1. Chapter 12 Blood Type of connective tissue
Cells suspended in a liquid extracellular matrix
Vital in transporting substances between body cells and the external environment
Promotes homeostasis
Whole blood is
Heavier than water
3-4 times more viscous than water
Cells form mostly in red bone marrow
Red blood cells that carry oxygen
White blood cells fight infections
Platelets help blood clot

2. Formed Elements and Plasma
Cells and platelets found in blood are called formed elements
Red blood cells (RBCs) make up about 45% of blood
Percentage of RBCs in a blood sample is called the hematocrit
White blood cells (WBCs) and platelets make up less than 1% and are sometimes called the buffy coat
Liquid portion of blood is called plasma
Normally straw colored and clear
Makes up about 55% of blood
Mixture of water, amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular waste

3. Origins of Blood Cells

4. Red Blood Cells Also called erythrocytes Biconcave discs
Increased surface area
No nucleus in mature RBCs
Life span about 120 days
Adapted to transport gases (O2 & CO2)
Contains a protein called hemoglobin
Makes up about 1/3 of RBCs
Binds to oxygen in blood
Oxyhemoglobin bright red when oxygen present
Deoxyhemoglobin darker color when oxygen absent
Oxygen-carrying capacity increases as numbers of RBCs increase
Normal RBC count:
Males: 4.6 – 6.2 million cells per microliter
Females: 4.2 – 5.4 million cells per microliter

5. Red Blood Cells A person with a decreased oxygen-carrying capacity
Has hypoxia
May appear bluish in color and be cyanotic
Sickle cell disease
Genetic disorder causes an abnormal form of hemoglobin to be produced
Hemoglobin crystallizes into a “sickled” shape when oxygen levels are low
Blocks circulation and causes severe pain
More common in people of African descent

6. White Blood Cells Also called leukocytes Protect against disease
Transported to sites of infection by blood
Leave bloodstream to fight infection
Two main types of WBCs:
Granulocytes
Have granular cytoplasm
Include neutrophils, eosinophils, and basophils
About twice the size of RBCs
Agranulocytes
No cytoplasmic granules
Include monocytes and lymphocytes
Normal WBC count:
4,500 – 10,000 cells per microliter

7. White Blood Cells – Neutrophils
Have fine cytoplasmic granules that appear light purple in a neutral stain
The nuclei of older cells are lobed and have 2-5 segments
Sometimes called “segs”
Nuclei attached by thin strands of chromatin
The nuclei of younger cells usually have a C – shape
Sometimes called “bands”
Account for 54 – 62% of WBCs in an adult
Phagocytize bacteria and other small particles

8. White Blood Cells – Eosinophils
Contain coarse cytoplasmic granules that appear deep red in an acid stain
The nucleus usually has only two lobes (bilobed)
Make up about 1-3% of WBCs
Kill parasites
Help control inflammation
Increase in number with allergic reactions

9. White Blood Cells – Basophils
Similar to eosinophils in size and shape of nuclei
Contain fewer cytoplasmic granules that stain deep blue in a basic stain
Usually account for less than 1% of WBCs in adults
Release heparin and histamines
Increased count may indicate a problem such as cancer

10. White Blood Cells – Monocytes
Largest blood cells
2 – 3 times larger in diameter than an RBC
Nuclei vary in shape from spherical to lobed
Account for 3 – 9% of WBCs in an adult
Phagocytize larger particles
May live for several weeks or even months

11. White Blood Cells – Lymphocytes
Usually only slightly larger than RBCs
Contain a large round nucleus surrounded by a thin rim of cytoplasm
Account for about 25 – 33% of WBCs in an adult
Provide immunity in the form of antibodies
Proteins that attack foreign particles in the blood
Usually increase in number when an individual has a viral infection
Ex: mononucleosis or EBV
2 main types: T-cells and B-cells
T-cell counts drop to almost zero in AIDS patients
May live for years

12. White Blood Cells Leukocytosis
Increased WBC count over 10,000 cells per microliter
May indicate acute infection
Number of neutrophils increases with bacterial infections
Number of lymphocytes increases with viral infections
Leukopenia
Decreased WBC count under 5,000 cells per microliter
May accompany influenza, measles, mumps, AIDS, or chickenpox
Leukemia
Cancer of WBCs

13. Platelets Also called thrombocytes Fragments of cells
Arise from very large cells called megakaryocytes
Lack nuclei
Less than half the size of an RBC
May live for about 10 days
Normal platelet count
130,000 – 360,000 per microliter
Help close breaks in damaged blood vessels
Initiate formation of blood clots
Inactivated by the use of aspirin for up to a week

14. Blood Plasma Clear, straw-colored liquid portion of blood
Cells and platelets are suspended
Approximately 92% water
Contains a complex mixture of organic and inorganic biochemicals
Functions
Transporting nutrients, gases, and vitamins
Help regulate fluid and electrolyte balance
Maintain normal pH

