Blood Functions

1
Blood Functions

• Blood maintains
• Appropriate body temperature by absorbing and
  distributing heat to other parts of the body
• Normal pH in body tissues
• Adequate fluid volume in the circulatory system

2
Blood Functions Protection

• Blood prevents blood loss by
• Activating plasma proteins and platelets
• Initiating clot formation when a vessel is broken
• Blood prevents infection by
• Synthesizing and utilizing antibodies
• Activating complement proteins WBCs to defend
  the body against foreign invaders

3
Physical Characteristics of Blood

• Average volume
• 56 L for males 45 L for females
• The pH is 7.357.45
• Accounts for approximately 8 of body weight

4
Composition of Blood

• Blood is the bodys only fluid tissue (a
  connective tissue)
• 2 major components
• Liquid plasma (55)
• Formed elements (45)
• Erythrocytes, or red blood cells (RBCs)
• Leukocytes, or white blood cells (WBCs)
• Platelets cell fragments

5
Components of Whole Blood
Plasma(55 of whole blood)
Buffy coatleukocyctes and platelets(lt1 of
whole blood)
Formed elements
Erythrocytes(45 of whole blood)
Withdraw blood and place in tube
Centrifuge
1
2
6
Blood Plasma

• Blood plasma components
• Water 90-92
• Proteins 6-8
• Albumins-maintain osmotic pressure of the blood
• Globulins-used for transport purposes
• Fibrinogen-a clotting protein
• Organic nutrients glucose, carbohydrates, amino
  acids
• Electrolytes sodium, potassium, calcium,
  chloride, bicarbonate
• Non-protein nitrogenous substances lactic acid,
  urea, creatine
• Respiratory gases oxygen and carbon dioxide

7
Formed Elements

• Only WBCs are complete cells
• RBCs have no nuclei or organelles, and platelets
  are just cell fragments
• Most F.E. survive in the bloodstream for only a
  few days
• Most do not divide but are renewed by cells in
  bone marrow

8
Erythrocytes (RBCs)

• Biconcave disc
• Folding increases surface area (30 more surface
  area)
• Anucleate, no centrioles, no organelles
• No cell division
• No mitochondria means they generate ATP
  anaerobically
• This prevents consumption of O2 being transported
• Filled with hemoglobin (Hb) - 97 of cell
  contents
• Hb functions in gas transport
• Most numerous of the formed elements

9
Erythrocyte Function

• Erythrocytes are dedicated to respiratory gas
  transport
• Hb reversibly binds with oxygen and most oxygen
  in the blood is bound to Hb
• Composition of Hb
• A protein called globin
• A heme molecule (a metal complex with iron as the
  central metal atom, that can bind or release
  molecular oxygen.) Heme groups are embedded in
  the hemoglobin protein,

10
Production of Erythrocytes

• Hematopoiesis blood cell formation
• Occurs in the red bone marrow
• Axial skeleton and girdles
• Epiphyses of the humerus and femur

11
Erythrocyte Disorders

• Anemia blood has abnormally low oxygen-carrying
  capacity
• There are many forms of anemia, each with its own
  cause.
• Anemia can be temporary or long term, and it can
  range from mild to severe.
• Blood oxygen levels cannot support normal
  metabolism
• Signs/symptoms include fatigue, paleness,
  shortness of breath, and chills

12
Leukocytes (WBCs)

• Protect the body from infectious microorganisms
• Can leave capillaries
• Move through tissue spaces
• Many are phagocytic- that engulfs and absorbs
  waste material, harmful microorganisms, or other
  foreign bodies in the bloodstream and tissues.
• Two major types of leukocytes
• Granulocytes Neutrophils, Eosinophils, Basophils
• Agranulocytes Monocytes, Lymphyocytes
• Leukemia - a cancer of WBC

13
Granulocytes

• Contain cytoplasmic granules that stain
  specifically with Wrights stain
• Are larger and usually shorter-lived than RBCs
• Have lobed nuclei
• Are all phagocytic cells

14
Granulocytes Neutrophils

• Account for 65-75 of total WBCs
• Neutrophils have two types of granules that
• Contain peroxidases, hydrolytic enzymes, and
  defensins (antibiotic-like proteins)
• Neutrophils are our bodys bacteria slayers

15
Granulocytes Eosinophils

• Eosinophils account for 14 of WBCs
• Function
• Lead the bodys counterattack against parasitic
  infections
• Lessen the severity of allergies by phagocytizing
  immune complexes (ending allergic reactions)

16
Granulocytes Basophils

• Account for 0.5-1 of all WBCs
• Have large, purplish-black granules that contain
  histamine
• Histamine inflammatory chemical that acts as a
  vasodilator and attracts other WBCs
  (antihistamines counter this effect)

17
Agranulocytes Lymphocytes

• Account for 20-25 or more of WBCs and
• Found mostly in lymphoid tissue (some circulate
  in the blood)
• Most important cells of the immune system
• Involved in graph rejection, fighting tumors and
  viruses
• There are two types of lymphocytes T cells and B
  cells
• T cells - attack foreign cells directly
• B cells give rise to plasma cells, which produce
  antibodies

18
Monocytes

• Account for 37 of leukocytes
• They are the largest leukocytes
• They have purple-staining, U- or kidney-shaped
  nuclei
• They leave the circulation, enter tissue, and
  differentiate into macrophages
• Increase in during chronic infections.

19
Platelets

• Platelets are fragments of megakaryocytes
• Platelets function in the clotting mechanism by
  forming a temporary plug that helps seal breaks
  in blood vessels.

Platelet
20
Human Blood Groups

• RBC membranes have glycoprotein antigens on their
  external surfaces
• These antigens are
• Unique to the individual
• Recognized as foreign if transfused into another
  individual
• Promoters of agglutination and are referred to as
  agglutinogens
• Presence or absence of these antigens is used to
  classify blood groups

21
ABO Blood Groups

• The ABO blood groups consists of
• Two antigens (A and B) on the surface of the RBCs
  
• Two antibodies in the plasma (anti-A and anti-B)
• Agglutinogens (antigens) and their corresponding
  antibodies cannot be mixed without serious
  reactions

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Group A has only the A antigen on red blood
cells (and B antibody in the plasma) Group B
has only the B antigen on red blood cells (and A
antibody in the plasma) Group AB has both A
and B antigens on red blood cells (but neither A
nor B antibody in the plasma) Group O has
neither A nor B antigens on red blood cells (but
both A and B antibody are in the plasma)

• The universal donor has Type O negative blood
  type.
• The universal plasma donor has Type AB positive
  blood type.

23
Transfusion Reactions

• Transfusion reactions occur when mismatched blood
  is infused
• Donors cells are attacked by the recipients
  plasma agglutinins causing
• Diminished oxygen-carrying capacity
• Clumped cells that impede blood flow
• Ruptured RBCs that release free hemoglobin into
  the bloodstream
• Circulating hemoglobin precipitates in the
  kidneys and causes renal failure

24
Rhesus (Rh) factor

• Is an inherited trait that refers to a specific
  protein found on the surface of RBCs. If your
  blood has the protein, you're Rh positive the
  most common Rh factor. If your blood lacks the
  protein, you're Rh negative.
• Rh factor doesn't affect your health, it can
  affect pregnancy. your body might produce Rh
  antibodies after exposure to the baby's red blood
  cells.
• Typically, the antibodies aren't a problem during
  the first pregnancy.
• with a subsequent pregnancy with an Rh positive
  baby. In this case, your existing Rh antibodies
  might cross the placenta and fight the baby's red
  blood cells.
• This could lead to life-threatening anemia