Chapter 20 Flashcards
Anterior surface of heart
Deep to sternum and ribs
Inferior surface of heart location
Between apex and right surface, rests mostly on diaphragm
Right surface of heart location
Faces the right lung and extends from the inferior surface to the base
Left surface of heart location
Faces the left lung and extends from the base to the apex
Pericardium
Membrane that surrounds and protects the heart
Confines heart to its position in the mediastinum, while allowing for rapid contraction movement
What are the two main parts of the pericardium?
- Fibrous pericardium
- Serous pericardium
Fibrous pericardium
Composed of tough, inelastic, dense irregular connective tissue
Resembles a bag that rests on and attaches to the diaphragm
It’s open ends are fused to the connective tissue of the blood vessels entering and leaving the heart
Prevents overstretching of the heart, provides protection, and anchors the heart in the mediastinum
Serous pericardium
Thinner more delicate membrane forms a double layer around the heart
Parietal layer of the serous pericardium is fused to the fibrous pericardium
Visceral layer of the serous pericardium is one of the layers of the heart wall and adheres tightly to the surface of the heart
What is between the parietal and visceral layers of the serous pericardium?
Pericardial fluid found in the pericardial cavity
What are the three layers of the heart wall?
- Epicardium
- Myocardium
- Endocardium
Epicardium
Outer most layer is called the visceral layer of the serous pericardium
Composed of mesothelium, Fibroelastic tissue and adipose tissue
Contains blood vessels, lymphatics, and vessels that supply the myocardium
Myocardium
Responsible for the pumping action of the heart and is composed of cardiac muscle tissue
makes up 95% of the heart wall
wrapped in bundles with connective tissue sheath’s composed of Endomysium and Perimysium
Endocardium
A thin layer of endothelium overlying a thin layer of connective tissue
provides a smooth lining for the Chambers of the heart and covers the valves of the heart
minimizing surface friction as blood passes through the heart
Auricle
A wrinkled pouch like structure on the anterior surface of each atrium
Slightly increases the capacity of an atrium
Sulci
Series of grooves that contain coronary blood vessels in a variable amount of fat on the surface of the heart
Coronary sulcus
In circles most of the heart and marks the external boundary between the superior atria and inferior ventricles
Anterior interventricular sulcus
Shallow groove on the anterior surface of the heart that marks the external boundary between the right and left ventricles on the anterior aspect of the heart, continues around to the posterior surface of the heart as the posterior interventricular sulcus
Where does the right atrium receives blood from?
- Superior vena cava
- Inferior vena cava
- Coronary sinus
Pectinate muscles
Muscular ridges
Interstitial septum
A thin partition between the right and left atrium
Fossa ovalis
An oval depression which is a prominent feature on the inter-atrial septum is the remnant of the foramen ovale
Foramen ovale
An opening in the inter atrial septum of the fetal heart that normally closes soon after birth
Tricuspid valve
A valve where blood passes from the right atrium into the right ventricle
Through three cusps or valves
Also called right atrioventricular valve
Right ventricle
4-5 mm, Forming most of the anterior surface of the heart
Series of ridges inside Formed by raised bundles of cardiac muscle fibres called trabeculae carneae
Blood passes from the right ventricle through the pulmonary valve into a large artery called the pulmonary trunk which divides into right and left pulmonary arteries and carries blood to the lungs
Left atrium
4-5 mm, forms most of the base of the heart
Receives blood from the lungs through four pulmonary veins
Blood passes from the left atrium into the left ventricle through the bicuspid valve
Left ventricle
10-15 mm, forms apex of heart
Blood passes from the left ventricle through the aortic valve into the ascending aorta
During fetal life a temporary blood vessel called the ductus arteriosus shunt blood from the pulmonary trunk into the aorta
Ligamentum arteriosum
The remnant of the clothes ductus arteriosus connecting the arch of the aorta and the pulmonary trunk
Fibrous skeleton of the heart
Four dense connective tissue rings that surround the valves of the heart fuse with one another and merge with the interventricular septum
Form structural foundation for the heart valves and prevents overstretching of the valves as blood passes through them
serves as a point of insertion for bundles of cardiac muscle fibres and acts as an electrical insulator between the atria and ventricles
Atrioventricular valves
Located between a atrium and ventricle, Called tricuspid and bicuspid valves
When ventricles are relax the Papillary muscles are relaxed the chordae tendineae are slack and blood moves from high pressure in the atria to a lower pressure in the ventricles through the open AV valves
Semilunar valves
Three crescent moon shaped cusps
Each cusp attaches to the arterial wall by its convex outer margin the SL valves allow ejection of blood from the heart into arteries but prevent backflow of blood into ventricles
