The Heart 1 Flashcards
what are the 2 types of pericardium?
serous and fibrous
what are the inferior, anterior and superior attachments of the fibrous pericardium?
- a strong fibrous sac that fuses inferiorly with the central tendon of the diaphragm
- anteriorly it is loosely attached to the posterior aspect of the sternum
- superior attachments are the adventitia of the neighbouring great vessels
what is the purpose of the fibrous pericardium?
prevents overfilling of the heart
describe the serous pericardium. what layers does it consist of and what separates the layers?
- a double-layered sac that’s encloses the heart
- parietal layer lines the fibrous pericardium, visceral layers covers the outer surface of the heart
- 2 layers separated by the pericardial cavity.
name A-F (D to F are the layers of the heart wall)
A = LV B = RV C = intraventricular septum
D = endocardium E = myocardium F = epicardium
what is another name for the epicardium?
visceral pericardium
what is the superior border of the heart formed from and what are the surface markings?
- right atrium (mainly),left atrium, auricles
- 2nd left costal cartilage to 3rd right costal cartilage
what is the right (pulmonary) border formed by and what are the surface markings?
- formed by the right atrium
- 3rd - 6th right costal cartilages
- extends over just 1cm to RHS of sternum
what is the inferior (diaphragmatic) border formed from and what are the surface markings?
- mainly RV, also LV
- 6th right costal cartilage to 5th intercostal space in midclavicular line on the left
what is the left (pulmonary) border formed from and what are the surface markings?
- mainly LV, also left auricle and aortic knuckle
- 2nd left costal cartilage to 5th intercostal space in midclavicular line
what forms the anterior wall of the heart and why?
mostly formed by right atrium and ventricle, due to the twisting of the heart during heart development, causing the left ventricle and atrium to lie posteriorly
what forms the base of the heart?
the atria, but mostly the left
what forms the apex of the heart and where is it?
left ventricle — 5th intercostal space mid clavicular line on LHS
what should the transverse diameter of the heart not usually be more than in relation to the thoracic cage?
should not be more than one half the width of the thoracic cage
what type of blood does the RA receive and from where?
receives deoxygenated blood from the SCV and IVC, and from the coronary veins
what valve is located between the right atrium and right ventricle?
tricuspid
what does the right atrium form?
right border of the heart
what is an auricle and what is its function?
a muscular pouch that acts to increase the capacity of the atrium
what is the inferior surface of the right atrium divided into and what is it divided by?
- divided by a muscular ridge called the crista terminalis
- sinus venarum
- atrium proper
what and where is the crista terminalis?
a smooth ridge of tissue that begins at the roof of the right atrium anterior to the superior vena cava orifice and extends inferiorly to the anterior lip of the inferior vena cava
what is the key difference between sinus venarum and atrium proper?
each have a distinct embryo logical origin
describe the sinus venarum
- posterior to crista terminalis
- receives blood from the SVC and IVC
- has smooth walls
- derived from the embryonic sinus venosus
describe the atrium proper
- anterior ti the crista terminalis
- includes right auricle
- derived from the primitive atrium
- has rough muscular walls formed by the pectinate muscles
where does the coronary sinus open into?
opens into the RA between the IVC orifice and the right AV orifice
what is the septal wall in the RA marked by?
the fossa ovalis
what is the fossa ovalis?
remnant of the foramen ovale in the foetal heart
what type of blood does the left atrium receive?
receives oxygenated blood from the 4 pulmonary veins
what valve is between the LA and LV?
mitral (bicuspid) valve
what is the inferior surface of the LA divided into?
- inflow portion
- outflow portion
describe the inflow portion of the LA
- receives blood from the pulmonary veins
- its internal surface is smooth
- derived from pulmonary veins themselves
describe the outflow portion of the LA
- located anteriorly
- includes the left auricle
- lined by the pectinate muscles
- derived from the embryonic atrium
identify A-D in the right atrium
A = pectinate muscles B = fossa ovalis C = IVC D = SVC
what is the difference between pectinate muscles and trabeculae carnae?
the same, just the first are in the atria and the second are in the ventricles
describe the auricles
- auricles mean ear — look like ear flaps on the atria
- normally flat when resting
- when the heart needs to increase the stroke volume, they expand allowing the atria to fill with more blood
during the cardiac cycle, does there tricuspid or bicuspid valve close first?
the bicuspid (mitral) valve closes first
which valve has cusps which consist of fibrous tissue covered by endocardium?
mitral valve
describe the right ventricle
- receives deoxygenated blood from the RA, and pumps it through the pulmonary orifice (guarded by the pulmonary valve) into the pulmonary artery
- triangle shaped
- forms the majority of the anterior border of the heart
- divided into inflow and outflow portion, separated by a muscular ridge called the supraventricular crest
which portion of the RV contains trabeculae carnae?
inflow portion
what ‘pulls’ on the chordae tendinae to prevent prolapse of the 3 valve leaflets of the tricuspid valve during ventricular systole?
papillary muscles
what portion of the RV leads to the pulmonary artery?
outflow portion
which portion of the RV is located in the superior aspect of the ventricle?
outflow portion — leads to pulmonary artery
what is the outflow portion of the RV derived from?
bulbis cordis
how is the outflow portion of the RV visibly different from the rest of the RV?
has smooth walls, no trabeculae carnae
what does the LV form?
apex of heart, as well as left and inferior borders
what is the LV divided into?
inflow and outflow portions
same as RV: outflow is a derivative of bulbus cordis and is smooth walled (AKA. aortic vestibule), inflow portion lined by trabeculae carnae
where is the pulmonary valve located (surface anatomy)?
2nd intercostal space, left of sternum
where is the pulmonary valve? how many cusps?
between RV and pulmonary artery, 3 cusps
where are each of the 4 valves (surface anatomy)?
how many cusps does the aortic valve have?
3
what do the semi lunar (pulmonary and aortic) valves prevent?
prevent backflow of blood into the ventricles during ventricular diastole
in terms of pressure, when does the pulmonary valve open?
when pressure ventricle > pressure in pulmonary trunk
in terms of pressure, when does the aortic valve open?
pressure in ventricle > pressure in aorta
what unites to form the right brachiocephalic vein?
right internal jugular and right subclavian veins
in what direction does the aortic arch pass?
anterior —> posterior
what does the aortic arch give rise to?
brachiocephalic trunk, left common carotid artery and left subclavian artery
what does brachiocephalic trunk give rise to?
right common carotid and right subclavian arteries
what does the pulmonary trunk bifurcate into?
right and left pulmonary arteries
what 2 main nerves innervates the heart and what do each do?
1) phrenic nerve — transmits pain information from the parietal and fibrous pericardium
2) left vagus nerve — supplies PS innervation to the heart
identify A-F
A = right atrium B = right ventricle C = interventricular septum D = left ventricle E = aortic valve F = fibrous pericardium
name each valve
what is the “lub” sound?
AV valves closing = mitral and tricuspid
what is the “dub” sound?
semilunar valves closing = aortic and pulmonary
what is the auscultation sequence of the 4 valves?
aortic, pulmonary, tricuspid, mitral (All Politicians Take Money)
where can each valve be found? (surface anatomy)
identify each
