Transcript Circulation and Heart Structures

Circulation and
Heart Structures
Unit D – Human Systems
Circulatory Systems in your Body
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There are two circulatory systems in your
body:
Pulmonary circulatory system
Systemic circulatory system
1. Pulmonary Circulatory System
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Blood vessels that circulate blood between
the heart and the lungs.
Carries deoxygenated blood to the lungs
and brings oxygenated blood back to the
heart.
2. Systemic Circulatory System
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Blood vessels that carry blood between your heart
and all other parts of the body.
Pumps oxygenated blood to all body tissues and
returns deoxygenated blood back to the heart.
Watch this:
http://www.youtube.com/watch?v=0jznS5psypI
Basic Heart Anatomy
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The heart is made up of two halves, the left
and the right.
Each side of the heart is comprised of two
chambers.
Upper chambers are called atria, lower
chambers are called ventricles.
Starting with deoxygenated blood
coming from the vena cava
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Deoxygenated blood from your head and
upper body enters the right atrium of your
heart from the superior vena cava.
Deoxygenated blood from the lower regions
of your body enters the right atrium of your
heart from the inferior vena cava.
Events occurring in the right
atrium
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Blood collects in the right atrium until the
pressure inside forces a set of valves called
the right atrioventricular (AV)/tricuspid
valves open.
Valves make sure that blood only travels in
one direction.
Blood now enters the right ventricle, where
it pools until the pressure inside increases,
forcing the semilunar valves open.
Blood flow to the lungs
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Semilunar valves separate the ventricles
from the arteries.
Deoxygenated blood now flows through the
left and right pulmonary arteries to the
lungs.
In the lungs, carbon dioxide will be
released, and oxygen will combine with
hemoglobin.
Blood flow back to the heart
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Oxygenated blood returns to the heart via
the left and right pulmonary veins, where
they will empty into the left atrium of the
heart.
Blood will pool in the left atrium of the
heart, until the pressure builds up, forcing
the left AV (bicuspid) valves to open.
Blood flow to the body
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Blood passes through the left AV valves into the
left ventricle.
Again, blood collects until sufficient pressure
builds up.
Blood passes through the left semilunar valves
into the aorta, the largest artery in your body.
The aorta branches off into smaller arteries,
taking blood to all parts of your body.
Heart Muscle
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Made of myogenic muscle.
Myogenic muscle has the ability to contract
without stimulation from the nervous system…it
can beat by itself.
For a short time, your heart will continue to beat,
even if it is removed from the body.
Watch this:
http://www.youtube.com/watch?v=iX6HnUyzgQ0&
NR=1
Heart Rate and Contractions
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Set by the sinoatrial (SA) node, a bundle of
nerves known as the “pacemaker” of the heart.
Heart rate is typically set at about 70 beats per
minute.
SA node sends nerve impulses to another bundle
of nerves called the atrioventricular (AV) node.
Watch this:
http://www.youtube.com/watch?v=Vq0_5RL7cUk
&NR=1
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This nervous impulse causes the atria of
the heart to contract, pushing blood into
ventricles.
The signal is then continued to the end of
the ventricles causing them to contract,
pushing the blood into the arteries.
Diastole
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Relaxation of heart muscle, when the atria
of the heart are filling with blood.
Increased blood volume and muscle
contraction increase blood pressure,
forcing the AV valves open.
Blood rushes into the ventricles of the
heart, causing the AV valves to shut.
This causes the heavy “LUBB” sound.
Systole
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Very quickly, increase blood volume and
muscle contractions increase pressure in
the ventricles.
This forces semilunar valves open, letting
blood rush into arteries.
Semilunar valves close, causing the lighter
“DUBB” sound.
Heart Murmur
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Occurs when heart valves do not close
properly.
Can be diagnosed by hearing a gurgling
sound when listening with a stethoscope.
This means that blood can flow backwards,
not in the direction it is intended to.
Decreases oxygen delivery to body tissues.
Student Tasks for Lesson
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Label Heart Structures diagram given to
you by your teacher and colour parts of
heart accordingly: red for parts carrying
oxygenated blood, blue for parts carring
deoxygenated blood.
Complete #1-3, 7 on page 327.