Anatomy and Functions of the Heart
The four chambers of the heart
What are the right and left atrium and right and left ventricles?
What are the types of channels found in contractile cells and pacemaker cells
Contractile: Sodium, calcium, potassium
Pacemaker: Calcium, HCN, potassium
Name the muscular walls that separate the atria from each other and the ventricles from each other.
What are the Interatrial septum and the interventricular septum
Define the AV node delay, explain why it occurs, and explain its importance
A stalling of the AV node that allows for the heart to fill with blood
What is coronary circulation
The circulation of blood in the arteries and veins that supply the heart muscle (myocardium)
Compare and contrast the function of the atria from that of the ventricles
the atria are smaller chambers that do not pump as hard as the ventricles. The atria only have a valve that controls blood flow going out, whereas ventricles have valves controlling the flow of blood both in and out.
Which is a shorter refractory period of skeletal muscle fibers or cardiac contractile cells
Skeletal muscle fibers
Compare and contrast the right and left ventricle in terms of the thickness of the heart wall, including an explanation of why they are different
What is the left ventricle is thicker due to having to pump high-pressure blood through the body?
What is the R-R interval
The heart rate
Which side of the heart is connected to the pulmonary circuit?
The right side of the heart is with the pulmonary circuit
Describe the difference in function between an artery and a vein.
Arteries carry oxygenated blood away from the heart and veins transport deoxygenated blood back to the heart
Differentiate between the functions of cardiac pacemaker and cardiac contractile cells.
Pace maker cells set the heart rhythm and contractile cells respond to the signal from the pacemaker cells to contract. Contractile cells make up 99% of the heart.
Name the four great vessels and identify if they are an artery or a vein and if they carry deoxygenated or oxygenated blood
What are the aorta (artery, oxygenated), pulmonary trunk (artery, deoxygenated), pulmonary veins (vein, deoxygenated), and the vena cava (vein, deoxygenated)
What obscures the repolarization of the atria?
the QRS complex
Which side of the heart is connected with the systemic circuit
The left side of the heart is connected to the systemic circuit
Differentiate between the pulmonary and systemic circuits. Which side of the heart serves as the pump for each circuit Which circuit is considered the low-pressure circuit Which circuit is considered the high-pressure circuit.
What is blood flow to the heart and blood flow to the body?
What is the right side of the heart and the left side of the heart?
What is the pulmonary circuit?
What is the systemic circuit?
Describe the steps of an action potential in a contractile cell, including which ion channels are involved in each step.
1. rapid depolarization as positive Na+ ions rush into the cell through the voltage- gated Na+ channels
2. initial repolarization phase - + ions moving out of cell through K+ channels only ones open, very short phase
3. plateau phase - Ca2+ and K+ are both open K+ moving out, Ca2+ moving in can last for a long time.
4. repolarization phase - Ca2+ have closed only K+ channels open moving it out of the cell allowing for the return of resting membrane potential.
Describe the chambers each vessel enters or exits from.
Aorta: Exits the left ventricle
Pulmonary trunk: Exits the right ventricle
Pulmonary vein: Enters left atrium
Vena cava: Enters right atrium
the interval between ventricular depolarization and repolarization
What are the main structures of the systemic circuit?
Pulmonary vein, left atrium, bicuspid valve, left ventricle, aortic valve, aorta
Name the four heart valves. For each valve, be able to:
a. Determine whether the valve is an atrioventricular or semilunar.
b. List the structures (the two chambers or the chamber and the great vessel) that are connected by the valve
c. What type of tissue they are made of
Tricuspid: AV valve, between the right atrium and ventricle
Pulmonary: SL valve, between the right ventricle and the pulmonary trunk
Mitral (bicuspid): AV valve, between the left atrium and ventricle
Aortic: SL valve, between the left ventricle and the aorta
Describe the steps of an action potential in a pacemaker cell, including which ion channels are involved in each step
1. slow initial depolarization phase - have no resting membrane potential, much slower because positive ions move both ways in nonspecific cation channel.
2. full depolarization phase - Ca2+ are open nonspecific channels closed and the range of membrane potential is more narrow
3. repolarization - only K+ channels open bringing potential down.
4. minimum potential phase - K+ open and reaches a certain potential and the cycle starts over again with slow depolarization.
Describe the importance of the following structures: auricles, fossa ovalis, chordae tendineae, and papillary muscles
Auricles: projections on the atria that expand to hold extra blood
Fossa ovalis: depression in the right atrium, remnant of fetal hole
Chordae tendineae: inelastic cords of fibrous connective tissue, that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart
Papillary muscles: in the ventricles of the heart and attach the cusps to the AV valves
Name the three populations of pacemaker cells that are part of the cardiac conduction system, describe the location of each population, and identify which populations can pace the heart successfully for a long period of time. Make sure to identify the population that normally paces the heart.
3 populations of pacemaker cells:
1. sinoatrial (SA) node - located at the superior right atrium sets the regular heart rhythm, also known as the sinus rhythm.
2. atrioventricular (AV) node - has the second fast rhythm located at lower back section of the interatrial septum near the opening of the coronary sinus, if something goes wrong with the SA node the AV node can set the rhythm.
3. purkinje fiber system - sets the slowest heart rate and the slowest depolarization. Located in the inner ventricular walls of the heart and allow the heart's conduction system to create synchronized contractions of its ventricles.
Trace a molecule in the blood through the heart and the pulmonary and systemic circuits until it returns to its starting point (to the level of detail of heart chambers, valves, great vessels, and capillaries/circuits) Start with systemic capilaries