Circulatory System

Question 1

Heart

Answer 1

• the muscular four chambered organ that drives the circulatory system
• has specific input channels (veins) and output channels (arteries)

Question 2

Aorta

Answer 2

-the major artery (outflow) vessel from the left ventricle into the systemic circulation, arches caudally, sends oxygenated blood from the left heart to the heart itself and the rest of the body through its systemic branches

Question 3

Ascending Aorta

Answer 3

-the initial part of the aorta, originating from the left ventricle at the center of the hearts base

Question 4

Aortic Arch

Answer 4

-the continuation of the ascending aorta, is senses branches to the head, neck and thoracic limbs

Question 5

Descending Aorta

Answer 5

-the part of the aorta caudal to the aortic arch, divided into the thoracic aorta and the abdominal aorta of the diaphragm

Question 6

Pericardium

Answer 6

-the fibroserous sac enclosing the heart, composed of the fibrous and serous pericardium, covered by mediastinal (pericardiac pleura)

Question 7

Cranial Vena Cava

Answer 7

-the large vein returning blood from the head, neck and thoracic limbs to the right atrium

Question 8

Caudal Vena Cava

Answer 8

-the large vein returning blood from part of the thorax, the viscera and the caudal part of the body to the right atrium

Question 9

Right Atrium

Answer 9

• the chamber of the heart receiving deoxygenated blood from the body
• vena Cavae enters it

Question 10

Right Ventricle

Answer 10

• the chamber receiving blood from the right atrium and sending it to the lungs. The conus is the funnel-shaped end of the right ventricle leading to the pulmonary trunk.
• makes up most of the heart on the right side, wraps around the cranial side of he heart to continue as the pulmonary trunk

Question 11

Pulmonary Trunk

Answer 11

-the large vessel carrying blood from the right ventricle to the pulmonary arteries, thus to the lungs

Question 12

Pulmonary Arteries

Answer 12

-two branches of the pulmonary trunk carrying blood to the lungs , one to the right lung and one to the left

Question 13

Lungs

Answer 13

-receive deoxygenated blood through the pulmonary veins it oxygenates the blood and sends it back to the heart through pulmonary veins

Question 14

Pulmonary Veins

Answer 14

-the numerous vessels emptying oxygenated blood from the lungs into the left atrium of the heart

Question 15

Left Atrium

Answer 15

-receives oxygenated blood from the lungs via the pulmonary veins

Question 16

Left Ventricle

Answer 16

• sends oxygenated blood to the body and the heart

- forms the caudal boundary of the heart and its apex

Question 17

Apex of the Heart

Answer 17

• the most caudoventral part of the heart, always formed by the left ventricle
• having a “tip”

Question 18

Base of the Heart

Answer 18

• the hilus of the organ facing dorsocranially, the broad “top” of the heart
• receives the great veins and sends out the great arteries

Question 19

Right Auricle

Answer 19

-seen from the left side of the heart, in front of the pulmonary trunk

Question 20

Left Auricle

Answer 20

-also seen on the left side of the heart, caudal to the pulmonary trunk

Question 21

Interatrial Septum

Answer 21

-the wall separating the two atria

Question 22

Interventricular Septum

Answer 22

-the wall separating the ventricles

Question 23

Right Tricuspid Valve

Answer 23

• operates the right atrioventricular opening, there are only two major cusps in the dog with intervening secondary cusps
• in other species there are three major cusps (angular, parietal and septal)

Question 24

Left Bicuspid/Mitral Valve

Answer 24

-has a heavier construction due to the greater pressure of the left ventricle during contraction (systole)

Question 25

Aortic (Semilunar) Valve

Answer 25

-the three semilunar cusps attached to the aortic fibrous ring in the origin of the aorta

Question 26

Pulmonary (Semilunar) Valve

Answer 26

• the valve between the conus of the right ventricle and the pulmonary trunk
• similar to the aortic valve, but of lighter construction

Question 27

Coronary Artery

Answer 27

-the arteries encircling the base of the heart like a crown, these are the first branches off the aorta

Question 28

Common Carotid Artery

Answer 28

-arise from the brachiocephalic trunk, they ascend the neck to terminate in the internal and external carotid arteries supplying the head, face and brain

Question 29

External Carotid Artery

Answer 29

-the large direct continuation of the common carotid artery that becomes the maxillary artery, first small branch is the occipital artery

Question 30

Internal Carotid Artery

Answer 30

-the smaller terminal branch of the common carotid artery

Question 31

Femoral Artery

Answer 31

• the continuation of the external iliac artery through the femoral triangle, passing distally to continue as the popliteal artery caudal to the stifle joint
• the last branch of the femoral artery in all species is the caudal femoral artery, passes caudally on the gastrocnemius to supply the caudal thigh (hamstring)

Question 32

Chordae Tendinae

Answer 32

-thin strands of connective tissue that anchor the leaflets of each AV valve so that they cannot open into the atrium (thus allowing backflow of blood into the atrium).