Chapter 20 - The Heart - PART 2

Question 1

What is the function of the atria?

Answer 1

to collect blood that is returning to the heart and convey it to the ventricles

Question 2

The demands of the left and right atrium are ___

Answer 2

similar

Question 3

What is the relationship in APPEARANCE between the left and right ventricle

Answer 3

they look almost identical

Question 4

The demands of left and right ventricle are ____

Answer 4

very different (and they also have significant structural differences)

Question 5

The right ventricle pushes blood through which circuit?

Answer 5

the pulmonary circuit

Question 6

Why does the right ventricle not have to work very hard to push blood through the pulmonary circuit?

Answer 6

Because the lungs are close to the heart and the pulmonary blood vessels are short and wide

Question 7

The muscular wall of the right ventricle is relatively _____

Answer 7

thin

Question 8

____ to ____ times as much pressure must be exerted to push blood around the systemic circuit as around the pulmonary circuit

Answer 8

4-6 times as much pressure must be exerted

Question 9

The muscular wall of the left ventricle is extremely _____

Answer 9

thick

Question 10

The pressure generated by the left ventricle contraction is more than enough to do what?

Answer 10

to open the aortic valve and eject blood into the ascending aorta

Question 11

The right ventricle has a ____ like shape

Answer 11

pouch

Question 12

As the powerful left ventricle contracts, it bulges into….

Answer 12

the right ventricular cavity

Question 13

“As the left ventricle contracts, it bulges into the right ventricular cavity.”

this makes the right ventricle more _____

Answer 13

efficient

Question 14

Why is it that individuals with severe damage to the right ventricle may still survive?

Answer 14

because the contraction of the left ventricle helps push blood into the pulmonary circuit

Question 15

the heart has ___ pairs of ___way valves

Answer 15

the heart has…
TWO pairs of ONE-WAY valves

Question 16

What is the purpose of the 2 pairs of one way valves?

Answer 16

to prevent the backflow of blood as the chambers contract

Question 17

The atrioventricular (AV) valves prevent the backflow of blood from the ____ to the ____ when the _____ are contraction

Answer 17

AV valves prevent the backflow of blood from the VENTRICLES to the ATRIA when the VENTRICLES are contracting

Question 18

What 2 structures play an important role in the normal function of the AV valves?

Answer 18

the papillary muscles and the chordae tendineae

Question 19

When the ventricles are relaxed, the chordae tendineae are _____, and the AV valves offer no _____ as blood flows from the atria into the ventricles

Answer 19

LOOSE, NO RESISTANCE

Question 20

When the ventricles contract, blood moving back towards the _____ swing the _____ together, closing the ______

Answer 20

When the ventricles contract, blood moving back towards the ATRIA swing the CUSPS together, closing the VALVES

Question 21

When the ventricles contract, the contraction of the ____ ____ tenses the ____ ____ , stopping the ____ before they swing into the atria

Answer 21

When the ventricles contract, the contraction of the PAPILLARY MUSCLES tenses the CHORDAE TENDINEAE, stopping the CUSPS before they swing into the atria

Question 22

What would happen if the papillary muscles were damaged or if the chordae tendineae were cut?

Answer 22

REGURGITATION would occur
this is backflow of blood into the atria each time that the ventricles contract

Question 23

What are the 2 semilunar valves?

Answer 23

The pulmonary and aortic valves

Question 24

The semilunar valves prevent the backflow of blood from the ____ ____ and _____ into the right and left ______, respectively

Answer 24

the semilunar (aortic and pulmonary) valves prevent the backflow of blood from the PULMONARY TRUNK and AORTA into the right and left VENTRICLES

Question 25

the pulmonary trunk is also known as the.....

Answer 25

pulmonary artery

Question 26

do the AV valves need muscular braces?

Answer 26

yes

Question 27

do the semilunar valves need muscular braces?

Answer 27

no

Question 28

Why do the semilunar valves not need muscular braces?

Answer 28

because the arterial walls do not contract and the position of the cusps are stable

Question 29

What is adjacent to each cusp of the aortic valve?

Answer 29

aortic sinuses -- saclike dilations of the base of the ascending aorta

Question 30

what is the FUNCTION of the aortic sinuses?

Answer 30

to prevent the individual cusps from sticking to the wall of the aorta when the valve opens

Question 31

The right and left _____ ____ deliver blood to the myocardium

Answer 31

the right and left CORONARY ARTERIES deliver blood to the myocardium

Question 32

where do the right and left coronary arteries originate?

