Podcast
Questions and Answers
Which layer of the heart is responsible for protecting, anchoring, and preventing overfilling?
Which layer of the heart is responsible for protecting, anchoring, and preventing overfilling?
Which layer of the heart is in contact with the heart and is the outer layer?
Which layer of the heart is in contact with the heart and is the outer layer?
Which layer of the heart lines the inner surface of the fibrous pericardium?
Which layer of the heart lines the inner surface of the fibrous pericardium?
Which layer of the heart is continuous with the endothelial lining of blood vessels?
Which layer of the heart is continuous with the endothelial lining of blood vessels?
Signup and view all the answers
What is the name of the muscle cells that make up approximately 70% of the heart's mass?
What is the name of the muscle cells that make up approximately 70% of the heart's mass?
Signup and view all the answers
What is the name of the ridges and strips of muscle found on the walls of the heart chambers?
What is the name of the ridges and strips of muscle found on the walls of the heart chambers?
Signup and view all the answers
What is the function of the Papillary muscles?
What is the function of the Papillary muscles?
Signup and view all the answers
Which node is responsible for initiating the action potential in the heart?
Which node is responsible for initiating the action potential in the heart?
Signup and view all the answers
What is the pathway of the electrical activity in the heart?
What is the pathway of the electrical activity in the heart?
Signup and view all the answers
How is the action potential transmitted through the myocardium?
How is the action potential transmitted through the myocardium?
Signup and view all the answers
Which space is the heart located between?
Which space is the heart located between?
Signup and view all the answers
What is the function of the pericardial cavity?
What is the function of the pericardial cavity?
Signup and view all the answers
What are the components of the ventricles?
What are the components of the ventricles?
Signup and view all the answers
What is the name of the node responsible for initiating the action potential in the heart?
What is the name of the node responsible for initiating the action potential in the heart?
Signup and view all the answers
What is the function of the syncytium formed by cells connected via gap junctions?
What is the function of the syncytium formed by cells connected via gap junctions?
Signup and view all the answers
Which type of channels open during cardiac muscle contraction, allowing Ca2+ to enter from the outside to inside of the cell?
Which type of channels open during cardiac muscle contraction, allowing Ca2+ to enter from the outside to inside of the cell?
Signup and view all the answers
Where does calcium bind to initiate crossbridge cycling?
Where does calcium bind to initiate crossbridge cycling?
Signup and view all the answers
What happens when calcium binds to the troponin C molecule?
What happens when calcium binds to the troponin C molecule?
Signup and view all the answers
What blocks the myosin binding sites on actin in resting muscle?
What blocks the myosin binding sites on actin in resting muscle?
Signup and view all the answers
What causes the exposure of the myosin binding sites on actin?
What causes the exposure of the myosin binding sites on actin?
Signup and view all the answers
What is the name of the theory that explains muscle contraction?
What is the name of the theory that explains muscle contraction?
Signup and view all the answers
What produces the movement of thin filaments over thick filaments during muscle contraction?
What produces the movement of thin filaments over thick filaments during muscle contraction?
Signup and view all the answers
What is the role of the L-type Ca channels (LTCC) in cardiac muscle contraction?
What is the role of the L-type Ca channels (LTCC) in cardiac muscle contraction?
Signup and view all the answers
What is the process called when calcium released from the sarcoplasmic reticulum combines with calcium entering through the L-type Ca channels?
What is the process called when calcium released from the sarcoplasmic reticulum combines with calcium entering through the L-type Ca channels?
Signup and view all the answers
Which mechanism is responsible for removing Ca2+ from the cytosol during cardiac myocyte relaxation?
Which mechanism is responsible for removing Ca2+ from the cytosol during cardiac myocyte relaxation?
Signup and view all the answers
Which protein is responsible for inhibiting SERCA, the pump that removes Ca2+ from the cytosol during cardiac myocyte relaxation?
Which protein is responsible for inhibiting SERCA, the pump that removes Ca2+ from the cytosol during cardiac myocyte relaxation?
Signup and view all the answers
What is the primary energy source used by SERCA during the removal of Ca2+ from the cytosol?
