Formed elements

1. The Formed
Elements

2. More on the Formed Elements:
Red Blood Cells or Erythrocytes
Limited life span = 120 days (4 months)
Shape = “biconcave”
discs which allows
for increased surface
area for gas diffusion.
5 million in one mm
3
(about 1/50
th
of a drop)
25 trillion total in human body (average)
Main Function = carry oxygen (O
2
) and
carbon dioxide (CO
2
)

3. Note the concave or
“depressed” surface
of the erythrocytes.
In Red Blood Cells the nucleus is removed to allow
for more volume for hemoglobin. This allows for
greater 0
2
carrying capacity per cell, but is also why
erythrocytes have a limited life span.
Erythrocytes

4. Iron (Fe)
Heme
Iron (Fe)
Heme
Red Blood Cells contain hemoglobin (Hgb), the O
2

carrying protein that also gives blood its distinct color.
Hemoglobin is made from a complex protein
molecule called “globin” combined with an iron
(chemical symbol = Fe) containing a pigment called
“heme”.

5. Oxyhemoglobin – the oxidized form which is
bound with O
2
and has a “bright red” color.
Carbaminohemoglobin – form that is bound
with CO
2
and has darker, more “burgundy”
color.
Deoxyhemoglobin - bound to neither oxygen
or carbon dioxide and has a “darker red” color.
Hemoglobin changes color depending on what it is
complexed or bound with. It therefore comes in
“three” forms:

6. White Blood Cells or Leukocytes
WBC : RBC ratio = 1 : 700 – 1000
Main Function = Fight infection
lymphocyte
monocyte
eosinophil
basophil
neutrophil
There are five different types of leukocytes

7. Granulocytes
Cytoplasm has a “granular” look
Produced in red bone marrow
Short-lived
~ 60%
Agranulocytes
Cytoplasm has a non-granular look
Monocytes produced in red bone marrow
Lymphocytes produced in lymph tissue
monocyte
lymphocyte
eosinophil
basophil
neutrophil
~ 2 – 4%
~ 1%
~ 30%
~ 3 – 9%
Long-lived (especially lymphocytes)
The five are divided into
two categories:

8. Platelets or Thrombocytes
Actually non-nucleated cellular fragments
They function in the process of
“Hemostasis”, which is simply
“the stoppage of bleeding,” by
the following mechanisms:
Platelets
- Platelet plugs
- Vasoconstriction or vessel spasms
causing a decrease in vessel diameter, as
well as fibrin precipitation are also
involved in larger clot formation
- Blood clot formation
(coagulation)

9. “Activated” platelets
are “sticky” and cling
to damaged tissue and
each other at the edge
of wounds. For small
wounds a platelet plug
can prevent further
blood loss.
Common Hemostasis Mechanisms:

10. Coagulation occurs at
the site of larger
wounds when
fibrinogen precipitates
out as fibrin trapping
activated platelets and
red blood cells in a
“web-like” mesh
forming a blood clot.

11. http://en.wikipedia.org/wiki/Infectious_mononucleosi
s
<a href="http://www.thefreedictionary.com/leukemia">leukemia</a>
http://en.wikipedia.org/wiki/Leukemia
<a
href="http://www.thefreedictionary.com/infectious+mononucleosis">inf
ectious mononucleosis</a>