Heart lecture Heart

Heart lecture Heart

Question Answer
The right side of the heart receives _____________ blood from the __________ Oxygen poor, tissues
The left side of the heart receives ________________ blood from __________ Oxygenated, lungs
The circulatory system is a _______________ system Closed system.
What are the receiving chambers of the heart? Right and left atrium.
The right atrium receives blood returning from what circuit? Systemic
The left atrium receives blood returning from what circuit? Pulmonary
What are the pumping chambers of the heart? Right and left ventricle
the right ventricle pumps blood through which circuit? Pulmonary circuit
The left ventricle pumps blood through which circuit? Systemic circuit
Whats the approximate size of the heart? About the size of a fist
How much does the heart weigh? Less than a pound
Where is the heart located? In the mediastinum between second rib and fifth intercostal space
How much of the heart is to the left of the midsternal line? Two-thirds
What is the pericardium? It is a double walled sac that surrounds the heart.
What are the two layers of the pericardium? 1. Superficial fibrous pericardium. 2. Serous pericardium
What is the function of the fibrous pericardium? To protect it, anchor heart to surrounding structures, and prevent overfilling
What are the two layers of the serous pericardium? 1. Parietal layer (lines internal surface of fibrous pericardium) 2. Visceral layer (Epicardium) (on external surface of the heart)
What is the cavity i between the parietal and visceral layers called? Pericardial cavity
What is the function of the pericardial cavity? The fluid filled cavity keeps the two layers from sticking together and pulling on each other when the heart beats
List the layers of the pericardium from superficial to deep. 1. Fibrous pericardium 2. Serous pericardium 3. Parietal layer 4. Pericardial cavity 5. Visceral layer (Epicardium)
What are the three layers of the heart wall? 1. Epicardium 2. Myocardium 3. Endocardium
The epicardium is what layer of the serous pericardium? The visceral layer
What is the Myocardium? Circular or spiral bundles of contractile cardiac muscle cells.
What is the Endocardium? Innermost layer of the heart wall. Endothelial lining of blood vessels
What is coronary circulation? Functional blood supply for the heart muscle itself.
What is the shortest circulation in the body? Coronary circulation
When is the coronary blood supply delivered? When the heart is relaxed
Which part of the heart receives the most of the coronary blood supply? The left ventrical receives the most of the coronary blood supply
What does the left coronary artery supply? Interventricular septum, anterior ventricular walls, left atrium, and posterior wall of left ventricle.
What are the two branching arteries from the left coronary artery? Anterior interventricular artery and Circumflex artery
What does the right coronary artery supply? Right atrium and most of the right ventrical.
What are the two branching arteries from the right coronary artery? Right marginal artery and posterior interventricular artery
What is the function of cardiac veins? To collect blood from capillary beds.
Great cardiac vein of ____________________. anterior interventricular sulcus
Middle cardiac vein in ________________________. Posterior interventricular sulcus
Small cardiac vein from _____________________. Inferior margin
What is the coronary sinus formed by? Merging cardiac veins
Where does the coronary sinus empty? into the right atrium
Where do several anterior cardiac veins empty directly into? The right atrium anteriorly
What is the function of the interatrial septum? Seperates atria
What is the fossa ovalis? It is the remnant of foramen ovale of fetal heart
Whats the function of interventricular septum? Seperates ventricles
What are the superior chambers of the heart? The atria
What are the inferior chambers of the heart? The ventricles
What are Trabeculae carnea? Irregular ridges of muscle on ventricular walls
What is the function of the papillary muscles? They project into ventricular cavity and anchor chordae tendineae
Whats the function of heart valves? To open and close in response to pressure changes
What are the two major types heart valves? Atrioventricular valves and semilunar valves
Where are the Atrioventricular valves located? In between atria and ventricles
Where are the Semilunar valves located? In between ventricles and major arteries
Two atrioventricular valves prevent backflow into atria when ________________ Ventricles contract
What is the Tricuspid valve? The right Atrioventricular valve (AV Valve). Its made up of three cusps and lies between right atria and ventricle
What is the Mitral valve? Left Atrioventricular valve (AV Valve). Made up of two cusps and lies between left atria and ventricle
What is the function of Chordae tendineae? Anchors cusps of AV valves to papillary muscles
Two semilunar valves prevent backflow from __________ back into ___________ Major arteries, ventricles
Semilunar valves got there name because…….. Each valve consists of three cusps that roughly resemble a half moon
Where is the pulmonary semilunar valve located? Between right ventricle and pulmonary trunk
Where is the aortic semilunar valve located? Between left ventricle and aorta
Unique vascular modifications seen only during prenatal development and are occluded at birth include: Umbilical arteries and umbilical vein
What are the three vascular shunts? Ductus venosus, Foramen ovale, Ductus arteriosus
Where is the apical impulse palpated? Between fifth and sixth rib, just below left nipple.
