Blood
and The Cardiovascular System
Volume and Composition
Average human adult has a blood volume
of about 5.3 liters.
Sample of blood =
45% cells by volume – called Hematocrit (HCT) or
Packed Cell Volume (PCV)
Types of CellsRed Blood Cells
White Blood Cells
Platelets
Volume and Composition
Other 55% is a clear, straw colored liquid
called plasma.
Plasma components:
 Water
 Proteins
 Amino Acids
 Nutrients
 Electrolytes
 Wastes
Red Blood Cells
Also called Erythrocytes
Biconcave Shape –Thin in the middle and thick
on the outside.
Why might these be shaped in this way?
Reason #1 – Increases surface area, assisting in
transportation of gases
Reason #2 - places the membrane closer to
oxygen-carrying hemoglobin in the cell.
Reason #3 – Shape allows it to squeeze through
the tiny capillaries.
Red Blood Cells
What is hemoglobin?
A molecule in red blood cells that transports
oxygen.
 It is responsible for the red color of red blood
cells
 Equals about 1/3 of each RBC by volume
 With Oxygen it is oxyhemoglobin and a very
bright red.
 Without Oxygen it is deoxyhemoglobin and a
darker red
White Blood Cells
• Also known as Leukocytes
• Primary Function = fight disease and
infection
• Two groups
– Granulocytes – granules in cytoplasm
• Short life spans, mainly in blood
– Agranulocytes – no granules in cytoplasm
• Longer life spans, can leave bloodstream
Platelets
• Also called Thrombocytes
– Not necessarily Red Blood Cell fragments
– Arise from Megakaryocytes
• These fragment, releasing small sections into
cytoplasm
– Each platelet:
• Half the size of a RBC
• Lack a nucleus
• Function in the formation of blood clots
• Break up and review three types of cells
and their functions.
Plasma
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92% Water
Functions
1. Transport materials
2. Regulate Fluid and electrolyte levels
3. Regulate pH
Components
– Plasma proteins
– Nutrients and Gases
– Plasma Electrolytes
Plasma Proteins
• 3 Types
• Albumins
– Smallest in Size, make up 60% of volume
– Function – Osmotic Pressure
– Why are so many needed?
• Globulins
– Alpha and Beta – transport lipids and vitamins
– Gamma – are a type of antibody
• Fibrinogen
– Least common plasma protein (4%)
– Function – Blood Coagulation
Nutrients and Gases
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Includes amino acids, simple sugars, and lipids
Where do these nutrients come from?
How are lipids able to be in the plasma?
Lipoproteins
– Low density Lipoproteins
• Bad Cholesterol (LDL)
• Why bad?
– High Density Lipoproteins
• Good Cholesterol (HDL)
• Why good?
• How do they have different densities?
Plasma Electrolytes
• Plasma Electrolytes
• Include: Sodium, Potassium, Calcium, Chloride,
and others
• Where do they come from?
• Purposes:
• 1. Maintain Osmotic Pressure
• 2. Supply tissues with electrolytes when needed
• 3. Regulate pH
Production of a Blood Cell
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Occurs in the red bone marrow
All types start out as a Hemocytoblast
Platelets then become what?
Megakaryocytes, which break apart
WBCs become leukocytes, many diff. types
RBCs
• Use a negative feedback system – means what?
• Low oxygen = more erythropoietin
– More oxygen = less erythropoietin
• Become erythrocytes
Blood Clotting
• Hemostasis – stoppage of bleeding
• Done in three ways
• 1. Vasospasm
– What is this?
• Muscular layers in the walls of the vessel
contract
– Can sometimes close the vessel completely
– May only last for a few minutes
Hemostasis
• 2. Platelet plug
– What is this?
• Platelets stick to any rough surface, to
collagen, and to eachother
• When a break occurs, they stick to the
vessel, then to each other
– This keeps building, creates a dam.
– Fig. 12.12 on page 333
Hemostasis
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3. Blood Coagulation
What is this?
Formation of a blood clot
This is the most effective, but also most
complex way
• Many things must occur for this to happen
– Prothrombin to thrombin
– Fibrinogen to Fibrin
– Positive feedback system
Blood Coagulation
• What must happen?
Parts of the heart
• External Anatomy
• Covered with the Pericardium
– A sac like structure filled with fluid
surrounding the heart.
– Why would this be here?
• Used mainly for protection
• Walls of the heart are thick and muscular
– Why would this be?
Parts of the heart
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Internal Anatomy
4 Chambers
Atria –
Blood enters heart here
– From where?
• Body or the lungs
• Ventricles – Blood leaves heart from here
– The walls are much thicker around the
ventricles, why?
Parts of the heart
• Atria and Ventricles separated by valves.
• What are they going to do?
• They prevent blood from flowing the wrong
direction
• Tricuspid valve – between right atrium and
right ventricle
• Bicuspid valve – between left atrium and left
ventricle
• Also valves at the beginning of pulmonary
veins and aorta
Path of Blood
• Right atrium  Right ventricle 
pulmonary artery  lungs  pulmonary
vein  left atrium  left ventricle  aorta
 body  vena cava  right atrium
Blood Vessels
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3 types
Arteries
Veins
Capillaries
All of these provide a closed system for
blood to continuously flow through
– But each are structurally and functionally
different.
Blood Vessels
• Arteries
• Carry blood away from the heart at high
pressures
• Characteristics of the walls:
– Strong
– Thick
– Elastic
• Why would the walls have these
characteristics?
Blood Vessels
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Veins
Designed to carry blood back to the heart.
Run parallel to arteries
Wall is similar in structure to arteries, but
muscular layer is less developed.
– Wall is thinner, weaker, and less elastic
Blood Vessels
• Capillaries
• Smallest of blood vessels
– Some are so small that only a single RBC can
make it through at a time
• Have extremely thin walls
• Why would they have such thin walls?
• This is the point where gases and
nutrients are exchanged.
Not sure what this is !?!
Red Blood Cells
Erythrocytes
Have
Sample of blood =
45% cells by volume – called Hematocrit (HCT)
Types of CellsRed Blood Cells
White Blood Cells
Platelets