heart and mediastinum Flashcards
sytole
contraction of ventricles
diastole
relaxation of ventricles
pulmonary circulation pressure and distance
low and short
systemic circulation pressure and distance
high and long
origin of systemic circulation
left ventricle
termination of systemic circulation
right atrium
origin of pulmonary circulation
right ventricle
termination of pulmonary circulation
left atrium
thoracic cage composed of __
ribs, costal cartilage, sternum, thoracic vertebrae
regions of the thoracic cavity
right pleural cavity, mediastinum, left pleural cavity
mediastinum contains __
all thoracic structures except the lungs
how is the mediastinum so mobile
consists of hallow visceral structures joined by loose connective tissue
sternal angle
joint between the manubrium (top) and the body oil the sternum
thorax plane is at what level in the vertebrae
between T 4 and 5
mediastinum sub sections
superior and inferior (anterior, middle, posterior)
superior mediastinum contains __
oesophagus, trachea, neurovasculature
anterior mediastinum contains __
fat and the thymus
middle mediastinum contains __
heart and pericardium
posterior mediastinum contains __
descending aorta and branches, oesophagus, thoracic duct, Sympathetic chains
Azygos system of veins
drains the posterior thoracic wall
thoracic duct
main lymphatic vessel for return of lymph to systemic venous system,
thymus
T cell producing lymphoid organ
phrenic nerve
paired nerve, one left one right, supplies the diagphram
vagus nerve
paired nerve one left one right, parasympathetic input to the gastrointestinal system and to the heart
pericardium
membrane covering the heart (middle mediastinum)
pericardial layers
outer fibrous, inner thin serous
fibrous pericardium
Blended inferiorly with central tendon of diaphragm, rigid,
serous pericardium
Contained within the fibrous pericardial sac, double layer, Analogous to pleural membrane (respiratory)
2 layers of the serous pericardium
visceral (inner), parietal (outer)
pericardium functions
protect from infection, limits the hearts motion, lubrication, prevents rapid overfilling of the heart
superior vena cava
right - de-oxygenated blood to the right atrium from the systemic circulation superior to the heart
inferior vena cava
right - brings de-oxygenated blood to the right atrium from the systemic circulation inferior to the hear
pulmonary trunk (arteries)
right - exits the right ventricle, taking deoxygenated blood to the lungs.
pulmonary veins
left - enter the left atrium on the posterior aspect of the heart, carrying oxygenated blood from the pulmonary circulation.
aorta
left - carries high pressure, oxygenated blood to the body in the systemic circulation
base of the heart is directed towards which vertebrae
T6-9
apex of the heart
Antero-inferiorly, forwards and down
anterior surface formed mostly from __
right ventricle
inferior surface formed mostly from __
left ventricle
3 layers that make up the wall of the heart
epicardium, myocardium, endocardium
epicardium
layer of connective tissue, protecting layer
myocardium
muscular component of the wall, myocytes and cardiac muscle cells
endocardium
epithelium and connective tissue, covers the valves
cardiac muscle
striated, not under voluntary control, rules on sliding filament mechanism, branched fibre network
what does functional syncytium mean
one stimulus can contract the whole myocardium
intercalated discs
separate sarcoplasms of adjacent muscle cells, action via desmosomes, allow excitation to pass via gap junctions
fibrous skeleton
cardiac muscle anchored to this more structural support, dense collagen, four fibrous rings around the valves
purpose of the fibrous skeleton
prevent valves collapsing, provides base for attachment form leaflets and cusps of valves, electrical barrier between atria and ventricles
what separates the chambers
interatrial/interventricular septum
right atrium fills with __
de-oxygenated blood from the systemic circulation
left atrium fills with __
oxygenated blood from the pulmonary circulation
