The Heart (Ch. 21)

Question 1

2 Circuits of the Circulatory System

Answer 1

Pulmonary and Systemic Circuits

Question 2

Pulmonary Circuit

Answer 2

Pulmonary arteries + veins
- To the lungs
- Carries CO2 rich blood to lungs to be oxygenated
- From Right side of the heart and carried back to the left side

Question 3

Systemic Circuit

Answer 3

Systemic arteries + veins
- To the rest of the body
- Carries oxygenated blood to body cells and returns deoxygenated
- From Left side of the heart and carried back to the right side

Question 4

Arteries

Answer 4

Transport blood away from heart

Question 5

Veins

Answer 5

Transport blood toward the heart

Question 6

Capillaries

Answer 6

Blood vessels that interconnect arteries and veins

Question 7

Vena Cava

Answer 7

Carries blood to the heart from the systemic circuit

Question 8

Pulmonary Vein

Answer 8

Carries blood to the heart from the pulmonary circuit

Question 9

Aorta

Answer 9

Carries blood from the heart to the systemic circuit

Question 10

Pulmonary Arteries

Answer 10

Carries blood from the heart to the pulmonary circuit (lungs)

Question 11

Pericardium Sac

Answer 11

3 layers:
Serous pericardium (2 layers):
Visceral layer - epicardium, closest to the heart
Pericardial Cavity - contains pericardial fluid
Parietal Layer - fuse with fibrous layer (attach to diaphragm)
+
Fibrous Pericardium
- fuse with parietal layer

Question 12

Location of the Heart

Answer 12

Thoracic cavity -> mediastinum -> pericardium cavity

Question 13

Heart Wall

Answer 13

3 layers:
epicardium
myocardium
endocardium

Question 14

Epicardium

Answer 14

External surface, consists of visceral pericardium
- mesothelium, areolar tissue

Question 15

Myocardium

Answer 15

(Myo- muscle, cardi- heart)
Consists of cardiac tissue, cardiac muscle cells, connective tissue, blood vessels, and nerves

Question 16

Endocardium

Answer 16

Internal, endothelial surface (areolar tissue)

Question 17

Intercalated Discs

Answer 17

-specialized cell-to-cell junction
-connect myofibrils of adjacent cells

Question 18

Desmosomes

Answer 18

-specialized cell-to-cell junction
- connect plasma membranes of adjacent cardiac cells

Question 19

Gap Junction

Answer 19

-connect cardiac muscle cells
-ions move directly -> create direct, electrical connection
-forms functional syncytium (function as one unit)

Question 20

Coronary Blood Vessels

Answer 20

• supply cardiac muscle tissue via coronary circulation
  -originates from the ascending aorta

Question 21

Coronary Arteries

Answer 21

Right Coronary Artery
- passes between right auricle and pulmonary trunk
- Atrial arteries, right marginal artery, Posterior interventricular artery
Left Coronary Artery
- circumflex artery (left marginal artery), anterior interventricular artery

Question 22

Coronary Veins

Answer 22

-Great coronary vein (posterior coronary vein)
-Middle coronary artery (parallels interventricular artery)
- Coronary sinus (drains into posterior aspect of right atrium)
- Small cardiac vein (parallels right coronary artery)

Question 23

Trabeculae Carnae

Answer 23

Muscular ridges

Question 24

Interatrial Septum

Answer 24

separates right and left atrium

Question 25

Interventricular Septum

Answer 25

separates right and left ventricle

Question 26

Cardiac Cycle

Answer 26

-1 heartbeat = atria contract while ventricles relax + ventricles contract while atria relax - contraction - systole - relaxation - diastole

Question 27

Heart Valves

Answer 27

2 between atria and ventricles - Atrioventricular (AV) valves: - Tricuspid valve (RA - RV) - Bicuspid valve (mitral valve) (LA - LV) Ventricles and outflow vessels - Semilunar valves - Pulmonary Valve (RV - pulmonary artery) - Aortic valve (LV - aorta)

Question 28

Atrioventricular Valves

Answer 28

Cusps (2/3)-> Chordae tendineae-> Papillary muscles Tricuspid = 3 cusps, 3 papillary muscles Bicuspid = 2 cusps, 2 papillary muscles

Question 29

Semilunar Valves

Answer 29

prevent backflow into ventricles - 3 cusps, half moon shape -

Question 30

Heart Sounds

Answer 30

Lub: AV valves Dub: Aortic/Pulmonary valves

Question 31

Nodal Cells

Answer 31

Sinoatrial and atrioventricular nodes - rate of contraction - cell membranes automatically depolarize

Question 32

Conducting Cells

Answer 32

- distribute contractile stimulus to myocardium

Question 33

SA node

Answer 33

- posterior wall of right atrium "cardiac pacemaker" - pacemaker cells- generate 80-100 action potentials a minute

Question 34

Bradycardia

Answer 34

slower-than-normal heart rate

Question 35

Tachycardia

Answer 35

faster-than-normal heart rate

Question 36

AV node

Answer 36

sits on the floor of right atrium

Question 37

Right Atrium

Answer 37

- recieves oxygen poor blood via superior vena cava, inferior vena cava, coronary sinus - auricle, interatrial septum, SA node (posterior wall), AV node (floor)

Question 38

Right ventricle

Answer 38

- receives oxygen poor blood from RA via right atrioventricular valve (tricuspid valve) - leaves through pulmonary valve into pulmonary trunk -> then right and left pulmonary arteries - moderator band

Question 39

Moderator band

Answer 39

Interventricular septum to ventricular wall (RV) - prevents overexpansion of the thin walled right ventricle

Question 40

Left Atrium

Answer 40

- receives oxygen rich blood from left and right pulmonary veins - passes through left atrioventricular valve into left ventricle - bicuspid valve or left AV valve (mitral valve)

Question 41

Left Ventricle

Answer 41

- receives oxygen rich blood from LA, via left AV (bicuspid/mitral valve) - leaves via aortic valve (semilunar) to ascending aorta -> aortic arch -> descending aorta -> body