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What are the three circuits of blood flow in the body?
- pulmonary circuit (to the lungs)
- systemic circuit (to the body)
- cardiac cycle (for heart only)
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Where is the heart located?
- beneath the sternum
- within the diaphragm
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What are the functions of the pericardium (heart wall)?
- protect / anchor heart
- prevent heart from overfilling with blood
- allow friction free environment
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From outside to within the heart, what are the layers of the heart?
- Fibrous pericardium
- Parietal layer
- Pericardial cavity (filled with serous fluid)
- Visceral layer/ Epicardium
- Myocardium
- Endocardium
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What layer of the heart is the heart muscle?
myocardium
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What are the receiving chambers of the heart?
atria
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What does each atrium have attached to it?
Auricle
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Where are pectinate muscles found?
within atria of the heart
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What are the discharging chambers of the heart?
ventricles
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Which is larger, ventricle or atria?
ventricle
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Which ventricle is larger, and why?
- left ventricle
- because it has to pump harder (with more pressure) to send blood to the body
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What are two muscles found in the ventricle of the heart?
- papillary muscle
- trabeculae carnae muscle
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What side of the heart is associated with the pulmonary circuit?
right side
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Which circuit sends blood to the lungs?
pulmonary
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Which ventricle sends blood to the systemic circuit?
left
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What carries blood AWAY from the heart?
arteries
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What transports blood INTO the heart?
veins
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What are the arteries of the heart?
- aorta
- left and right pulmonary arteries
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What are the veins of the heart?
- superior and inferior vena cava
- left and right pulmonary veins
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What type of blood travels into the heart via pulmonary veins?
oxygen rich
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What type of blood travels into the heart via vena cavae?
oxygen deficiet
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What are two types of valves found in the heart?
- atrioventricular
- semilunar
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Where are atrio ventricular valves located?
between atria and ventricle
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What are the two atrioventricular valves and what side of the heart are they located?
- right - tricuspid/ right atrioventricular valve
- left - bicuspid /mitral /left atrioventricular valve
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What are the two semilunar valves and where are they located?
- right- pulmonary semilunar valve
- left - aortic semi lunar valve
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What is the coronary circulation?
functional blood supply to the heart muscle (myocardium)
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What arteries and veins are involved in the coronary circulation?
- Right coronary artery
- Right marginal artery
- Anterior interventricular artery
- Posterior interventricular artery
- Left coronary artery
- Circumflex artery
- Anterior cardiac veins
- Small cardiac vein
- Middle cardiac vein
- Great cardiac vein
- Coronary sinus
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What maintains unidirectional blood flow through heart?
heart valves
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What valves prevent backflow into the atria when ventricles contract?
- Atrioventricular valves
- (right - tricuspid/ right atrioventricular valve
- left - bicuspid /mitral /left atrioventricular valve)
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What anchors the Atrioventricular valves?
Chordae tendineae
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When the ventricles are in diastole, are the AV valves open or closed?
open
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When the ventricles are in systole, are the semilunar valves open or closed?
open
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What are some characteristics of the cardiac muscle (myocardium)?
- intercalated discs - gap junctions and desmosomes
- highly branched
- large mitochondria
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What is the difference between gap junctions and desmosomes?
- desmosomes are anchoring junctions for sharing stress
- gap junctions allow ions and molecules to pass for communication
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Where are the intercalated discs found in cardiac muscle?
at the end of one cell and beginning of another
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What is the ability of cardiac muscle to depolarize and contract?
intrinsic property
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What kind of cells are found throughout the heart with no consistent membrane potential?
autorhythmic cells
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What happens in the intrinsic conduction system?
- SA node generates impulese
- AV node pauses impulse
- AV node sneds impulse to AV bundle
- AV bundle sends signal to bundle branches
- Bundle branches send signal to Purkinje fibers
- Ventricle contract
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What are the signals per minute the SA node, AV node and bundles/fibers can send?
- SA node- 75 times/ minute
- AV node- 50 times/ minute
- Bunclde branches and Purkinje fibers - 30 times/minute
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What are two defects associated with the Intrinsic conduction system?
arrhythmias and fibrillation
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What defect of the intrinsic conduction system shows an irregular heart beat?
arrhythmias
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What defect of the intrinsic conduction system has uncoordinated atrial and ventricular contraction?
fibrillation
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What happens when the SA node is damaged?
