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Introduction to
Blood
Interesting things about
blood
• Blood has a salty taste due to the
large amount of sodium it carries
• Blood is 5 times thicker than
water
• Blood is at a basic pH between
7.3-7.5
• Blood accounts for 8% of you
body weight
• Humans have around 1.5 gallons
of blood in their bodies
What does blood do?
• Blood has three main jobs:
distribution, regulation, &
protection
• Distribution
• Delivers oxygen from lungs
& nutrients to cells
• Transports wastes to areas
where they can be expelled
• Transports hormones for our
endocrine system
What does blood do?
• Regulation
• Blood is the most important
factor in changing body
temperature
• Blood maintains the body’s
pH…too low or too high a pH
leads to cell death
• Maintains adequate fluid
within the body
What does blood do?
• Protection
• Clotting
• Preventing sickness &
infection
Blood Basics
• Blood – not what typically comes
to mind: 2 parts,
• Plasma – Straw-colored, waterbased fluid. 90% water, 10%
solutes (mostly the protein
albumin)…Functions to absorb
heat and also provide a
medium for the other
component of the blood to flow
in
Blood Basics
• Elements or Formed Elements –
these are the actual cells that flow
through the fluid. These make up a
smaller portion of the actual fluid.
• 3 types of cells make up the
elements
• Erythrocytes
• Leukocytes
• Platelets
Erythrocytes
• These are the red blood cells
• Disk shaped, look like Frisbees, or
small doughnuts when you see them
• Lack nuclei & organelles
• Composed primarily of the protein
hemoglobin (97%)
• Hemoglobin is important as it is the
protein that exchanges the gasses
within the blood cells
• Uses anaerobic metabolism for
energy so it does not use oxygen
Erythrocyte Shape
Hemoglobin
• Two different components:
• Globin protein – four polypeptide
chained protein.
• Heme pigment – Atom of iron around
which the four globin proteins bind
• This means 1 molecule of
hemoglobin can carry 4 molecules of
oxygen
• A typical RBC can carry 250,000,000
molecules of hemoglobin…that’s
1,000,000,000 molecules of oxygen
Making Blood
• Our red blood cells are made in a
process called hematopoiesis
• This process occurs in the red
bone marrow
• Blood cells mature within the
bones, and once “of age” they
migrate through the bone out into
the blood stream
RBC Problems
• There are many problems associated
with faulty RBC’s:
• Anemia: Blood has low oxygen
carrying capacity
• Hemoglobin deficiency: RBC’s carry
too few hemo. molecules
• Sickle-Cell Anemia: RBC’s are
misshapen to be spiky & sharp
instead of smooth & round
• Polycythemia: too many RBC’s
causing blood to be too thick
Leukocytes (2nd type)
• Leukocytes are also known as white
blood cells
• Contain nuclei and organelles
• Less than 1% of you body’s blood
• Function as the body’s defense
• Classified into 2 different types:
• Granulocytes: spherical, large,
function as phagocytes
• Agranulocytes: spherical, smaller,
responsible for immune responses
and antibodies
Leukocytes
• These are normally sphere shaped,
without the doughnut hole
• Prevents damage in body from bacteria,
viruses, parasites, toxins, & tumors
• Not confined to the circulatory system
• Diapedsis – when white blood cells
leave the circulatory system and
affect other tissues
• When they leave the blood stream,
they move like simple organisms
using their cytoplasm like legs
Leukocytes
Leukocyte Production
• Produced in the same fashion
as RBC’s, just in a different
place
• Produced in just the bone
marrow, not the red bone
marrow
Leukocyte Malfunction
• Like RBC’s, WBC’s can malfunction
causing bodily harm:
• Leukemia: cancer of the white blood
cells…one white blood cells has it, it
keeps multiplying until it overruns
the normal WBC’s
• Mono: Mono causes an actual
excess of WBC’s that are attacking
healthy cells, making patient feel
weak and tired
Platelet (3rd Type)
• Large cells within the circulatory
system
• Platelets are what causes our blood to
clot
• Do not contain nuclei, but do have
membranes that are chemically
designed to stick together
• Contain proteins actin and myosin (the
same proteins muscles have) which
allows platelets to pull areas close
together
Clotting
• Platelets clot blood in 3 steps
• Vascular Spasms – Vasoconstriction
of the injured blood vessel
• Platelet Plug Formation – Platelets
aggregate together, sticking to each
other pulling the injured vessel back
together
• Coagulation – blood turns from
liquid to gel in area where there is
injury
Platelets
Platelet Malfunctions
• Thrombus – blood clots in a vessel that
is not damaged, causing a blockage
• Thrombocytopenia – low number of
platelets. Causes spontaneous
bleeding of small vessels all over the
body
• Hemophilia – platelets are unable to
stick together, meaning that blood
cannot clot. Causes prolonged
bleeding on minor cuts