Borders, surfaces, chambers of the heart Flashcards
anterior view of the heart
posterior view of the heart
medial view of heart
heart location
middle mediasteinum
enclosed within pericardium
describe the placement of the heart
obliquely behind the body of the sternum and adjoining parts of costal cartilage
one third of the heart lies to the right and two thirds to the left of median plane
what Is the direction of blood flow from atria to ventricles
downwards, forwards and to left of median plane
what does the heart measure and weight in males and females
12 times 9 cm and weights about 300g in males and 250 in females
what are the external features of the heart
four chambers - right and left atria and left and right ventricles
where do the atria lie
above and behind the ventricles
how are atria and ventricles separated
atrioventricular groove
how are the atria separated from one another
interatrial groove
how are the ventricles separated from one another
interventricular groove
apex of heart location
directed downwards, forwards and to the left of base (posterior surface) directed backwards
three surfaces of heart
anterior, sternocostal, inferior and left lateral
borders of heart
upper, inferior, right and left borders
sulcus the divides atria and ventricles
coronary sulcus - divided into anterior and posterior parts
anterior part of coronary sulcus
consists of right and left halves
right half of anterior part of coronary sulcus
oblique between right auricle and right ventricle lodging right coronary artery
left half of anterior part of coronary sulcus
small between left auricle and left ventricle lodging circumflex branch of left coronary artery
what is coronary sulcus overlapped anteriorly by
ascending aorta and pulmonary trunk
position of anterior intraventricular groove
nearest to left margin of heart
position of posterior intraventricular groove
nearest to diaphragmatic surface of heart
what is apex of heart entirely made of
left ventricle
how is apex of heart positioned
directed downwards, forwards and to the left
what is apex of the heart overlapped by
anterior border of the left lung
where is apex of the heart located
left 5th intercostal space, 9cm lateral to the midsternal line
base of the heart (posterior surface of heart) is formed from what
left atrium and a small part of the right atrium
in relation to the base of heart what are the openings
four pulmonary veins which open into left atrium, superior and inferior vena cavae which open into right atrium
upper border of the heart
slightly oblique formed by two atria, chiefly left atrium
right border of the heart
vertical and formed by right atrium extends from SVC to IVC
inferior border of heart
nearly horizontal and formed by right ventricle IVC to apex
left border of heart
formed by left ventricle and left atrium separates anterior left surface of heart
anterior or sternocostal surface (surface of heart) formed by
right atrium and right ventricle and partly by left ventricle and left auricle
what is the sternocostal surface mostly covered by
lungs but a part lies behind cardiac notch of left lung (uncovered - dull in percussion) - area of superficial cardiac dullness
inferior or diaphrammatic surface
rests on the central tendon of diaphragm
left 2/3 formed by left ventricle
right 1/3 formed by right ventricle
left surface
formed mostly by left ventricle and at upper end by left auricle
what is the upper left surface crossed by
coronary sulcus
what is left surface related to
left phrenic nerve / pericardiophrenic vessels
crux of heart
meeting point of intertribal atrioventricular and posterior inter ventricular grooves
What role do the auricles have in the adult?
The lower right chamber pumps the oxygen-poor blood to your lungs through the pulmonary artery. The lungs reload blood with oxygen. Left atrium: After the lungs fill blood with oxygen, the pulmonary veins carry the blood to the left atrium. This upper chamber pumps the blood to your left ventricle
Fossa ovalis is the adult remnant of the foetal foramen ovale. What function did the latter perform in the foetus?
allows blood to pass from the right atrium to the left atrium, bypassing the nonfunctional fetal lungs while the fetus obtains its oxygen from the placenta
What is the function of musculi pectinati in the right atrium?
The right atrium has thick and coarse pectinate muscles while these are few smooth and thinner in the left atrium - The pectinate muscle folds act as RA volume reserve during adverse loading conditions . It helps RA dilate with out much wall stress
Atrial Septal Defect (ASD)
Atrial septal defect (ASD) is one of the more commonly recognized congenital cardiac anomalies presenting in adulthood. Atrial septal defect is characterized by a defect in the interatrial septum allowing pulmonary venous return from the left atrium to pass directly to the right atrium.
right ventricle
pulmonary trunk
pulmonary valve
septomarginal trabeculum (moderator band)
papillary muscles
chordae tendineae
tricuspid valve cusp
trabeculae carneae
What is the function of the trabeculae carneae?
serve a similar function to papillary muscles in that their contraction pulls on the chordae tendinae, preventing inversion of the mitral (bicuspid) and tricuspid valves. This prevents backflow of blood from the ventricles into the atriums.
What is the function of the septomarginal trabeculum (moderator band)?
band of cardiac muscle found in the right ventricle of the heart… contract the APM to prevent the tricuspid regurgitation through tension of the chordae tendineae
The thickness of the right ventricular wall is 3x thinner than the left ventricular wall. Why is this?
The right ventricle has thinner wall because the right ventricle only has to pump it to the lungs but left ventricle has to pump blood all the way around the body. Moreover, the blood in arteries is under higher pressure than blood in the veins
How many papillary muscles are found in the right ventricle? (This matches the number of cusps in the right atrioventricular valve - see the correlation?).
three papillary muscles of the right ventricle have highly variable anatomy with the anterior papillary muscle usually being the most prominent. The anterior and septal papillary muscles are connected by the moderator band
left ventricle / atrium
ventricle contains
aortic valve
bicuspid (mitral) valve
papillary muscles
chordae tendineae
trabeculae carneae
atrium received
right and left pairs of pulmonary veins
What is the name of the atrioventricular valve that guards the entry from the left atrium to the left ventricle?
mitral valve
cadaveric dissection
how many papillary muscles are found in left ventricle
two
What is the function of the papillary muscles?
helping to prevent leakage through the AV valves during systole - they pull on the chordae tendinae and help to prevent prolapsing of the AV valves
What is the function of the chordae tendineae?
strong, fibrous connections between the valve leaflets and the papillary muscles. These are attached to the leaflets on to the ventricular side and prevent the cusps from swinging back into the atrial cavity during systole
ventricular septal defect
the inerventricular septum separates the left and right ventricles of the heart. if there is a hole in the wall between the two ventricles, it is called a ventricular septal defect
cause is usually congenital - can also spontaneously occur in adult.
genes an environment may be risk factor - may be common in children with genetic problems (downs syndrome)