Test 1 Flashcards
Adult heart approximately
The size of a fist
Right ventricle = moves venous blood to the
Pulmonary Circulation
Left ventricle = moves arterial blood to the
Systemic Circulation
separates right and left atria
Interatrial septum
depression in the interatrial septum; remnants of foramen ovale
Fossa ovalis
is the term used to describe an interatrial septum that fails to develop properly
Atrial Septal Defect
separates right and left ventricles
Interventricular septum
are the most common CONGENITAL cardiac abnormalities ; they are found in 30-60% of all newborns with a congenital heart defect, or about 2-6 per 1000 births
Ventricular septal defects
In order to pump blood…
Right and Left Ventricles of the Heart
Must contract forcefully and overcome aortic and pulmonary pressures
end diastolic volume is usually about
150 mL
How much blood dos the heart eject with each stroke?
About 50% the volume ejected is about 70-80mL
What are the 3 Layers of the heart
Epicardium
Myocardium
Endocardium
Lines inner chambers,valves, chordae tendineae, and papillary muscles.
Endocardium
The different things cardiac muscle has compared to skeletal muscle…
Single central nucleus Intercalated discs (help contraction)
Also called the
visceral pericardium
Epicardium
Includes blood capillaries, lymph capillaries, nerve fibers, and epicardial fat
Epicardium
covers approx. 60- 80% of the heart’s surface and constitutes 20% of total heart weight
Epicardial fat
The pericardial space usually contains…
What is this used for?
Normally contains approximately 10 mL of fluid
Acts as a lubricant, preventing friction as the heart beats
Primary function of the heart valves
Ensure blood flow in one direction through
heart chambers and Prevent regurgitation
• Lies between right atrium and right ventricle • Consists of three separate leaflets • Larger in diameter and thinner than mitral valve
TRICUSPID VALVE
• Has only two cusps
• Lies between left
atrium and left
ventricle
MITRAL (BICUSPID) VALVE
What are the distinct features of AV valves?
Cusps of AV valves are attached to chordae tendineae (“heart strings”): papillary muscles contract when the ventricular walls contract preventing bulging too far backward.
have three cusps shaped like half-moons
Semilunar valves
• Pulmonic valve (Right Ventricle)
• Aortic valve (Left Ventricle)
Function of the “ventricular valves”
Prevent backflow of blood from the aorta and pulmonary arteries into the ventricles during ventricular diastole
Associated with closure of tricuspid and mitral
(AV) valves
First Heart Sound (Lub)
Associated with closure of pulmonic and aortic
(semilunar) valves
Second Heart sound (Dub)
receives blood from: Superior vena cava, Inferior vena cava, and Coronary sinus.
Receives blood from: Superior vena cava, Inferior vena cava, and Coronary sinus.
Order of blood flow through RIGHT SIDE of heart
Right Atrium Tricuspid Valve Right Ventricle Semilunar pulmonic valve Pulmonary trunk Pulmonary arteries Lungs (pulmonary capillaries) Pulmonary veins
Blood flow starting in the LEFT SIDE of the heart
Left atrium Mitral Valve Left Ventricle Semilunar Aortic valve Aorta Systemic Circulation
Acute Pericarditis Manifestations
Chest Pain
Friction rub
ECG changes
Acute Pericarditis Causes
Infections: viral, bacterial or fungal
autoimmune: RA, SLE
Trauma
Drug toxicity
This Pericarditis is associated with systemic lupus erythematosus (SLE), rheumatic fever, and a variety of viral infections.
SEROUS PERICARDITIS
This Pericarditis is characterized by production of a clear, straw-colored, protein-rich exudate containing small numbers of inflammatory cells.
SEROUS PERICARDITIS
This Pericarditis is characterized by a fibrin-rich exudate. It may be caused by uremia, myocardial infarction, or acute rheumatic f e v e r.
FIBRINOUS PERICARDITIS
This Pericarditis is characterized by a grossly cloudy exudate. It is almost always caused by bacterial infection.
