Blood
Chapter 12
Introduction
• What is the function of blood?
• Blood transports substances (nutrients, oxygen, wastes, and hormones)
• Also maintains homeostasis in the body with hormones
• Hematophobia = fear of blood
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Blood and Blood Cells
• Blood is a type of connective tissue with two basic components:– 1. Cells (red blood cells, white blood cells,
and platelets) = 45%
– 2. Plasma (water, amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes) = 55%
http://www.virtualmedicalcentre.com/uploads/VMC/TreatmentImages/2309_blood_450.jpg
• Hematocrit – percentage of cells in a blood sample– Should be 45%, remaining 55% is plasma– Have to centrifuge a blood sample to test this
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Three types of cells
• Red blood cells - erythrocytes
• White blood cells - leukocytes
• Platelets - thrombocytes
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Red blood cells - erythrocytes
• Have a biconcave shape
• RBCC stand for red blood cell count which is the amount of blood cells in a cubic millimeter (5 million per cubic millimeter)
• They lack nuclei in a mature stage so they will not divide
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• Hematopoiesis – formation of new blood cells (done in bone marrow)
• Blood cells live for about 120 days, then are phagocytized by the liver and spleen
http://daley.med.harvard.edu/assets/Willy/hematopoiesis.jpg
• Erythropoietin – a hormone that is part of a negative feedback mechanisms that controls the rate of red blood cell formation– Produced in the liver and kidneys (controlled
by oxygen levels
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Main functions of Red blood cells
• Transports oxygen throughout body
and picks up carbon dioxide
• Hemoglobin - molecule which combines with oxygen to transport it within the blood
• Iron is critical to the creating of hemoglobin
http://gassama.myweb.uga.edu/hemoglobinmolecule.gif
Oxygen levels in blood
• Oxyhemoglobin – blood has plenty of oxygen, appears bright red
• Deoxyhemoglobin – blood is not carrying much oxygen, appears "bluish red"
• Red blood cell production requires:– Iron– Vitamin B12– Folic Acid
• Anemia = too few red blood cells
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White blood cells – leukocytes
• General function - defend the body against disease-causing agents (microorganisms)
• Five different types in two groups:– 1. Granulocytes (granular cytoplasm):
Neutrophils, Eosinophils, Basophils
– 2. Agranulocytes (lacking granular cytoplasm): Monocytes, Lymphocytes
http://illuminationstudios.com/wp-content/uploads/2011/10/leukocytes.jpg
1. Neutrophils
• Very active in phagocyting bacteria
• Are present in large amount in the pus of wounds
• Most common make up 60% of WBC
http://images.wisegeek.com/neutrophil.jpg
2. Eosinophils
• Attack parasites
• Control allergic reaction
• 2% WBC
3. Basophils
• Produces Heparin (prevents blood clots) and Histamines (causes inflammatory reaction)
• Less then 1% WBC
4. Monocytes
• Precursors of macrophages
• Phagocytes
• Make up 6% of WBCs
5. Lymphocytes
• Main constituents of the immune system which is a defense against the attack of pathogenic micro-organisms such as viruses, bacteria, fungi and protista
• Yield antibodies and arrange them on their membrane
• Make up 30% of WBCs White blood cell interactive
Platelets – Thrombocytes
• Help initiate formation of blood clots,
• They close breaks in damaged blood vessels
http://www.ouhsc.edu/platelets/Platelet%20Pics/Platelets3.jpg
Blood Plasma
• The liquid portion of the blood– 92% water
– transports nutrients, gases, vitamins, maintains fluid and electrolyte balance, and pH
– Four types of proteins
in plasma
http://blog.inceptsaves.com/files/2011/02/45497505_c0013438-frozen_blood_plasma-spl-1.jpg
Albumin
• Origin: Liver
• Function: Helps maintain osmotic pressure and blood volume (blood pressure)
http://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/ALB_structure.png/250px-ALB_structure.png
Alpha Globulin
• Origin: Liver
• Function: Transport lipids and fat – soluble vitamins
Beta Globulin
• Origin: Liver
• Function: Transport lipids and fat – soluble vitamins
Gamma Globulin
• Origin: Lymphatic tissue
• Function: Constitute a type of antibody for immunity
Fibrinogen
• Origin: Liver
• Function: Largest molecules of plasma proteins; important for blood clotting. Major event in blood clotting is the change of fibrogen into fibrin
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Hemostasis
• The process of stopping bleeding
• Coagulation causes the formation of a blood clot
• 3 Key Events
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1. Blood Vessel Spasm (vasoconstriction)
• Damaged or broken vessels stimulate muscle tissue in the walls of the blood vessels to contract
• This slows or stops blood flow, lasts for several minutes.
• Also, platelets release serotonin, a vasoconstrictor which maintains the muscle spasm even longer.
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2. Platelet plug formation
• Platelets stick to surfaces of damaged blood vessels and to each other to form a "plug"
http://www.baileybio.com/plogger/images/anatomy___physiology/10._powerpoint_-_cardiovascular_system/platelet_plug_formation.jpg
3. Blood coagulation
• Most effective, forms a blood clot (hematoma).
• Injury causes an increase in the release of coagulants.
• Main event - conversion of fibrinogen into long protein threads called fibrin.
• Tissue damage cause the prodction of prothrombin activator (calcium ions must be present)
• Prothrombin get converted to thrombin
• Thrombin acts as an enzyme to cause change of fibrinogen to fibrin, which traps platelets and blood cells to form a hematoma
http://images.emedicinehealth.com/images/eMedicineHealth/illustrations/blood_clot.jpg
• Thrombus - a blood clot abnormally forming in a vessel
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• Embolus - when the clot moves and becomes lodged in another place
http://www.thrombosisadviser.com.tw/html/images/library/atherothrombosis/embolus-cerebral-artery-illustration-PU.jpg
Blood Groups and Transfusions
• Blood types are controlled by three alleles:– A, B, & O
• A & B are codominant; O is recessive
• This makes the genetics of blood very interesting
Antigens and Anitbodies
• Agglutination is the clumping of red blood cells following a transfusion reaction
• It is due to a reaction between red blood cell surface molecules called antigens and protein antibodies carried in plasma
• The type of antigens deternmines what blood type a person is
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Blood transfusions
• Blood that has antibodies on it that is not recognized by the body will be attacked by your immune system
• O is the Universal Donor because a person with this type of blood does not have antigens on the surface of the blood cells
• This will not cause an immune reaction in the patient.
• AB is the universal Acceptor because this person will not have an immune reaction to A, B, AB, or O
http://www.bankofmontana.com/blog/wp-content/uploads/2013/04/Blood_Group_Compatibility.gif
Rh Blood group
• A person can either be Rh+ (have Rh surface antigens) or Rh- (do not have Rh surface antigens)– Positive is the dominant genotype
http://www.arcinlandempire.org/wp-content/uploads/2012/10/blood-type.png
• Problem: When a fetus is Rh+ and the mother is Rh-, this can cause the mother's immune system to attack the fetus.
• Called Erythroblastosis fetalis
• Doctors can prevent this reaction by giving the woman an injection that will suppress her immune reaction.
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