Cardiovascular System Lecture 2- The Heart Within The Thorax

Front 1

Position of the heart
Lies in the

Back 1

mediastinum ( the partition between the right and left pleural cavities) enclosed within its pericardial sac
Usually situated between the third and sixth ribs

Front 2

Dorsal boundary of the heart

Back 2

Lies on a horizontal plane through the center of the first rib

Front 3

Caudal boundary of the heart

Back 3

Is the dome of the diaphragm

Front 4

Ventral boundary of the heart

Back 4

Is the sternum

Front 5

The long axis of the heart is
Essentially vertical in...
Almost vertical in...
Progressively more oblique in the...

Back 5

horses
ruminants
pig, dog, cat

Front 6

Shape of the heart

Back 6

Cone shaped
Slightly flattened on the left and right sides, to conform to other similar compression of the thorax

Front 7

Base of the heart

Back 7

Most dorsal part of the heart, low dome formed by the left and right atria

Front 8

Great veins
Systemic and pulmonary,

Back 8

enter the base of the heart

Front 9

Great arteries
Aortic and pulmonary,

Back 9

emerge from the base of the heart

Front 10

The heart is held in position by

Back 10

the great vessels but otherwise lies entirely free within the pericardium

Front 11

Apex of the heart

Back 11

Tapered portion of the cone, formed by the left ventricle, lies close to the sternum

Front 12

Long axis of the heart

Back 12

Extends from middle of the base to the apex

Front 13

Cranial aspect of the heart

Back 13

Extensively relates to thymus in young animals

Front 14

Right and left lateral surfaces
of the heart

Back 14

Face the corresponding lungs

Front 15

The pericardium

Back 15

A serous sac deeply invaginated by the heart
Closed and is lined by simple squamous epithelium

Front 16

Function of the pericardium

Back 16

Protect the heart
Maintain the heart in its position
Minimize friction
Possibly prevent heart from becoming overly distended

Front 17

Pericardial cavity

Back 17

Occupied by a thin film of serous fluid, a lubricant
Enables visceral and parietal layers of pericardial member to slide over each other during the cardiac cycle

Front 18

Visceral pericardium

Back 18

Inner wall of the pericardial sac, coats the outer surface of the heart

Front 19

Parietal pericardium

Back 19

At the neck of the sac, the visceral pericardium continues onto the outer wall of the sac.

Front 20

the fiberous pericardium

Back 20

parietal pericardium is reinforced by a strong later of fibroelastic tissue

Front 21

Back 21

Front 22

Dorsally the fiberous layer of parietal pericardium continues over the

Back 22

great vessels

Front 23

Ventrally the fiberous pericardium continues on and attaches to the sternum in
Ruminants-
Horse-
In carnivores and the pig it attaches to the diaphragm as

Back 23

as paired sternopericardiac ligaments
as a single midline sternopericadiac ligament
the phrenico-pericardiac ligament

Front 24

Base of the heart is formed by the thin walled

Back 24

atria, separated from the ventricles by the encircling coronary groove

Front 25

Each atrium has a blind diverticulum (or free appendage) called the

Back 25

auricle

Front 26

The... is the wall dividing the left and right internal chambers of the ventricle
It is marked externally by the ... on the left side of the heart and the ....on the right side of the heart

Back 26

INTERVENTRICLAR SEPTUM
left interventricular groove
right interventricular groove

Front 27

The left surface of the heart ( or auricle surface)
Formed mainly by

Back 27

left atrium and left ventricle
Right ventricle and right auricle extend round the cranial border contributing to the left side

Front 28

The right surface ( or atrial surface)
Is formed mainly by the

Back 28

right atrium and right ventricle
Left ventricle extends around the caudal border contributing to the right side

Front 29

Back 29

Front 30

The right atrium

Back 30

Chamber into which principal systemic veins discharge

Front 31

The right atrium

Four main openings

Back 31

Cranial vena cava
Caudal vena cava
Coronary sinus
Right atrioventricular orifice guarded by the right A-V valve

Front 32

pectinate muscles

Back 32

Wall of auricle is interlaced with muscular ridges

Front 33

Vestiges of fetal circulation

Back 33

Fossa ovalis
Intervenous tubercle

Front 34

Right ventricle

Back 34

Receives blood from the right atrium
Pumps blood to the pulmonary trunk

Front 35

Back 35

Front 36

...separates right and left ventricles
Has two components:

Back 36

Thick muscular interventriuclar septum

larger muscular part is thick myocardium formed by the combining walls of the two ventricles. the collagenous but thin membranous part is a small inconspicuous area in the extreme dorsal part of the septum

Front 37

right atrioventricular or TRICUSPID valve

Back 37

guards opening of right ventricle

Valve cusps composed of layer of collagen fibers sandwiched between two layers of endothelium
Three thin flap like cusps
Free edge of cusp= retained chordate tendineae
Chordate tendineae arise from papillary muscles

Front 38

Left atrium

Back 38

Receives atrial blood from the lungs via the pulmonary veins.
Small coronary veins also empty into left atrium
Left auricle has pectinate muscles as in the right atrium

Front 39

Left ventricle

Back 39

Connected to left atrium via the left A-V opening guarded by the left A-V valve or MITRAL valve.
This has two cusps and is aka the bicuspid valve.
Wall of left ventricle 2-3 times as thick as right

Front 40

aorta

3 major segments

Back 40

Ascending aorta
Aortic arch
Descending aorta

Front 41

In thorax two major vessels arise from aortic arch

Back 41

Brachiosphalic trunk and left subclavian artery
Both vessels give rise to branches that supply the head, beck, thorax and thoracic limbs

Front 42

Back 42

Front 43

Back 43

Front 44

Back 44