Transcript Blood
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 CellsRed 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 CellsRed Blood Cells
White Blood Cells
Platelets