Module 1 Flashcards
Where is the anterior of the heart located?
Deep to Sternum and Ribs
Where is the inferior of the heart located?
Rests on Central Tendon of Diaphragm
What does the right side of the heart face?
Faces Lung, atrium only
What does the right side of the heart face?
Pulmonary Border, faces left lung
Where does the base of the heart face?
Faces posterior chest,
4 pulmonary veins/2 pulm arteries
Where does the apex of the heart face?
Faces anterior chest
Another name for sternocostal?
Anterior of the Heart
Synonym for Diaphramatic
Inferior of the heart
What is the function of the Pericardium?
Surrounds, protects, confines heart to its position, allows for vigorious movement
Name the 3 Layers of the Pericardium
Fibrous Pericardial Layer
Parietal Layer
Visceral Layer
Define and Describe the Fibrous Pericardium
1) Superficial
2) Tough, Dense Irregular
3) “Open End” Fused to systemic vessels
What composes the Serous Pericardium?
1) Double Layer (Parietal/Viscera;)
2) Parietal outer Layer fused to Fibrous
3) Visceral (Epicardium) adheres tightly to the heart
Where does the pericardial cavity sit?
Between Visceral and Parietal
What is in the pericardial cavity and what is its purpose?
Pericardial Fluid
Name the three layers of the heart
Epicardium, Myocardium, Endocardium
Explain the epicardium
Contains blood vessels and lymphatics/Composed of mesothelium covering delicate fibroelastic tissue and adipose
Myocardium
Responsible for pumping the heart, 95% of the heart wall, wrapped/bundled sheaths, involuntary cardiac muscle
Endocardium
Smooth lining for the heart chambers/Covers the valves of the heart/Continuous with lining of large blood vessels
Auricles
Slightly increases the atria capacity, different sizes, Left one has some muscular
Sulci
Grooves in the Surface of the heart:
1) Coronary sulcus- externally seperates atria from ventricle (atrioventricular sulcus)
2) Interventricular sulcus- Externally seperateds right and left ventricles (Holds vessels)
Trabecule Carneae
Raised bundles of cardiac muscle fibers in ventricles
Papillary Muscles
- Cone shaped trabeculae carneae
- Found only in ventricles
Chordae Tendineae
Tendon-like cords connected to Papillary Muscles, connected to tri/bicuspid valves/VENTRICLES only
Pectinate Muscles
Special ridges of muscle found in anterior portion right atrium/left & right auricles
Crista Terminalis
Divides right atrium between pectinate/smooth surface
Interatrial Septum
Seperates left/right atria , contains fossa ovalis
Tricuspid Valve
(Atrioventricular valve) Right atrium to right ventricle (3 Cusps)
Aortic Valve
(Semilunar Valve) Blood from left ventricle passes through this valve and also to coronary arteries
How thick is the Left ventricle?
10-15mm
What chamber forms the apex of the heart
Left Ventricle
What is the size of the left atrium?
2-3mm thick
What chamber forms most of the base of the heart?
Left atrium
Bicuspid Valve
Left atrium to left ventricle/(Mitral Valve. AV (atrioventricular Valve)
Septum
Medial border between left and right atria and ventricles, houses much of the electrical conduction system
Fibrous Skeleton
“Rings” of dense connective tissue around valves and throughout the heart tissues/ electrical insulator
Foramen Ovale
Opening though atria septum/ Allows RA to LA blood movement, bypasses vent/lungs
Ductus Atteriosus
- Fetal shunts blood from pulm. artery to descending aorta
- Allows lung bypass
- Closes after birth
Leaves Ligamentum arteriosim connecting aorta with pulm trunk
What happens in contractile fibers in PHASE 0?
- Rapid Influx of Na+
- Multiple Voltage Gated Channels open at the same time
- Becomes POSITIVE and therefore DEPOLARIZED
What happens in contractile fibers in PHASE 1?
- BRIEF RE POLARIZATION
- Peak Positive +
- (Fast Channel) Na+ Influx slows/shuts off
- Balance of inta vs extra cellular
- K+ Still leaking from out from cell
- Slow voltage gated Na+ and Ca++ channels open
What happens in contractile fibers in PHASE 2?
PLATEAU PHASE
- Slow influx of Ca++ and Na+ and Efflux of K+ keeps cell depolarized
- This is when the cell begin its contraction
What happens in contractile fibers in PHASE 3?
REPOLARIZATION
- Volatage gated K+ channels open allowing rapid Efflux from the cell
What happens in contractile fibers in PHASE 4?
RESTING MEMBRANE POTENTIAL
- K+ is equal concentration both intra and extra cellular
What is the absolute refractory period?
Phase 0-3 when another action potential cannot occur
Where is the SA Node located?
Right atrium endocardium lateral to the opening of the superior vena cava
Does the SA Node have a resting potential?
No
How does the SA Node transmit conduction to the left atrium?
Through the anterior internodal tract of Bachmann, allowing for simultaneous contraction
Where is the AV Node Located?
In/near the interatrial septum, anterior to the opening of the coronary sinus
What are the fiber velocities of the conduction system?
SA/AV: 0.01-0.02 m/s (slowest
Atria/Ventricles: 1 M/s (intermediate)
Purkinje fibers: 2 m/S
What are the two things that the autonomic nerve impulses and hormones modify?
Timing/Strength
What do Desmosomes do?
Hold Fibers together
What is the purpose of Gap Junctions?
Allow muscle action potentials to conduct from one muscle fiber to its neighboring fibers which help it contract as a single unit
How many heart sounds are produced? How many can you typically hear?
4 and 2
How do we determine Stroke Volume (SV)?
Stroke Volume= End Diastolic Volume- End Systolic Volume
Define Cardiac Output
Volume of Blood ejected from the left ventricle into the Aorta each minute
Define Stroke Volume
Volume of blood ejected by the ventricle each contraction
HR
Beats per minute
Define Cardiac Reserve
Difference between CO Max and CO at Rest, usually 4 to 5x resting CO
What three factors regulate Stroke Volume and ensure they are pumping the same amount? Define them
Preload- Degree of stretch of heart before contraction
Contractility- Forcefulness of contraction
Afterload- Pressure that must be exvceeded before injection of the blood from the ventricles occurs
Characteristics of Pre-Load
greater the preload the greater the contraction
Describe Frank Starling Law of the Heart
- The more the heart fill with blood during diastole the greater the force of contraction
- this equalizes output of the right/left ventricles
Characteristics of Contractility
Inotrope: something that alters the force of contraction
Positive Inotrope: Increases contractility
(increased influx of Ca+)
Negative Inotrope: Decreased contractility (Calcium channel Blockers)
Differences between Physiological & Pathological Cardiomegaly
Physiological: enlargement due to exercise
Pathological: Enlargement due to Disease