What is the primary energy source used by SERCA during the removal of Ca2+ from the cytosol?
Signup and view all the answers
Which protein binds Ca2+ within the sarcoplasmic reticulum (SR) to help reduce the concentration of free Ca2+ within the SR during cardiac myocyte relaxation?
Which protein binds Ca2+ within the sarcoplasmic reticulum (SR) to help reduce the concentration of free Ca2+ within the SR during cardiac myocyte relaxation?
Signup and view all the answers
Which transporter is responsible for pumping Ca2+ out of the cell during cardiac myocyte relaxation?
Which transporter is responsible for pumping Ca2+ out of the cell during cardiac myocyte relaxation?
Signup and view all the answers
Under what conditions can the Na/Ca exchanger (NCX) reverse and pump Ca2+ into the cell during cardiac myocyte relaxation?
Under what conditions can the Na/Ca exchanger (NCX) reverse and pump Ca2+ into the cell during cardiac myocyte relaxation?
Signup and view all the answers
What happens to the myosin binding site on the thin filament during cardiac myocyte relaxation?
What happens to the myosin binding site on the thin filament during cardiac myocyte relaxation?
Signup and view all the answers
What is the consequence of inadequate ATP concentrations during cardiac myocyte relaxation?
What is the consequence of inadequate ATP concentrations during cardiac myocyte relaxation?
Signup and view all the answers
What can result from a lack of coronary blood flow during cardiac myocyte relaxation?
What can result from a lack of coronary blood flow during cardiac myocyte relaxation?
Signup and view all the answers
What happens to the heart's filling with blood if it cannot relax properly during cardiac myocyte relaxation?
What happens to the heart's filling with blood if it cannot relax properly during cardiac myocyte relaxation?
Signup and view all the answers
Which neurotransmitter is responsible for the positive inotropic effect on cardiac contractility?
Which neurotransmitter is responsible for the positive inotropic effect on cardiac contractility?
Signup and view all the answers
What happens when norepinephrine binds to the beta receptor?
What happens when norepinephrine binds to the beta receptor?
Signup and view all the answers
Which receptor is responsible for the negative inotropic effect on atrial contractility?
Which receptor is responsible for the negative inotropic effect on atrial contractility?
Signup and view all the answers
What is the primary effect of ACh binding to the M2 receptor?
What is the primary effect of ACh binding to the M2 receptor?
Signup and view all the answers
What is the effect of phosphorylation of phospholamban on SERCA activity?
What is the effect of phosphorylation of phospholamban on SERCA activity?
Signup and view all the answers
What is the consequence of decreasing the duration of cardiac contraction?
What is the consequence of decreasing the duration of cardiac contraction?
Signup and view all the answers
Which ion enters the cell through L-type Ca channels during cardiac contraction?
Which ion enters the cell through L-type Ca channels during cardiac contraction?
Signup and view all the answers
Which protein is responsible for inhibiting SERCA during cardiac relaxation?
Which protein is responsible for inhibiting SERCA during cardiac relaxation?
Signup and view all the answers
What is the primary neurotransmitter released by the sympathetic nervous system?
What is the primary neurotransmitter released by the sympathetic nervous system?
Signup and view all the answers
What is the primary neurotransmitter released by the parasympathetic nervous system?
What is the primary neurotransmitter released by the parasympathetic nervous system?
Signup and view all the answers
Which of the following is true about the effect of heart rate on contractility?
Which of the following is true about the effect of heart rate on contractility?
Signup and view all the answers
Which of the following is true about the effect of cardiac glycosides on contractility?
Which of the following is true about the effect of cardiac glycosides on contractility?
Signup and view all the answers
What is the primary function of cardiac glycosides?
What is the primary function of cardiac glycosides?
Signup and view all the answers
What is the mechanism of action of cardiac glycosides?
What is the mechanism of action of cardiac glycosides?
Signup and view all the answers
What is the effect of cardiac glycosides on the NCX?
What is the effect of cardiac glycosides on the NCX?
Signup and view all the answers
What is Starling's Law of the Heart?
What is Starling's Law of the Heart?
Signup and view all the answers
What is the primary effect of increasing heart rate on contractility?
