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BIO 230
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fluid secreted by pericardial membranes->acts a lubricant to decrease friction
Visceral pericardium
outermost layer of the heart itself

Layers of the heart

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Myocardium (muscle tissue)-the meat that actually does the contracting
Contains:
* cardiac muscle tissue
* connective tissue
* blood vessels
* nerves
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Mononucleated
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more extensive circulatory supply-basically have one capillary per muscle fiber, ten
capillary beds make up one hair fiber
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able to contract without nervous stimulation-heart can actually work by itself, place in
heart that beats rhythmically by itself, specialized cardiac cells, that don't contract, and
if it fails another place in the heart will take other and so on and so forth
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The right atrium
Atria (general)-smaller than ventricles
Thinner walls than ventricles
Highly distensible-meaning it can hold a lot of blood but it doesn’t necessarily have to
Separated by interatrial septum
*Foramen Ovale (GA 5 wk-birth)
*Fossa Ovalis
Pectinate musculature (muscular ridges)-muscle on inside of atria
The Right Atrium
Receives O2 poor blood from systemic circuit through vena cavae

Right side of the heart-Pulmonary circuit
The right ventricle
Superficial border between right atrium and right ventricle is the coronary sulcus
Receives blood from the right atrium
Right A-V valve (USE THIS ONE THOUGH atrioventricular), other names for valve
also called “tricuspid”, will take both
- 3 fibrous flaps attached to chordae tendinae
- which arise from papillary muscles-these contract that will make sure the flap stays
anchor and blood doesn't flow back through
Trabecular carnae: irregular muscular folds of internal ventricle wall-tubular lines inside
chambers, helps give rigidity so heart doesn't collapse on itself

Internal anatomy and organization of the heart (right ventricle)
Superior end of RV tapers to pulmonary valve (a right semilunar valve)
Into the pulmonary trunk

Left side of the heart-systematic circuit

Left atrium
Receives O2 rich blood from pulmonary veins
Left A-V valve between left atrium and left ventricle (also called: mitral valve, bicuspid valve)

The left ventricle
Receives blood from Left Atrium
Thickest wall of any chamber
Blood leaves through aortic valve (the left semilunar valve) into the ascending aorta (Coming
up out of the heart)
-Left ventricle will get bigger with exercise
-Left ventricle also gets bigger with congestive heart failure because it is not sending out
enough blood so heart tries to compensate by making a bigger ventricle but it does not
actually send out anymore blood, just creates more tissue, to make ventricle bigger the
cells just grow in size not in number

Valves
Atrioventricular valves
Right a-v valve (tricuspid)
Left a-v valve (bicuspid) Mitral Valve
Semilunar valves
Right semilunar valve (pulmonic valve-going to the lungs)
Left semilunar valve (aortic valve-systemic circuit)
You want ventricles open while aortic and pulmonary are closed and ventricles closed while
aortic and pulmonary are open

Functioning during cardiac cycle
Systole: Contraction of the heart
Diastole:When the heart is at rest, pause between contraction
Functioning during cardiac cycle
During ventricular diastole (when the ventricle is at rest) (ventricle fills with blood)
*papillary muscles relaxed
*open a-v valves/no resistance (tricuspid and mitral)
*semilunar valves are closed
During ventricular systole (ventricle contraction)
*blood opens semilunar valves
*blood swings a-v valves closed
*papillary muscles & chordae tendinae prevent further swing into atria (leaky
valves)

Note: KNOW SLIDE 38, BE ABLE TO REPRODUCE
Review the path of blood flow sketch on the next slide - using specific names of arteries,
veins, chambers, and valves
I HIGHLY recommend you recreate this sketch until you have it down flawlessly!
Recommend beginning the sketch with the right atrium

