18 1-5

Question 1

Describe the size, shape, location, and orientation of the heart in the thorax.

Answer 1

Size: 250-300gm/10-14oz/fist

Shape: heart??

Location: 2/3 left of sternum, in mediastinum (medial cavity of thorax), resting on diaphragm

Orientation: base directed towards right shoulder-apex towards left hip.

Question 2

PMI - point of maximal intensity

Answer 2

Apical impulse - felt where the heart’s apex touches the chest wall. Just below L nipple

Question 3

Fibrous pericardium

Answer 3

Dense irr CT, lined by the parietal layer of the serous pericardium

Question 4

Serous pericardium

Answer 4

Parietal - lines the internal surface of the fibrous layer.

Visceral (aka epicardium) - forms the superficial layer of the heart wall.

Question 5

Pericardial cavity

Answer 5

Space containing serous fluid between the visceral and parietal layers of the serous membrane.

Question 6

Pericarditis

Answer 6

Inflammation of the pericardium.

Virus/bacteria/fungi.

Often detected as a friction rub.

Question 7

Cardiac tamponade

Answer 7

Severe case of pericarditis -

inflammatory fluid in pericardial cavity compresses the heart and limiting the capacity to pump blood.

Question 8

Function of the heart’s coverings?

Answer 8

Fibrous pericardium: protects, anchors to surrounding structures, prevents overfilling

Serous pericardium: parietal - lines surface of fibrous, visceral - forms heart surface.

In between parietal and visceral is the pericardial cavity which contains serous fluid - reduces friction

Question 9

Coronary Sulcus?

Answer 9

(aka atrioventricular groove) Encircles the junction of the atria and ventricles

Question 10

Anterior interventricular sulcus?

Answer 10

Marks the anterior position of the septum separating the R/L ventricles

Question 11

Posterior interventricular sulcus?

Answer 11

Marks the posterior position of the septum separating the R/L ventricles

Question 12

Left and right auricles?

Answer 12

“dog ear” Cover the atria. Vestibular in function.

Question 13

Layers of the heart wall?

Answer 13

Epicardium, myocardium, endocardium

Question 14

Epicardium

Answer 14

Visceral layer of serous pericardium.

Simple squamous + areolar ct (endothelium)

Question 15

Myocardium

Answer 15

Mainly cardiac muscle, bulk of heart, circular/spiral arrangement.

This layer contracts.

Cardiac muscle cells are tethered together by CT.

Question 16

Endocardium

Answer 16

Simple squamous + areolar ct (endothelium)

Lines chambers of the heart.

Continuous with the endothelial linings of blood vessels.

Question 17

Cardiac skeleton

Answer 17

Dense network of ct

Reinforces the myocardium internally and anchors the cardiac muscle fibers. Supports where the great vessels leave the heart.

Collagen, elastin.

Limits the spread of APs (not conductive).

Question 18

Pectinate muscles

Answer 18

Ridges on the anterior wall of the R atrium and within the auricles of L+R atria. (Pectin = comb)

Question 19

Fossa Ovalis

Answer 19

Shallow depression on the interatrial septum (marks the spot where the foramen ovale existed in the fetal heart)

Question 20

Coronary sinus

Answer 20

Drains blood from heart wall (to R atrium)

Question 21

Pulmonary veins

Answer 21

Return blood from the lungs (to L atrium)

Question 22

bicuspid (mitral) valve

Answer 22

L atrioventricular valves. Has 2 cusps.

L atrium to L ventricle

Question 23

tricuspid valve

Answer 23

R atrioventricular valves. Has 3 flexible cusps (endocardium reinforced by ct)

R atrium to R ventricle

Question 24

R Atrium

Answer 24

Receives blood from: Superior vena cava, Inferior vena cava, Coronary sinus

Question 25

L Atrium

Answer 25

Receives blood from: 4 pulmonary veins

Question 26

Superior vena cava

Answer 26

Returns blood from body areas superior to the diaphragm (to R atrium)

Question 27

Inferior vena cava

Answer 27

Returns blood from body areas below the diaphragm (to R atrium)

Question 28

L ventricle

Answer 28

Pumps blood into the aorta.

Question 29

R ventricle

Answer 29

Pumps blood into the pulmonary trunk.

Question 30

Trabeculae carneae

Answer 30

Irregular ridges of muscle on the interior walls of the ventricular chambers. Provide structural support - reinforce

Question 31

Papillary muscles

Answer 31

Muscular nipples that protrude from ventricular walls.

Question 32

Chordae tendineae

Answer 32

"heart strings" collagen fibers that anchor the cusps to the papillary muscles

Question 33

Papillary muscle and chordae tendinae function to?

Answer 33

Anchor AV flaps in their closed position. If not anchored they would be everted into the atria.

Question 34

Pulmonary semilunar valve

Answer 34

Guards the base of the pulmonary trunk artery. 3 cusps.

Question 35

Aortic semilunar valve

Answer 35

Guards the base of the aorta. 3 cusps.

Question 36

Prolapse

Answer 36

Eversion of valve

Question 37

Cardiac output?

Answer 37

HR x SV - amount of blood pumped by each ventricle

Question 38

Aorta

Answer 38

Largest artery in the body - receives blood from the L ventricle.

Question 39

Pulmonary trunk

Answer 39

Recieves blood from the R ventricle and routes it to the lungs.

Question 40

Pressure generated by each ventricle?

Answer 40

(L vent - 0-120 mmHg, R vent - 0-24 mmHg)

Question 41

How long do the atria and ventricles contract?

Answer 41

Atria - 0.1 sec, ventricle - 0.3 sec At hr of 75, 0.5 sec rest At he of 180, 0.125 sec rest (chambers do not fill properly)