1. Biology 322 Human Anatomy I
Blood

2. Blood: Volume: 4 - 6 liters, ~ 8% of body weight Components:
Formed Elements:
Erythrocytes (Red blood cells)
Leukocytes (White blood cells)
Platelets
Plasma:
Water
Many proteins
Ions, nutrients, wastes, hormones, etc
pH: , Buffered to remain stable

5. Erythrocytes Primary Function - Transport of oxygen and carbon dioxide
Cytoplasm full of hemoglobin
Biconcave disks ~7.5 um diameter
~2 um thick
No nucleus
million per cubic millimeter
billion per milliliter (cubic cm)
Slightly higher in men
Normally survive ~120 days in circulation
Trapped and destroyed (mostly in spleen)

6. Hemoglobin Each molecule: 4 large Globin proteins
Each surrounding an iron-
containing Heme Group
Oxygen reacts reversibly with iron:
Binds in lungs
Unbinds in consumer tissues

7. Leukocytes (White blood cells) Five different types of cells
All formed in
bone marrow
4,000 to 10,000 per cubic millimeter or
4,000,000 to 10,000,000 per milliliter (cubic centimeter)

8. Each type has
specific functions,
but in general:
Leukocytes function in body defenses by:
Engulfing & digesting invading organisms & debris
Directly killing invading cells
Producing antibodies
Secreting chemicals which activate other immune cells
Secreting chemicals which promote inflammation

9. Leukocytes Grouped into two categories based upon appearance
of granules in
cytoplasm:
Abundant, distinct granules = Granular Leukocytes
or Granulocytes
Few, small granules = Agranular Leukocytes
or Agranulocytes

10. Granular
Leukocytes
Named according
to how these
granules react to
routine lab stains
("Wright's Stain"
is most common)
The nucleus of each type also has a characteristic shape and/or density
Three types: Neutrophils, Eosinophils, Basophils

11. Neutrophils
40% - 60% of
leukocytes
in blood.
Granules present
in cytoplasm but
stain weakly with
both acidic and
basic stains
Nucleus has 3 to 7 lobes
Also called Polymorphonuclear Leukocytes

12. Eosinophils
1% - 4% of
leukocytes
in blood.
Granules attract
acidic stain eosin,
therefore stain
red or orange
Nucleus is indented or bilobed

13. Basophils
0.5% - 1% of
leukocytes
in blood.
Granules attract
the basic stain
hematoxylin,
therefore stain
blue or purple
Nucleus is indented or bilobed, but is often obscured by the granules
Outside of circulation: Mast cells

14. Agranular
Leukocytes
Two unrelated
types of
leukocytes,
neither of which
has abundant
granules:
Lymphocytes, Monocytes
The nucleus of each type also has a characteristic shape and density

15. Monocytes
4% to 8% of
leukocytes in
blood
Nucleus indented,
may be kidney
shaped or
horseshoe shaped.
Stains only moderately blue.
Cytoplasm is abundant, typically stains an even
light blue or bluish-gray
Outside of circulation: Macrophages

16. Lymphocytes
20% to 40% of
leukocytes in
blood
Nucleus usually
spherical, may be
slightly indented.
Stains darker blue.
Varying amounts of cytoplasm which stains a pale to medium blue

17. Lymphocytes
Two types of
lymphocytes with
different functions
in immune system,
but they appear
identical in blood:
T-lymphocytes and B-lymphocytes

18. All leukocytes formed in bone marrow, then enter blood
But:
Not particularly active when in the blood.
Most leukocytes are using the blood to get to other
tissues and organs, where they differentiate and
become active

19. Since they generally function outside of the circulatory system, primarily in the connective tissues of other organs,
All leukocytes can leave
(and most can also reenter)
the blood vessels by a
process called Diapedesis.
Therefore: All of the leukocytes, and the cells which they mature into, are normally found in connective tissues throughout the body

20. Platelets
Function in
clotting of blood
when vessels
are injured
250,000 to 500,000 per cubic millimeter or
250,000,000 to 500,000,000 per milliliter (cubic centimeter)

21. Platelets
Fragments of much
larger cells, called
megakaryocytes,
which remain in the
bone marrow