Anatomy of Heart Flashcards
where is the heart located
in thorax between lungs
protected by ribs and sternum
lies between ribs 2-5 (apex in the 5th intercostal space
what is the heart covered by
pericardium
what is the fibrous pericardium composed of and what does this say about its properties?
outer fibrous layer - inelastic (dense connective tissue)
fuses to the diaphragm and with great vessels
prevents overfilling of heart and anchors it
what is the serous pericardium made up of and what does this say about its properties?
two layers of serous membrane - parietal (lines the inner lining of fibrous pericardium) and visceral (or the epicardium - adheres to surfacce of heart)
between these layers = pericardial cavity
contains pericardial fluid = prevents friction
what happens if the pericardial fluid overfills (or any fluid overfills in the heart itself)?
pushes the perietal layer outwards and caught against fibrous pericardium
cardiac tamponade - heart stops beating
layers of the heart and what muscle its made out of
endocardium (inner) - endothelium
myocardium (biggest) (middle) - cardiac muscle
epicardium (outer) = visceral pericardium
vessels connected to the right atrium
superior vena cava
inferior vena cava
pulmonary trunk - and pulmonary arteries
vessels connected into left atrium
pulmonary veins
what causes the rough inner surface of the heart
bundles of muscle fibres
called trabeculae carnae (in ventricles)
called pectinate muscles (in atria
what electrically seperates the atria and ventricles
bands of fibrous connective tissue
aka fibrous skeleton of the heart
encircles the pulmonary trunk and aorta
heart valves are suspended from it
what are the names of the atrioventricular valves
tricuspid (right)
bicuspid/mitral (left)
where are the semilunar valves based
pulmonary
aorta
both pump blood up and out so it needs valves
function of papillary muscles
splits off into chordae tendinae
contraction of these muscles after the pressure increases in the ventricle
= prevents eversion of the valves = thf prevents backflow of blood in atria
(NOT OPENING AND CLOSING VALVES- that happens with pressure naturally)
how do the semilunar valves work
opened by force of blood as ventricles contract
blood flows backwards in aorta/pulmonary trunk
this pools up in cusps and forces them shut
coronary circulation - what stage must blood be delivered to heart
during ventricular relaxation (when contracted, all muslces are squeezed and vessels compressed)
aided by semilunar valves - when heart contracts, SL open - covers opening to the coronary vessels
when heart relaxes - exposes ostium of coronary vessels
name the 2 vessels that branch off the left coronary arteries
- anterior interventricular/descending (goes down) (meets the posterior interventricular)
- cicumflex(wraps around)
name the vessels that branch off the right coronary artery
- marginal (runs along right ventricle)
- posterior interventricular (runs around back of heart) (meets the anterior interventricular)
why is it important that 2 different interventricular arteries are supplying the same area)
if one becomes blocked, then another one can take over
what is the main coronary vein that drains into the right atrium
coronary sinus
which veins run into the coronary sinus?
great (runs with ant IV artery), middle (runs with post IV artery) and small (runs with marginal)
which cardiac veins run directly into the right atrium
anterior cardiac vein
what type of cells does the cardiac conducting system consist of?
non-contractile cells
pathway of the conducting system
sinoatrial node
atroventricular node
AV bundle (bundle of His) (slows down impulse)
Right &Left bundle branches
purkinje fibres
why is foetal circ different from normal
O2 and nutrients recieved from placenta via umbilical vein
lungs annd liver non functioning so they need to be bypassed
where does the umbilical vein running from and to
blood rich in O2 from placenta
goes through ductus venosus (to bypass the liver)
to inf vena cava into heart
which circulatory shortcut in foetuses bypass the right ventricle and pulmonary system
Foramen Ovale
connects the right and left atria
so blood flows from right ->left
rather than down into ventricle and up and out
which circulatory shortcut in foetuses bypass the pulmonary system and left side of heart
ductus arteriosus
connects pulmonary trunk to aorta
so instead of blood going to lungs (which wouldnt happen anyway cuz lungs are collapsed and high pressure) the blood goes to aorta
which circulatory shortcut in foetuses bypass the liver
ductus venosus
connects umbilical vein to inf vena cava
newborn 1st breath: what happens when lungs expand
blood rushes into pulmonary circulation
O2 levels rise
ductus arteriosus is constricted
newborn 1st breath: what happens when left atrium pressure rises
foramen ovale closes
newborn 1st breath: what happens when umbilical cord tied
umbilical vessels are closed
ductus venosus fibroses
newborn 1st breath: ductus venosus into?
ligamentum venosum
newborn 1st breath:: foramen ovale into?
fossa ovalis
newborn 1st breath: ductus arteriosus into?
ligamentum arteriosum
