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)
Where is the heart located?
- beneath the sternum
- within the diaphragm
What are the functions of the pericardium (heart wall)?
- protect / anchor heart
- prevent heart from overfilling with blood
- allow friction free environment
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
What layer of the heart is the heart muscle?
What are the receiving chambers of the heart?
What does each atrium have attached to it?
Where are pectinate muscles found?
within atria of the heart
What are the discharging chambers of the heart?
Which is larger, ventricle or atria?
Which ventricle is larger, and why?
- left ventricle
- because it has to pump harder (with more pressure) to send blood to the body
What are two muscles found in the ventricle of the heart?
- papillary muscle
- trabeculae carnae muscle
What side of the heart is associated with the pulmonary circuit?
Which circuit sends blood to the lungs?
Which ventricle sends blood to the systemic circuit?
What carries blood AWAY from the heart?
What transports blood INTO the heart?
What are the arteries of the heart?
- left and right pulmonary arteries
What are the veins of the heart?
- superior and inferior vena cava
- left and right pulmonary veins
What type of blood travels into the heart via pulmonary veins?
What type of blood travels into the heart via vena cavae?
What are two types of valves found in the heart?
Where are atrio ventricular valves located?
between atria and ventricle
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
What are the two semilunar valves and where are they located?
- right- pulmonary semilunar valve
- left - aortic semi lunar valve
What is the coronary circulation?
functional blood supply to the heart muscle (myocardium)
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
What maintains unidirectional blood flow through heart?
What valves prevent backflow into the atria when ventricles contract?
- Atrioventricular valves
- (right - tricuspid/ right atrioventricular valve
- left - bicuspid /mitral /left atrioventricular valve)
What anchors the Atrioventricular valves?
When the ventricles are in diastole, are the AV valves open or closed?
When the ventricles are in systole, are the semilunar valves open or closed?
What are some characteristics of the cardiac muscle (myocardium)?
- intercalated discs - gap junctions and desmosomes
- highly branched
- large mitochondria
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
Where are the intercalated discs found in cardiac muscle?
at the end of one cell and beginning of another
What is the ability of cardiac muscle to depolarize and contract?
What kind of cells are found throughout the heart with no consistent membrane potential?
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
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
What are two defects associated with the Intrinsic conduction system?
arrhythmias and fibrillation
What defect of the intrinsic conduction system shows an irregular heart beat?
What defect of the intrinsic conduction system has uncoordinated atrial and ventricular contraction?
What happens when the SA node is damaged?
- AV node becomes pacemaker
- pace is slower than SA node
- more space between heartbeats in EKG
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
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
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
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
What affects the extrinisic innervation of the heart?
- autonomic nervous system
- (sympathetic and parasympathetic system)
- (medulla oblongata and vagus nerve)
What autonomic nervous system increases the heart rate?
sympathetic nervous system
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)
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)
What are the three phases of the cardiac cycle?
- mid to late diastole
- ventricle systole
- early diastole
What is the cycle fo blood flowing through the heart called?
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
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
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
What is the technical name for a heart attack?
Myocardial Infarction (MI)
What are two types of Congestive Heart Failure?
- right: pulmonary congestion
- left: peripheral congestion
What causes congrastive heart failure?
- clogging of coronary arteries
- high blood pressure
- multiple MI’s
What treats congestive heart failure?
- lowering blood pressure
Where does blood stagnate in peripheral congestion?
Where does fluid accumulate in pulmonary congestion?
What is the pressure range for ventricles, atria, and the aorta?
- ventricles: 5-120
- atria: less than 20
- aorta: always high
How is a heart block, where there is damage to SA and AV node treated?
What does the end diastolic volume (EDV) measure?
volume(in mL) at the end of ventricle relaxation when they are filled with blood
What does end systolic volume (ESV) measure?
volume (in mL) of blood remaining in ventricles after contraction
What are some problems you may see on an EKG?
- junctional rhythm
- second degree heart block
- ventricle fibrillation
What does a junctional rhythm look like and indicate?
- P wave absent
- heart pace is slower
- SA node is non functional
What does a second degree heart block look like?
- more P waves than QRS complexes
- AV node receiving but not sending signal
What does a ventrcular fibrillation look like?
- irregular EKG
- due to electrical shock and heart attacks