Cardiovascular system Flashcards
location of heart
thoracic –> mediastinum (between 2nd rib and 5th intercostal space) –> pericardial
orientation of heart
2/3 of heart is left of midsternal line
oblique orientation –> base to right shoulder, apex to left hip
structure and function of pericardium
visceral layer (epicardium)
parietal layer
- serous secreting side, allows frictionless movement of pericardial layers as heart beats
- fibrous side stuck to vertebrae sternum diaphragm pleura
innervation of pericardium
phrenic nerve (sensory), shared by C3-C5 dermatomes, referred pain in neck and shoulder
layers of heart wall
endocardium: inner lining and valves
myocardium: middle muscle layer
epicardium
major arteries from aorta
left subclavian - to the left upper limb
left common carotid - to the head
brachiocephalic - to the right upper limb and head
chordae tendinae and papillary muscles structure and function
found in the ventricles, PM extends from wall, attaches to CT which attaches to valve
prevents valves from inverting
why does left of heart have thicker myocardia than right
generate more pressure for systemic circulation
views of the heart
ANTERIOR: RV, RA most visible, LV slightly visible, LA not visible
POSTERIOR: LA LV most visible, RA RV less visible
atria and ventricle features
ATRIA: fossa ovalis, pectinate muscles (allowing expansion of atria), vena cavae and coronary sinus for RA
VENTRICLES: papillary muscle, trabeculae carnae (keeps blood turbulent preventing clotting)
coronary circulation structure types and function
ARTERIES: supply myo and epi
originates at base of ascending aorta, right, left, anterior interventricular
VEINS: coronary sinus delivers deoxygenated blood from myo to RA
cardiac control from brain
heart rate regulated by cardiac plexus
SYMPATHETIC:
noradrenaline/adrenaline, increase SA node rate of depolarisation, increase force of contractions, dilates coronary arteries
PARASYMPATHETIC:
acetylcholine, slow SA node rate of depolarisation, less force of contractions, constricts coronary arteries
heart conduction and relationship to contraction
sinoatrial node –> interatrial pathway (ATRIA CONTRACT) and internodal pathway –> AV node –> AV bundles –> purkinje fibres
electrical conduction precedes mechanical contraction
