Heart

Question 1

Pulmonary circuit:

Answer 1

blood flows from right heart to lungs, gas exchange occurs in lungs where O2 is loaded into blood

Question 2

Systemic circuit:

Answer 2

blood flows from left heart to all body organs, gas exchange in organs where O2 is unloaded from blood

Question 3

Function of pericardium:

Answer 3

restricts heart movements so that is moved only slightly within the thorax

Question 4

Components of pericardium (3):

Answer 4

fibrous pericardium, serous pericardium, and pericardial cavity

Question 5

Fibrous pericardium (“pericardial sac”):

Answer 5

tough outer sac

Question 6

Serous pericardium:

Answer 6

epicardium composed of parietal and visceral layers

Question 7

Pericardial cavity:

Answer 7

thin space between layers containing serous fluid

Question 8

Three layers of the heart wall:

Answer 8

epicardium, myocardium, endocardium

Question 9

Epicardium:

Answer 9

visceral layer of serous pericardium and areolar connective tissue

Question 10

Myocardium:

Answer 10

cardiac muscle, thickest of the three layers

middle layer

Question 11

Endocardium:

Answer 11

internal surface of heart chambers, simple squamoud epithelium and areolar connective tissue

Question 12

Why does cardiac muscle contract as a single unit?

Answer 12

they are connected via gap junctions

Question 14

Gap junctions:

Answer 14

parts of intercalated discs between adjacent fibers

Question 15

Auricls:

Answer 15

anterior part of each atrium

Question 15

Each cardiac electric impulse is distributed _______

Answer 15

immediately and spontaneously throughout the myocardium

Question 16

Right atrium feeds _____

Answer 16

right ventricle, pulmonary trunk, and pulmonary circulation

Question 17

Left atrium feeds _____

Answer 17

left ventricle, aorta, and system circulation

Question 18

Coronary sulcus:

Answer 18

groove separating atria and ventricles

Question 19

Interventricular sulcus:

Answer 19

between right and left ventricles

Question 20

Coronary circulation:

Answer 20

supplies the myocardium with blood

Question 21

Blockage in coronary circulation causes ___

Answer 21

myocardial infarction, due to death of heart tissue

Question 22

Coronary arteries (right/left):

Answer 22

travel within coronary sulcus and supply heart wall with O2 and nutrients

Question 23

Right coronary artery branches into:

Answer 23

Right marginal artery: supplies the right border of the heart

Posterior interventricular artery: supplies posterior surfaces of left/right ventricles

Question 23

Left coronary artery branches into:

Answer 23

**Anterior interventricular artery:** supplies anterior surface of both ventricles and most interventricular septum **Circumflex artery: **supplies the left atrium and ventricle | Anterior interventricular artery = Left anterior descending artery

Question 24

What major veins does venous return of blood from heart wall occur?

Answer 24

Great, middle, and small cardiac veins

Question 25

The three major cardiac veins drain into ____, which drains into right atrium

Answer 25

coronary sinus

Question 26

Great cardiac vein:

Answer 26

runs along anterior interventricular artery

Question 27

Middle cardiac vein:

Answer 27

runs alongside posterior interventricular artery

Question 28

Small cardiac vein:

Answer 28

travels close to the right marginal artery

Question 29

Characteristics of left and right atria:

Answer 29

1. thin-walled 2. separated by interatrial septum 3. receiving chambers 4. contain auricles (earlike extensions) 5. contain pectinate muscles (internal ridges)

Question 30

Characteristics of left and right ventricles:

Answer 30

1. thin-walled 2. separated by interventricular septum 3. pumping chambers

Question 31

Attaches muscle to atrioventricular valve and prevents cusps from flipping into atrium when ventricle contracts:

Answer 31

chordae tendineae

Question 32

Right atrium receives venous blood through 3 large veins:

Answer 32

superior vena cava, inferior vena cava, and coronary sinus

Question 33

Tricuspid valve:

Answer 33

ensures one-way blood flow from right atrium to right ventricle

Question 34

Smooth funnel shaped region at superior end of right ventricle to pulmonary semilunar valve

Answer 34

conus arteriosus

Question 35

Semilunar valve:

Answer 35

ensures one-way flow from ventricle to pulmonary trunk

Question 36

Mitral valve:

Answer 36

controls flow through opening between left atrium and ventricle, valve is forced shut when left ventricle contracts

Question 37

Left ventricle function:

Answer 37

pumps blood through entire systemic circulation, generates HIGH BP *3x thicker wall compared to right ventricle

Question 38

Aortic semilunar valve function:

Answer 38

controls flow from left ventricle to aorta

Question 39

AV valves close when ___

Answer 39

ventricles contract

Question 40

Semilunar valves close when ____

Answer 40

ventricles relax

Question 41

Fibrous skeleton:

Answer 41

dense regular connective tissue between the atria and ventricles *provides structural support and acts as electrical insulator between atria and ventricles

Question 42

SA node:

Answer 42

pacemaker

Question 43

Purkinje fibers:

Answer 43

nerve like processes travel up the ventricular myocardium

Question 44

5 steps cardiac conduction system:

Answer 44

1. SA node fires 2. excitation spreads through atrial myocardium 3. AV node fires 4. excitation spreads down AV bundle 5. purkinje fibers distribute excitation through ventricular myocardium

Question 45

Vagus nerve will ___

Answer 45

decrease heart rate *parasympathetic

Question 46

Cardiac nerves will __

Answer 46

increase heart rate *sympathetic

Question 47

Systole:

Answer 47

contraction of a chamber

Question 48

Diastole:

Answer 48

relaxation of a chamber

Question 49

In fetal heart, ____ and ____ cause most blood to bypass pulmonary circuit

Answer 49

foramen ovale, ductus arteriosus

Question 50

When lungs inflate at birth, ___

Answer 50

resistance to blood flow decreases

Question 51

As the heart ages, what happens?

Answer 51

arteries stiffen, heart works harder to overcome resistance, valves are more fibrous, loss of cells from intrinsic conduction system (irregular rhythms), loss of myocytes that weaken contractions

Question 52

Mitral valve prolapse:

Answer 52

insufficiency in which one or both mitral valve cusps bulge into the atrium during ventricular contraction * may cause chest pain and SOB

Question 53

Valvular stenosis:

Answer 53

cusps are stiffened, opening is constricted by scar tissue * results of rheumatic fever autoimmune attack on the bicuspid and aortic valve