Heart & Circulation
CHAPTERS 12 & 13
Announcements
 Test grades are posted on Skyward
 Overall better grades! Many more B’s and C’s and far fewer D’s
and F’s!
 I will be holding weekly review sessions on Wednesday’s.
Come with questions!
Upcoming Review Sessions:
 Wednesday, March 13 at 7:15
 Wednesday, March 20 at 3:15
 I will send around an attendance sheet and make sure everyone
who is there receives credit for a study tool (one study tool for
every session you attend)!

Monday, March 11
CHAPTERS 12 & 13
Agenda
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Return Tests
Work on:
Test Corrections (NOT for a grade)
 Test Analysis – Due Friday
 Anticipation Guide – Due Tomorrow
 Sketch anterior and posterior views of the heart found on page
408 – Due tomorrow
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Aids Quiz on Wednesday
Tuesday, March 12
EXTERNAL HEART ANATOMY &
GENERAL FUNCTION
Agenda
 Turn in Anticipation Guide
 Notes: External Heart Anatomy & General Function
 Homework
Background Information
 Interstitial Fluid: fluid that bathes the cells
 Kept stable by exchanging oxygen, waste and nutrients with
the surrounding tissues and the blood
 Heart is a muscular pump that moves blood through
the body
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Beats approximately 100,000 times a day
Pumps about 8000 liters of blood (40 55 gallon drums)
 Heart is about the size of a clenched fist
 Four chambers
Blood Flow Through the Body
Blood flows through the body through two
circuits.
Pulmonary Circuit: Blood is oxygenated
Systemic Circuit: Oxygen is exchanged
from the bloodstream to the
body tissues
Left chambers of the heart are responsible
for pumping oxygen rich blood
Right chambers of the heart are
responsible for pumping oxygen
poor blood
Blood Flow Through the body
 Arteries
 Aka, efferent vessels
 Carry blood away from the heart
 Veins
 Aka, afferent vessels
 Carry blood toward the heart
 Capillaries
 Small, thin walled vessels between the smallest arteries and
the smallest veins
Blood Flow Through the Body
 Looking at the diagram, answer
the following questions:
 What is the function of the
capillaries?
 Why are they so small?
 Why are they between the
arteries and the veins?
Anatomy of the Heart
 Heart lies near the
anterior chest wall,
behind the sternum
 Surrounded by the
pericardial cavity