What is pericarditis? Inflammation of the pericardium. Roughens membrane surfaces, causing pericardial friction rub (creaking sound) heard with stethoscope
What is cardiac tamponade? Excess fluid that leaks into pericardial space. Can compress hearts pumping ability.
What is the treatment for cardiac tamponade? Fluid is drawn out of cavity (usually with syringe)
What are coronary sulci(atrioventricular groove)? Encircle junction of atria and ventricles
Anterior interventricular sulcus: Anterior position of interventricular septum
Posterior interventricular sulcus: Landmark of posteroinferior surface
What are Auricles? They are appendages that increase atrial volume
Characteristics of the right atrium: Anterior portion is smooth walled. Posterior portion contains ridges formed by pectinate muscles. Posterior and anterior portions are seperated by crista terminalis
Name the three veins that empty into the right atrium. Superior vena cava,inferior vena cava, coronary sinus
Where does the superior vena cava return blood from? returns blood from body regions above the diaphragm
Where does the inferior vena cava return blood from? returns blood from body regions below the diaphragm
Where does the coronary sinus return blood from? returns blood from coronary veins
Characteristics of the left atrium: Pectinate muscles found only in auricles. Four pulmonary veins return blood from lungs.
Which heart chambers have thicker walls? The ventricles
Into what does the right ventricle pump blood? The pulmonary trunk
Into what does the left ventricle pump blood? The aorta(largest artery in the body)
No valves are found between major veins and atria. This is not a problem because: Inertia of incoming blood prevents backflow.Heart contractions compress venous openings
What is the pathway of blood through the right side of the heart? 1. Superior Vena Cava (SVC), Inferior Vena Cava (IVC), and coronary sinus. 2. Right Atrium 3. Tricuspid valve 4. Right ventricle 5. Pulmonary semilunar valve 6.Pulmonary trunk 7. Pulmonary arteries 8. Lungs
What is the pathway of blood through the left side of the heart? 1. Four pulmonary veins 2. Left atrium 3. Mitral valve 4.Left ventricle 5. Aortic semilunar valve 6. Aorta 7. Systemic circulation
How much blood is pumped to the pulmonary and systemic circuits? Equal volumes of blood are pumped through both circuits.
What are some characteristics of the pulmonary circuit? Its a short , low pressure circulation.
What are some characteristics of the systemic circuit? Its a long, high friction circulation.
How much of the bodys blood supply does the heart receive? About 1/20th
Where do the right and left coronary arteries arise from? They arise from the base of the aorta.
What do the left and right coronary arteries encircle? The coronary sulcus
What is Angina Pectoris? Thoracic pain caused by fleeting deficiency in blood delivery to myocardium. The cells are weakend
What causes a Myocardial Infarction (heart attack)? Prolonged coronary blockage
What happens after a Myocardial Infarction? Areas of cell death are repaired with non contractile scar tissue
Cardiac muscle cells: Striated, short, branched, fat, and interconnected. Contain numerous large mitochondria that afford resistance to fatigue
What are intercalated discs? They are connecting junctions between cardiac cells that contain desmosomes and gap junctions.
Whats the function of Desmosomes? To hold cells together: prevent cells from seperating during contraction
Whats the function of Gap Junctions? Allows ions to pass from cell to cell: electrically couple adjacent cells. (This allows the heart to be a functional syncytium, a single coordinated unit)
What is Endomysium? Connective tissue matrix in the intercellular space between cells.
Whats the function of Endomysium? Connects cardiac muscle to cardiac skeleton, giving cells something to pull against. It also contains many capillaries
What are the similarities that cardiac muscle has with skeletal muscle? 1. Muscle contraction is preceded by depolarizing action potential 2. Depolarization wave travels down T tubules; causes sarcoplasmic reticulum to release Ca2+. 3. Excitation-Contraction coupling occurs (Ca2+ binds troponin causing filaments to slide)
What are the differences between cardiac muscle and skeletal muscle? 1. The heart contracts as a unit 2. Influx of Ca2+ from extracellular fluid triggers Ca2+ release from SR 3. Some cardiac cells are self excitable. 4. Cardiac muscle fibers have a longer refractory period than skeletal muscle. Cardiac cells like aerobic.