- AV node becomes pacemaker
- pace is slower than SA node
- more space between heartbeats in EKG
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What happens after SA node sends a signal when there is damage to the AV node?
- "heart block"
- ventricles may not receive impulse
- missing P wave in EKG
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What do the waves of the EKG/ECG represent?
- P wave: atria depolarization / contraction/ systole
- P-Q interval: pause between atria depolarization and ventricle depolarization
- QRS complex: ventricle depolarization, atria repolarization
- S-T segment: pause between ventricle depolarization and ventricle repolarization
- T wave: ventricle repolarization
- Q-T interval: time it takes for ventricle depolarization and ventricle repolarization
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What nodes or fibers are represented by the waves on the EKG/ECG?
- P wave: Impulse initiated by SA node
- P-Q interval: Impulse delayed at AV node
- QRS complex: Impulse passed from AV node to bundle fibers and then Purkinje fibers
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What is the difference between the intrinsic conduction system and the extrinsic innervation of the heart?
- Intrinsic conduction system: signals and chemicals exchanged to make the reaction which keeps heart pumping
- Extrinsic innervation: Influence of the autonomic nervous system on the heart activity
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What affects the extrinisic innervation of the heart?
- autonomic nervous system
- (sympathetic and parasympathetic system)
- (medulla oblongata and vagus nerve)
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What autonomic nervous system increases the heart rate?
sympathetic nervous system
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How does the sympathetic nervous system increase the heart rate and strength of contractions?
- medulla oblongata or vagus nerve send signal to spinal cord
- spinal cord sends signal through sympathetic trunk ganglion
(medulla oblongata / vagus nerve >> spinal cord >> sympathetic trunk ganglion >> heart)
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How does the parasympathetic nervous system decrease the heart rate?
Vagus nerve sends signal to the SA/AV nodes in the heart
(vagus nerve (X) >> heart)
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What are the three phases of the cardiac cycle?
- mid to late diastole
- ventricle systole
- early diastole
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What is the cycle fo blood flowing through the heart called?
cardiac cycle
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What happens during the mid to late diastole phase of the cardiac cycle?
- atria contract, ventricle relaxation
- AV valves open, SL valves closed
- Aortic valve closed, pulomonary valve closed
- ventricles fill with blood
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What happens during the ventricle systole phase of the cardiac cycle?
- 1. Isovolumetric contraction
- SL valves closed, AV valves closed
- 2. ventricle contraction, atria relaxation
- SL valves open, AV valves closed
- Aortic and pulmonary valves open
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What happens during the early diastole phase of cardiac cycle?
- 1. Isovolumetric relaxation
- Av valves closed, SL valves closed
- Aortic and pulmonary valves closed
2.ventricle relaxation, atria relaxation
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What is the technical name for a heart attack?
Myocardial Infarction (MI)
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What are two types of Congestive Heart Failure?
- right: pulmonary congestion
- left: peripheral congestion
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What causes congrastive heart failure?
- clogging of coronary arteries
- high blood pressure
- multiple MI’s
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What treats congestive heart failure?
- digitalis
- diuretics
- lowering blood pressure
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Where does blood stagnate in peripheral congestion?
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Where does fluid accumulate in pulmonary congestion?
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What is the pressure range for ventricles, atria, and the aorta?
- ventricles: 5-120
- atria: less than 20
- aorta: always high
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How is a heart block, where there is damage to SA and AV node treated?
artificial pacemaker
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What does the end diastolic volume (EDV) measure?
volume(in mL) at the end of ventricle relaxation when they are filled with blood
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What does end systolic volume (ESV) measure?
volume (in mL) of blood remaining in ventricles after contraction
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What are some problems you may see on an EKG?
- junctional rhythm
- second degree heart block
- ventricle fibrillation
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What does a junctional rhythm look like and indicate?
- P wave absent
- heart pace is slower
- SA node is non functional
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What does a second degree heart block look like?
- more P waves than QRS complexes
- AV node receiving but not sending signal
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What does a ventrcular fibrillation look like?
- irregular EKG
- due to electrical shock and heart attacks
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