What lies in the mediastinum, behind the body of the sternum between the points of attachment of ribs 2-6?
Approximately two thirds of the heart's mass lies to which side of the midline?
Posteriorly the heart rests on what?
Bodies of the thoracic vertebrae 5-8
Where does the Apex of the heart lie?
On the Diaphragm pointing to the left
Where does the base of the heart lie?
Just below the second rib
What are clinically important as an aid in diagnosing heart disorders?
Boundries of the heart
What are the boundries of the heart influenced by?
-Age -Body build -State of contraction
What is the shape of the heart at birth?
Transvers and appears lage in proportion to the diameter of the chest cavity
What age does the heart attain it's adult shape and weight?
What are the two kinds of Pericardium?
-Fibrous pericardium -Serous pericardium
What is the tough, loose-fitting inextensible sac?
What is the parietal layer that lies inside the fibrous pericardium?
What layer of tissue adhears to the outside of the heart?
What seperates the two layers of Serous pericardium?
pericardial space with pericardial fluid
What is the function of the heart coverings?
Provide protection against friction
How many layers make up the wall of the heart?
3 distinct layers
What are the 3 distinct layers that comprise the heart wall (superficial to deep)?
-Epicardium -Myocardium -Endocardium
What is the outer layer of the heart wall?
What is the thick, contractile middle layer of the heart wall; that compresses the heart cavities and blood within them with great force?
What is the delicate inner layer of endothelial tissue?
The chambers of the heart are divided into how many cavities?
What are the 2 superior chambers of the heart?
What are the Atria also known as?
"receiving chambers" (they recieve blood from the veins)
What are the characteristics of the Myocardium within the atria?
-Not very thick because little pressure is needed to move blood such a small distance
What is the earlike flap protruding from each atrium?
What are the 2 lower chambers of the heart?
What are the Ventricles also known as?
"pumping chambers" (because they push blood into the large network of vessels)
What is the characteristics of the Myocardium within the ventricles?
-Thicker than the atria because great force must be generated to pump the blood a large distance
Which ventricle's myocardium is thicker and why?
Left ventricle is thicker than the right because it must push blood much further
What are the mechanical devices that permit the flow of blood in one direction only?
Valves of the heart
What prevents blood from flowing back into the atria from the ventricles when the ventricles contract?
Atrioventriclular (AV) valves
What is the name of the right AV valve?
What guards the right atrioventricular orifice?
What are the free edges of the three flaps of endocardium that make up the tricuspid valve attached to papillary muscles by?
What is the name of the left AV valve?
Bicuspid valve or Mitral valve
What guards the left atrioventricular orifice?
What is similar in structure to the tricuspid valve except only having two flaps present?
What are the half-moon shaped flaps growing out from the lining of the pulmonary artery and aorta; preventing blood from flowing back into the ventricles from the aorta and pulmonary artery?
Semilunar (SL) valves
What is the valve at the entrance of the pulmonary artery?
Pulmonary semilunar valve
What valve is at the enterance of the aorta?
Aortic semilunar valve
What is a set of connected rings that serve as a semirigid support for the heart valves and for the attachement of cardiac muscle of the myocardium?
Skeleton of the heart
What serves as an electrical barrier between the myocardium of the atria and myocardium of the ventricles?
Skeleton of the heart
What is characterized by listening to the sounds of the heart on the body surface with a stethoscope?
What is the flow of blood in the right side of heart from begining until it enters the Left side of the heart?
-Right Atrium through R Atriventricular valve into the R Ventricle -From R Ventricle through Pulmonary Semilunar valve into the Pulmonary artery, the Pulmonary trunk -Pulmonary trunk branches to form L and R Pulmonary arteries which conduct gas exhange with lungs -From lungs blood flows through Pulmonary Veins into L Atrium
What is the flow of blood in the left side of the heart from blood from pulmonary veins flowing from lungs into the left Atrium?
-Blood from pulmonary veins flows into Left Atrium which passes through the L AV valve into the L Ventricle -From L Ventricle blood flows through Aortic Semilunar valve into the Aorta -Branches of the aorta supply all the tissues of the body except the gas exchanging tissues of the lungs
Where does blood leaving the head and neck and chest walls tissues empty?
Into the superior vena cava
Where does blood leaving the lower body empty into?
Into the inferior vena cava
Where does the blood of both the Superior and Inferior vena cava flow?
Into the Right Atrium
Ventricles recieve blood from branches of what?
Both right and left Coronary arteries
The first branches of the Coronary artery come off what?
The most abundant blood supply goes into the myocardium of what ventricle?
What coronary artery is dominant in approximately 50% of all hearts?
Right coronary artery
What coronary artery is dominant in approximately 20% of all hearts?
Left coronary artery
What percent of all hearts are neither of the coronary arteries dominant?
Few anastomoses (connections between vessels) exist between the larger branches of what?
As a rule veins of the coronary circulation follow a course that closely parallels that of what?
Several veins of coronary cirulation drain directly into what?
After blood goes through the cardiac veins where does it enter?