The heart (p1) Flashcards
What is the internal anatomy of the heart?
- Simply a transport system pump via hollow blood vessels that provide delivery routes
- Enclosed within mediastinum of thorax
- Extends obliquely
- Broad flat base = towards right shoulder
- Apex = points towards left hip
- 3 layers
What are the 3 layers within the heart?
Pericardium
Myocradium
Endocardium
What is the pericardium? What are the 2 subtypes?
Outer covering of heart; double walled, firbo-serous sac
a) fibrous pericardium
- protect against physical trauma, anchorage while still allowing contracting and filling of the heart
- prevents overfilling of the heart; when you exercise and blood is circluating faster than normal, also so walls of the heart arent damaged by excessive blood filling
b) serous pericardium
- consists of parietal and visceral (epicardium) layers, these can easily slide over each other without much friction so that this process can occur comfortably
- a fluid-filled pericardial cavity
What is the myocardium? What are its main functions?
The bulk of the heart = cardiac muscle
The branching cardiac muscle cells are arranged into bundles, CT wrappings of these bundles;
- reinforce myocardium internally
- anchor cardiac muscle fibers
- additional support for all large vessels (aorta, superior vena cava…)
- direct spread of APs - spreads first to atria then ventricles
Bundles conduct electrical impulses from one cell to the next
What is the role of CT wrappings in the heart? where can they be found?
Found = myocardium
Role = act as insulation to direct the flow of electricity
- Bundles of branching cardiac muscles conduct electrical impulses from one cell to the next
What is the endocardium?
Layer of endothelium and CT layer on inner myocardial surface
Continuous with endothelium of vells leaving and entering heart
Endothelium lines both the blood vessels and the chambers of the heart (atria and ventricles) because they directly connect for blood flow within the heart
What are the 2 exterior grooves that can be found within the heart?
1) Coronary sulcus (atrioventricular groove)
2) Anterior-posterior interventricular sulcus
- runs as a passageway between left and right ventricles
What do the interatrial and interventricular septa do?
Septa separates different oxygen rich and poor blood from each other
Interatrial = separates the 2 atria from each other
Interventricular = separates the 2 ventricles from each other
What are the atria? What structures compose it?
Atria = receiving chambers, conveys blood to ventricles, smaller and thin walled
Deoxygenated, systemic blood enters right atrium from;
- superior vena cava (O2 poor blood from areas above the brai)
- inferior vena cava (O2 poor blood from below the heart)
- coronary sinus (O2 poor blood from the walls of the heart itself)
What are pectinate muscles?
Muscle bundles found especially in the right atrium
Indicated by a bumpy appearance
What is the foramen ovale? The fossa ovalis?
Foramen ovale = direct communicating pathway between left and right of heart and allows the 2 bloods to mix
- only seen when a baby still receives O2 from the placenta and will close when the baby is breathing
Fossa ovalis = creates a shallow depression between the left and right heart when the baby is able to breathe forming the fossa ovalis
What are the ventricles?
Ventricles = discharging chambers
The real pumps of the heart, walls are much thicker especially the lft because it has to push blood to the aorta and all other areas
Internal walls have muscle bundles; trabeculae carneae, papillary muscles
a) right ventricle = pumps O2 poor blood → pulmonary trunk
b) left ventricle = pumps O2 rich blood → aorta
What is chordae tendineae? How are they linked?
Chordae tendineae = extensions of CT
Linked by the papillary muscles within the walls of the ventricles
What are heart valves?
4 heart valves in place to enforce the unidirectional flow of bloos
- Atrioventricular valves (AV)
- paired (left and right)
- tricuspid valve (right atrium to right ventricle)
- mitral (bicuspid) valve (left atrium to left ventricle)
- Semilunar valves (SL)
- paired (ventricles to pulmonary or systemic circuits)
- pulmonary valve = right ventricle to pulmonary trunk
- aortic valve = left ventricle to aorta
What are some examples of valve problems?
Valvular insufficiency = valves that dont close 100%
Valvular stenosis = valves dont open as wide or big as they should, heart has to push harder, valves are stiff due to calcification/scar tissue
In what directions do the AV and SL valves push blood?
AV = blood pushed down
SL = blood pushed up
Why do the 2 ventricles have unequal workloads even though equal volumes are pumped through the pulmonary and systemic circuits?
1) pulmonary (right ventricle) = short, low pressure circulation
2) Systemic (left ventricle) = long pathway with 5x resistance
Walls of left ventricle are 3x thicker than the right, more resistance to flow of blood as well
What is the coronary circulation?
Shortest, but high importance
- right and left coronary arteries branch from base of aorta, encircle the heart in the coronary sulcus (atriventricular groove)
What are some diseases of coronary vessels?
Angina pectoris = chest pain, felt as passageways get more narrow
Myocardial infarction = complete blockage of some areas of the heart; heart attacks
What are anastosomes?
Direct connections between blooos vessels that provide alternate routes for nourishmenr if a given artery begins to be occluded (blocked)
Role;
- actively deliver blood when heart is relaxed
- largely ineffective when ventricles contract - occurs in between bearts, therefore when you are perfusing coronary circulation
