Heart & Mediastinum Flashcards
What are the boundaries of the mediastinum?
superior: thoracic inlet
inferior: diaphragm
anterior: sternum and costal cartilages
posterior: thoracic vertebrae
lateral: pleura
What are the contents of the superior mediastinum?
great vessels of heart, thoracic duct (left), parts of azygos system, R&L vagus nerves, pulmonary plexus, esophageal plexus, cardiac plexus, thymus, parts of trachea & esophagus
What are the contents of the inferior, anterior mediastinum?
fat, lymph tissue, and vessels
What are the contents of the inferior, middle mediastinum?
the heart and its pericardial tissues
What are the contents of the inferior, posterior mediastinum?
thoracic aorta, esophagus, pulmonary arteries & veins, azygos system, thoracic duct, sympathetic trunk & thoracic splanchnic nerves
What side does the brachiocephalic trunk go to in the mediastinum?
right
What is special about the left recurrent laryngeal nerve in the mediastinum?
it wraps around the aortic arch and then ascends
Describe the thoracic sympathetic trunk in the mediastinum
bilateral; continuous with cervical and lumbar parts of sympathetic trunk; paravertebral ganglia along its course; it is lateral to the vertebral bodies
Describe the thoracic splanchnic nerves
bilateral; emerge from thoracic sympathetic trunks; there is a greater, lesser and least nerve; all three are part of the abdominopelvic sphlanchnic nerves and are all presynaptic fibers that will synapse with pre vertebral ganglia in abdomen
What type of innervation do the thoracic sphlanchnic nerves provide?
sympathetic innervation to viscera inferior to the diaphragm
What are the three locations in the mediastinum that are areas of constriction where swallowed foreign objects are most likely to lodge and where a stricture may develop after drinking caustic liquid
arch of aorta; left main bronchus; diaphragm
What is the esophageal hiatus?
location where the esophagus opens up and meets the stomach
What are the functions of the heart?
center of the cardiovascular system, connects to blood vessels that transports blood between the heart and other body tissues
What is the main difference between arteries and veins?
arteries carry blood away from the heart
veins carry blood back to the heart
True or False?
Arteries carry blood high in oxygen and veins carry blood low in oxygen.
True; except for the pulmonary arteries/veins
What are the arteries and veins entering and leaving the heart called?
the great vessels
What type of blood flow occurs through both the heart and blood vessels?
unidirectional flow
Backflow of blood is prevented by ___ within the heart
valves
True or False
The two side-by-side pumps of the heart work independently but at the same rate.
true
How is blood pressure in the heart developed?
through alternate cycles of heart wall contraction and relaxation
What does the pulmonary circuit consist of?
the right atrium and ventricle of the heart as well as the pulmonary arteries and veins
When blood returns to the left side of the heart it enters the ___ circuit
systemic
What does the systemic circuit consist of?
left atrium and left ventricle along with the other named blood vessels
Gas exchange in tissues occurs from what?
capillaries