Download Circulation

The 3 main parts of The
Circulatory system
 The
Heart
 The
Blood Vessels
 Blood
The 3 main parts of
The Circulatory system

Blood circulates through a network of vessels
throughout the body to:
– provide individual cells with oxygen and
nutrients
– help dispose of metabolic wastes.

The heart pumps the blood to move it through
the blood vessels.
What is Blood tissue?
Blood is made up of about
45% solids (cells)
and 55% fluids (plasma).
The plasma is largely water, containing proteins,
nutrients, hormones, antibodies, and dissolved
waste products.
Functions of blood and circulation:
Circulates OXYGEN and removes Carbon
Dioxide.
 Provides cells with NUTRIENTS.
 Removes the waste products of metabolism to
the excretory organs for disposal.
 Protects the body against disease and infection.
 Clotting stops bleeding after injury .
 Transports HORMONES to target cells and
organs.


Helps regulate body temperature.
Parts of The Heart

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The Atria
-Receiving Chambers
The Ventricles
-Pumping Chambers
The Valves
-Controls Flow
The Septum
-Divides the Heart
The Heart

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The heart is a hollow, muscular organ about the
size of a fist
It beats over 100,000 times a day to pump blood
around the body's 60,000 miles of blood vessels.
The right side of the heart receives blood and
sends it to the lungs to be oxygenated.
The left side receives oxygenated blood from the
lungs and sends it out to the tissues of the body.
The Heart has three layers:

The ENDOCARDIUM
(inner layer),

The EPICARDIUM
(outer layer),

and MYOCARDIUM
(middle layer).
The heart is protected
by the
PERICARDIUM
which is the
protective membrane
surrounding it.

The heart has FOUR CHAMBERS, in the
lower heart the right and left Ventricles,
and in the upper heart the right and left
Atria.
In a heart beat...


In a normal heart beat the atria contract
while the ventricles relax, then the
ventricles contract while the atria relax.
There are VALVES through which blood
passes between ventricle and atrium, these
close in such a way that blood does not
backwash during the pauses between
ventricular contractions.

The walls of the left ventricle are
thicker as it has to pump blood to all
the tissues, compared to the right
ventricle which only pumps blood as
far as the lungs.
A single heart beat

The right and left ventricles are
divided by a thick wall (the
VENTRICULAR SEPTUM), babies born
with "hole in the heart" have a small
gap here, which is a problem since
oxygenated and deoxygenated can
blood mix.



All babies have this
hole until birth.
Normally, the
foramen ovale
closes at birth and
heals shut very
quickly.
If this flap of tissue
fails to cover the
hole and heal
completely the
child has a “hole in
the Heart”
Electrical
Stimulus
•
•
•
•
SV node
AV node
Bundle of His
Purkinje Fibres
http://web.buddyproject.org
/web019/web019/heart.html
CHECK THIS OUT!
Types of Blood Vessels

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Arteries
-Carry blood away from the Heart
-The Aorta is the largest artery
Veins
-Carry blood to the Heart
-Veins contain valves
-The Vena Cava is the largest vein
Capillaries
-Known as the “Distribution Pipes”
Arteries


Thick, muscular, hollow tubes which are highly
ELASTIC
– allows them to DILATE (widen) and
CONSTRICT (narrow) as blood is forced down
them by the heart
Arteries branch and re-branch, becoming smaller
until they become small ARTERIOLES which
are even more elastic.
– Arterioles force blood into the capillaries (high
pressure).
Veins

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VENULES (very small veins) merge into
VEINS which carry blood back to the heart
(low pressure).
The vein walls are similar to arteries but
thinner and less elastic.
Veins possess valves at intervals to prevent
the backflow of blood as it moves against
the force of gravity back to the heart.

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Valves only open one direction
Faulty valves and weak vein walls can
lead to varicose veins
How do veins
return blood to the heart
if they are not muscular of elastic?
3 strategies:
– Valves prevent backflow (only open
one way)
– Heart is pumping and pushing blood
from behind to keep it moving
forward
– As muscles around the vein contract,
the veins are squeezed forcing the
blood along
CAPILLARIES

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Distribute the nutrients and oxygen to the
body's tissues (blood pressure) and remove
deoxygenated blood and waste by diffusion.
They are extremely thin, the walls are only
one cell thick and connect the arterioles with
the venules (blood cells travel single-file).
No cell in the body is more than 2 cells away
from a capillary
Blood is made up of:

