BLOOD
Blood is a Liquid Connective Tissue that constitutes the
transport medium of the circulatory system. The Two main
functions of blood are to transport nutrients and oxygen to
the cells and carry carbon dioxide and waste materials away
from the cells. Blood also transfers heat to the body surface
and plays a role in defending the body against disease.
• OBJECTIVES: List the components of blood.
Distinguish between red blood cells, white
blood cells, and platelets in terms of structure
and function. Summarize the process of blood
clotting. Explain what determine the
compatibility of blood types for transfusion.
• 1. The Main Function of the Circulatory System is to Transport
Material in a FLUID Medium throughout the body.
• 2. THIS FLUID MEDIUM IS CALLED BLOOD. BLOOD IS A TYPE OF
LIQUID CONNECTIVE TISSUE THAT HAS MANY FUNCTIONS. Blood is
composed of a Liquid Medium and Blood Solids. The liquid makes
up about 55 percent of the blood, and blood solids make up the
remaining 45 percent.
• 3. BLOOD TRANSPORT NUTRIENTS, DISSOLVED GASES (O2, CO2),
ENZYMES, HORMONES, AND WASTE PRODUCTS.
• 4. BLOOD REGULATES BODY TEMPERATURE, pH, and ELECTROLYTES.
• 5. BLOOD PROTECTS THE BODY FROM INVADERS, AND BLOOD
RESTRICTS THE LOSS OF FLUID.
• 6. Our Bodies contains 4 to 5 liters of Blood.
BLOOD PLASMA
• 1. Approximately 55 percent of Blood in made
up of a Fluid Portion called PLASMA.
• 2. Plasma is the Straw-Colored Liquid portion
of Blood and is 90 Percent Water and 10
percent dissolved fats, salts, sugars, and
Proteins called PLASMA PROTEINS.
THE PLASMA PROTEINS ARE DIVIDED
INTO THREE TYPES:
•
A. ALBUMINS - HELP REGULATE OSMOTIC
PRESSURE (MAINTAIN NORMAL BLOOD VOLUME
AND BLOOD PRESSURE). THIS IS THE MOST
ABUNDANT PLASMA PROTEIN.
• B. GLOBULINS OR ANTIBODIES - INCLUDE
ANTIBODIES THAT HELP FIGHT OFF
INFECTION. ANTIBODIES INITIATE THE
DESTRUCTION OF PATHOGENS AND PROVIDE US
WITH IMMUNITY.
• C. FIBRINOGEN - RESPONSIBLE FOR THE
ABILITY OF BLOOD TO CLOT.
BLOOD CELLS OR SOLIDS
• THE CELLULAR PORTION OF BLOOD MAKE UP
THE OTHER 45 PERCENT AND INCLUDES
SEVERAL TYPES OF HIGHLY SPECIALIZED CELLS
AND CELL FRAGMENTS. THEY ARE RED BLOOD
CELLS (RBC), WHITE BLOOD CELLS (WBC), AND
PLATELETS.
RED BLOOD CELLS (RBC)
ERYTHROCYTES
• 1. RBC are the most numerous of the Blood Cells.
One microliter of blood contains approx. 5 million
RBCs. (Figure 47-11)
• 2. RBC are BICONCAVE, or shaped so that they
are narrower in the center than along the edges.
• 3. RBC are produced from cells in the Bone
Marrow, they are gradually filled with
HEMOGLOBIN which forces out the nucleus and
other organelles.
• 4. Mature RBC do not have a Cell Nucleus and
Organelles. The Mature RBC becomes little more
than a membrane sac containing Hemoglobin.
• 5. Hemoglobin is the iron-containing protein that
gives RBC the ability to carry
Oxygen. Hemoglobin gives the RBC their color.
• 6. RBC stay in circulation for about 120 days
before they are destroyed by special WBC in the
liver and spleen. RBC in your body are dying and
being replace at a rate of about 2 million per
second.
WHITE BLOOD CELLS (WBC)
LEUKOCYTES
• 1. Outnumbered by RBC almost 500 to 1.
• 2. WBC are produced in the Red Bone Marrow,
The Lymph Nodes, and the Spleen. They are
larger than RBC, almost Colorless, and do NOT
Contain Hemoglobin. (Figure 47-12)
• 3. WBC have a Nucleus and can live for many
months or years.
• 4. THE MAIN FUNCTION OF WBC IS TO PROTECT THE
BODY AGAINST INVASION BY FOREIGN CELLS OR
SUBSTANCES.
• 5. WBC called PHAGOCYTES can destroy bacteria and
foreign cells by Phagocytosis (engulfed and digested),
some produce special proteins called ANTIBODIES, and
some release special chemicals that help the body fight
off disease and resist infection.
• 6. Doctors are able to detect the presence of infection
by counting the number of WBC in the blood. When a
person has an infection, the number of WBC can
Double.
PLATELETS AND BLOOD CLOTTING
• 1. Platelets are NOT Cells; they are tiny Fragments of
other Cells that were formed in the bone marrow.
• 2. Platelets are formed when small pieces of Cytoplasm
are pinched off the large cells in the Red Bone Marrow
called MEGAKARYOCYTES, which are found in the Bone
Marrow. Platelets lack a nucleus and their life span is
about 7 to 11 days.
• 3. Platelets play an important role in Blood Clotting.
• 4. Platelets help the Clotting process by Clumping
together and forming a Plug at the site of a wound and
then releasing proteins called CLOTTING FACTORS.
• 5. Clotting Factors start a series of Chemical
Reactions that ends with a sticky meshwork of
Fibrin Filaments that stop bleeding by producing
a clot. (Figure 47-14)
• 6. A genetic disorder of Clotting Factors is called
HEMOPHILIA, suffers may bleed uncontrollably
from even a small cut or scrape.
• 7. Clotting of blood in Vessels can block the flow
of blood, if this happens in the brain, brain cells
may die, causing a STROKE.