Cardiovascular System: The Blood

1
Cardiovascular System The Blood

• Dr. Michael P. Gillespie

2
Constituents Of Blood

• Blood is a connective tissue composed of a liquid
  matrix called plasma that dissolves and suspends
  various cells and fragments.
• Interstitial fluid is the fluid that bathes body
  cells.

3
Functions of Blood

• Transportation oxygen, carbon dioxide,
  nutrients, hormones, heat, waste products.
• Regulation maintains homeostasis (ph, heat,
  osmotic pressure).
• Protection clotting, WBCs, antibodies.

4
Physical Characteristics Of Blood

• Blood is denser and more viscous than water.
• The temperature is 38 degrees C (100.4 degrees
  F).
• Slightly alkaline ph ranging from 7.35 to 7.45.
• 20 of the extracellular fluid (about 8 of total
  body mass).
• The blood volume is 5 to 6 liters (1.5 gal) in an
  average adult male and 4 to 5 liters (1.2 gal) in
  an average adult female.

5
Withdrawing Blood

• Blood samples for laboratory testing are obtained
  in various ways.
• Venipuncture (the most common method).
• A finger or heel stick is utilized for children
  and people who must monitor their blood daily
  (I.E. Diabetics).
• An arterial stick is utilized when the level of
  O2 must be determined.

6
Components Of Blood

• Whole blood has two components
• Blood plasma, a watery liquid matrix that
  contains dissolved substances.
• Formed elements (cells and cell fragments).
• 45 formed elements and 55 plasma.

7
(No Transcript)
8
Blood Plasma

• A straw-colored liquid which is about 91.5 water
  and 8.5 solutes.
• Plasma proteins maintain osmotic pressure.
• Albumins, globulins, and fibrinogen (synthesized
  by hepatocytes).
• Gamma globulins (antibodies 0r immunoglobulins).
• Electrolytes, nutrients, regulatory substances
  (i.E. Enzymes and hormones), gases, waste
  products (urea, uric acid, creatinine, ammonia,
  and bilirubin).

9
Formed Elements

• RBCs.
• WBCs perform many functions.

10
Formed Elements

• Platelets cell fragments.

11
Formed Elements

• Hematocrit the percentage of total blood
  occupied by RBCs.
• Males have a higher hematocrit than females
  because testosterone stimulates the production of
  erythropoeitin (EPO).
• Menstruation leads to lower values for females
  during their reproductive years.
• Anemia is a significant drop in the hematocrit.
• Polycythemia is an.
• Abnormally high percentage of RBCs.

12
Causes of Polycythemia

• Abnormal increase in RBC production.
• Tissue hypoxia.
• Dehydration.
• Blood doping or use of Epoetin alfa (Procrit or
  Epogen) by athletes.
• This increases the work load of the heart.
• The increased s of RBCs raise the viscosity of
  the blood, which increases the resistance to
  blood flow. This can cause high blood pressure
  and stroke.

13
Formation of Blood Cells

• Hemopoiesis (hematopoiesis) the process by
  which the formed elements of blood develop.
• Blood cells, macrophages, reticular cells, mast
  cells, and adipocytes arise from the red bone
  marrow.
• Pluripotent stem cells in the bone marrow
  reproduce themselves, proliferate and
  differentiate into mature blood cells.

14
Two Types of Pluripotent Stem Cells

• Myeloid stem cells.
• Give rise to red blood cells, platelets,
  monocytes, neutrophils, eosinophils, and
  basophils.
• Lymphoid stem cells.
• Give rise to lymphocytes.

15
Generations Of Cell Lines In The Development Of
Blood Cells

• Pluripotent stem cells mesenchymal cells which
  have the capacity to develop into many different
  types of cells. They can reproduce themselves.
• Progenitor cells cannot reproduce themselves.
• Precursor cells (blasts) they develop into the
  actual formed elements of the blood.

16
(No Transcript)
17
(No Transcript)
18
Hormones That Regulate Blood Cell Development

• Hemopoietic growth factors regulates
  differentiation and growth of progenitor cells.
• Erythropoietin (EPO) from the kidneys increases
  the of RBC precursors.
• Thrombopoietin (TPO) from the liver stimulates
  the formation of platelets.
• Colony-stimulating factors (CSFs) or interleukins
  stimulate WBC formation.

19
Medical Uses of Hemopoietic Growth Factors

• EPO is utilized in end stage kidney disease to
  increase RBC formation.
• CSFs are utilized to stimulate WBC formation in
  cancer patients undergoing chemotherapy.
• Thrombopoietin helps induce platelet formation in
  chemotherapy patients.

20
Red Blood Cells

• Red blood cells (RBCs) or erythrocytes
• Contain hemoglobin oxygen-carrying protein
  which gives the cell its color.
• Approximately 5 million RBCs are present per
  microliter of blood.
• Approximately 2 million RBCs are created and
  destroyed per second.

21
RBC Anatomy

• Biconcave discs with a diameter of 7-8
  micrometers.
• The plasma membrane is flexible, which allows
  them to deform without rupturing as they squeeze
  through capillaries.
• RBCs lack a nucleus and other organelles.
• RBCs cannot reproduce or carry on extensive
  metabolic activities.

22
(No Transcript)
23
RBC Physiology

• With no nucleus, RBCs have more space available
  for oxygen transport.
• RBCs lack mitochondria and generate ATP
  anaerobically Consequently, they do not use up
  the oxygen they are transporting.

24
RBC Physiology

• The biconcave disc has a greater surface area
  allowing greater diffusion of gas molecules.
• Hemoglobin binds to oxygen, carbon dioxide, and
  nitric oxide (NO).
• NO causes vasodilation which enhances oxygen
  delivery to cells.