Lining of the pericardial
cavity is a serous
membrane called the
pericardium
Anatomy of the Heart
 Pericardium is a fluid filled sack
 Three subdivisions
 Visceral pericardium: closest to the heart
 Pericardial cavity: filled with pericardial fluid
 Parietal pericardium: furthest from the heart
External Anatomy of the Heart
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Auricle
Coronary sulcus
Aorta
Aortic Arch
Superior Vena Cava
Left Pulmonary Artery
Right Ventricle
Left Ventricle
Right Atrium
Left Atrium
Pulmonary Arteries
Pulmonary Veins
Internal Anatomy of the Heart
Interatrial septum
Interventricular septum
Coronary Sinus
Atrioventricular valves
Pulmonary semilunar
valve
 Bicuspid valve
 Mitral valve
 Aortic semilunar valve
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Quick Quiz
 Write this on a piece of paper to be turned in
 Fill in the blanks with either artery or vein
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____________  Heart  ______________
Tell me one fact about the systemic system
Tell me one fact about the pulmonary system
T/F: The veins always carry deoxygenated blood
Thursday, March 14
INTERNAL ANATOMY: VALVES, VESSELS &
BLOOD FLOW
Quick Quiz
 What are the arrows pointing to?
4
1
2
3
Blood Vessels
Review
 Blood flows away from the heart through arteries.
 Blood flows toward the heart through veins.
 Blood exchanges its contents with the interstitial
fluid through capillaries.
Mechanics
Internal Anatomy
 Valves
 Flaps between the chambers of the heart
which prevent the backflow of blood
 Major valves within the heart
 AV Valves
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Tricuspid valve
Bicuspid valve
Semilunar Valves
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Aortic valve
Pulmonary valve
 Supporting Characters
 Chordae tendineae: attached to papillary
muscles, opens AV valves
 Papillary muscles: Pulls chordae
tendineae, which opens AV valve
Valves
 AV Valves allow blood from the atria into the
ventricles
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Tricuspid Valve: Allows blood from the left atrium into the left
ventricle
Bicuspid Valve: Allows blood from the right atrium into the
right ventricle
 Aortic Valve
 Allows blood from the left ventricle into the aorta
 Pulmonary Valve
 Allows blood from the right ventricle into the pulmonary
artery
Blood Flow Review
 What are the names of the two circuits?
 Where do the circuits take the blood?
Apply what you know to answer these
questions…
Is the blood in the veins of the pulmonary circuit
oxygenated or deoxygenated?
Is the blood in the arteries of the systemic circuit
oxygenated or deoxygenated?
Blood Flow Race
 We haven’t gone over it yet, but you have all the
information necessary to determine the path of blood
flow through the heart & body. Use the page
provided & your notes to outline where the blood
moves. Include the chambers of the heart, the valves
and the major arteries and veins. The first group
with the correct answer will win a prize.
 We will go over this in detail after!!!
Path of Blood Flow
 Deoxygenated comes in through the vena cava and enters
the right atrium where it is moved into the right ventricle
 Pumped into the pulmonary arteries headed for the lungs
 At the lungs, blood passes through
, where it picks up
oxygen
 Travels through the pulmonary
vein to the left atrium and to the
left ventricle
 Pumped into the aorta where it
flows to body tissues, flows through
and is returned to
the vena cava
Valves
 AV Valves are connected to the wall of the heart by
the
chordae tendineae and the papillary
muscle
Mechanics of Blood Flow in the Heart
 Ventricle:
 When relaxed the ventricle is large
The papillary muscles are relaxed
 The chordae tendineae is loose
 The Bicuspid valve is open
 Semilunar valves are CLOSED
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When contracted, the ventricle is small
The papillary muscles are contracted
 The chordae tendineae is tight
 Bicuspid valve is closed
 Semilunar valves are CLOSED
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Aortic & Pulmonary Valves
 Pulmonary valve (aka, Semilunar Valve)
 Have three flaps
 Open when the pressure from the blood rises due to heart
contraction
Review
 Arteries Review
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Take blood _____ from the heart
Within the systemic system they carry ______________ blood
Within the pulmonary system they carry ____________ blood
 Veins Review
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Take blood ____ the heart
Within the systemic system they carry ______________ blood
Within the pulmonary system they carry ____________ blood
 Capillaries
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Bridge between _________ and ____________
Site of exchange
Anatomy of Vessels
 Composed of 3 layers surrounded by epithelial cells
 Tunica interna
Most internal layer
 Composed of endothelial cells
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Tunica media
Middle layer
 Composed of smooth muscle
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Tunica externa
External layer
 Made of connective tissue
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Lumen
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Hollow center for blood flow
Types of Arteries
 Elastic Arteries
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Largest arteries, can be up to 2.5 cm
Examples: Pulmonary Trunk and Aorta
Tunica media has elastic fibers instead of smooth muscle
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Absorb pressure from heart pumping blood
 Muscular Arteries
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Medium sized arteries, about 0.5 cm
Carries blood to skeletal muscles and organs
Tunica media has more smooth muscle fibers and less elastic fibers
than elastic arteries
 Arterioles
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Smallest
1-2 layers of smooth muscles
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Alter the diameter of the lumen to alter blood pressure and blood flow
Anatomy of Capillaries
 Only blood vessel capable of exchange
 Thin walls allow diffusion of gases, nutrients and
wastes
 Composed of a single layer of endothelial cells
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No tunica externa or tunica media
 About the thickness of one red
blood cell
 Individual capillaries make up
a capillary bed
Types of Veins
 Large veins
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Thin tunica media with smooth muscle tissue
Thick tunica externa with bundles of elastic and collagen fibers
Examples: vena cava
 Medium-sized veins
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About the size of muscular arteries
Tunica media has smooth muscle layers
Thick tunica externa has longitudinal bundles of elastic and
collagen fibers
 Venules
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Look like extended capillaries
No tunica media
How do arteries perform their function?
 Arteries must deal with changes in pressure caused
by the pumping of blood
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Elastic arteries can expand to absorb pressure and shrink
when the pressure lessens
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What would happen if the elastic arteries were not able to absorb
the pressure?
Arterioles have smooth muscle layers that can adjust the size of
the lumen
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Alters the blood pressure and rate of flow
 How would smooth muscles adjust the size of the lumen during
exercise?
How do capillaries perform their function?
 One atriole leads to dozens of capillaries, which lead
to several venules
 Entrance of each capillary is guarded by a
precapillary sphincter
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Made of smooth muscle
Opens and closes to regulate blood flow to the capillaries

Remember what happens when you’re out in the cold?
 First, skin turns red, what is happening at the precapillary
sphincter?
 Next, skin becomes pale and if you don’t get warm frostbite will
occur. What is happening at the precapillary sphincter?
Anastomosis
 Anastomosis
 The joining of two vessels
 Arteriovenous joins an arteriole and a venule in order to
bypass a capillary bed
 Arterial joins two arteries
 Insures that even if one path to the capillaries is hindered,
there is another way
How do veins perform their function?
 Veins have thinner walls than arteries because they
have less pressure to withstand
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In venules and medium-sized veins there is not enough
pressure to overcome the force of gravity.
Valves prevent the backflow of blood
 Body movements move blood back to the heart
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Problems caused by faulty valves:
Varicose veins
 Hemorrhoids
 In both, blood pools in a vein
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Questions for Review
 What are the three layers of vessels?
 What is the role of the precapillary sphincters?
 Why do veins need valves, but arteries do not?
 What is the function of arteriole anastomosis?