1What is the primary function of the heart?
The heart acts as a pump to provide the pressure gradient for blood flow.
2Where is the heart located?
The heart is located in the mediastinum in the thoracic cavity.
3What is the role of the septum in the heart?
The septum divides the left and right sides of the heart.
4Which vessels bring deoxygenated blood into the right atrium?
The superior and inferior vena cava and the coronary sinus bring deoxygenated blood into the right atrium.
5What valve does blood pass through to move from the right atrium to the right ventricle?
Blood passes through the tricuspid valve.
6What valve does the right ventricle pump blood through to reach the lungs?
The right ventricle pumps blood through the pulmonary valve.
7Which vessels return oxygenated blood to the left atrium?
The left and right pulmonary veins return oxygenated blood to the left atrium.
8What is the function of the mitral (bicuspid) valve?
The mitral valve allows blood to flow from the left atrium to the left ventricle.
9What is the role of the aortic valve?
The aortic valve allows blood to flow from the left ventricle into the aorta.
10What are the three layers of the heart wall?
The three layers are the epicardium, myocardium, and endocardium.
11What are the three main coronary arteries?
The left anterior descending artery, the left circumflex artery, and the right coronary artery.
12What is the role of the coronary arteries?
The coronary arteries supply oxygenated blood to the myocardium.
13What is systole?
Systole is the phase of the heartbeat when the heart contracts and pumps blood.
14What is diastole?
Diastole is the phase of the heartbeat when the heart relaxes and fills with blood.
15Why do coronary arteries supply blood primarily during diastole?
During diastole, the heart is relaxed, so the coronary arteries are not compressed and can deliver blood.
16What are the three layers of blood vessel walls?
The layers are the tunica interna, tunica media, and tunica externa.
17What is the function of capillary beds?
Capillary beds are networks of capillaries where exchange of nutrients, gases, and waste occurs between blood and tissues.
18What are the main ions involved in myocardial cell action potentials?:
The main ions are sodium, calcium, and potassium.
19What is membrane potential?
Membrane potential is the difference in charge across a cell membrane.
20What occurs during depolarization of a cell?
During depolarization, the cell's membrane potential becomes more positive, leading to the generation of an action potential.
21What is the role of the SA node?
The SA node is the heart's primary pacemaker, initiating the electrical impulses that set the rhythm of the heartbeat.
22What is the function of baroreceptors?
Baroreceptors detect the stretch on blood vessel walls, helping regulate blood pressure.
23What neurotransmitter does the sympathetic nervous system use?
The sympathetic nervous system primarily uses noradrenaline and adrenaline.
24What neurotransmitter does the parasympathetic nervous system use?
The parasympathetic nervous system uses acetylcholine.
25How does sympathetic stimulation affect the heart?
Sympathetic stimulation increases heart rate and blood pressure.
26How does parasympathetic stimulation affect the heart?
Parasympathetic stimulation decreases heart rate and blood pressure.
27What is normal sinus rhythm?
Normal sinus rhythm is a heart rate of 60-100 beats per minute.
28What is the pericardium?
The pericardium is a protective sac surrounding the heart.
29What are chordinae tendinae?
Chordae tendineae are fibrous cords that connect AV valves to papillary muscles in the heart, preventing valve inversion.
30What is the function of the brachiocephalic artery?
The brachiocephalic artery splits into the right common carotid and right subclavian arteries, supplying the head, neck, and right upper limb.
31What is the significance of the diastolic period for coronary circulation?
The coronary arteries primarily supply blood to the heart muscle during diastole, when the heart is relaxed.
32What is the role of myofibrils in myocardial cells?
Myofibrils contain actin and myosin, proteins essential for muscle contraction.
33What is electromechanical coupling in the heart?
Electromechanical coupling is the process by which electrical action potentials trigger muscle contraction in heart cells.
34What is the sliding fiament theory?
The sliding filament mechanism describes how actin and myosin filaments slide over each other, shortening muscle fibers to produce contraction.
35What are the four phases of the cardiac action potential?
The phases are depolarization, initial repolarization, plateau phase, and repolarization.
36What is the role of troponin in muscle contraction?
Troponin binds calcium, triggering a conformational change that allows myosin to bind actin for contraction.
37What is vasoconstriction?
Vasoconstriction is the narrowing of blood vessels, which increases blood pressure.
38When is a 3-lead ECG typically placed?
On the wrists and ankles
39What does an ECG measure?
Voltage difference over time
40What is the isoelectric line?
The baseline on an ECG, showing no electrical activity
41Where does the electrical impulse in the heart originate?
In the SA node
42What does the P wave represent?
Atrial depolarization
43What does the QRS complex represent?
Ventricular depolarization
44What does the T wave represent?
Ventricular repolarization
45How long should the P wave last in a normal ECG?
0.08-0.10 seconds
46What is the duration of the P-R interval?
0.12-0.20 seconds
47What is the maximum duration for the QRS complex?
0.12 seconds
48How is the QT interval measured?
From the start of the Q wave to the end of the T wave
49What is the purpose of the grid paper on an ECG?
To measure both speed and voltage
50What does each small square on ECG paper represent in time?
0.04 seconds
51What rule can be used to calculate heart rate on an ECG?
The 300 rule
52What is an arrhythmia?
A deviation from normal heart rhythm
53What is a first-degree AV block?
An AV block with an extended PR interval
54What is a second-degree type 1 AV block?
Gradually increasing PR interval with a dropped QRS
55What is a third-degree AV block?
Complete heart block with no correlation between atrial and ventricular impulses
56What is the standard duration for the PR interval on a 12-lead ECG?
120-200 milliseconds