Blood is composed of plasma, red blood cells, white blood cells, and platelets. Red blood cells transport oxygen throughout the body while removing carbon dioxide. White blood cells are part of the immune system and help fight infection. Platelets help the blood clot and stop bleeding. Together, these components transport nutrients, oxygen, waste products, and provide immune system functions throughout the body.

1. Components of blood
• Blood is an essential fluid in the human body making up
normally 7-8% of the body weight (about 4.7 liters in adults).
• Blood transports oxygen and nutrients to cells throughout the
body as well as removing wastes such as carbon dioxide, and
chemicals such as ammonia.
• Plasma and the following elements: red blood cells
(Erythrocytes), white blood cells (Leukocytes), and platelets
(thrombocytes) are four main components of human blood.
erythrocyte (left), thrombocyte
(center), and leukocyte (right)
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2. Red blood cells
(Erythrocytes)
• Red blood cells, or erythrocytes, are large cells that
make up 40-50% of blood.
• Their function is to transport oxygen from the alveoli
in the lungs to the cells in the body, and remove
Carbon Dioxide and other waste chemicals.
• Red blood cells live for about 4 months, and are
produced from stem cells in the bone marrow at a
rate of between 2-3 million cells per second!
Human red blood cell
(7-8 micrometers diameter)

3. White Blood Cells
(Leukocytes)
• White blood cells, also known as leukocytes, exist in a variety
of different types and quantities and make up a large part of
our immune system.
• White blood cells only live between 18 -36 hours, before they
too get removed.
• There are a few different types of white blood cells:
• Lymphocytes – The first responders of the immune system: they
search for bacteria, viruses and fungi.
• Macrophages and Granulocytes- Surround and eliminate the
alien bacteria, viruses or fungi.
Human white blood cell
(9-12 micrometers in diameter)

4. Platelets (Thrombocytes)
• Platelets, also known as thrombocytes, work with
chemicals in the blood to clot the blood at the site of
wounds.
• Recently, studies have proven that platelets also play a
role in the immune system in fighting infections by
releasing proteins that kill microorganisms and alien
bacteria.
• Platelets are produced in the bone marrow: like red and
white blood cells, and live an average of 9-10 days.
Platelets
(2-4 micrometers)

5. Blood Plasma
• Plasma is the fluid that makes up blood, and transports red
blood cells, platelets, and white blood cells throughout the
body. Plasma is a yellow-tinted, clear fluid that normally makes
up 55% of the blood’s volume.
• Plasma brings the cells nourishment, and removes the waste
products of metabolism.
• Plasma is made up of over 92% water, but it also contains
sugars, lipids, vitamins, minerals, hormones, enzymes,
antibodies, blood clotting factors, and a variety of other
proteins.

6. Blood Components
Resources:
• http://answers.yahoo.com/question/index?qid=201105291515
20AAyV0FO
• http://www.nsbri.org/humanphysspace/focus3/earthphys-
frame.html
• http://thenextweb.com/shareables/2011/02/09/its-art-when-
white-blood-cells-attack-each-other/
• http://www.fi.edu/learn/heart/blood/white.html
• http://www.bloodservices.ca/centreapps/internet/uw_v502_
mainengine.nsf/page/Plasma
• https://ahdc.vet.cornell.edu/clinpath/modules/heme1/pltc.ht
m
• http://www.beltina.org/health-dictionary/blood-plasma-
blood-cells.html
• http://answers.yahoo.com/question/index?qid=200901011219
10AAHRDXX