The Heart Flashcards
What is the pericardium?
fibro-serous envelope of the heart and is contained within the middle mediastinum
What are the layers of the pericardium?
- fibrous pericardium
- Serous pericardium (parietal pericardium and visceral pericardium (epicardium))
What is the pericardial cavity?
space between the parietal and visceral pericardium
What fuses with the external surface of the fibrous layer of the pericardium?
the mediastinal (parietal) pleura
What is the name of where the fibrous pericardium attaches to the diaphragm?
phrenicopericardial ligament
What is the name for heart muscle?
myocardium
What are the cavities within the heart (atrium/ventricles) lined by?
endocardium
How is the heart of the dog positioned?
positioned obliquely within the thoracic cavity and lies between the 3rd and 6th intercostal spaces
What direction does the base of the heart face? apex?
base: craniodorsally
apex: caudoventrally (directed more towards the left of the thorax
Which ventricle is most cranial?
Right ventricle
What are the functions of the heart?
- serve as pump which generates the needed pressure for the delivery of blood throughout the body
What are the two circuits of the circulatory system?
pulmonary circuit
Systemic circuit
What is the fibrous skeleton of the heart?
fibrous tissue that separates the atria and ventricles.
- all four heart valves are part of the fibrous skeleton
Where are atrial myocardial cell bundles located?
attached to the upper margin of the fibrous skeleton
Where are ventricular myocardial cell bundles located?
anchored to the lower margin of the fibrous skeleton
What are the atrioventricular orifices? What are they guarded by?
the openings between the atria and ventricles, and are guarded by the atrioventricular (AV) valves
What does the right atrium recieve blood from?
the cranial and caudal vena cava, and the coronary sinus
What does the intervenous tubercle do?
Diverts blood from the caval veins toward the right AV orifice
What do the AV valve cusps originate from?
either the outer (marhinal) ventricular wall (parietal cups) or from the interventricular septal wall (septal cusp)
What are chordae tendineae?
fibrous strings that anchor AV valves to the inner walls of ventricles
What secures the chordae tendineae to the inner walls of the ventricles?
papillary muscles
How does the blood flow during diastole?
blood flows through the right and left AV valves and into the ventricles
What is a significant characteristic of the semilunar valves?
they have 3 cusps (tricuspid)
What do semilunar valves do?
prevent backflow of blood into the ventricles during diastole
What are the two semilunar valves? Where are they located?
- pulmonary semilunar valve - located between right ventricle and pulmonary artery
- aortic semilunar valve - located between the left ventricle and the aorta
What are the names of the interventricular grooves on the external surface of the heart that correlate with the (internal) interventricular septum?
- Paraconal interventricular groove
- Subsinusoidal interventricular groove
Where is the sinus venosus?
directly above the subsinuosal interventricular groove
Where is the conus arteriosus?
on the right ventricle right next to the paraconal interventricular groove
Where is the subsinusoidal interventricular groove located?
on the caudodorsal surface of the heart (ventricular or diaphragmatic surface)
What is the first branch off the aorta? First tissue supplied?
Right and left coronary arteries - supply the heart
What are the aortic sinuses?
the pockets formed by the aortic valve cusps
What do the left and right aortic sinuses give rise to?
Right: right coronary artery
Left: left coronary artery
What are the branches of the left coronary artery?
- Circumflex branch
- Paraconal interventricular branch
What branches from the circumflex branch of the left coronary artery?
the subsinuosal interventricular branch
Where does the right coronary artery travel to?
- encircles the right side of the heart in coronary groove
- Extends to caudodorsal (diaphragmatic) surface of the heart
What is the puncta Maxima?
most distinctive valve sounds during ausculation
What is ‘PAM’? Where can they be heard?
Left side
P= pulmonary valve sound (3rd IC space)
A= Aortic valve sound (4th IC space)
M= Mitral/left AV sound (5th IC space)
What sound can you hear on the right side? Where can it be heard?
T= Tricuspid/Right AV sound (4th IC space)
What are important anatomical landmarks for ausculation and thoracocentesis?
- point of the elbow
- Tricipital margin (caudal)
What are the nodal tissues of the heart?
- Sinoatrial node
- Atrioventricular node
- Atrioventricular bundle with right and left limbs
What is the Trabecula septomarginalis?
nodal tissue
- Extensions from the AV bundle fibers from septal wall to the opposite ventricular wall
In the fetus, what are the two structures that allow blood to bypass pulmonary circulation?
- foramen ovale
- Ductus arteriosus
What/where is the foramen ovale?
opening between the atria that allows blood to shunt from right atrium into the left atrium.
- located caudal to the intervenous tubercle
- Closes after birth
What is the remnant of the foramen ovale after it closes?
fossa ovalis
What is the ductus arteriosus?
Arteriole connection between the pulmonary trunk and the aorta
- Closes after birth and regresses to a fibrous remnant
What is the remnant of the ductus arteriosus after it has regressed?
ligamentum arteriosum
What causes a constricted esophagus (megaesophagus)?
esophagus runs between the aorta and ligamentum arteriosum and becomes constricted
- also called persistant right aortic arch
What forms the subsinuosal interventricular branch in the pig and horse? Dog and ox?
The subsinuosal interventricular branch originates from the left coronary artery in the dog, cat, and ox, and from the right coronary artery in the horse and pig.
How is the left subclavian artery arranged in the horse, ox, dog, and pig?
In the dog and pig, the left subclavian artery branches directly from the aorta; in the horse and ox, both subclavian arteries branch from the brachiocephalic trunk.
