1. Chapter 14
Blood

2. Structure & Function
Blood is a type of connective tissue (consists of cells in a matrix)
Function – transports O2 & nutrients, maintains homeostasis, protection from blood loss & infection
pH –
Volume – 5L (in avg. adult male)
Temp. – º F.
Accounts for 8% of body weight
Color varies from scarlet (O2 rich) to dark red (O2 poor)

3. Structure Composition – composed of 3 types of cells
(called solid portion):
1. RBCs –
erythrocytes
2. WBCs – leukocytes
3. platelets - thrombocytes

4. Structure The solid portion makes up 45% of a blood sample
Called the hematocrit
(HCT) or packed cell
volume (PCV)
Matrix (liquid portion) – plasma;
clear, straw-colored
Makes up remaining 55% of
sample; mostly H2O, nutrients, etc.

5. Hematopoiesis – Production of blood cells (RBCs, WBCs & platelets)

6. Erythrocytes (RBCs) Structure: 1. biconcave disks three advantages:
A. increase SA
B. no point within the cytoplasm is far from the surface; ideal for gas exchange
C. flexible; can squeeze thru tiny b.v.

7. Erythrocytes Structure: 2. Contain hemoglobin (Hb);
allows them to carry
resp. gases more efficiently
3. Mature RBCs lack nuclei; allows more room for Hb (each RBC is 1/3 Hb by volume)
Normal RBC count: 4-6 million/mm³ of blood (in avg. adult) (slight incr. after meals or exercise; decr. from anemia, leukemia, or hemorrhage)

8. Hemoglobin Hb consists of the protein globin→
Each has 4 polypeptide chains
& 4 heme groups (pigment)
where O2 binds
Hb combines easily w/O2 – called affinity ( or attraction) for O2
Produces oxyhemoglobin; makes blood bright red
When O2 is released from the RBC, deoxyhemoglobin is produced; makes blood dark bluish-red

9. Hemoglobin
Normal Hb levels – gm/100 ml of blood (in avg. adult male)
Cyanosis – occurs when O2 is deficient (hypoxia) & levels of deoxyhemoglobin incr.
Symptoms – bluish lips &
nail beds, dizziness, fainting,
fatigue, muscle weakness

10. Leukocytes- WCBs 2 main classes:
Granulocytes – have a grainy cytoplasm
Agranulocytes – have a clear cytoplasm

11. Types There are 5 types of white blood cells: Granulocytes
Neutrophils %
Eosinophils 5%
Basophils 0.5%
Agranulocytes
Lymphocytes 20-50%
Monocytes 1-5%
The range is because the requirement for different types of WBCs vary from time to time.

12. Neutrophils Structure: Multilobed nucleus Inconspicuous granules
Amount:
3-7,000/mm³
Functions:
Engulfing bacteria & viruses
(phagocytosis)
Life Span:
hours → days

13. Eosinophils Structure: Bilobed nucleus Large, red granules Amount:
/mm³
Functions:
phagocytosis
Protects against parasitic infections
Neutralize histamines (their amts. incr. during
hay fever & allergy attacks)
Life Span – hours → days

14. Basophils Structure: Lobed nucleus Large granules, but fewer Amount:
20-50/mm³
Functions:
Become mast cells when they leave b.v. & produce histamines
Respond to allergens rapidly (anaphylactic shock)
Produce heparin (anticoagulant)
Life Span – hours → days

15. Monocytes Structure: Largest WBC U-shaped nucleus
Grayish blue cytoplasm
Amount:
/mm³
Functions:
Phagocytosis
Become macrophages & remove dead cells
Life Span – weeks → months

16. Lymphocytes Structure: Most numerous in children; 2nd most in adults
Spherical nucleus
Small “ring”of cytoplasm; pale blue
Amount:
/mm³
Functions:
T cells – attack foreign antigens directly
B cells – produce antibodies for immunity
Life Span – months → lifetime

17. White Blood Cell Count Normal adult has 5,000-10,000 cells/mm3
Leukocytosis- WBC count above 10,000 cells/mm3
Can be a sign of acute infection
Occurs during times of stress and vigorous exercise.
Leukopenia- WBC below above 10,000 cells/mm3
Can be a sign of virus such as influenza, measles, mumps and HIV

18. Thrombocytes- Platelets
Fragments of giant cells
(megakaryocytes) (each produces
b/t 5-10,000 platelets)
Pieces break off these
cells in bone marrow
Enter circulation – live for approx.
1 wk.; destroyed by spleen & liver
Disk-shaped, w/o nucleus
½ the size of an RBC
Release serotonin to contract
blood vessel walls.

19. Function Normal platelet count – 130,000-360,000/mm³
Stem blood flow (hemo-
stasis) 2 ways:
1. Form a platelet plug
2. Initiate the clotting
process

20. Platelet Plug Formation
1. B.V.damaged
2. Some blood
escapes
3. Platelets adhere to
each other & rough
surfaces
4. When platelets come in
contact w/collagen from connective tissue, they develop spiny projections; helps them adhere
5. Eventually platelet plug is formed & bleeding stops

21. Blood Clots Thrombus – blood clot that forms in a b.v. abnormally
Embolus – blood clot or
fragment of one that
dislodges & travels to
major organ

22. Plasma Clear, straw-colored fluid; matrix of blood 92% water
Functions:
1. transport
2. maintain fluid balance
3. maintain pH

23. Contents of Plasma
Contains 3 plasma proteins (all produced in the liver):
Albumin – accounts for 60% of all plasma proteins - maintains osmotic pressure (keeps concentration of H2O & solutes in plasma stable
- example – a decrease in albumin causes cells to lose H2O; it collects in interstitial spaces (b/t cells) & causes edema

24. Plasma Proteins Globulins – Accounts for 36% of all plasma proteins
- transports lipids & vitamins
Fibrinogen – Accounts for 4% of all plasma proteins
- responsible for blood clotting

25. Other Substances Plasma also contains:
nonprotein nitrogenous substances –
amino acids, urea, uric acid
electrolytes – release ions when dissolved in H2O; maintain osmotic pressure & pH;
include Na, K, Cl, Ca Mg, bicarbonate, PO4 & SO4 ions