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plasma (which accounts for about 3
liters)
red blood cells
white bloods cells
and platelets.
Vitamins, electrolytes and other nutrients
are dissolved in the blood and carried to
the body's cells and organs.
The Composition of Blood
Blood Composition

The Plasma
(Fluid) makes up
55% of the blood
volume.
60
50
40
30

The Solids
(Cells) make up
45% of the blood
volume.
20
10
0
Plasma
Solids
Blood Plasma
 97%
Water
 Other 3%
-Antibodies and Proteins
- Nutrients and Wastes
Blood Solids
Red Blood Cells(ERYTHROCYTES)
- Carry oxygen
- Contain Hemoglobin
White Blood Cells (LEUKOCYTES) 
-Attack bacteria & other invaders
 Platelets (THROMBOCYTES )
-Control the blood clotting process
ERYTHROCYTES (red cells)
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Small red disk shaped cells. They
contain HAEMOGLOBIN, which
combines with oxygen in the lungs
and is then transported to the body's
cells.
The haemoglobin then returns carbon
dioxide waste to the lungs.
Erythrocytes are formed in the bone
marrow in the knobby ends of bones.
LEUKOCYTES (white cells)

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Help the body fight bacteria and infection.
When a tissue is damaged or has an
infection the number of leukocytes
increases.
Leukocytes are formed in the small ends of
bones.
Leukocytes can be classed as
granular or non granular.

There are three types of granular leukocytes:
– eosinophils
– neutrophils
– and basophils

There are three types of non-granular:
– monocytes
– T-cell lymphocytes
– and B-cell lymphocytes
White Blood Cells
THROMBOCYTES (platelets)
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Aid the formation of blood CLOTS by releasing
various protein substances.
When the body is injured thrombocytes
disintegrate and cause a chemical reaction with the
proteins found in plasma, which eventually create a
thread like substance called FIBRIN.
The fibrin then "catches" other blood cells which
form the clot, preventing further loss of blood and
forms the basis of healing.
How much blood is in the
average person?

Enough to fill one
or two one-gallon milk
jugs.

Blood accounts for
about seven percent of
human body weight,
and its density is only
slightly more than that
of pure water.

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A man weighing 154 pounds (70
kilograms) would have about 5.5
quarts (5.2 liters) of blood.
A woman weighing 110 pounds (50
kilograms) would have about 3.5
quarts (3.3 liters) of blood.
How much blood can a
human lose?
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An adult human can lose 10-15%
without clinical damage.
If one loses 30% it can be fatal
(haermorraghic [shock due to loss of
blood]).
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An "average" adult male has some 5
litres of blood.
Sudden loss of 1/3 of his blood can be
fatal.
However if the lose rate us slow (say:
24 hours) he can lose as much as 2/3
of the blood with much risk (well
documented).

So it's not only the amount of blood
that one is losing but, the rate one
loses it. It's also a matter of
maintaining the blood pressure.
Interesting....
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In one day, your blood travels nearly
12,000 miles.
Your heart beats around 35 million
times per year.
Your heart pumps a million barrels of
blood during the average lifetime -enough to fill three supertankers.
The spleen
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This is a large flat oval organ located below the
diaphragm, it's main function is to STORE BLOOD.
The size of the spleen can vary, for example it
may enlarge when the body is fighting infection
also it's size tends to decrease with age.
It is a non-vital organ and it is possible to survive
after removal of the spleen.
– Perinicious anaemia is a Vitamin B12 deficiency
resulting in a reduction in number of erythrocytes.
– Aplastic anemia is a failure of the bone marrow to
produce the enough red blood cells.
– Septicaemia - bacterial toxins in blood.
Vascular System Problems
Aneurysm
Arteriosclerosis
Atherosclerosis
Varicose veins
Anemia
Aneurysm
A fluid-filled
bulge found in
the weakened
wall of an
artery which
may eventually
rupture and
lead to cell
death (common
cause of
strokes)
Arteriosclerosis
Degeneration of
blood vessel
due to
accumulation
of fat deposits
along the inner
wall.
Atherosclerosis
Blood vessels thicken, harden, wind,
and lose their elasticity
Varicose
Veins
Weakening
of the veins
that causes
blood to
pool and
vessels to
bulge.
Anemia
Reduction of blood oxygen due to low
levels of hemoglobin or poor red
blood cell production
Resources
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http://www.studystack.com/studytable
-896
From the Heart video
Human Blood slide show
Credits
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Graphics courtesy of Crystalcafe.com
& The Franklin Institute online.
Presentation by Steve Kennette
Thanks to:
Spartanburg School District #5
Duncan, S. C.