Heart and Pericardium Flashcards
Heart position
Dog: 3rd rib to 6th intercostal space
Cat: 3rd or 4th rib to the 6th or 7th
Base of heart is located dorsally, apex located ventrally, caudally, and usually toward the left (formed by L ventricle)
Layers of heart
Epicardium - outer layer of heart; serous membrane (mesothelium, loose CT)
Myocardium - middle layer (thickest); cardiac muscle, CT, nerves, blood vessels
Endocardium - inner layer; endothelium and CT
Pericardium
Fibroserous sac that surrounds the heart and the roots of the great vessels
Clinical pericardium
Pericardial mediastinal pleura - outer serous layer
Fibrous pericardium - middle fibrous layer
Parietal pericardium - inner serous layer
Anatomical pericardium
Fibrous pericardium
Parietal pericardium
Pericardial cavity
Visceral pericardium/epicardium
Phrenicopericardial ligament
Connects fibrous pericardium to sternal part of diaphragm
Atrial surface
Surface of heart facing the right side of thorax
Right atrium is visible
Auricular surface
Surface of the heart facing the left side of thorax
Both auricles are visible
Coronary groove
Between the atria and ventricles
Contains coronary vessels
Interventricular grooves
Between the right and left ventricles at the location of the interventricular groove
Paraconal interventricular groove - on the auricular surface
Subsinuosal interventricular groove - on atrial surface; caudally located
Fossa ovalis
Remnant of foramen ovale (fetal structure)
Located caudal to intervenous tubercle
Chordae tendineae
Fibromuscular cords that attach cusps to papillary muscles
Papillary muscles
Conical muscular projections in the ventricles
Give rise to chordae tendineae
Conus arteriosus
Narrowing or coning down of terminal part of right ventricle; outflow tract of right ventricle
Coronary arteries
Supply cardiac muscles
Arise from ascending aorta at the right and left aortic sinuses
Left coronary artery
Arises from left aortic sinus. Gives rise to:
-Paraconal interventricular br. - courses in paraconal interventricular groove
-Circumflex br. of left coronary a. - courses in coronary groove; gives rise to subsinuosal interventricular br. in subsinuosal interventricular groove (in dogs)
Right coronary artery
Arises from right coronary sinus; gives rise to:
-Circumflex br. of right coronary a. - courses in coronary groove and supplies blood to right free wall of heart
Great cardiac v.
Arises near the apex of the heart and ascends in the interventricular groove, then courses within coronary groove to drain into coronary sinus in the right atrium
Middle cardiac (coronary) v.
Ascends in subsinuosal interventricular groove and drains into coronary sinus
Ligamentum arteriosum
Remnant of the fetal structure ductus arteriosus
Attaches pulmonary trunk to aorta
Puncta maxima of cardiac valves in dogs
Pulmonary valve - Left 3rd intercostal space
Aortic valve - Left 4th intercostal space
Left AV (mitral) valve - Left 5th intercostal space
Right AV (tricuspid) valve - 3rd or 4th intercostal space
Puncta maxima of cardiac valves in cats
Pulmonary valve - high in left 4th intercostal space
Aortic valve - high in left 4th intercostal space
Left AV (mitral) valve - over left 6th costal cartilage
Right AV (tricuspid) valve - low in right 5th intercostal space
Umbilical arteries
Arise from internal iliac arteries (terminal branches of aorta)
Carry less-oxygenated blood from the fetus to placental circulation
Umbilical veins
Paired in umbilical cord; become a single umbilical vein in fetal abdomen and course to liver
Carry oxygen and nutrient-rich blood from placenta to fetus
Fetal bypass structures
Foramen ovale
Ductus arteriosus
Ductus venosus
Ductus venosus
Connects umbilical vein with caudal vena cava
Blood by-passes liver
Ligamentum venosum in adults
Foramen ovale
Shunts blood from right atrium to left atrium
Blood by-passes pulmonic circulation
Fossa ovalis in adults
Ductus arteriosus
Shunts blood from pulmonary trunk to aorta
Blood by-passes pulmonic circulation
Ligamentum arteriosum in adults
PDA
Patent Ductus Arteriosus; condition in which the ductus arteriosus remains open after birth. In some cases allows poorly oxygenated blood to flow in the wrong direction
