Chapter 5A

Question 1

The heart has four chambers: the two superior (on top) receiving chambers are the A and
the two inferior pumping chambers are the B.

Answer 1

atria
ventricles.

Question 2

The paired atria receive blood from blood vessels returning blood to the heart,
called X, while the ventricles eject the blood from the heart into blood vessels
called X

Answer 2

veins
arteries

Question 3

This atrium forms the right surface of the heart and receives blood from three
veins: the superior vena cava, inferior vena cava, and coronary sinus.

Answer 3

right atrium

Question 4

Blood passes from the right atrium into the right ventricle through a valve that is
called the tricuspid valve

true/false

Answer 4

true

Question 5

• Blood passes from the right ventricle through the pulmonary (semilunar) valve into a
  large artery called the pulmonary trunk, which divides into right and left pulmonary
  arteries and carries blood to the X.

Answer 5

lungs

Question 6

The X atrium receives blood from the lungs through four pulmonary veins

Answer 6

left

Question 7

Blood passes from the left atrium into the left ventricle through the bicuspid (mitral)
valve which has two cusps

Answer 7

ok

Question 8

The left ventricle is the thickest chamber of the heart and forms the apex of the
heart.

true/false

Answer 8

true

Question 9

• Blood passes from the left ventricle through the aortic semilunar valve into the
  ascending aorta

true/false

Answer 9

true

Question 10

Some of the blood in the aorta flows into the coronary arteries, which branch from
the ascending aorta and carry blood to the heart wall.

• The remainder of the blood passes into the arch of the aorta and descending aorta
  (thoracic aorta and abdominal aorta).
• Branches of the arch of the aorta and descending aorta carry blood throughout
  the body

Answer 10

ok

Question 11

systemic vs pulmonary circulation: which goes to the lungs?

Answer 11

pulmonary = to the lungs

Question 12

Exchange of nutrients and gases occurs across the
thin capillary walls.

true/false

Answer 12

true

Question 13

Blood unloads O2 (oxygen) and picks up CO2 (carbon
dioxide)
true/false

Answer 13

true

Question 14

In most cases, blood flows through only one capillary
and then enters a systemic venule.
* Venules carry oxygen-poor/-rich blood
away from tissues and merge to form larger systemic
veins.

Answer 14

poor

Question 15

The …. side of the heart is the pump for
pulmonary circulation.
* It receives all of the dark-red
deoxygenated blood returning from the
systemic circulation.
* Blood ejected from the right ventricle
flows into the pulmonary trunk, which
branches into pulmonary arteries that
carry blood to the right and left lungs.
* In pulmonary capillaries, blood unloads
CO2, which is exhaled, and picks up O2
from inhaled air.
* The freshly oxygenated blood then flows
into pulmonary veins and returns to the
….. atrium.

Answer 15

right side
left atrium

Question 16

There are two types of cardiac fibers or cardiomyocytes:

Autorhythmic cardiac cells
Contractile cardiac cells

Explain

Answer 16

Autorhythmic: specialized cells, form a specialized excitatory and conductive (conduct electrical signals) system of the heart. self-excitable. Generate action potentials that trigger heart contractions.

> Controls cardiac contractions

Contractile: ventricular or working cells

Question 17

What are the two important functions of autorhythmic cardiac cells?

Answer 17

1. pacemaker, setting the rhythm
2. cardiac conduction system: provide a path for each cycle of cardiac excitation

Question 18

True/false:

SA node cells have a stable resting potential

Answer 18

False

SA node cells do not have a stable resting potential. Rather, they repeatedly
depolarize to threshold spontaneously.
* The spontaneous depolarization is a pacemaker potential (!!)

Question 19

Membrane potential of sinus nodal fibers are similar to ventricular muscle fibers

Answer 19

false: the “resting membrane potential” of the sinus nodal fiber is more positive than ventricular muscle fiber

Question 20

The cause of this lesser negativity of nodal fibers vs ventricular muscle fibers is that the cell membranes of the sinus fibers are
naturally …. to sodium and calcium ions, and positive charges of the entering
sodium and calcium ions neutralize some of the intracellular negativity.

Answer 20

leaky

Question 21

Na+ leaks into SA nodal cells through “funny” channels
Between heartbeats, influx of positively charged sodium ions causes a slow
decline/rise in the resting membrane potential in the positive/negative direction

Answer 21

rise, positive

Question 22

SA node sets the rhythm for contraction of the heart
true/false

Answer 22

true, is the pacemaker of the heart

Question 23

Nerve impulses from the …..nervous system (..NS) and blood-borne hormones
(such as epinephrine) modify the timing and strength of each heartbeat (see section
“regulation of heart rate”), but they do not establish the fundamental rhythm.

Answer 23

autonomic

Question 24

Put in right order of transmission of electrical signal:

• Right and left bundle branches
• AV bunde (bundle of HIS)
• Purkinje fibers
• SA node
• AV node

Answer 24

1. SA node
2. AV node
3. AV bundle
4. Right and left
5. Purkinje fibers

Question 25

at the SA, there are/are not contractile muscle filaments

Answer 25

are virtually not

Question 26

At the AV node, the action potential slows to provide time for..

Answer 26

the two atria contract at the same time and empty their blood into the ventricles.

Question 27

only site where action potentials can conduct from the atria to the ventricles = ?

Answer 27

AV bundle

Question 28

Purkinje fibers -> ventricles contract -> pushing blood upwards true/false

Answer 28

true

Question 29

Can you see if the heart is enlarged with an ECG?

Answer 29

yes

Question 30

Can you determine the cause of chest pain with an ECG?

Answer 30

Yes

Question 31

ECG: Lead .... is the most common, most popular, and generally the best view.

Answer 31

2

Question 32

Why is lead 2 the best? Because... By setting the ECG monitor to Lead II, we are essentially viewing the impulse as it travels from the .... atria toward the .... ventricle.

Answer 32

right atria left ventricle

Question 33

Three clearly recognizable waves appear with each heartbeat: .... wave, ... complex and ... wave

Answer 33

P wave, QRS complex and T wave

Question 34

Analysis of an ECG also involves measuring the time spans between waves, which are called intervals or segments

Answer 34

See p.51

Question 35

P wave: is a small upward deflection on the ECG. The P wave represents atrial depolarization/repolarization, which spreads from the SA node through contractile fibers in both atria.

Answer 35

depolarization

Question 36

P–R interval: the time from the beginning of the P wave to the beginning of the .... It represents the conduction time from the beginning of atrial excitation to the beginning of .... excitation: time required for the action potential to travel through the atria, atrioventricular node, and the remaining fibers of the conduction system.

Answer 36

QRS complex ventricular

Question 37

QRS complex: begins as a downward deflection, continues as a large, upright, triangular wave, and ends as a downward wave. The QRS complex represents rapid ventricular de/repolarization, as the action potential spreads through ventricular contractile fibers

Answer 37

depolarization

Question 38

T wave: is a dome-shaped upward deflection. It indicates ventricular de/repolarization and occurs just as the ventricles are starting to relax. The T wave is smaller and wider than the QRS complex because repolarization occurs more slowly than depolarization

Answer 38

depolarization

Question 39

Q–T interval: extends from the start of the QRS complex to the end of the T wave. It is the time from the beginning of ..... depolarization to the end of ...... repolarization

Answer 39

ventricular ventricular