Heart Flashcards
Know the structure of a cardiac muscle cell. What is the function of intercalated discs? What is the function of gap junctions?
Cardiac muscle fibers: striated, branching cells w/ 1 or 2 nuclei
Intercalated discs: Contain desmosomes that hold cardiac fibers together and gap junctions
Gap junctions: enable AP to spread quickly from cell to cell, allowing cardiac muscle to contract as a unit
Know the location and orientation of the heart.
Located in mediastinum
Surrounded by pericardium
Lies 2/3 on left
Why do chest compressions work?
You are mimicking the heart pumping and manually pushing blood throughout the body through a compression betweent the sternum and the vertabrae.
Know the structures of the heart. This overlaps with the lab objectives. It is important for lecture in terms of function.
A. Interventricular Sulcus: idea of where right and left ventricles split on anterior side
Coronary Sulcus: idea of where atrium and ventricles divide
Auricles:
Ventricles: hold blood and pumps it out of the heart
Atria: brings in blood and sends it to the ventricles
P. Interventricular Sulcus: idea of where right and left ventricles plit on posterior side
Aorta: receives oxygenated blood and delivers to the rest of the body, part of systemic circulation
Sup/Inferior Vena Cava: deoxygenated blood from body delivered to atrium through these
Coronary Sinus: deoxygenated blood from heart delivered to inside the heart through this
Pulmonary Trunk: takes deoxygenated blood to pulmonary circulation to get oxygenated
Pulmonary Arteries: delivers deoxygenated blood to lungs to get oxygenated
Pulmonary Veins: brings back oxygenated blood to heart to get disbursed throughout the body
AV Valves: valve where blood from atrium goes through to the ventricles, prevent back wash of blood
SL Valves: valve where blood gets removed from the heart, prevents back wash
Chordae Tenidineae: stings attached to valves to help open and close AV valves
Trabeculae Carneae: muscle inside ventricles for contraction
Papillary Muscle: muscle in ventricles attached to chordae tenidineae for open and close valves
Pectinate Muscle: muscle in atria to assist in the atrial contraction
Interventricular Septum: devides left and right ventricles
Know the function and location of the pericardium (fibrous and serous), epicardium, myocardium, endocardium. Know which are the layers of the heart wall.
Pericardium: rests on & attaches to diaphragm to prevent overstretching, provide protection, anchor heart
Fibrous Pericardium: Attaches to diaphragm to hold heart in place
Serous Pericardium: forms double layer around heart to protect & reduce friction, fused to fibrous pericardium
Epicardium: outermose layer is visceral layer of pericardium
Myocardium: Cardiac muscle tissue, middle of cardiac wall
Endocardium: Smooth inner layer of heart that lines heart chambers and covers heart valves
Be able to describe what is happening in the atria and ventricles in terms of blood flow pathways and if the blood is oxygenated or dexoygenated.
Atria receives oxygenated (left) or deoxygenated (right) blood from the body and sends it to the ventricles via the AV valves. The ventricles send out the oxygenated (left) and deoxygenated (right) blood to systemic (left) or pulmonary (right) circulation sytem via the SL valves.
Know the role of the fibrous skeleton of the heart.
Forms foundation for which heart valves attach, serves as a point of insertionof cardiac muscle bundles, prevents overstretching of heart valves, acts as electrical insulator
Be able to name the heart valves and know the circulation of blood through them. Know that the design of the valves is mechanical and is responsible for how they open and close in response to blood pressure.
Tricuspid Valve: deoxygenated blood goes through to right ventricle
Bicuspid Valve: oxygenated blood goes through to left ventricle
Pulmonary Semilunar Valve: Deoxygenated blood goes through to the pulmonary trunk
Aortic Semilunar Valve: Oxygenated blood goes through to the ascending aorta
Valves are mechanical and open/close in response to BP
Be able to name the circulation types: coronary, systemic, pulmonary, hepatic, and fetal.