Answer 32

at the right and left aortic sinuses

Question 33

Inflammation of the heart

Answer 33

carditis

Question 34

what does VHD stand for?

Answer 34

valvular heart disease

Question 35

when may symptoms of VHD appear?

Answer 35

if valve function deteriorates to the point where the heart cannot maintain adequate circulatory flow

Question 36

what does congenital mean?

Answer 36

present from birth

Question 37

give 2 causes of valvular heart disease

Answer 37

may be caused by congenital malformations or develop as a result of carditis

Question 38

what is an important cause of carditis?

Answer 38

rheumatic fever

Question 39

what is rheumatic fever?

Answer 39

an inflammatory autoimmune response to an infection caused by streptococcal bacteria. most often occurs in children

Question 40

What connective tissues are in the heart?

Answer 40

collagen and elastic fibers

Question 41

What is each cardiac muscle cell wrapped in?

Answer 41

a strong but elastic sheath

Question 42

How are adjacent cardiac muscle cells kept together?

Answer 42

they are tied together by fibrous cross links, or "struts"

Question 43

Name 4 functions of connective tissue fibers in the heart

Answer 43

1. Provide physical support for cardiac muscle fibers, blood vessels, and nerves of the myocardium 2. Help distribute the forces of contraction 3. Add strength and prevent overexpansion of the heart 4. Provide elasticity that helps return the heart to its original size and shape after a contraction

Question 44

The cardiac skeleton could also be called....

Answer 44

the fibrous skeleton

Question 45

What does the cardiac skeleton consist of?

Answer 45

4 dense bands of tough elastic tissue that encircle that heart valves and bases of the pulmonary trunk and aorta

Question 46

What are 2 functions of the tough bands of elastic tissue in the cardiac skeleton?

Answer 46

1. Stabilize the positions of the heart valves and ventricular muscle cells 2. Electrically insulate the ventricular cells from the atrial cells

Question 47

Why do cardiac muscle cells need a very reliable supply of oxygen and nutrients?

Answer 47

because the heart works continuously

Question 48

the _____ has its own, separate blood supply

Answer 48

the myocardium

Question 49

coronary circulation supplies blood to where?

Answer 49

the muscle tissue of the heart (myocardium)

Question 50

The left and right coronary arteries originate where?

Answer 50

at the base of the ascending aorta, at the aortic sinuses

Question 51

Each time the left ventricle contracts, it forces blood where?

Answer 51

to the aorta

Question 52

When the left ventricle relaxes, blood no longer flows into the _____, ___ declines, and the walls of the aorta_____.

Answer 52

blood no longer flows into the aorta, pressure declines, and the walls of the aorta recoil

Question 53

"When the left ventricle relaxes, the walls of the aorta recoil" What is this recoil called and what does it do?

Answer 53

this recoil is called elastic rebound. it pushes blood forward, into the systemic circuit, and backward through the left and right aortic sinuses and then into the respective coronary arteries

Question 54

The combination of elevated blood pressure and elastic rebound ensures what?

Answer 54

ensures a continuous flow of blood to meet the demands of active cardiac muscle tissue

Question 55

What is myocardial blood flow?

Answer 55

the amount of blood that flows through the coronary arteries and into the myocardium

Question 56

Is myocardial blood flow steady?

Answer 56

no

Question 57

explain why myocardial blood flow is not steady

Answer 57

it peaks while the heart muscle is relaxed and almost ceases when it contracts

Question 58

What do coronary arteries do?

Answer 58

they deliver oxygenated blood and nutrients to the myocardiu

Question 59

what structures are essential for establishing a normal heart rate?

Answer 59

the sinoatrial node (SA) and the atrioventricular (AV) node

Question 60

what do coronary veins do?

Answer 60

remove carbon dioxide and wastes from the myocardium

Question 61

Branches of the coronary veins converge where?

Answer 61

at the coronary sinus (empties there)

Question 62

What is coronary artery disease characterized by?

Answer 62

interrupted blood flow to the myocardium

Question 63

Damage to the semilunar valve of the right ventricle would affect blood flow into which vessel?

Answer 63

the pulmonary trunk (artery)

Question 64

What prevents the AV valves from swinging into the atria?

Answer 64

Contraction of the papillary muscles (just before the rest of the ventricular myocardium contracts) pulls on the chordae tendineae, which prevent the AV valves from opening back into the atria

Question 65

Why is the left ventricle more muscular than the right ventricle?

Answer 65

the left ventricle must generate enough force to propel blood throughout the body, except the lungs; the right ventricle only has to generate enough force to propel blood a few centimeters to the lungs