Chapter 21-The Cardiovascular System: The Heart

Question 1

introduction to the heart

Answer 1

• vital for survival
• carries oxygen and nutrients to tissues
• carries wastes away from tissues
• closed system

Question 2

double circuit of the heart

Answer 2

pulmonary
--heart to lungs and back
--oxygenates blood
systemic
--heart to body and back
-delivers oxygen to tissues

Question 3

structure of heart

Answer 3

• cone shaped
• inside pericardial cavity
• inside mediastinum
• apex tipped toward the inferior and left
• base superior

Question 4

membranes of the heart

Answer 4

pericardium
epicardium
myocardium
endocardium

Question 5

pericardium

Answer 5

• double serous membrane with fibrous coat
• made of several layers
• -parietal pericardium:
• –outer layer of sac
• –fibrous and areolar layer
• -epicardium:
• –aka visceral pericardium
• –inner layer of sac
• –adheres to the heart wall
• pericardial cavity:
• -between layers
• -contains serous fluid

Question 6

epicardium

Answer 6

• visceral pericardium

- functions as protective outer layer

Question 7

myocardium

Answer 7

middle layer

• responsible for contractions
• made of cardiac muscle

Question 8

endocardium

Answer 8

• inner layer
• lines and protects chambers and valves
• continuous with endothelium of heart blood vessels

Question 9

cardiac muscle tissue

Answer 9

• striated
• aerobic respiration
• short t-tubules
• autorhythmic
• connected mechanically and chemically
• -intercalated discs
• -gap junctions

Question 10

chambers

Answer 10

4 chambers

• 2 atria
• 2 ventricles

Question 11

2 atria

Answer 11

• superior chambers
• receive blood from veins
• have auricles
• -flaps where blood pools

Question 12

2 ventricles

Answer 12

• inferior chambers
• force blood out to arteries
• structural differences:
• -left thicker and stronger
• -right goes only to lungs
• -left is round
• -right pouch shaped

Question 13

valves

Answer 13

atrioventricular

• tricuspid
• bicuspid (mitral) valve

Question 14

tricuspid valve

Answer 14

• right AV valve
• at right atrioventricular orifice
• open when atrial force is greater and closed when ventricular force is greater
• 3 cusps

Question 15

bicuspid (mitral) valve

Answer 15

left AV valve

• at left atrioventricular orifice
• 2 cusps

Question 16

chordae tendonae

Answer 16

• heart strings
• hold valves in place
• attached to cusps on ventricle side
• prevents
• -cusps from collapsing into atria when valve is closed
• backflow of blood

Question 17

papillary muscles

Answer 17

• small bundles of mucles
• attache to the chordae tendonae
• when valve closed, these muscles contract and tighten cords

Question 18

trabeculae carneae

Answer 18

-scaffolding on interior walls

Question 19

vlaves

Answer 19

semilunar valves: between ventricle and artery

• pulmonary valve
• aortic valve

Question 20

pulmonary valve

Answer 20

• right
• at entrance to pulmonary trunk
• opens when right ventricle contracts

Question 21

aortic valve

Answer 21

• left
• at entrance to aorta
• opens when left ventricle contracts

Question 22

path of blood

Answer 22

• right atrium: receives blood from superior and inferior vena cava plus coronary sinus
• right av valve
• right ventricle
• -conus artiosus: funnel leading from right ventricle to pulmonary trunk
• pulmonary valve
• pulmonary trunk
• -goes to lungs
• left atrium
• -receives blood from pulmonary veins
• left av valve
• left ventricle
• aortic valve
• aorta
• -to tissues

Question 23

coronary circulation

Answer 23

• supplies the heart tissues with blood

- blockage can result in a heart tissue dying

Question 24

coronary arteries

Answer 24

• branch directly off of the aorta as it emerges
• left coronary artery
• right coronary artery

Question 25

left coronary artery

Answer 25

- circumflex artery | - anterior interventricular artery

Question 26

right coronary artery

Answer 26

- posterior interventricular artery | - marginal artery

Question 27

cardiac veins

Answer 27

- drain myocardium - travel with arteries - cardiac veins: - -great - -middle - -small - coronary sinus - -empties into right atrium

Question 28

cardiac cycle

Answer 28

- systole= contractile phase; empties chamber - diastole= relaxation phase; chambers fill - heart sounds - -lub= av valves close - -dub=semi-lunar valves

Question 29

conduction system of heart

Answer 29

- heart beat enabled by: - nodal cells: specialized muscle cells taht conduct action potentials - conducting fibers: distributes stimulus to myocardium - aps move down heart, causing it to contract unevenly - -atria contract before ventricles - 5 step process

Question 30

SA node

Answer 30

sinoatrial node - pacemaker - spontaneously depolarizes - at back of wall of right atrium

Question 31

av node

Answer 31

av node (atrioventricular) - where 4 chambers meet - signal transmitted to av node through internodal pathways

Question 32

av bundle

Answer 32

transmits down interventricular septum

Question 33

bundle branches

Answer 33

- branch off the av bundle - moves further down the septum - one supplies each ventricle

Question 34

purkinje fibers

Answer 34

- reflect up external wall of ventricle | - extend into papillary muscles

Question 35

ECG/EKG

Answer 35

- electrocardiogram - P wave: depolarization of atria - QRS: depolarization of ventricle - T-wave: repolarization of ventricle - cardiac output: 5L/min

Question 36

autonomic control

Answer 36

- autorhythmicity: spontaneous contractions - chemical control: NE and E: increase rate and force - neural control in medulla - -cardioacceleratory centers: release NE/increase HR - -cardioinhibitory centers: release Ach/decrease HR