Coronary Circulation: feeds heart tissue through coronary arteries/veins
Systemic Circulation: throughout body
Pulmonary Circulation: through lungs via pulmonary arteries/veins
Hepatic Circulation: goes through liver
Fetal Circulation: maternal blood to fetus & back to mother
Be able to trace a molecule through the blood stream from the right atrium through the body and back to the right atrium with systemic and pulmonary circulation.
- Deoxygenated blood enters right atrium through sup/inferior vena cava and coronary sinus
- From right atrium is goes through the tricuspid valves into the
- Right ventricle where it is squeezed through the pulmonary valve into the pulmonary trunk entering pulmonary circulation
- From there it goes through the pulmonary arteries into
- Pulmonary capillaries to get oxygenated from lungs then goes to
- Pulmonary veins where the now oxygenated blood will return back to the heart
- Oxygenated blood flows into the left atrium through the pulmonary veins and pushes through the
- Bicuspid valve to enter into the left ventricle
- The left ventricle then contracts to push to oxygenated blood into the systemic circulation system through the aortic semilunar valve
- From the aortic semilunar valve it goes into the systemic arteries and then to the
- systemic capillaries where the oxygenated blood carrying nutrients will deliver and do capillary exchange
- The blood then becomes deoxygenated and travels through the systemic veins to the sup/inferior vena cava back into the right atrium
Be able to trace a drop of blood through coronary circulation.
Starting at the aorta
1. Oxygenated blood enters into the right and left coronary arteries
2. Goes to the Marginal Branch and A. Interventricular Branch
3. From there it goes into the P. Interventricular Branch
4. Circumflex Branch gets its oxugenated blood from teh P./A. Interventricular Branches
5. The blood from the P. Interventricular Branch and the Circumflex Branch go into artioles
6. Then capillaries where capillary exchange takes place
7. Then to the venules
8. Then to the Great, Small, and Middle Cardiac Veins
9. Then to the Coronary Sinus to get oxygenated again
Be able to describe the electrical conduction of the heart pathway. This includes knowing the pathway through the following: SA node, AV node, right and left bundle branches, Purkinje fibers. What is meant by the term autorhythmic? Which structure is the pacemaker of the heart? Is this what sets the heart’s intrinsic rhythm? Why is there a signal delay at the AV node?
- Sinoatrial (SA) Node fires to Atrioventricular (AV) Node & across both atria
- AV Node slows impulse to allow time for atria to contract and ventricles to fill
- At the Bundle of His, the impulse increases in speed
- impulse quickly runs down the right/left bundle branches
- Then up and around ventricles through the Perkinje Fibers
- At last! Ventricular Contraction
Autorhythic: self-exciting
Pacemaker of heart: SA Node
SA Node sets intrinsic rhythm
Signal delay at the AV Node to allow the ventricles to fill and the atria to contract.
Be able to discuss the influences on the heart’s conduction system to include intrinsic and extrinsic control.
The heart beats without nervous system control but is influenced by the nervous system
-This “Intrinsic” conduction system; initiates the action potential that results in contraction of muscle cardiac fibers and provides a pathway for conducting the action potential to all cardiac muscle fivers
-“Extrinsic” control of the heart from the Nervous System includes; ANS and hormones from the endocrine system
Be able to describe how the action potentials propagate through a ventricular fiber. This is the action potential occurring in the contractile fibers of the heart. Be sure to know how the following ions play a part in this process: potassium, sodium, calcium.
-Rapid depolarization; due to Na+ inflow when voltage gated fast Na+ channels open
-Plateau (maintained depolarization) due to Ca2+ inflow when voltage gated slow Ca2+ channels open and K+ outflow when some K+ channels open
-Repolarization; due to closure of Ca2+ channels and K+ outflow when additional voltage-gated K+ channels open
Be able to describe the waves on the EKG (ECG) and know the action potential events happening in the heart as related to those waves.
-P wave; atrial depolarization
-QRS complex; ventricular depolarization, atrial repolarization
-T wave; ventricular repolarization