15. Plasma Proteins Most abundant of the dissolved substances in plasma
All are made in the liver
Albumins (60%)
Smallest plasma proteins
Important in maintaining osmotic pressure
Globulins (36%)
Can be subdivided into alpha, beta, and gamma globulins
Alpha & beta globulins transport lipids and fat-soluble vitamins
Gamma globulins make antibodies that fight foreign substances in the body (viruses, transplanted organs)
Fibrinogen (4%)
Functions in blood coagulation
One of the largest plasma proteins

16. Plasma Proteins

17. Gases and Nutrients Most important plasma gases:
Oxygen (O2) – needed for cellular respiration
Carbon dioxide (CO2) – waste product
Other plasma gases:
Nitrogen (N2) – no function
Plasma nutrients:
Absorbed from digestive tract
Include: Amino acids, simple sugars, nucleotides, lipids
Nonprotein Nitrogenous Substances
Products of protein metabolism
Include: Amino acids, urea, and uric acid

18. Gases and Nutrients Plasma electrolytes Absorbed from the intestines
Released as by-products of cellular metabolism
Include ions of: sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, and sulfate
Bicarbonate ions are important in maintaining
Osmotic pressure
Plasma pH

19. Hemostasis The stoppage of bleeding
Important after damage to blood vessels
Actions that limit blood loss include:
Blood vessel spasms
Also called vasospasms and result from contractions of smooth muscles in blood vessels
Platelet plug formation
Platelets adhere to rough surfaces and collagen in connective tissue
Platelets adhere to each other
Controls blood loss in small breaks
Blood coagulation
Formation of a blood clot
Uses biochemicals called clotting factors
Fibrinogen converts to fibrin to help form blood clot

20. Hemostasis Plasma vs. serum Plasma contains clotting factors
Serum contains no clotting factors
Thrombus – a blood clot that forms abnormally in a blood vessel
Embolus – a clot that dislodges or a fragment of a clot that breaks loose and is carried away by blood flow
A blood clot that forms in a vessel that supplies a vital organ may be fatal
Coronary thrombosis
Cerebral thrombosis
A blood clot that travels and then blocks a blood vessel may be fatal
Pulmonary embolism
Myocardial infarction

21. Blood Groups
Agglutination – clumping of RBCs following a transfusion reaction
Antigens - molecules on the surface of RBCs
Also called agglutinogens
Identify RBCs as belonging to a person
More than 260 different antigens can be found on RBCs
Important antigens include those of the ABO and Rh blood groups
Antibodies – proteins made by the body to attack foreign antigens
Also called agglutinins
Carried in plasma

22. ABO Blood Group
Based on the presence or absence of two major protein antigens on red blood cell membranes
Antigen A
Antigen B
Inherited ABO blood types:
Only antigen A – blood type A
Produce antibody B
Only antigen B – blood type B
Produce antibody A
Both antigen A & B – blood type AB
Produce no A or B antibodies
Neither antigen A or B – blood type O
Produce antibodies to both A & B

23. ABO Blood Group

24. ABO Blood Group
Antibodies to antigens A & B form about 2 – 8 months following birth.
An antibody of one type will react with an antigen of the same type and clump (or agglutinate) RBCs

25. Coagulation Disorder – Hemophilia A
Results from a lack of clotting factor VIII
Sex-linked recessive allele
Usually males are affected
Symptoms:
Severe hemorrhage following minor injury
Frequent nosebleeds
Large intramuscular hematomas
Blood in the urine
Achieved notoriety when factor VIII pooled from blood donations were shown to transmit HIV (1985)
90% of those who used factor VIII in the few years prior to 1985 developed AIDS

26. Rhesus Blood Group
Named after the rhesus monkey in which it was first studied
In humans, this group includes several Rh antigens
Most prevalent is antigen D
If the D antigen is present on RBCs, the blood is said to be Rh-positive
If the D antigen is absent on RBCs, the blood is said to be Rh-negative
Exposure to Rh-positive blood can cause a person with Rh-negative blood to form anti-D antibodies

27. Hemolytic Disease of the Fetus & Newborn
If an Rh-negative mother with an Rh-positive husband has a baby
If the baby is Rh-negative, no problem
If the baby is Rh-positive, the mother can form antibodies to the baby.
The first baby is usually not harmed
The second and any following babies may have agglutination of RBCs
May cause lack of oxygen and permanent damage or death
May need a transfusion of blood that is compatible with the mother’s blood
Rh-negative mothers that may have Rh-positive babies receive RhoGam at 28 weeks of pregnancy
Contains Anti-D
Fools mother’s body into thinking it’s already formed Anti-D

28. Hemolytic Disease of the Fetus & Newborn