Coronary circulation (arteries)-KNOW
When you hear about cardiovascular disease (athroscleroses) scarring of tissue in
coronary circulation
Bifurcation: branching off of vessels
When it makes its first bifurcation in coronary arteries the right coronary becomes
the anterior interventricular branch (aka the LAD)
Anterior Interventricular services the left ventricle
Coronary artery bypass graft surgery (CABG pronounces cabbage)-where you
harvest a vein, come find whatever is acluded, cut it in half, and reattach with vein
that was harvested
Right Coronary Artery (RCA)
Branches to supply blood to:
• Right atrium
• Left atrium (portion of)
• Interatrial septum (wall between two atria)
• Right ventricle
• Left ventricle (portion of)
• Interventricular septum (portion of) (in between ventricles, important)
• Conducting system of heart (SA and AV node)
Left Coronary Artery(LCA)
Branches into Anterior Interventricular Branch (LAD) and Circumflex
(Circumnavigates around heart, has another name on other side)
Supplies blood to:
• Most of LV, part of RV, most of LA, part of interventricular septum
-Anastimoses: do they touch?
-Circumflex and coronary do touch
-Oxygenated blood is red
-Venous blood is blue (in book, but not in body)
-Small cardiac vein sends blood to left atrium which goes to vena cava
-Great cardiac vein where most blood is sent
-One reason for stethoscope on heart is listening for integrity of tricuspid and mitral valves and
aortic and pulmonic valves
-Lub-tricuspid and mitral valves

-Dub-Aortic and pulmonic valves

Coronary circulation (VEINS)
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Great cardiac vein
Middle cardiac vein
Together collect blood and deliver to coronary sinus (on posterior surface of heart)
Coronary sinus drains into the…
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Stimulus passes down internodal pathways
• To AV Node (through conducting fibers)
• To cardiac muscle cells of Atria
-The SA node surrounds the (sinoatrial) nodal artery (on lumen in the image), a branch of the
right coronary artery, abuts cardiac myocytes (of the right atrium) on its deep aspect (left of
image) and adipose tissue on its superficial (epicardial) aspect (right of image) SLIDE 53
-Why do we need fat? Fuel source
-A group of cells (cardiocytes) positioned on the wall of the right atrium, near the entrance of the
superior vena cava
-Nodal artery: Blood coming through that
-Seven cells in charge of electrical activity in your heart

Conducting system continued
Atrioventricular Node (AV Node)
Floor of right atrium
Impulse “slows” here
Travels to AV bundle; located along the interventricular septum
Branches into R/L bundle branches
To the Purkinje fibers
Independent of SA node, this pacemaker run at 40-60 bpm, of SA node is damaged to
dies then the heart would beat much slower (40-60bpm)
This coordination allows
Atria to contract BEFORE ventricles
Contraction of ventricles begins at APEX(bottom of heart) and moves upward (like
squeezing toothpaste from bottom of tube)
Know slide 58

Cardiac cycle-whole cardiac cycle shown on slide 60
Note:1,000 milliseconds is a second
The conduction system regulates the flow of blood into and out of the heart
Sequence of cardiac cycle phases
Atrial Systole
Ventricular Systole
Ventricular Diastole

Cardiac cycle
Atrial Systole:
Atrial contraction (blood moves into relaxed ventricles)
Ventricular Systole
Phase 1
• Ventricular contraction pushes AV valves closed
Phase 2
• Ventricular pressure rises and forces blood thru SL valves (blood is ejected from
heart)
Ventricular Diastole
Early: ventricles relax, blood flows back against SL valves; blood flows into relaxed
atria
Late: all chambers are relaxed; ventricles fill passively

ECG(EKG)-German scientists pronounces C as K
SA node, AV node, Bundle of His, pukinje fibers, all of that is represented by ECG
Picture of electrical activity of the heart
P wave-when we send out electrical activity out from the SA node to the AV node
The gap between P wave before the QRS complex must be very small, which is why measured
on graph paper, movement of electrical activity from place to place
QRS complex-All movement of electrical activity inside heart is being measured here
T wave-reset of all the cells
P wave to T wave is all one second
This tells you is it in the right order at the right time
Do this during exercise to see if heart responds to stress the way it is supposed to
Quiz on thursday about electrical activity through heart and components of ECG (Names and
components)



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