The Heart

Question 1

What is the pericardium?

Answer 1

fibro-serous envelope of the heart and is contained within the middle mediastinum

Question 2

What are the layers of the pericardium?

Answer 2

• fibrous pericardium

- Serous pericardium (parietal pericardium and visceral pericardium (epicardium))

Question 3

What is the pericardial cavity?

Answer 3

space between the parietal and visceral pericardium

Question 4

What fuses with the external surface of the fibrous layer of the pericardium?

Answer 4

the mediastinal (parietal) pleura

Question 5

What is the name of where the fibrous pericardium attaches to the diaphragm?

Answer 5

phrenicopericardial ligament

Question 6

What is the name for heart muscle?

Answer 6

myocardium

Question 7

What are the cavities within the heart (atrium/ventricles) lined by?

Answer 7

endocardium

Question 8

How is the heart of the dog positioned?

Answer 8

positioned obliquely within the thoracic cavity and lies between the 3rd and 6th intercostal spaces

Question 9

What direction does the base of the heart face? apex?

Answer 9

base: craniodorsally
apex: caudoventrally (directed more towards the left of the thorax

Question 10

Which ventricle is most cranial?

Answer 10

Right ventricle

Question 11

What are the functions of the heart?

Answer 11

• serve as pump which generates the needed pressure for the delivery of blood throughout the body

Question 12

What are the two circuits of the circulatory system?

Answer 12

pulmonary circuit

Systemic circuit

Question 13

What is the fibrous skeleton of the heart?

Answer 13

fibrous tissue that separates the atria and ventricles.

- all four heart valves are part of the fibrous skeleton

Question 14

Where are atrial myocardial cell bundles located?

Answer 14

attached to the upper margin of the fibrous skeleton

Question 15

Where are ventricular myocardial cell bundles located?

Answer 15

anchored to the lower margin of the fibrous skeleton

Question 16

What are the atrioventricular orifices? What are they guarded by?

Answer 16

the openings between the atria and ventricles, and are guarded by the atrioventricular (AV) valves

Question 17

What does the right atrium recieve blood from?

Answer 17

the cranial and caudal vena cava, and the coronary sinus

Question 18

What does the intervenous tubercle do?

Answer 18

Diverts blood from the caval veins toward the right AV orifice

Question 19

What do the AV valve cusps originate from?

Answer 19

either the outer (marhinal) ventricular wall (parietal cups) or from the interventricular septal wall (septal cusp)

Question 20

What are chordae tendineae?

Answer 20

fibrous strings that anchor AV valves to the inner walls of ventricles

Question 21

What secures the chordae tendineae to the inner walls of the ventricles?

Answer 21

papillary muscles

Question 22

How does the blood flow during diastole?

Answer 22

blood flows through the right and left AV valves and into the ventricles

Question 23

What is a significant characteristic of the semilunar valves?

Answer 23

they have 3 cusps (tricuspid)

Question 24

What do semilunar valves do?

Answer 24

prevent backflow of blood into the ventricles during diastole

Question 25

What are the two semilunar valves? Where are they located?

Answer 25

- pulmonary semilunar valve - located between right ventricle and pulmonary artery - aortic semilunar valve - located between the left ventricle and the aorta

Question 26

What are the names of the interventricular grooves on the external surface of the heart that correlate with the (internal) interventricular septum?

Answer 26

- Paraconal interventricular groove | - Subsinusoidal interventricular groove

Question 27

Where is the sinus venosus?

Answer 27

directly above the subsinuosal interventricular groove

Question 28

Where is the conus arteriosus?

Answer 28

on the right ventricle right next to the paraconal interventricular groove

Question 29

Where is the subsinusoidal interventricular groove located?

Answer 29

on the caudodorsal surface of the heart (ventricular or diaphragmatic surface)

Question 30

What is the first branch off the aorta? First tissue supplied?

Answer 30

Right and left coronary arteries - supply the heart

Question 31

What are the aortic sinuses?

Answer 31

the pockets formed by the aortic valve cusps

Question 32

What do the left and right aortic sinuses give rise to?

Answer 32

Right: right coronary artery Left: left coronary artery

Question 33

What are the branches of the left coronary artery?

Answer 33

- Circumflex branch | - Paraconal interventricular branch

Question 34

What branches from the circumflex branch of the left coronary artery?

Answer 34

the subsinuosal interventricular branch

Question 35

Where does the right coronary artery travel to?

Answer 35

- encircles the right side of the heart in coronary groove | - Extends to caudodorsal (diaphragmatic) surface of the heart

Question 36

What is the puncta Maxima?

Answer 36

most distinctive valve sounds during ausculation

Question 37

What is 'PAM'? Where can they be heard?

Answer 37

Left side P= pulmonary valve sound (3rd IC space) A= Aortic valve sound (4th IC space) M= Mitral/left AV sound (5th IC space)

Question 38

What sound can you hear on the right side? Where can it be heard?

Answer 38

T= Tricuspid/Right AV sound (4th IC space)

Question 39

What are important anatomical landmarks for ausculation and thoracocentesis?

Answer 39

- point of the elbow | - Tricipital margin (caudal)

Question 40

What are the nodal tissues of the heart?

Answer 40

- Sinoatrial node - Atrioventricular node - Atrioventricular bundle with right and left limbs

Question 41

What is the Trabecula septomarginalis?

Answer 41

nodal tissue | - Extensions from the AV bundle fibers from septal wall to the opposite ventricular wall

Question 42

In the fetus, what are the two structures that allow blood to bypass pulmonary circulation?

Answer 42

- foramen ovale | - Ductus arteriosus

Question 43

What/where is the foramen ovale?

Answer 43

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

Question 44

What is the remnant of the foramen ovale after it closes?

Answer 44

fossa ovalis

Question 45

What is the ductus arteriosus?

Answer 45

Arteriole connection between the pulmonary trunk and the aorta - Closes after birth and regresses to a fibrous remnant

Question 46

What is the remnant of the ductus arteriosus after it has regressed?

Answer 46

ligamentum arteriosum

Question 47

What causes a constricted esophagus (megaesophagus)?

Answer 47

esophagus runs between the aorta and ligamentum arteriosum and becomes constricted - also called persistant right aortic arch

Question 48

What forms the subsinuosal interventricular branch in the pig and horse? Dog and ox?

Answer 48

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.

Question 49

How is the left subclavian artery arranged in the horse, ox, dog, and pig?

Answer 49

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.