Lec. 23 Heart Flashcards
(51 cards)
What are the circulation systems
SYSTEMIC CIRCULATION (loses O)
- carry oxygenated blood from heart to body & return deoxygenated blood to heart
PULMONARY CIRCULATION (gains O)
- carry deoxygenated blood from heart to lungs & return oxygenated blood to heart
CARDIAC CIRCULATION
- circulate blood through heart
Describe the cardiac conduction system
cardiac muscle cells (auto rhythmic self excitable cells) allow heart to beat rhythmically - Gap junctions allow action potentials to jump to next cell
Describe the cardiac cycle
All events that take place during one heartbeat
- alternating period of contraction/relaxation
- fluctuating pressures cause valves to open and close
What organs are contained in the thoracic cavity
- heart & great vessels
- trachea, bronchi, lungs
- esophagus
- thymus gland
Boundaries of the thoracic cavity
Ranges from thoracic inlet to diaphragm
What are the 3 spaces the thoracic cavity is divided into
- pleural cavities (lateral sides)
- contains the lungs
- mediastinum (space between the lungs)
- can be subdivided into posterior, anterior, middle and superior
- middle section contains the heart
- can be subdivided into posterior, anterior, middle and superior
What are the great vessels around the heart
Drain blood into the two atria
- Pulmonary veins
- superior & inferior vena cava
Receive blood from the two ventricles
- Aorta
- Pulmonary arteries
- pulmonary trunk
What are the 3 layers of the heart wall
Epicardium
- thin outer layer of connective tissue
Myocardium
- thick middle layer of cardiac muscle tissue
Endocardium
- thin inner layer of endothelial tissue
What membrane surrounds the heart
Pericardium membrane
- consists of an inner fibrous portion and an outer serous portion
Describe fibrous pericardium’s job
Connective tissue layer that anchors heart to the diaphragm and blood vessels entering/exiting the heart
Describe serous pericardium’s job
Double layered membrane with small fluid filled space called pericardial cavity between the layers:
- parietal layer (outer layer fused to the fibrous pericardium)
- visceral layer (inner layer fused to the heart)
What are the 4 chambers of the heart
Left & Right Atrium - superior chambers that receive blood
Left & Right Ventricle - inferior chambers that eject blood
What are the 4 valves that separate the chambers
Left & Right Atrioventricular Valves (left = bicuspid valve)
(right = tricuspid valve)
- separate atria from ventricles
Left & Right Semilunar Valves
(left = aortic valve)
(right = pulmonary valve)
- separate ventricles from the arteries that emerge from them
How do the atrioventricular valves (bicuspid/tricuspid) open
- flaps open inferiorly to allow blood to enter the ventricles
How do the semilunar valves (pulmonary/aortic) open?
- flaps open superiorly to allow blood to exit the ventricles
Describe coronary sulcus
Externally encircles the heart and marks the external boundary between atria and ventricles
Describe the interventricular sulcus
Grooves on anterior and posterior surface that roughly mark the external boundary between the ventricles
What is the path of blood flow in cardiac circulation
Right atrium —> tricuspid valve —> right ventricle —> Pulmonary valve
—> pulmonary trunk —> Pulmonary arteries —> pulmonary circulation —> lungs ~> pulmonary veins ~> left atrium ~> bicuspid vale ~> left ventricle ~> aortic valve ~> aorta ~> superior/inferior vena cava
Arteries carry blood ____ from the heart
Away
Veins carry blood _____ the heart
Toward
Most veins carry ____ blood
Deoxygenated
Pulmonary veins are an exception
Most arteries carry _____ blood
Oxygenated
Pulmonary arteries are an exception
What is A
Epicardium
What is B
Myocardium