What are the two kinds of myocytes? Contractile cells and pacemaker cells
What do contractile cells do? They are responsible for contraction
What do pacemaker cells do? They are noncontractile cells that spontaneously depolarize.
What is the relationship between cardiac muscle and the nervous system? Heart depolarizes and contracts without nervous system stimulation, but the nervous system can intervene
What are the two things that make a coordinated heartbeat happen? 1. Presence of gap junctions 2. Intrinsic cardiac conduction system(network of noncontractile(autorhythmic) cells)
What part of the heart sets the rhythm? The SA(Sinoatrial) Node
What are pace maker potential? Cardiac pacemaker cells have unstable resting potentials called pacemaker potentials or prepotentials. They start the action potential initiation, but the SA node keeps it in check
What are the steps in the action potential of the SA node? 1. Pacemaker potential(Sodium channels open) 2. Depolarization (Sodium channels close. Calcium channels open) 3. Repolarization (Calcium channels close. Potassium channels open)
What is the sequence of excitation? 1. Sinoatrial node 2. Atrioventricular node 3. Atrioventricular bundle 4. Right and left bundle branches 5. Subendocardial conducting network (Purkinje fibers)
Where is the Sinoatrial node located? In the right atrial wall
What is AFiB? It's a problem with the SA node. The SA node is firing, but not controlling the heart. Once that happens the AV node takes over.
What is normal sinus rhythm? 75 beats per minute
What are the paddles used for? For shocking the SA node back into rhythm
What are some characteristics of the AV node? It is located in the inferior interatrial septum. Delays impulses by approximately 0.1 seconds. Inherent rate of 50 beats per minute in absence of SA node imput
What is the function of the Atrioventricular (AV) bundle? Only electrical connection between atria and ventricles
What is the alternate name for the AV bundle? Bundle of His
What is the AV bundle located? In the superior interventricular septum
Whats the function of the right and left bundle branches? They are the two pathways in interventricular septum
What is the alternate name for the right and left bundle branches? Left and right bundles of His
What are arrhythmias? They are a change in rhythm
What are the two types of arrhythmias? Ventricular and supraventricular(Atria)
Whats Bradycardia? Its when the rhythm is slower than it should
Whats Tachycardia? Its when the rhythm is faster than it should be.
To reach ventricles, impulse must pass through AV node. What will happen if the AV node is defective? It will cause a heart block either partial or total. That will cause the ventricles to beat at their own intrinsic rate
Whats the treatment for a heart block? Artificial pacemaker, which recouples atria and ventricles
What part of the nervous system can intervene in modifying the basic heart rhythm The heartbeat can be modified by the Autonomitc Nervous System (ANS) via cardiac centers in medulla oblongata
What does the cardioacceleratory center do? Sends signals through sympathetic trunk to increase both rate and force
What does cardioinhibitory center do? Parasympathetic signals via vagus nerve to decrease rate
What are the steps in the action potentials of contractile cardiac muscle cells? 1.Depolarization (Sodium channels open) 2. Plateau( Calcium channels open) 3. Repolarization (Potassium channels open)
Whats the difference in action potentials in skeletal muscle and cardiac muscle? Action potentials in skeletal muscle last 1-2 ms; in cardiac muscle it lasts 200 ms
Whats the difference in contraction in skeletal muscle and cardiac muscle? Contraction in skeletal muscle lasts 15 – 100 ms; in cardiac muscle contraction lasts over 200 ms
Whats the function of an Electrocardiograph? It can detect electrical currents generated by heart
Whats the function of an Electrocardiogram? Is a graphic recording of electrical activity (composite of all action potentials generated by nodal and contractile cells at a given time; not a tracing of a single AP ) Usually refered to as a 12 lead EKG
What are some of the benefits of longer action potential and contraction? Sustained contraction ensures efficient ejection of blood. Longer refractory period prevents tetanic contractions.
