Download February 16, 2017 Cardiovascular System

February 16, 2017
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Objective:
◦ Identify the structures within the heart
◦ Trace the movement of blood through the
heart
Journal:
◦ Do you know any parts of the heart? If so,
which ones?
Cardiovascular System
Major Components
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Heart: pumps blood throughout the system
Blood: connective tissue made of plasma, cells,
and other substances
Blood Vessels: vessels that carry blood around
the body
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Arteries
Arterioles
Capillaries
Venules
Veins
Heart Overview
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Size of your fist
Surrounded by
protective layers
Slightly left of the center
of your chest and above
your diaphragm
Heart Protective Layers =
Pericardium
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Fibrous Pericardium –outer
layer
Parietal Pericardium – middle
layer
Visceral Pericardium – inner
protective layer that attaches
directly to the heart surface
Three Layers of the Heart Wall:
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Epicardium – outer layer
◦ Made up of visceral pericardium
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Myocardium – middle layer
◦ Made up of cardiac muscle
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Endocardium – inner layer
◦ Epithelium lining of the heart
Heart Structure
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Base
◦ Top of the heart
◦ Tilted towards the head
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Apex
◦ Bottom of the heart
◦ Points away from the head
Chambers of the Heart
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Right Atrium: Collects blood
returning to the heart from
circulating around the body
Left Atrium: Collects blood
returning from the pulmonary
circuit
Right Ventricle: Pumps blood
through the pulmonary circuit
Left Ventricle: Pumps blood
throughout the rest of the body
Valves
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Tricuspid Valve - aka AV valve
◦ Between right atrium and right ventricle
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Bicuspid Valve – aka mitral valve
◦ Between left atrium and left ventricle
Separation of the Chambers
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Septum: walls of the heart that separate the
chambers
◦ Interatrial Septum: separates the two atria
◦ Interventricular Septum: separates the two ventricles
Vessels Around the Heart
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Superior vena cava: brings blood
back to the heart from above the
heart
Inferior vena cava: brings blood back
to the heart from below the heart
Aorta: artery that blood travels from
the left ventricle to the rest of the
body
Pulmonary Veins: carries blood back
from the lungs
Pulmonary Arteries: carries blood to
the lungs
February 22, 2016
▶ Journal:
What is the function of
the left atrium?
Cardiac Cycle
Phases
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The cardiac cycle has two phases:
◦ Systole: contracting phase
◦ Diastole: resting phase
Steps of the Systole Phase
Step 1
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Blood enters the right atrium of the heart through
the superior and inferior vena cava
◦ The tricuspid valve is closed and blood collects in the
right atrium
Step 2
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The tricuspid valve opens and the blood flows
from the right atrium to the right ventricle
◦ Then the tricuspid valve closes to prevent blood from
flowing backwards into the right atrium
Step 3
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The right ventricle contracts causing the blood to
flow through the pulmonary semilunar valve into
the pulmonary trunk
Step 4
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The blood divides into the left and right pulmonary
arteries which bring the blood to the capillaries in
the respective lung
◦ While at the lungs, the blood gives up carbon dioxide and
picks up a fresh supply of oxygen
** Note: The pulmonary artery carries deoxygenated blood.
Step 5
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The blood flows from the capillaries through
increasingly larger blood vessels until it reaches
the left and right pulmonary veins.
**Note: The pulmonary veins
carry oxygenated blood.
Step 6
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The pulmonary veins meet and pour the
oxygenated blood into the left atrium.
Step 7
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Once the left atrium is full, blood flows through the
bicuspid valve into the left ventricle.
◦ Once the left ventricle is full the bicuspid valve closes so
blood cannot flow back into the left atrium.
Step 8
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The left ventricle then contracts and blood is
pumped through the aortic semilunar valve into
the aorta, from which the blood will be sent around
the body.
Diastole Phase
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While the atria fill with blood the heart rests before
contracting again.
Timing
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Both atria fill at the same time
Both ventricles fill at the same time
Both ventricles eject blood at the same time when
the heart contracts
◦ Contraction begins at the apex and travels upward to
ensure all the blood is expelled from the heart