Blood

Question 1

General Characteristics (3)

Answer 1

A. Cells of the body receive all of their nutrients and eliminate all of their waste products via the blood and lymph.
B. An element is not considered clinically to be truly in the body’s internal environment until it is in the body fluids, which means it must be in the blood, lymph, interstitial fluid, or within the cells of the body themselves
C. Blood compared to Water:
1. Blood contains cellular material = blood cells
2. Blood contains hemoglobin and is therefore red in color- also other plasma proteins
3. Blood is heavier, thicker, and more viscous than water
4. Blood is slightly more alkaline than water (pH 7.4)
5. Contains NaCl (0.85 - 0.90%) and other ions

Question 2

Average blood volume (Male/Female)

Answer 2

A. Male - 5-6 liters (or 5-6 quarts)

B. Female - 4-5 liters (or 4-5 quarts)

Question 3

Functions of Blood (9)

Answer 3

A. Transports oxygen and carbon dioxide between cells and lungs
B. Transports nutrients from digestive system to tissues
C. Transports wastes away from tissues to liver, kidney, and lungs
D. Transports hormones from endocrine glands to target cells
E. Transports and contains enzymes
F. Helps to regulate body pH
G. Regulates body fluid volumes
H. Regulates body temperature
I. Protects against toxins and the invasion of harmful microorganisms

Question 4

Blood Composition (2 big details)

Answer 4

A. Formed Elements

1. Platelets or Thrombocytes
2. Erythrocytes or Red Blood Cells
3. Leukocytes or White Blood Cells

B. Plasma

1. Water
2. Electrolytes and Plasma Proteins
3. Serum = Plasma minus clotting factors = clear yellowish fluid that forms over clot or scab

Question 5

Hemopoiesis or Hematopoiesis (2 big details)

Answer 5

A. Blood cells do not multiply in the blood stream
B. All blood cells originate either directly or indirectly from the bone marrow
1. Erythrocytes, Granulocytes, and Platelets are formed completely in the marrow
2. Lymphocytes and Monocytes are formed mainly in lymph nodes, the spleen, the thymus, and in lymphatic nodules of the G. I. tract, however precursor cells are formed in the bone marrow

Question 6

Erythrocytes = Red Blood Cells (Structure) *4 details

Answer 6

1. Shape = “biconcave disc”
2. 7 micrometers in diameter on average
3. 33% hemoglobin (responsible for red color of blood)
4. No nucleus, therefore no cellular repair or cell division possible

Question 7

Erythrocytes = Red Blood Cells (Life of the Red Blood Cell) *8 Big Steps

Answer 7

1. RBC’s originate in the red marrow from cells called Rubriblasts (proerythroblasts). These cells pass through a series of developmental stages to become Reticulocytes which mature to form Erythrocytes (RBC’s).
2. RBC’s have a short life span of only about 120 days on the average. This is mostly due to the lack of a nucleus and DNA and the inability to repair itself or replace used enzymes.
3. RBC’s are removed from the blood stream by Reticuloendothelial Cells when they become older. These cells are found in many organs including: spleen, tonsils, lymph nodes, liver, lungs, and are also found roaming free in the blood stream.
   - when RBC’s are removed, hemoglobin is broken down into iron and molecules called bilirubin and urobilin. Bilirubin is excreted in the bile making feces brown and urobilin in the urine makin urine yellow.
4. Most of us have between 4 and 6 million RBC’s per cubic millimeter (4 to 6 billion per ml), with hundreds of thousands dying, and being replaced, all of the time. The total number present remains fairly constant, but will vary with oxygen demand. Formation of RBC’s is stimulated by a hormone produced by cells in the kidney when they become oxygen deficient. The hormone is called erythropoietin.
5. Reticulocyte Count - measures the rate of RBC formation. As RBC’s are formed, some reticulocytes escape the marrow before they become erythrocytes. The greater the number of reticulocytes free in the blood, the greater the rate of RBC synthesis.
6. Certain nutrients are required for RBC synthesis in the marrow. These include:
   a. - Iron
   b. - Vitamin B-12
   c. - Folic Acid
7. Anemia = a diminished concentration of RBC’s
   Causes:
   a. - lack or exercise (most common cause = mild)
   b. - acute blood loss
   c. - iron, folic acid, or vitamin B-12 deficiency in diet
   d. - Sickle Cell Anemia = poorly formed cells with fragile membranes
   e. - Pernicious Anemia = imability of body to make intrinsic factor in the stomach which protects Vitamin B-12 from digestion prior to its absorption in the small intestine.
   Physiological effects = poor oxygen transport to tissues and a decreased viscosity of the blood which causes an increased load on the heart.
8. Polycythemia = excess of RBC’s
   a. A mild polycythemia is normal in athletes and people who live at high altitudes
   b. Myoloma = bone marrow cancer - can cause this
   c. Physiologic Effects include :
   - increased viscosity of the blood which may oclude small vessels producing infarction of tissue supplied
   - increased blood pressure and increased load on the heart

Question 8

Leukocytes or White Blood Cells (WBC’s) *2 points

Answer 8

A. Unlike RBC’s, WBC’s have nuclei but do not contain hemoglobin

B. Two basic forms:

1. Granular Leukocytes - formed in bone marrow
   a. Neutrophils - normally 60 - 70% of total WBC’s
   b. Eosinophils - normally 2 - 4% of total WBC’s
   c. Basophils - normally about 0.5% of total WBC’s
2. Agranular Leukocytes - precursor formed in the marrow, but mature forms produced in lymphoid tissues
   a. Lymphocytes - normally 20 - 30% of total WBC’s
   b. Monocytes - normally 4 - 8% of total WBC’s

