Chr. 20 - The Heart Flashcards
[20.1] Describe the heart.
An organ comprised mostly of cardiac muscle found in the mediastinum. The heart rests on the diaphragm in the thoracic cavity.
[20.1] What is the mediastunim?
An anatomical region from the sternum to the vertebral column, and from the first two ribs to the diaphragm.
[20.1] What is the apex of the heart?
The tip of the left ventricle, found at the inferior aspect of the heart.
[20.1] What is the base of the heart?
The posterosuperior aspect of the heart.
[20.1] What is the pericardium?
The membrane surrounding and protecting the heart. Allows for freedom of movement and vigorous beating contraction of the heart while minimizing friction.
[20.1] What is the fibrous pericardium?
The superficial layer of the pericardium composed of dense irregular connective tissue.
[20.1] What is the serous pericardium?
Deep layer of the pericardium, composed of two layers: parietal and visceral.
[20.1] What is the pericardial cavity?
The space between the parietal serous pericardium and the visceral serous pericardium.
[20.1] What is pericardial fluid?
Fluid inhabiting the pericardial cavity reducing friction.
[20.1] What are the layers of the heart wall?
- Epicardium
- Myocardium
- Endocardium
[20.1] Describe the epicardium.
Composed of two layers: the visceral serous pericardium composed of mesothelium; and a layer of fibroelastic tissue and adipose tissue. Contains coronary blood vessels.
[20.1] Describe the myocardium.
95% of the heart wall, this layer is composed of cardiac musscle wrapped in sheaths of endocardium and pericardium.
[20.1] Describe the endocardium.
A thin layer of endothelium laying over a connective tissue layer. Provides lining for the lumens of the heart. Continuous with lining of large blood vessels stemming from the heart.
[20.1] What are the chambers of the heart?
- Right atrium
- Left atrium
- Right ventricle
- Left ventricle.
[20.1] What are the atria?
Superior receiving chambers of the heart, receives blood from the body/lungs.
[20.1] What are the ventricles?
Inferior pumping chambers responsible for ejecting blood into the body/lungs.
[20.1] What is the auricle of the heart?
A pouchlike structure in each atrium increasing capacity of the atrium.
[20.1] Describe the sulci of the heart.
Series of grooves on the surface of the heart accommodating coronary blood vessels.
[20.1] What’s the coronary sulcus?
A deep sulcus encircling the heart and marking external boundaries between superior and inferior heart.
[20.1] What is the anterior interventricular sulcus?
A shallow groove on the anterior of the heart marking the boundary between right and left ventricles.
[20.1] What is the posterior interventricular sulcus?
A sulcus on the posterior aspect of the marking the boundary between ventricles.
[20.1] Describe the right atrium.
Forming the right superior surface of the heart receiving blood from three veins. Separated from the left atrium by the interatrial septum and from the right ventricle by the tricuspid valve.
[20.1] What are the pectinate muscles?
Muscular ridges in the right atrium extending into the right auricle.
[20.1] What is the fossa ovalis?
An oval depression in the interatrial septum, remnant of the foramen ovale, present only in a fetus before birth.
[20.1] What is the tricuspid valve?
A valve with three flaps separating the right atrium and ventricle. Prevents backflow into the atrium when the ventricle contracts.
[20.1] Describe the right ventricle.
Forms the inferior anteromedial aspect of the heart. Separated from the right atrium by the tricuspid valve and contains the pulmonary semilunar valve which prevents backflow from arteries leading to the lungs.
[20.1] What are the trabeculae carneae?
Muscular ridges within the right ventricle.
[20.1] What are the chordae tendinaea?
Cordlike tendons attaching the leaves of the tricuspid valve to the inside of the right ventricle at the trabeculae carneae. These attachment points are called papillary muscles.
[20.1] Describe the left atrium.
Receives blood from the lungs through pulmonary veins. Separated from the left ventricle by the bicuspid valve.
[20.1] Describe the left ventricle.
Receives blood from the left atrium. Separated from the left atrium by the bicuspid, and from the arch of aorta by the aortic semilunar valve.
[20.1] What is the ductus arteriosus?
A temporary blood vessel only found in a fetus, rerouting blood from the pulmonary arteries to the aorta.
[20.1] What is the ligamentum arteriosum?
A ligament connecting the arch of aorta to the pulmonary arteries; remnant of the ductus arteriosus.
[20.1] Why does the thickness of the myocardium vary between chambers?
Due to difference in function and pressure.
[20.1] What is the fibrous skeleton of the heart?
Four dense connective tissue rings surrounding valves of the heart, fusing with one another and merging in the interventricular septum. Also acts as insertion for cardiac muscle and provides insulation between atria and ventricles.
[20.2] What are the atrioventricular valves?
The bicuspid and tricuspid valve preventing backflow from ventricles into atria.
[20.2] What are the semilunar valves?
Crescent moon-shaped valves preventing backflow from arteries into ventricles.
[20.2] What are the two systems of circulation?
Systemic circulation and pulmonary circulation.
[20.1] Describe systemic circulation.
Blood flows from the left ventricle into the body and returns via the inferior vena cava, superior vena cava, and the coronary sinus.
[20.2] Describe pulmonary circulation
Blood flows from the right ventricle to the lungs, and back into the left atrium.
[20.2] Describe coronary circulation.
A subdivision of systemic circulation where blood flows to the heart. Coronary arteries branch off from the ascending aorta and supply the heart.
[20.2] List the main coronary arteries.
Left and right coronary arteries.
[20.2] Where does the left coronary artery travel?
Passes inferior of the left auricle and divides into two branches: anterior interventricular branch and the circumflex branch.