What is the primary effect of increasing heart rate on contractility?
Signup and view all the answers
What is the primary effect of cardiac glycosides on contractility?
What is the primary effect of cardiac glycosides on contractility?
Signup and view all the answers
What is the primary function of cardiac glycosides?
What is the primary function of cardiac glycosides?
Signup and view all the answers
Study Notes
Heart Structure and Function
- The epicardium is the outer layer of the heart, in contact with the heart and responsible for protecting, anchoring, and preventing overfilling.
- The epicardium lines the inner surface of the fibrous pericardium.
- The myocardium is the layer of the heart that is continuous with the endothelial lining of blood vessels.
- Cardiac muscle cells make up approximately 70% of the heart's mass.
- Trabeculae carneae are the ridges and strips of muscle found on the walls of the heart chambers.
- Papillary muscles function to prevent the atrioventricular valves from bulging into the ventricles during systole.
Electrical Activity and Conduction
- The sinoatrial (SA) node is responsible for initiating the action potential in the heart.
- The pathway of electrical activity in the heart is: SA node → atrioventricular (AV) node → bundle of His → Purkinje fibers → ventricles.
- Action potential is transmitted through the myocardium via gap junctions.
Heart Location and Pericardial Cavity
- The heart is located between the lungs, in the mediastinum.
- The pericardial cavity is a space between the fibrous pericardium and the epicardium, which reduces friction between the heart and surrounding tissues.
Ventricles and Syncytium
- The components of the ventricles are the ventricular myocardium, papillary muscles, and chordae tendineae.
- The syncytium formed by cells connected via gap junctions allows for rapid transmission of electrical activity.
Muscle Contraction and Relaxation
- During cardiac muscle contraction, L-type Ca channels open, allowing Ca2+ to enter from the outside to inside of the cell.
- Calcium binds to troponin C to initiate crossbridge cycling.
- In resting muscle, tropomyosin blocks the myosin binding sites on actin.
- Calcium binding to troponin C causes a conformational change that exposes the myosin binding sites on actin.
- The sliding filament theory explains muscle contraction, where the movement of thin filaments over thick filaments produces muscle contraction.
- The process of calcium released from the sarcoplasmic reticulum combining with calcium entering through the L-type Ca channels is called calcium-induced calcium release.
Relaxation and Calcium Removal
- The mechanism responsible for removing Ca2+ from the cytosol during cardiac myocyte relaxation is the sarcoplasmic reticulum calcium ATPase (SERCA) pump.
- Phospholamban is a protein that inhibits SERCA, and its phosphorylation increases SERCA activity.
- The primary energy source used by SERCA during the removal of Ca2+ from the cytosol is ATP.
- Calsequestrin is a protein that binds Ca2+ within the sarcoplasmic reticulum to help reduce the concentration of free Ca2+ within the SR during cardiac myocyte relaxation.
- The Na/Ca exchanger (NCX) is a transporter responsible for pumping Ca2+ out of the cell during cardiac myocyte relaxation.
- Under conditions of low intracellular Na+, the NCX can reverse and pump Ca2+ into the cell.
Neurotransmitters and Contractility
- Norepinephrine is responsible for the positive inotropic effect on cardiac contractility.
- Norepinephrine binds to the beta receptor, increasing cardiac contractility.
- Acetylcholine (ACh) is responsible for the negative inotropic effect on atrial contractility.
- ACh binding to the M2 receptor decreases cardiac contractility.
- The primary effect of phosphorylation of phospholamban on SERCA activity is to increase SERCA activity, leading to faster calcium removal and cardiac relaxation.
Heart Rate and Contractility
- Starling's Law of the Heart states that the strength of cardiac contraction increases with increasing end-diastolic volume.
- Increasing heart rate increases contractility due to the positive inotropic effect of norepinephrine.
- Cardiac glycosides, such as digoxin, increase cardiac contractility by inhibiting the Na+/K+-ATPase pump, leading to increased intracellular Ca2+.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of basic heart anatomy with this quiz! Learn about the location of the heart, its protective layers, and more. Perfect for students and medical professionals.
