The Heart Flashcards
Where is the heart located?
The heart is located in the mediastinum and the base lies on the 5th rib.
What is the function of the heart?
The heart is basically a pump: it receives deoxygenated (more CO2) blood, sends it to the lungs to be exchanged with oxygenated blood and then pump it to the rest of the body.
What encloses and holds the heart in place?
The pericardium
What is another way to describe the inner layer of the pericardium?
The serous pericardium (has 2 layers)
What are the two layers of the serous pericardium?
The parietal (outer) and visceral (inner) layer
What is the space between the visceral and parietal layers of the serous pericardium called?
The pericardial space/cavity (fluid-filled)
What is the role of the coronary arteries?
Supplies O2 + nutrients to the muscles of the heart (myocardium)
The coronary arteries branch from the…
Ascending aorta
Which artery supplies the left ventricle?
The left main coronary artery supplies the left ventricle.
What does the left main coronary artery branch into? (3)
- It goes around the back of the heart into the left circumflex artery
- Then there’s the anterior interventricular artery (lies in the interventricular sulcus — separates the ventricles)
- Comes down and becomes the left anterior descending artery (LAD)
What does the right coronary artery branch into? (2)
- The right marginal artery (hint: marginal = side)
- Then the inferior interventricular artery (posterior)
What is the role of the coronary veins?
Picks up CO2 and waste from the heart
Where do the branches of the coronary veins converge?
- The coronary sinus (think of it like rivers dumping water into a lake)
Is the coronary sinus at the posterior or anterior of the heart?
The posterior of the heart
Where does the coronary sinus dump its waste?
The right atrium
What vein dumps CO2 and waste into the coronary sinus?
The great cardiac vein (LEFT)
What are the coronary veins on the anterior of the heart? (4)
The great cardiac vein (LT) ; the small cardiac vein (RT); the anterior cardiac vein; and the oblique vein of the left atrium.
What are the coronary veins on the posterior of the heart? (3)
The coronary sinus (in the coronary sulcus); the middle cardiac vein; and the posterior vein of the left ventricle.
What are the branches of the left side of the thoracic aorta? (2)
The left subclavian artery and the left common carotid artery (CCA)
Does the right branches of the thoracic aorta come directly from the aorta?
No, they come from the brachiocepahalic artery
What are the branches of the brachiocephalic artery? (right branches of the thoracic aorta) (2)
The right common carotid and the right subclavian artery
What are the branches of the superior vena cava?
The left and right innominate veins (each has their own LT/RT subclavian and internal jugular vein)
What are the heart’s layers in its wall?
The epicardium, myocardium, and the endocardium
What is the endocardium’s location?
The most inner layer
What is the myocardium’s location?
The middle layer of the heart’s wall
The myocardium is the major structure for… (2)
Electrical conductivity and contraction
What is the epicardium’s location?
The outer layer of the wall (attaches to visceral pericardium)
What are intercalated discs?
Exclusive to the heart, they connect myocytes (muscle cells) together.
What are gap junctions?
They are membrane channels that control ion and small cell movement.
What are desmosomes?
Proteins that glue cells together
What is a sarcomere?
A basic unit of muscle fibers: myosin slides along actin during a contraction, which requires ATP using calcium, troponin, and tropomyosin
The right atrium receives blood from where? (3)
Superior/inferior vena cava and the coronary sinus
The right ventricle receives and sends blood where?
Receives blood from the right atrium; sends blood to the lungs
The left atrium receives blood where?
The pulmonary veins
The left ventricle receives and sends blood where?
Receives blood from the left atrium; sends blood to rest of body
What is the purpose of the right and left atrioventricular valves?
The atrioventricular valves prevent backflow from the ventricles into the atria
What are the atrioventricular valves?
RT: tricuspid; LT: bicuspid (or mitral)
What is the purpose of the right and left semilunar valves?
Prevents backflow from the arteries into the ventricles
What are the semilunar valves?
