruses
• B-cells- antibodies to bact. & tox
–Monocytes
• 3-8%
• largest in size
• when enter tissue called
macrophages
• engulf bacteria & cellular debris finish cleanup started by
neutrophils
• Thrombocytes
– Platelets
– Not complete cells, fragments of
megakaryocytes
• Develop from hemocytoblasts
– 250,000 – 500,000/mm3
– sticky & clump together to form platelet plugs
– initiate blood clots
Hemostasis
• stoppage of bleeding
• 3 separate but interrelated processes
– Vascular Constriction
• First response to blood vessel injury
• Contraction of smooth muscle in vessel
walls
– Restricts blood flow
• Serotonin is released by platelets ->
stimulates smooth muscle contract
– Platelet Plug Formation
• Platelets stick to collagen fibers
exposed from torn connective tissue
• Creates a mass of platelets, which
obstructs the tear
• Numerous tears daily
– Coagulation
• Formation of a blood clot
• Procoagulants -> found in blood - Promote clotting
• Anticoagulants - Inhibit clotting
• 3 main steps (Fig. 11-5)
– Platelets & damaged tissues release chemicals -> formation of
prothrombin activator
– Ca++ and prothrombin activator converts prothrombin to
thrombin
– Thrombin + Ca++ converts fibrinogen to fibrin -> forms a
mesh that adheres to tissue & traps blood cells and platelets
• Ca++, Vitamin K, platelets are
necessary
• After, fibrin strands contract
– Pulls edges of wound together
– Fibrinolysis
• Dissolve of clot
Blood Typing and Transfusions
• Transfusion
– Transfer of blood, plasma, or other solution into the
blood of another individual -> in the past were
unsuccessful
• Antigen
– Molecules, usually proteins, that elicit a response from
antibodies
• Antibodies
– Protein molecules that are produced in response to a
foreign antigen
– Very specific
• Blood types are based on specific antigens and
antibodies related to RBC’s
• Agglutinogens
– Antigens found on the cell membrane of erythrocytes
• Agglutinins
– Antibodies found in plasma
• Agglutination
– When agglutinins in plasma combine w/ agglutinogens
on the surface of RBC’s
– Causes clumping of RBC’s
• ABO Blood Groups
– Based on the presence or absence of certain agglutinogens
• A+B
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Type A -> A agglutinogens on cell membrane
Type B -> B “
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Type AB -> A and B “
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Type O -> neither A nor B “
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– Agglutinins develop in plasma shortly after birth
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Type A agglutinogens -> anti-B agglutinins
Type B agglutinogens -> anti-A agglutinins
Type AB agglutinogens -> neither agglutinin
Type O agglutinogens -> both anti-A and anti-B agglutinins
• Donor – gives blood
• Recipient – receives blood
– Agglutinins in plasma of recipient
must NOT react w/ cells of donor
blood
Type
Blood Can
Receive
Blood Can’t
Receive
A
A,O
B,AB
B
B,O
A,AB
AB
A,B,AB,O
--
O
O
A,B,AB
O = universal donor
AB = universal recipient
• Rh Blood Groups
– Rh+ -> Rh agglutinogens on surface of RBC’s
– 85% of pop.
– Rh- -> no Rh agglutinogens
– Normally, no anti-Rh agglutinins
• If Rh- person exposed to Rh+ blood (transfusion,
mother and fetus), the Rh- person develops Rh+
agglutinins
• If exposed to Rh+ a second time -> a transfusion
reaction results