Transcript 6.2 The Heart

The Cardiovascular System
CrashCourse Circulatory System Video
https://www.youtube.com/watch?v=9fxm85Fy4sQ
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37–1 The Circulatory System
Circulatory System
Introduction:
The circulatory system and
respiratory system work
together to supply cells
with the nutrients and
oxygen they need to stay
alive.
Functions of the Circulatory
System
Cardiovascular
System
Humans and other
vertebrates have closed
circulatory systems,
meaning that the blood is
contained within a
system of vessels
(tubes).
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The circulatory system as a system of tubes
with a pump (heart) and valves to ensure
one-way flow of blood
Describe the double circulation in terms of:
1. a low pressure circulation to the lungs
and
2. a high pressure circulation to the body
tissues
High
Pressure
Functions of the Circulatory
System
Circulatory Introduction
The human circulatory system consists of:
• the heart
• blood vessels
• blood
IB Assessment Statement
Draw and Label a diagram of the heart
showing the four chambers associated
blood vessels, valves and the route of the
blood through the heart. Know the relative
thickness of the four chambers.
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The Heart
The Heart
The heart is a double pump:
1.
The right side of the heart pumps blood to
the lungs
2.
The left side of the heart pumps blood to the
rest of the body.
The Heart
The Heart
The walls of the heart are composed of cardiac
muscle.
Contraction of cardiac muscle is myogenic.
• Myogenic means that it can contract on its
own it does not need to be stimulated by a
nerve.
The Heart
The Heart
The heart is enclosed in a protective sac of
tissue.
In the walls of the heart, two layers of tissue form
around a thick layer of muscle.
Contractions of the layer of muscle pump blood.
The Heart – Coronary
arteries
– There are many
capillaries in the muscular
wall of the heart.
These are called the
coronary arteries.
The Heart – Coronary arteries
The function of the coronary arteries are listed
below:
Bring nutrients to heart muscle
Bring oxygen for aerobic cell respiration,
which provides heart tissue with energy
necessary for heart contraction.
Remove waste products (CO2) from heart
muscle
IB LEARNING OBJECTIVE
State the function of the coronary arteries
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Coronary Heart Disease
If the coronary arteries or
veins become blocked, the
heart muscles become:
deprived of oxygen and
sugar
And poisonous waste
products build up
Resulting in a HEART
ATTACK.
Coronary Heart Disease
Blockage of coronary arteries is called
coronary heart disease.
People at Risk for Coronary Heart
Disease
Smoking Cigarettes – nicotine damages the
circulatory system
Diet – a diet high in saturated fat, salt and
cholesterol
Obesity – Being overweight
Stress – unmanageable or long term stress
Genes – Some people inherit genes that
make it more likely
A doctor can determine if you have a block
coronary arteries by doing an Angiogram.
It gives a picture of the coronary arteries.
If you have a blocked coronary artery or
veins, you can have surgery.
Coronary Bypass Surgery
In Coronary Bypass
Surgery a blood
vessel is removed
from one part of the
body and sewn in
the heart muscle
Preventing Heart Disease
Regular Exercise
Healthy eating
Maintaining weight
Heart Attack Video
http://www.hhmi.org/biointeractive/how-heartattack-occurs
IB LEARNING OBJECTIVE:
Describe the relative thickness of the four
chambers.
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The Heart
Structures of
the Heart
The Heart
Superior Vena Cava:
Large vein that
brings oxygenpoor blood from
the upper part of
the body to the
right atrium
Right Atrium
The Heart
Left Atrium
Pulmonary
Veins:
Bring oxygenrich blood from
each of the lungs
to the left atrium
Pulmonary
Veins:
The Heart
Semilunar Valves:
Prevents blood
from flowing
back into the
right ventricle
after it has
entered the
pulmonary artery.
Right Atrium
Pulmonary
Arteries
The Heart
Right Atrium
Atrioventricle (Tricuspid)
Valve:
Prevents blood from
flowing back into the
right atrium after it has
entered the right
ventricle
The Heart
Right Atrium
Inferior Vena Cava:
Vein that brings
oxygen-poor blood
from the lower part
of the body to the
right atrium.
The Heart
Left Atrium
Atrioventricle
(Bicuspid) Valve:
Prevents blood
from flowing back
into the left atrium
after it has entered
the left ventricle
Left Ventricle
The Heart
Aorta
Left Atrium
Semilunar Valve:
Prevents blood
from flowing
back into the left
ventricle after it
has entered the
aorta
Left Ventricle
The Heart
Pulmonary Arteries:
Bring oxygenpoor blood to
the right or left
lung
The Heart
Aorta:
Brings oxygenrich blood from
the left ventricle
to the body
The Heart
The septum divides the right side of the heart from
the left.
It prevents the mixing of oxygen-poor and oxygenrich blood.
The Heart
The heart has four chambers—two atria and two
ventricles.
There are two chambers on each side of the
septum.
The upper chamber, which receives the blood, is
the atrium.
The lower chamber, which pumps blood out of the
heart, is the ventricle.
Atria vs. Ventricles
Both Atria have thinner walls than the ventricles,
because they only need to pump blood to the
ventricles.
