Exam 3: Circulatory System 2: The Heart Flashcards Preview

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Flashcards in Exam 3: Circulatory System 2: The Heart Deck (21)
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Size and Shape of Heart

-essentially a muscular "pump"
-normal heart is about the size of your clenched fist
-enlarged hearts are sick hearts
-located behind sternum and left ribs
-enclosed in pericardium



-endothelium covering a CT layer
-lines the inside of the heart & covers its valves



-cardiac muscle
- thickest layer


Epicardium (Visceral layer of Serous Pericardium)

-thin serous membrane and some fat



-made up of fibrous pericardium and serous pericardium and pericardial cavity


Fibrous Pericardium

-outermost layer
-dense CT
-functions: prevents heart from overfilling with blood
-restricts heart movements


Serous Pericardium

-serous membrane that secretes serous fluid for lubrication
-parietal layer-adheres to fibrous pericardium
-visceral layer-adheres to heart wall (same as epicardium)


Pericardial Cavity

-space between visceral and parietal layers
-serous fluid secreted in here


Right Atrium

-receives venous (deoxgenated) blood from superior and inverior venae cavae
-blood will flow from right atrium to right ventricle through the right atrioventricular (tricuspid) valve


Right Ventricle

-receives blood from right atrium
-3 papillary muscles-conical muscle bulges
-chordae tendineae
-blood runs from right ventricle through pulmonary semilunar valve and into pulmonary trunk


Chordae Tendineae

-from papillary muscles to 3 flaps of right AV valve
-function: prevent R AV valve from turning inside out (everting/prolapsing) into R atrium when the ventricles contract


Pulmonary Semilunar Valve

-3 semilunar cusps
-prevents backflow into R ventricle
-blood will now travel into pulmonary arteries to lungs


Left Atrium

-receives oxygenated blood form lungs via 3 or 4 pulmonary veins
-blood will flow from left atrium to left ventricle via the left atrioventricular (mitral/bicuspid) valve


Left Ventricle

-pumps oxygenated blood into aorta
-papillary muscles and chordae tendineae
-blood is pushed from left ventricle through aortic semilunar valve


Pulmonary Trunk and Pulmonary Arteries

-blood is deoxygenated here


Overall Heart Blood Flow

1. blood LOW in oxygen enters right atrium
2. blood from right atrium goes to right ventricle
3. blood from the right ventricle goes through pulmonary trunk
4. pulmonary trunk branches into pulmonary arteries, which carry blood to lungs
5. exchange of gases occurs in the lungs
6. oxygenated blood travels through pulmonary veins to left atrium
7. blood from left atrium goes to left ventricle
8. blood from left ventricle is pumped through the aorta
9. body travels through the blood vessels, will return to right atrium of the heart, and the cycle repeats!


Blood Supply to Heart

-arterial Circulation: transports blood high in oxygen to heart wall
-right coronary artery
-left coronary artery
-venous circulation:returns blood low in oxygen back to right atrium (most of these veins unite/drain into coronary sinus which drains into right atrium)


Condicution System of Heart

- the heart exhibits autorhythmicity, which means the heart itself (and not external nerves) are responsible for initiating the heartbeat


Process of Conduction

-Sinoatrial (SA) Node: "pacemaker" initiates heart beat in wall of RA, makes atria contract and sends nerve impulse to AV node
-Atrioventricular (AV) Node): in RA, sends nerve impulse to AVB
-Atrioventricular bundle: in wall between ventricles, splits into L and R bundle branches
-Purinje fibers: special muscle cells that transmit nerve impulses throughout ventricles, make ventricles contract


ANS Innervation of Heart

-ANS doesn't initiate heartbeat only makes it faster or slower
-sympathetic innervation increases heart rate
-parasympathetic innervation decreases heart rate



-inflammation of pericardium