25
(No Transcript)
26
RBC Life Cycle

• Red blood cells live only about 120 days.
• Macrophages in the spleen and liver remove dead
  RBCs through phagocytosis.
• Hemoglobin is broken down into its globin and
  heme portions.
• Globin is broken down into amino acids, which are
  reused for proteins.
• Heme is converted into the yellow-orange pigment
  bilirubin.

27
(No Transcript)
28
(No Transcript)
29
Reticulocyte Count

• The rate of eryhtropoiesis is measured by a
  reticulocyte count.
• Low retic count could indicate a shortage of
  erythropoietin due to a nutritional deficiency or
  leukemia.
• High retic count could indicate a good
  response to previous blood loss, iron therapy, or
  illegal use of Epoetin by an athlete.

30
White Blood Cells

• White blood cells (WBCs) or leukocytes have a
  nucleus and do not contain hemoglobin.
• Classified as either granular or agranular.

31
Types Of White Blood Cells

• Eosinophil
• Basophil
• Neutrophil
• Small lymphocyte
• Monocyte

32
(No Transcript)
33
(No Transcript)
34
(No Transcript)
35
Numbers Of WBCs

• RBCs outnumber WBCs by about 7001.
• There are approximately 5000 10,000 cells per
  microliter of blood.
• Leukocytosis an increase in the number of WBCs
  due to stresses such as microbes, strenuous
  exercise, anesthesia, or surgery.
• Leukopenia a decrease in the number of WBCs
  due to radiation, shock, or chemotherapy.

36
Functions Of WBCs

• The WBCs combat pathogens by phagocytosis and
  other immune responses.
• WBCs leave the bloodstream by emigration.

37
Functions Of WBCs

• Neutrophils and macrophages are active in
  phagocytosis.
• Phagocytes are attracted to inflamed tissues
  through a process called chemotaxis.
• Phagocytes release the enzyme lysozyme, which
  destroys certain bacteria.

38
(No Transcript)
39
Functions Of WBCs

• Eosinophil release histamines. Respond to
  allergic responses and parasitic infection.
• Basophil liberate heparin, histamine, and
  serotonin. They intensify the inflammatory
  reaction and are involved in hypersensitivity
  (allergic) reactions.

40
Functions Of WBCs

• Neutrophil active in phagocytosis and ingest
  bacteria and dead matter. They respond to
  bacteria and fungi.
• Lymphocyte soldiers of the immune system.
• Monocyte turn into macrophages and clean up
  cellular debris after an infection.

41
Differential WBC Count

• Utilized to detect infection, inflammation,
  poisoning, blood disorders, effects of
  chemotherapy, allergic reactions, and parasitic
  infections.

42
Significance Of High Low WBC Counts
WBC Type High Count Low Count
Neutrophils Bacterial infection, burns, stress, inflammation Radiation, drug toxicity, B12 deficiency, SLE
Lymphocytes Viral infection, leukemia Prolonged illness, immunosuppression, cortisol tx.
43
Significance Of High Low WBC Counts
Monocytes Viral or fungal infection, chronic diseases Bone marrow suppression, cortisol tx.
Eosinophils Allergic rx., parasites, autoimmune dis. Drug toxicity, stress
Basophils Allergic rx., cancers, hypothyroidism Pregnancy, ovulation, stress, hyperthyroidism
44
Platelets

• The hormone thrombopoietin influences the
  production of platelets (thrombocytes).
• Platelets help stop blood loss by forming a
  platelet plug.

45
(No Transcript)
46
Complete Blood Count (CBC)

• A test that screens for anemia and various
  infections.
• Counts of RBCs, WBCs, platelets, hematocrit, and
  a differential white blood cell count are
  included.

47
Blood Clotting

• Serum is a straw colored liquid and the gel is
  called a clot.
• The process of gel formation is called clotting
  or coagulation.
• Clotting factors are involved in the coagulation
  cascade.

48
Blood Clotting

• Normal clotting requires vitamin K, which is
  produced by bacteria in the intestines.
• Dissolution of a clot is called fibrinolysis.
• Anticoagulants (heparin Warfaring a.K.A.
  Coumadin) are utilized for patients at risk of
  forming a blood clot.

49
(No Transcript)
50
Intravascular Clotting

• Thrombosis clotting in an unbroken blood
  vessel.
• Thrombus the clot itself.
• Embolus a blood clot, bubble of air, fat from
  broken bones, or a piece of debris transported by
  the bloodstream.
• Pulmonary embolism when an embolus lodges in
  the lungs.

51
ABO Blood Group

• Type A blood - RBCs display only antigen A.
• Type B blood RBCs display only antigen B.
• Type AB blood RBCs display both antigens A B.
• Type O blood RBCs display neither antigen A or
  B.

52
ABO Blood Group

• The blood plasma contains isoantibodies or
  agglutinins that react with A or B antigens if
  mixed.
• You do not have the antibodies that react with
  the antigens of your own RBC type, but you most
  likely have the antibodies for antigens your own
  blood lacks.

53
(No Transcript)
54
Rh Blood Group

• People with Rh antigens in their blood are Rh
  positive and people without the Rh antigen are Rh
  negative.
• Normally, plasma does not contain anti-Rh
  antibodies.

55
Rh Blood Group

• If an Rh- person receives Rh blood transfusion,
  he or she will start to make antibodies that will
  remain in the blood.
• The next time he or she receives Rh blood, the
  antibodies will cause hemolysis of the donated
  blood.

56
Hemolytic Disease Of The Newborn
57
(No Transcript)
58
ABO Blood Group Interactions
Characteristics A B AB O
Antibody in plasma Anti-B Anti-A Neither Both
Antigen on RBCs A B A B Neither
Donors A, O B, O A, B, AB, O O
Hemolysis B, AB A, AB None A, B, AB