Left ventricle vs. right ventricle
– Left Ventricle wall is thicker than the right
ventricle, because it pumps blood through the
arteries to all the tissues in the body
–Right Ventricle wall is thinner and less muscular
than the left ventricle because it is only pumps
blood to the lungs
Left vs. Right Ventricle Venn Diagram
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IB LEARNING OBJECTIVE
Explain the action of the heart in terms of
collecting blood, pumping blood, and
opening and closing the of valves.
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Flow of blood tutorial :
http://www.kscience.co.uk/animations/blood_system.swf
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The Heart
Circulation Through the Heart
Blood enters the heart through the right and left
atria.
As the heart contracts, blood flows into the
ventricles and then out from the ventricles to
either the body or the lungs.
The Heart
There are flaps of connective tissue called valves
between the atria and the ventricles.
When the ventricles contract, the valves close,
which prevents blood from flowing back into the atria.
The Heart
At the exits from the right and left ventricles, valves
prevent blood that flows out of the heart from
flowing back in.
Blood leaves the left ventricle, and enters the aorta.
The aorta is one of the blood vessels that carry the
blood through the body and back to the heart.
The Heart
Circulation Through the Body
The heart functions as two separate pumps.
The Heart
Pulmonary Circulation
One pathway circulates blood between the heart
and the lungs.
This pathway is known as pulmonary circulation.
In the lungs, carbon dioxide leaves the blood
and oxygen is absorbed. The oxygen-rich blood
returns to the heart.
The Heart
Systemic Circulation
The second pathway circulates blood between the
heart and the rest of the body.
This pathway is called systemic circulation.
After returning from the lungs, the oxygen-rich
blood is pumped to the rest of the body.
The Heart
Capillaries of
head and arms
Superior
vena cava
Aorta
Pulmonary
artery
Circulation of
Blood through the
Body
Pulmonary
Capillaries of vein
right lungs
Capillaries
of left lung
Inferior
vena cava
Capillaries of
abdominal organs
and legs
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Cardiac Cycle More details
Step 1
Diastole
The heart muscle is
relaxed this is called
diastole.
There is no pressure in
the heart chambers.
Blood tries to flow back
into the heart but closes
the semi-lunar valves.
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Cardiac Cycle More details
Step 2
Diastole
Both atria fill with blood returning to the
heart in the veins.
The right atria fills with blood returning
in the vena cava from the body tissues
(deoxygenated).
The atrio-ventricular valves are still
closed and the atria fill up.
When the pressure in the atria is
greater than the pressure in the
ventricles the atrio-ventricular valves
will open.
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Cardiac Cycle More details
Step 3
Late Diastole
In this diagram the heart is still relaxed
(diastole).
The pressure of blood returning to the
heart and filling the atria is now high
enough to open the atrio-ventricular
valves.
The pressure in the atria is greater than
the pressure in the ventricles.
Atrio-ventricular valves open
Ventricles begin to fill with blood..
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Cardiac Cycle More details
Step 4
Atrial systole
Both atria contract together
(see control of heart rate)
The muscles of the atria
contract.
volume of the atria reduces.
Pressure of blood increases
Blood flow into the ventricle,
filling this chamber and
causing the ventricle wall to
stretch...
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Cardiac Cycle More details
Step 6
Ventricular Systole
The ventricle contracts (systole)
The pressure increases in the
ventricle
The atrio-ventricular valve closes
The pressure rises further
Pressure in the ventricle is greater
than the artery, semi-lunar valve
opens
Blood pulses into the arteries
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IB LEARNING OBJECTIVE:
Describe the relationship between the
structure and function of blood vessels. [6]
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Blood Vessels
Blood Vessels Introduction
As blood flows through the circulatory system,
it moves through three types of blood vessels:
• arteries
• capillaries
• veins
Blood Vessels
Arteries
Large vessels that carry blood from the heart to
the tissues of the body are called arteries.
Except for the pulmonary arteries, all arteries
carry oxygen-rich blood.
Pulmonary artery carries oxygen poor blood
from the right side of the heart to the left side
Arteries have thick walls.
Four parts of the artery:
1.
2.
3.
4.
a narrow central tube
A smooth lining so no obstruction to
blood flow will occur
A thick layer of muscles and elastic fibers
A thick outer wall.
Thickouter
Thick
wall
outer wall
Thick
muscular
layer
Smooth lining
Blood Vessels
Capillaries
The smallest of the blood vessels are the
capillaries.
Their walls are only one cell thick, and most are
narrow.
The capillaries bring nutrients and oxygen to the
tissues and absorb carbon dioxide and other
waste products from them.
Blood Vessels
Blood Vessels
Veins
Blood vessels that carry blood back to the heart
are veins.
Veins have thinner walls than arteries.
Four parts to the structure of Veins:
1.
2.
3.
4.
Wide central tube
Thin layer of muscle
Valves
Thin outer wall
Thin Outer
Wall
Thin layer
Of muscle
Smooth lining
Blood Vessels
Large veins contain
valves that keep blood
moving toward the
heart.
Valve
open
Valve
closed
Valves
closed
Veins vs. Arteries Venn Diagram
IB LEARNING OBJECTIVE
Draw and Label a diagram of the heart showing the
four chambers associated blood vessels, valves and
the route of the blood through the heart (4 Points)
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Virtual Heart Dissection:
http://www.gwc.maricopa.edu/class/bio202/cyberhear
t/anthrt.htm
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