Lecture 1 Flashcards
Apex
-bottom
Formed by tip of left ventricle
Base
- top
- Approximately at the level of the 2nd costal cartilages
Anterior Surface
consists primarily of right ventricle
Number of upper chambers
- two
- right and left atria
Number of lower chambers
- two
- right and left ventricles
Right ventricle moves
venous blood to the pulmonary circulation
Left ventricle moves
arterial blood to the systemic cirvulation
Interatrial septum
separates right and left atria
Fossa Ovalis
- depression in the interatrial septum
- remnant of foramen ovale
Failure to close foramen ovale is
Patent foramen ovale
Atrial septal defect
an interatrial septum that fails to develop properly
Interventricular Septum
separates right and left ventricles
Ventricular septal defects
- most common congenital cardiac abnormalities
- Found in 30-60% of all newborns with congenital heart defect or about 2-6 per 1000 births
Ventricular septal defect is aquired by
a few days after myocardial infraction due to macrophage remodeling of dead heart tissue before scar tissue forms
Heart must contact forcefully and overcome
aortic and pulmonary pressure in order to pump blood.
Each ventricle hold about
- 150 ml (at end diastolic volume) when full
- Only about half is ejected (70-80 ml)
Stroke Volume
70-80 ml
Ejection Fraction equation
Stroke Volume/End Diastolic Volume x 100%
Layers of the heart
1- Endocardium
2-Myocardium
3-Epicardium
Endocardium
1- Innermost layer
2- Lines inner chambers, valves, chordae tendineae and papillary muscles
Myocardium
Middle layer
- thick, muscular layer
- responsible for pumping action
- not capable of regeneration (Hyperplasia)
- Is capable of hypertrophy
Cadiac Muscle Cells
1- Cylinderical branching cells
2- Single central nucleus
3- Intercalated discs
Epicardium
1- Also called the visceral pericardium
2- External layer of the heart
3-Includes blood capillaries, lymph capillaries, nerve fibers and EPICARDIAL FAT
Epicardial Fat weight and surface
- Covers 60-80% of heart surface
- 20% weight
Epicardial Fat distribution
Along Coronary arteries, over the right ventricle especially along the right border
- anterior surface
- Apex
Epicardial Fat purpose
provide fatty acids to cardiac muscles as a local energy source in times of high demand
Epicardial and Abdominal Adipose relationship
The more abdominal adipose present the more epicardial fat is present
Parietal Pericardium
Rough outer layer of the pericardial sac
Pericardial Space or pericardial cavity
exists between the parietal and visceral pericardial layers
Pericardial Space Volume
Contains approximately 10 ml of fluid
Pericardial Space purpose
acts as a lubricant, preventing friction as heart beats
Major Hear Valves
- 2 Atrioventricular (AV) valves
- 2 Semilunar valves
Heart Valve Functions
- Ensure blood flow in one direction through heart chambers
- Prevent back flow (REGURGITATION) of blood flow
Regurgitation of blood
Blood flows back through the valve in the wrong direction
Atrioventricular valves (AV) seperate
atria from ventricles
Atrioventricular valves
1- Tricupsid valve
2- Mitral (Bicuspid) Valve
Tricuspid valve
1- Lies between right atrium and right ventricle
2-Consists of 3 separate leaflets
3-Larger in diameter and thinner than mitral valve
Mitral (Bicuspid) Valve
1- Has only two cusps
2- Lies between left atrium and left ventricle
Cusps of AV valves are attached to
Chordae Tendineae (Heart Strings)
Chordae Tendineae originate from
Papillary Muscles
Chordae Tendineae purpose
- anchors in the closed position
- prevents valves from being blown upward into the atria
How do Chordae Tendineae work
- Papillary muscles contract when ventricular walls contract
- Pull the vanes of the valves inward toward the ventricles to prevent their bulging too far backward toward the atria during ventricular contraction
Semilunar Valves
1- Pulmonic Valve
2- Aortic Valve
Semilunar Valves Characteristic
Have 3 cusps shaped like half-moons
Semilunar Valve Functions
Prevent back flow of blood from the aorta and pulmonary arteries into the ventricles during ventricular diastole
Heart Sounds
1- First heart sound (S1)
2- Second Heart sound (S2)
S1 sound
1- Associated with closure of tricuspid and mitral (AV) valves
2- Often referred to as “lub)
S2 sound
1- Associated with closure of pulmonic and aortic (semilunar) valves
2- Dub
Blood Flow through Heart
1- Right Atrium 2- Tricuspid 3- Right Ventricle 4- Pulmonic Valve 5- Pulmonary Trunk 6-Pulmonary Arteries 7- Lungs (pulmonary capillaries) 8-Pulmonary Veins 9- Left Atrium 10-Mitral Valve 11- Left Ventricle 12- Aortic Valve 13- Aorta 14- Systemic Circulation
Right Atrium receives blood from
1- Superior vena cava
2- Inferior vena cava
3- Coronary Sinus