RT ventricle: pulmonary; LT ventricle: aortic
What are pectinate muscles?
Parallel ridges in the atrial walls
What are trabeculae carneae?
Muscular ridges projecting from the inner surface of the ventricles (prevents suction)
What are chordae tendineae?
Fibrous cords connecting valve edges to the papillary muscles
What are papillary muscles?
Pillar-like muscles in ventricular walls and connects to chordae tendinae
What is the purpose of the papillary muscles?
Prevents inversion or closure of valves during contraction
What is the process of pulmonary circulation?
The exchange of O2 and CO2 in the lungs
Describe the steps of pulmonary circulation — DEOXYGENATED blood (8)
- Superior/inferior vena cava
- RT atrium
- >>Right atrioventricular valve (tricuspid)>>
- RT ventricle
- >>Pulmonary valve>>
- Pulmonary trunk
- RT/LT pulmonary arteries
- Lung capillaries (exhale CO2)
Describe the steps of pulmonary circulation — OXYGENATED blood (7)
- Pulmonary capillaries (inhale O2)
- LT atrium
- >>LT atrioventricular valve (bicuspid/mitral)>>
- LT ventricle
- >>Aortic valve>>
- Aorta
- Rest of body
Nodal cells make up?
Specialized muscle cells that ignite the myocytes (spreading APs through heart)
What is polarization?
When the cell is at rest
What is depolarization?
When the action potential takes place
What is repolarization?
The return phase to polarization
What is systole also known as?
Heart contraction
What is diastole also known as?
Heart relaxation
What are some things involved in the cardiac cycle? (5)
Electrical events, pressure changes, heart sounds, volume changes, mechanical events
What is the function of the SA (sinoatrial) node?
The SA node is the pacemaker: it initiates depolarization and then atrial contraction
Where is the SA node?
Posterior wall of the RT atrium
What is the function of the AV node?
The AV node initiates ventricular depolarization
What is the function of the Bundle of His?
The Bundle of His causes depolarization of the interventricular septum
What is the function of the LT/RT Purkinje fibers?
Depolarizes/contracts LT and RT ventricles
What is the travel path of the conductive pathway? (4)
SA node; AV node; Bundle of His; LT/RT Purkinje fibers
The P wave represents?
The P wave represents atrial depolarization
The QRS complex represents?
The QRS complex represents the depolarization and contraction of the ventricles
The T wave represents?
The T wave represents the repolarization of the ventricles
What is the cardiac cycle?
A series of pressure changes in the heart chambers, resulting in movement of blood
What does atrial systolic pressure cause?
Blood moves from atria to ventricle via AV valves
What happens during the atrial filling phase? (atrial diastolic pressure)
- RT atrium fills with blood from inferior/superior vena cava
- LT atrium fills with blood from pulmonary veins
What happens to the heart’s blood flow in relation to ventricular systolic pressure?
- Ejected from LT ventricle → through aortic valve → aorta → rest of body
- Ejected from RT ventricle → through pulmonary valve → pulmonary trunk → lungs
What happens during the ventricular filling phase? (diastolic ventricular pressure — 5 to 7 mmHg)
Blood fills ventricles from atria
What does the S1 sound represent?
Closure of AV valves
What does the S2 sound represent?
Closure of semilunar valves
What does the S3 sound represent?
(Abnormal) AV valves open and ventricles rapidly fill with blood
What does the S4 sound represent?
(Abnormal) Associated with atrial contraction and always pathological
What is end diastolic volume?
Volume of blood in RT/LT ventricle at end of diastole filling
What is end systolic volume?
Amount of blood remaining in ventricle after systole end
What is cardiac output (CO)?
Volume of blood ejected from LT/RT ventricle at end of systole per min
What is ejection fraction?
Percentage of blood ejected from LT ventricle during systole (55-70 %)
What is the atrial contraction period?
Contraction of the atria after electrical stimulation
What is the isovolumetric period?
