Heart Ch 18

Question 1

2 Heart Circuits

Answer 1

Pulmonary Circuit

Systemic Circuit

Question 2

Coverings of the Heart

Answer 2

Pericardium: Double walled sac
Fibrous pericardium:Loosely fitting superficial part
Serous pericardium: Deep to fibrous, thin slippery two-layer serous membrane that forms a closed sac around the heart
Parietal layer: lines the internal surfaces

Question 3

Layers of the heart wall

Answer 3

Epicardium:on the heart also called visceral layer
Myocardium: heart muscle, forms the bulk of the heart
Endocardium:white sheet of epithelium that lines the inside surface of the heart

Question 4

Pericardial cavity

Answer 4

Slitlike space between the visceral and parietal layers, lubercated with serous fluid allowing the heart to glide.

Question 5

Cardiac skeleton

Answer 5

Dense network of fibrous connective tissue that reinforces the myocardium internally and anchors cardiac muscle fibers.

Question 6

3 Sulci

Answer 6

Coronary: encircles junction of atria and ventricles
Anterior interventricular: marks septum separating right and left ventricles
Posterior interventricular: similar landmark on the hearts posterioinferior surface

Question 7

3 veins blood enters the R Atria through

Answer 7

Superior vena cava
Inferior vena cava
Coronary sinus: collects blood draining from myocardium

Question 8

L atria blood supply

Answer 8

4 Pulmonary veins

Question 9

Papillary Muscles

Answer 9

Conelike muscle bundles that play a role in valve function and project into the ventricular cavity

Question 10

AV valves

Answer 10

Atrioventricular valves: Located at each AV junction, prevent backflow
Mitral and tricuspid

Question 11

Chordae tendineae

Answer 11

Tiny while collagen cords attached to each AV valve flap “heart strings” anchor cups to papillary muscles

Question 12

SL valves

Answer 12

Semilunar (pulmonary and aortic) valves: guard aortic and pulmonary trunk from ventricles to prevent back flow

Question 13

Coronary arteries

Answer 13

Left and right arise from the base of the aorta and full at diastole. Encircle the heart in the coronary sulcus.

Question 14

Left coronary artery

Answer 14

Anterior interverntricular (left anterior descending artery): supplies septum and anterior walls of both ventricles.
Circumflex: Supplies left atrium and posterior walls of left ventricle.

Question 15

Right coronary artery

Answer 15

Right marginal artery: supplies lateral right side of the heart
Posterior interventrivular: runs to the apex and supplies the posterior ventricular walls.
(merges with anterior interventrical artery near the apex)

Question 16

Coronary veins

Answer 16

Roughly follow the coronary arteries and merge into the coronary sinus which empties blood into the right atria.

Question 17

Cardiac muscle anatomy

Answer 17

Short fat branched and interconnected.1-2 large centrally located nuclei.
Gap junctions and desmosomes

Question 18

Functional Syncytium

Answer 18

Gap junctions electrically couple cardiac cells which allows ions to transmit across cells. A single coordinated unit.

Question 19

2 heart fiber types

Answer 19

1% autoahythmic

the bulk are contractile muscle fibers

Question 20

Action potential of contractile cardiac muscle

Answer 20

1. Depolarization: Na+ influx through fast voltage gated Na+ channels.
2. Plateau phase: due to Ca+ influx through slow Ca+ channels. Few K+ channels are open
3. Repolarizaion: Due to Ca+2 channels inactivating and K+ channels opening. K+ efflus brings membrane back to resting

Question 21

Extrinsic Innervation of the heart

Answer 21

Cardioacceleratory center

Cardioinhibitory center:

Question 22

Cardioacceleratory center

Answer 22

Located in medulla oblingata projects sympathetic neurons fron T1-T5 run to cervical and upper thoracic trung. Innervate the SA & AV nodes and heart muscle and coronary arteries.

Question 23

Cardioinhibitory center

Answer 23

Sends impulses to the parasympathetic dorsal vagus nucleus in the medulla, which sends inhibitory impulses to the heart via the vagus nerve.

Question 24

Bipolar leads

Answer 24

3 electodes that measure the voltage differences either between two arms or an arm and a leg

Question 25

Unipolar leads

Answer 25

9 chest leads

Question 26

Heart sounds

Answer 26

1st occurs when the AV valves close, louder longer and more resilient than the second.
2nd occures when the SL valves snap shut, this is a short sharp sound.

Question 27

Murmurs

Answer 27

Indicated an insufficient or incomplete valve closing.

Question 28

EDV

Answer 28

End diastolic volume: The maximum volume of blood the ventricles will contain in a cycle.

Question 29

Isovolumetric contraction phase

Answer 29

The split second the ventricles are full and contrace

Question 30

ESV

Answer 30

End systolic volume: blood remaining in ventricles after contraction

Question 31

Isovolumetric relaxation

Answer 31

Brief phase following the T wave when the ventricles relax and the back flow of blood closes the SL valves

Question 32

Quiescent period

Answer 32

the 0.4 sec of total heart relaxation in each cardiac cycle

Question 33

CO

Answer 33

Cardiac output: the amount of blood pumped out by each ventricle in 1 min

Question 34

Stroke volume

Answer 34

The amount of blood pumped out by one ventricle by one beat

Question 35

Cardiac reserve

Answer 35

The difference between resting and maximal CO

Question 36

Preload

Answer 36

The degree to which cardiac muscle cells are stretched just before they contract

Question 37

Frank-Sterlings Law

Answer 37

The greater the degree of stretch the greater the contraction

Question 38

After load

Answer 38

The pressure the ventricles must overcome to eject blood