PURULENT PERICARIDITIS
This Pericarditis is characterized by a bloody exudate. It usually results from tumor invasion of the pericardium, but can also result from tuberculosis or other bacterial infections.
HEMORRHAGIC PERICARDITIS
Define CARDIAC TAMPONADE
Represents an increase in pericardial sac pressure caused by an accumulation of fluid or blood in the pericardial sac
Define Myocardial Disease
Disorders originating from within the
myocardium, but not from cardiovascular
disease
Inflammation of the heart muscle (and conduction system) without evidence of myocardial infarction
Myocarditis
Causes of Myocarditis
viral (#1 cause), drug toxicity (e.g., cocaine), autoimmune diseases
Most often presents as biventricular heart failure in young persons who do not have valvular, rheumatic, or congenital heart disease
Myocarditis
Diseases of the heart muscle that are non-inflammatory and are not associated with hypertension, congenital heart disease, valvular disease, or coronary artery disease
Primary Cardiomyopathies
most common form of Cardiomyopathy Progressive cardiac hypertrophy and dilation & impaired pumping ability in one or both ventricles
Dilated Cardiomyopathy
are common during Dilated Cardiomyopathy and may be a source of thromboemboli
Mural thrombi
Causes: Dilated Cardiomyopathy
idiopathic, infectious myocarditis, alcohol
Characterized by ventricular hypertrophy and impaired diastolic ventricular filling. Is often inherited as an autosomal dominant characteristic; several genes have been implicated in the genesis of this disorder. Sudden death may occur if left ventricular outflow obstruction continues.
Hypertrophic Cardiomyopathy
Least common of the primary cardiomyopathies
Ventricular filling is restricted because of excessive rigidity and stiffness of the ventricular walls
Causes is unknown
Restrictive Cardiomyopathy
Relatively uncommon, life-threatening condition of the endocardial surface of the heart, including the heart valves
Infective Endocarditis (Bacterial Endocarditis)
The primary antibiotic regimen for select patients is_________, 2g orally 30-60 min before the procedure.
AMOXICILLIN
Patients who are allergic to penicillins can be treated with…
cephalexin (2g) or azithromycin or clarithromycin
Because cardiac fibers are electrically coupled by the gap junctions, the entire myocardium behaves as a…
coordinated unit or FUNCTIONAL SYNCYTIUM.
The cardiac troponin complex consists of three proteins, What are they?
- cardiac troponin C (cTnC)
- cardiac troponin I (cTnI)
- cardiac troponin T (cTnT)
cardiac troponin T (cTnT): T is for…
“tropomyosin binding”
cardiac troponin I (cTnI): I is for…
“inhibitory”
cardiac troponin C (cTnC): C is for…
“calcium binding”
What is the Clinical Application of Troponin
Cardiac troponins are the prefered markers for detecting myocardial cell injury
The two Tracts of the SA node…
Internodal Tracts (continues on) Interatrial Tracts
What is the path of a signal from the SA node traveling down the Internodal tract?
SA NODE»Internodal Tract»AV Node»AV Bundle»R/L Bundle Branches»Purkinje Fibers
Describe Non-Pacemaker or “Fast Response” Action Potentials
• Occur in the atria,
ventricles and Purkinje fibers
• Undergo “rapid”
depolarization
Describe Pacemaker or “Slow Response”
Action Potentials
• Occur in the SA node
and AV node
• Undergo “slow” depolarization
What happens in Phase 0 (Rapid Depolarization) Fast Response Cardiac Action Potentials?
- Upstroke of the AP
- “Fast” Na+-channels open
- Several types of K+- channels closed
What happens in Phase 1 (Early/Initial Repolarization) Fast Response Cardiac Action Potentials?
- Transient outward current as K+ channels open
* “Fast” Na+-channels are closed
What happens in Phase 2 (Plateau Phase) Fast Response Cardiac Action Potentials?