Question 9

General Function of Leukocytes

Answer 9

1. Combat Infection, respond to allergy, or moderate body’s response
2. Show Diapedesis = amoeba-like movement - able to move thru minute openings to all parts of the body

Question 10

Leukocytes (Differential Counts) *5

Answer 10

• these determine the percentage of each type of WBC present. This is used in diagnosis of disease.
  1. Neutrophils - respond to tissue destruction by bacteria
  a. major role = phagocytosis and release of lysozyme
  b. elevated count suggests bacterial infection
  2. Eosinophils - respond to allergy or parasite
  a. reduce inflammation by phagocytizing antigen-antibody complex
  b. large numbers in the respiratory passages in asthmatics
  c. may produce antihistamine
  d. elevated numbers suggest allergy or parasite
  3. Basophils - seem to work opposite of eosinophils
  a. also involved in the allergic response
  b. similar to mast cells found in C.T. and literature disagrees as to the relationship of these two cell types
  c. release heparin (anticoagulant), histamine (vasodialator), and serotonin (vasoconstrictor)
  d. elevation suggest allergy or parasite
  4. Monocytes - primarily phagocytic in function
  a. can become macrophages in C.T.
  b. slower to reactto infection than neutrophils, but when infection persists these will eventually arrive in larger numbers
  c. destroy microbes and clean up cellular debris
  d. elevated numbers indicate longer term or more chronic infection
  5. Lymphocytes - involved in the production of antibodies
  a. either B cells or T cells depending on roll in immune response
  b. elevated number usually indicates bacterial infection

Question 11

Leukocytes Total Cell Number

Answer 11

1. RBC’s normally outnumber WBC’s 700:1
   2. Total White Count - clinical test to indicate bacterial infection
   3. Leucocytosis = increase in the total number of WBC’s
   4. Leucopenia = decrease in total number of WBC’s

Question 12

Life span of the White Blood Cell (WBC) = variable

Answer 12

1. Often very short - only a few days
2. Die after phagocytosis of a few bacteria = “pus”
   - in an acute infection a WBC may only last a few hours
3. Some memory lymphocytes appear to last for many years

Question 13

Blood Coagulation (4 big details)

Answer 13

A. An injury or rupture of a blood vessel induces two immediate reactions

1. Smooth muscle in the wall of the vessel near the site of injury contracts restricting blood flow in the area
2. A blood clot forms at the site of injury to stop the escape of blood

B. A clot involves an aggregation of platelets together with a complicated sequential set of reactions involving a number of compounds known as coagulation factors:

1. 13 plasma coagulation factors present in the blood plasma
2. 4 platelet coagulation factors which come from the platelets

C. Unwanted Clotting

1. Thrombosis = unwanted clot in an unopened vessel.
   a. Clot = Thrombus
   b. often result of atherschlerosis and cholesterol containing masses forming in the walls of vessels and damaged endothelium
   c. may occlude vessel and produce infarction
2. Embolism = blockage of a vessel do to an embolus

D. Platelets = Thrombocytes

1. Fragments of cytoplasm only 2 to 5 micrometers in diameter surrounded by a plasma membrane
2. Derived from giant cells in the bone marrow called Megakaryocytes
3. It is possible that some minor role in phagocytosis may be accomplished by the platelets of very small bacteria or viruses
4. Primary Function = clot formation

Question 14

Blood Typing-ABO Typing (4 big details)

Answer 14

1. Based on the existence of two antigens on the surface of red blood cells
2. These antigens are special antigens and do not require a first exposure for sensitization = isoantigens or agglutinogens
3. Isoantigen either A or B
   a. Presence of antigen A = Blood Type A
   b. Presence of antigen B = Blood Type B
   c. Presence of both antigens A and B = Blood Type AB
   d. Presence of neither antigen A or B = Blood Type O
4. Individual will reject any blood containing an antigen not normally present. Rejection takes form of agglutination (clumping of thecell with the antigen).
   a. Type A agglutinates Type B or AB
   b. Type B agglutinates Type A or AB
   c. Type AB will accept any blood type without agglutination = universal recipient
   d. Type O agglutinates Type A, B or AB = universal donor

Question 15

Blood Typing-Rh Typing (7 big details)

Answer 15

1. A second antigen on the surface of RBC’s in addition to the A and B antigens which must also be determined before transfusion.
2. This antigen requires sensitization before rejection will occur.
3. Rh System - based on Rh antigen named for its discovery in the Rhesus monkey.
4. If agglutinogen (antigen) is present on the surface of the erythrocyte the blood is said to be “Rh positive,” if not it is “Rh negative”
5. 80 - 90% of the population = Rh+, 10 - 15% of population = Rh-
6. Rh negative blood will agglutinate Rh positive blood. Therefore Rh- blood cannot receive Rh+ blood.
7. Important complication involves Rh- mothers.
   a. Most likely to have Rh+ husband
   b. Since Rh+ is genetically dominant, child is likely to be Rh+
   c. Since maternal and fetal blood do not mix, first baby is usually no problem
   d. However, during birth process maternal is often mixed with some fetal blood causing exposure to Rh antigen
   e. Antibodies freely cross the placenta and antibodies against Rh in the Rh- mother will attack the blood of an Rh+ fetus
   f. Condition = Erythroblastosis Fetalis, or Hemolytic Disease of the Newborn
   g. Prevention: When each baby is delivered, a preparation of antibodies against the Rh agglutinogens is injected into the mother, which binds up any antigen which may have gotten into the mother’s blood, and prevents her from making her own antibodies.