What is a P wave? Depolarization of SA node and atria
What is the QRS complex? Results from ventricular depolarization and atrial repolarization
What is a T wave? Caused by ventricular repolarization
Whats the P-R interval? The time from beginning of atrial excitation to beginning of ventricular excitation
Whats the S-T Segment? Entire ventricular myocardium depolarized (plateau)
Whats the Q-T interval? Beginning of ventricular depolarization through ventricular repolarization
What could enlarged R waves indicate? They may indicate enlarged ventricles
What would elevated or depressed S-T segments indicate? Cardiac Ischemia (Inadequate blood flow)
What would a normal ECG tracing show? Normal sinus rhythm
What is wrong with a junctional rhythm? The Sa node is nonfunctional. As a result P waves are absent and the AV node paces the heart at 40-60 beats per minute
Whats wrong with a second degree heart block rhythm? The AV node fails to conduct some of SA node impulses. As a result there are more P waves than QRS waves. There are usually two P waves for every QRS wave
Whats wrong with ventricular fibrillation rhythm? Electrical activity is disorganized. Action potentials occur randomly throughout the ventricles. Results in chaotic abnormal ECG readings. Seen in acute heart attack and after an electrical shock. Pace maker may be recommended treatment
Define Systole Period of heart contraction
Define Diastole Period of heart relaxation
Define cardiac cycle Blood flow through heart during one complete heartbeat. Atrial systole and diastole are followed by ventricular systole and diastole
What are the three phase of the cardiac cycle? 1. Ventricular filling (mid-late diastole)2. Ventricular systole ( atria in diastole)3. Isovolumetric relaxation (early diastole)
What is the diotic notch? Closing of the aortic valve
What makes the two sounds when the heart beats? The first sound is closing of the AV(atrioventricular) valves at the beginning of ventricular systole. The second sound is closing of SL (semilunar) valves at beginning of ventricular diastole
Mitral valve closes slightly before __________, and aortic valve closes slightly before _____________________ Tricuspid valve, pulmonary valve
Which area of the thoracic surface can the Aortic valve sounds be heard? In second intercostal space at right sternal margin
Which area of thoracic surface can the pulmonary valve sounds be heard? In second intercostal space at left sternal margin
Which area of the thoracic surface can the Mitral valve sounds be heard? Over heart apex (In fifth intercostal space) in line with the middle of the clavicle
Which area of the thoracic surface can the Tricuspid valve sounds be heard? In fifth intercostal space at the right steral margin
What are heart murmurs? Abnormal heart sounds heard when blood hits obstructions
Whats wrong with a incompetent valve (or insufficient) valve? Fails to close completely, allowing a back flow of blood. This causes a swishing sound as blood regurgitates backward from ventricle to atria
Whats wrong with a Stenotic valve? Fails to open completely, restricting blood flow through valve
Whats cardiac output? Volume of blood pumped by each ventricle in 1 minute. Heart rate(HR) X stroke volume(SV) = Cardiac output (CO)
Whats the normal at rest cardiac output? CO (ml/min) = HR (75 beats/ minute) X SV (70 ml/beat) = 5.25 L/min
Whats cardiac reserve? Difference between resting and maximal CO
What are the factors affecting the CO? 1. Regulation of Stroke volume (SV) 2. Regulation of heart rate (HR)
List the factors affecting heart rate. Autonomic innervation, hormones, fitness levels, and age
List the factors affecting stroke volume Heart size, fitness levels, gender, contractility, duration of contraction, preload (EDV), afterload (resistance)
What are the main three factors affecting stroke volume? Preload, contractility, and afterload (resistance left ventricle must overcome to circulate blood)
What is the equation for SV SV= EDV(end diastolic volume)- ESV (end systolic volume)
What is Frank starling law of the heart? The relationship between preload and SV. Cardiac muscle exhibits a length tension relationship . The greater the starting volume the greater the force
What is the most important factor in preload stretching of cardiac muscle? Venous return (amount of blood returning to the heart)
What increases venous return? Exercise and slow heartbeat
Define contractility The contractile strength achieved at a given muscle length . Independent of muscle stretch and EDV
What lowers ESV? Increased contractility
What increases contractility 1. Sympathetic stimulation. 2. Positive inotropic agents
What decreases contractility Negative inotropic agents. (Acidosis (excess H+), increased extracellular K+, and calcium channel blockers)
Define Afterload Afterload is the pressure that ventricles must overcome to eject blood.
What does Increased afterload cause? Increased ESV and reduced SV
What causes increased afterload Hypertension
Whats the normal aortic pressure? 80 mm Hg
Whats the normal pulmonary trunk pressure? 10 mm Hg
What increases heart rate? Positive chronotropic factors
What decreases heart rate? Negative chronotropic factors
Heart rate can be regulated by: Autonomic nervous system, chemicals and other factors

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