Ventricular systole starts (all valves close, then ventricular contractions) — blood volume remains constant in ventricles
What happens in the ventricular ejection period?
Ventricles eject blood to large blood vessels (AV valves are closed)
What are the phases in ventricular systole? (2)
Isovolumetric contraction, ventricular ejection
What is the isovolumetric relaxation period?
Aortic and pulmonary valves close (S2 sound) after ventricular pressure drop below diastolic aortic/pulmonary pressures. (beginning of diastole)
What is the ventricular filling period?
AV valves open and ventricular filling starts
What are the phases in the relaxation period? (2)
Isovolumetric relaxation, ventricular filling
What is stroke volume?
Amount of blood ejected per beat
What is contractility?
Inherent strength of heart’s contraction in systole
What is preload?
Strength of muscles (which is dependent on amount of blood coming in to RT ventricle) before pumping at end of diastole
What is afterload?
Resistance heart needs to overcome during/after aortic contraction in order to eject blood from ventricles
What are the hormones involved in heart rate regulation? (2)
Epinephrine, norepinephrine
What are the ions involved in the heart?
Sodium, potassium, calcium
What is known as the aging pigment?
Lipofuscin
What happens to the heart as you age? (3)
Deposits of lipofuscin; heart muscles degenerate; heart valves thicken/stiffen
How is a person’s sex related to the heart?
Size of heart and major blood vessels are smaller in females
How does physical fitness affect the heart?
Muscles can pull O2 from blood easier (reducing need to pump) and reduces stress hormones
What are the nerves involved with the heart? (3)
Vagus, sympathetic, parasympathetic nerves
What is directly related to increasing cardiac output? (2)
Increased stroke volume and heart rate
What increases your heart rate? (3)
The nervous system (📈 sympathetic, 📉 parasympathetic); chemicals; other factors (age, sex, fitness, temperature)
What increases stroke volume? (3)
Increased preload; increased contractility; decreased afterload
What is coronary artery disease and its usual cause?
CAD is damage to the major blood vessels of the heart and its usual cause is plaque buildup (atherosclerosis) which limits blood flow (symptoms can vary)
What is heart arrhythmia and when does it occur?
Improper beating of heart (either too fast aka tachycardia or too slow aka brachycardia) due to electrical impulses not working properly
How can heart failure occur?
When the heart cannot pump (systolic) or fill (diastolic) properly… most common type is congestive heart failure
What are some examples of what happens to your heart valve during heart valve disease? (3)
Stenosis: valve narrowing (can’t open right); regurgitation: loose leaflets (can’t close right); prolapse: leaflets stay open
What is pericardial disease?
The heart’s pericardium inflames, which can cause pericardial friction (chest pain)
What is cardiomyopathy and some symptoms?
Acquired/hereditary disease of the heart’s muscle. Symptoms include swollen legs/feet, bloated belly, and breathlessness.
What is ischemia?
Inadequate blood/O2 flow to heart’s tissues
What is angina?
Chest pain due to ischemia
What is myocardia infarction?
Heart tissue death due to ischemia
What is cardiac tamponade?
External pressure on heart (fluid in pericardial sac)
What is carditis?
Inflammation of the heart
What is the purpose of a blood test?
Shows muscle damage (troponin, lipid, cardiac enzymes)
What is the purpose of an ECG?
ECGs tests cardiac electrical activity and detects things like arrhythmias
What is the purpose of an echocardiogram (ultrasound)?
An echocardiogram checks valves and heart muscle contractions
What is a coronary angiogram (catherization)?
XRAY that tests for coronary artery blockages
What is a CCTA (coronary computed tomography angiogram)?
Imaging test that looks at the heart’s arteries
What is a coronary angioplasty?
A procedure to improve blood flow to the heart
What is thrombolytic therapy?
Medication preventing clot formation
What does an artificial pacemaker surgery do?
Replaces SA or AV nodes
