Heart Anatomy

Question 1

name the layers of the heart from deep to superficial

Answer 1

endocardium
myocardium
fatty CT (contains coronary arteries/veins)
serous (visceral) pericardium
pericardial space
serous (parietal) pericardium
fibrous pericardium

Question 2

what are the functions of the pericardium layers?

Answer 2

anchors heart to diaphragm
prevents overfilling of heart

Question 3

what is the function of the pericardial space?

Answer 3

contains serous fluid to minimise friction between pericardium layers

Question 4

name the 4 heart valves and what they connect

Answer 4

tricuspid: RA -> RV
pulmonary: RV -> pulmonary artery
mitral: LA -> LV
aortic: LV -> aorta

Question 5

what are the branches of the aorta and where do they supply?

Answer 5

coronary arteries (heart muscle)

brachiocephalic trunk:
right common carotid (head/neck)
right subclavian (upper right limb)

left common carotid (head/neck)
left subclavian (left upper limb)

Question 6

what is the function of the umbilical vein?

Answer 6

provides fetus with maternal blood

Question 7

how is blood distributed to the fetus?

Answer 7

directly to liver (70%)
through ductus venosus to RA (30%)

Question 8

what is the function of the foramen ovale?

Answer 8

allows fetal blood to move directly from RA to LA

Question 9

what does the foramen ovale become in a developed heart?

Answer 9

fossa ovalis

Question 10

what is the right atrial appendage and what can it be used for?

Answer 10

addition of the RA
can be used as pacemaker site

Question 11

what are aortic sinuses and how many do we have?

Answer 11

dilatations above aortic valve (3)

Question 12

what structures originate at the cristae terminalis?

Answer 12

the RA opening and pectinate muscles

Question 13

what is the function of the musculi pectinati?

Answer 13

allows stretch to improve RA volume

Question 14

why is the LV wall 3x as thick as the RV wall?

Answer 14

to pump blood into systemic circulation
(more force required than pumping blood only to lungs)

Question 15

what are chordae tendinae and what is their function?

Answer 15

heart strings connecting to papillary muscle
prevents AV valves flipping back into atria during ventricular contraction

Question 16

what are the semilunar heart valves and how do they differ in structure/function from other heart valves?

Answer 16

pulmonary and aortic valves

no chordae tendinae, they hold blood to prevent ventricular backflow

Question 17

what coronary arteries originate from the left coronary artery?

Answer 17

circumflex
anterior interventricular

Question 18

what coronary arteries originate from the right coronary artery?

Answer 18

marginal artery
posterior interventricular artery

Question 19

what coronary veins stem from the coronary vein?

Answer 19

great
middle
small
anterior cardiac

Question 20

what are end arteries and what do they do?

Answer 20

only supply oxygenated blood to a specific portion of tissue
(e.g spleen, liver, penis, intestines)

Question 21

what happens to coronary arteries when they become end arteries?

Answer 21

collateral circulation development
(new vessel growth in area of new blood supply)

Question 22

what is the sinoatrial node and what is its function?

Answer 22

generates electrical signals
pacemaker of the heart

Question 23

where do the electrical signals travel through in the heart?

Answer 23

sinoatrial node -> atrioventricular node -> left/right bundles -> wall of left ventricle (or moderator band) -> interventricular septum

Question 24

what is the function of the moderator band? (septomarginal trabecula)

Answer 24

faster conduction times by allowing more rapid conduction across anterior papillary muscle

Question 25

what are purkinje fibres and what is their function?

Answer 25

specialised conducting fibres (bigger than cardiac myocytes) creates synchronised contraction across ventricles to maintain regular HR

Question 26

what do purkinje fibres do to contribute to contribute to impulse spreading?

Answer 26

interdigitate with myocytes to spread impulse across ventricles (excitation-contraction coupling)

Question 27

what do endothelial cells do in the heart?

Answer 27

line vessels/chambers control local BP prevent platelet aggregation angiogenesis/vessel remodelling permeability barrier for nutrients/fluid

Question 28

what structures can be seen on the anterior surface of the heart?

Answer 28

atrioventricular groove (coronary sulcus) between artia and ventricles anterior interventricular artery (between ventricles) auricle of LA

Question 29

what main structure can be seen on the posterior surface of the heart?

Answer 29

posterior interventricular artery (between ventricles)

Question 30

what structures are associated with fibrous pericardium?

Answer 30

attaches to diaphragm open end fused with great vessels

Question 31

explain the structure of the cristae terminalis

Answer 31

a boundary in the RA smooth wall (sinus venarum) posterior rough wall (pectinate muscles) anterior

Question 32

what are trabeculae carneae?

Answer 32

muscular ridges in ventricle wall

Question 33

what do the inside of the heart contain and what is their function?

Answer 33

trabeculae - increase blood flow

Question 34

explain the draining of cardiac veins

Answer 34

most drain into coronary sinus (lies in atrioventricular groove posteriorly) some small veins drain directly into RA

Question 35

explain the structure of the endocardium

Answer 35

endothelial layer (simple squamous) underlying CT (smooth lining) purkinje fibres and small vessels in CT

Question 36

explain the structure of the myocardium

Answer 36

thick layer with cardiac muscle cells (striated, branched, central nucleus) cardiomyocytes contain intercalated discs (ID) which contain gap junctions (synchronising cell contractions)

Question 37

explain the structure of the epicardium

Answer 37

contains mesothelial cells (visceral serous pericardium) producing pericardial fluid abundant adipose tissue and surrounds large coronary vessels/nerves

Question 38

explain the visual difference between cardiomyocytes and purkinje fibres

Answer 38

purkinje fibres appear paler due to less myofibrils

Question 39

name the muscle unit of the heart and key features in it

Answer 39

contractile unit contains cardiomyocytes, mitochondria, nuclei, microfibril bundles and intercalated discs

Question 40

what do intercalated discs contain?

Answer 40

gap junctions, desmosomes, opposing plasma membrane

Question 41

is coronary arterial flow systolic or diastolic?

Answer 41

diastolic

Question 42

what chamber pressures correlate to vessel pressure?

Answer 42

BP - aortic pressure changes (high - systolic, low - diastolic) JVP - atrial pressure changes