- Long-lasting (L-type) Ca+2 channels open leading to inward calcium movement
- Efflux of K+ through several types of K+- channels
Cardiac contraction has an absolute requirement for Ca+2 influx through these channels…
L-type Ca+2 channels
The influx of calcium during an action potential serves as a trigger to induce calcium release from the sarcoplasmic reticulum (calcium-induced calcium release = CICR), which then promotes actin-myosin interaction and hence contraction; occurs via…
ryanodine receptors (RyR2)
What happens in Fast Response Cardiac Action Potentials Phase 3 (Late or Final Repolarization)?
- Continual efflux of K+ through several types of K+-channels
- L-type Ca+2-channels eventually close
What happens in Fast Response Cardiac Action Potentials Phase 4 (RMP)
- K+-channels remain open
* Calcium extrusion mechanisms become highly active
The electrical and mechanical events in cardiac muscle overlap, this prevents…
Tetany
What happens in Phase 0 Slow Response Cardiac Action Potentials?
Is the upstroke of the AP
Is caused by an increase in Ca+2 conductance
What happens in Phase 3 Slow Response Cardiac Action Potentials?
repolarization Is caused by an increase in K+ conductance
What happens in Phase 4 Slow Response Cardiac Action Potentials?
slow depolarization
Is caused by an increase in Na+ conductance, which results in an inward current called I_f
I_f is “turned on” by
repolarization of the membrane potential during the preceding action potential
reflects the time required for excitation to spread throughout cardiac tissue.
Conduction Velocity (CV)
CV is fastest in the______ and Slowest in the ______
CV is fastest in the Purkinje system
CV is slowest in the AV node
produce changes in heart rate
Chronotropic effects
changes in HR are reflected on the ECG by changes
in the
R-R intervals
produce changes in conduction velocity, primarily in the
AV node
Dromotropic effects
cetylcholine (ACh), acts at…
muscarinic receptors
norepinephrine (NE), acts at…
β1-receptors
quantity of blood remaining in either ventricle at the end of ventricular diastole
End Diastolic Volume (EDV)
average 130ml
quantity of blood remaining in either ventricle at the end of ventricular systole
End Systolic Volume (ESV)
Three distinct phases of ventricular filling
- Rapid Passive Filling
- Slow passive filling (Diastasis, no one contracts)
- Atrial Systole
The third heart sound is associated with
The end of rapid passive filling of the ventricles.
occurs when a valve does not open properly.
VALVULAR STENOSIS
The_______ valve is the valve that is most frequently involved in rheumatic heart disease.
mitral
Most frequent heart valve problem, occurring in approximately 7% of the population, most often in young women…
Mitral valve prolapse
is the most common cause of calcific aortic stenosis in persons older than 60 years of age.
degenerative
calcific aortic stenosis,
is the most common cause of calcific aortic stenosis in persons older than 60 years of age.
degenerative calcific aortic stenosis,
The greater the preload, the greater the force of contractiond
HETEROMETRIC REGULATION (Pre-load)
Frank-Starling Law of the Heart
Enhanced contractility results in more complete ejection of blood from the heart,
HOMOMETRIC REGULATION
The BACK PRESSURE exerted on the aortic & pulmonary semilunar valves by arterial blood in the aorta and pulmonary trunk respectively
Afterload
Cardiac Contractility is also called…
Inotropism or Inotropy
cardiac output or performance is enhanced by:
↑ Preload ↑ Inotropy ↑ Heart rate ↓ Afterload
This type of Angina is associated with atherosclerotic disease that produces fixed obstruction of the coronary arteries.
Classic angina or exertional angina
This type of Angina is caused by spasms of the coronary arteries.
Variant angina or Prinzmetal’s angina
also referred to as vasospastic angina.
is considered to be a clinical syndrome of myocardial ischemia that falls between stable angina and myocardial infarction
Unstable angina
Myocardial Infarctions that traverses the entire ventricular wall from the endocardium to the epicardium.
Transmural infarction
Myocardial Infarctions that is limited to the interior one-third of the wall of the ventricle.
Subendocardial infarction
