The Heart

Front 1

What are the 3 functions of the heart? and there sub-functions?

Back 1

1. Transportation
- respiratory
- nutritive
- excretory
2. Regulation
- hormonal
- temperature
3. Protection
- clotting
- immune

Front 2

what side of the heart is considered pulmonary?
Why?

Back 2

right
Because it pumps blood to the lungs

Front 3

what side of the heart is consdiered systemic?
Why?

Back 3

left

Because it pumps blood to the body

Front 4

During systole, does blood pressure rise or fall?

Back 4

rises

Front 5

What vessel(s) deliver deoxygenated blood to the heart from the body?

Back 5

superior/inferior vena cava

Front 6

Blood pressure does what during diastole?

Back 6

falls

Front 7

Describe the structures that the blood travels through from the superior and inferior vena cavas to the lungs.

Back 7

Vena cavas ---> right atrium ---> right atrioventricular (tricuspid) valve ---> right ventricle ---> pulmonary semi-lunar valve ---> pulmonary artery ---> lungs

Front 8

Describe the structures oxygenated blood travels through from the lungs to the body.

Back 8

Lungs ---> pulmonary vein ---> left atrium ---> left AV (bicuspid/mitral) valve ---> left ventricle ---> aortic semi-lunar valve ---> aorta ---> body

Front 9

When heart rate increases, what happens with all the phases of cardiac cycle?

Back 9

they shorten, especially diastole

Front 10

Identify the layers of the heart wall

Back 10

Front 11

Back 11

Front 12

Back 12

Front 13

Name/Describe the 2 phases of systole

Back 13

1. Isovolumetric Contraction:
- Blood is not moving in or out of ventricle
- All valves are closed
- Pressure is building

2. Ejection:
- AV valves are closed
- Ventricular pressure causes semilunar valves to open
- Blood is ejected

Front 14

Name/Describe the 1st phase of diastole

Back 14

Isovolumetric relaxation:
- Semilunar valves close
- Ventricles/Atria relaxed
- Ventricular/Atrial pressure drops

Front 15

What is Heart Murmur?

Back 15

sounds produced by regurgitation through valves

Front 16

Name/Describe the 2nd phase of diastole

Back 16

Rapid Filling:
- Ventricular pressure drops below that of the atria
- AV valves open
- Blood rushes into ventricles

Front 17

Name/Describe 3rd phase of diastole

Back 17

Atrial Contraction (atrial systole):
- Pressure in atria now lower than that of ventricles
- Atria contract to deliver the remaining blood
- Immediately after atrial contraction, Isovolumetric Relaxation, and hence the cardiac cycle, start all over again.

Front 18

what is the main way that the ventricles are filled?

Back 18

passive ventricular filling during diastole

Front 19

During diastole:
the chordae tendineae tension is _______
the papillary muscle is ________
the cardiac muscle is _________
the ventricle is _______
the AV valves are ________
and the semilunar valves are

Back 19

low
relaxed
relaxed
dilated
open
closed

Front 20

What is adjusted by the autonomic nervous system or hormones?

Back 20

heart rate

Front 21

During systole:
the chordae tendineae tension is _______
the papillary muscle is ________
the cardiac muscle is _________
the ventricle is
the AV valves are ________
the semilunar valves are _______

Back 21

high
contracted
contracted
contracted
closed
open

Front 22

what are the two ways the AV valves stay closed?

Back 22

the cusp shape causes them to close as blood fills them
the chordae tendineae put tension on them to close them

Front 23

Do the atria and/or ventricles work together or separately?

Back 23

Atria: work as one
Ventricles: work separately from each other

Front 24

The Vagus nerves (X) carries what to small ganglia in cardiac plexus?

Back 24

parasympathetic preganglionic fibers

Front 25

does the nervous sytem cause the heart to contract?

Back 25

no

Front 26

Explain the electrical impulse cycle in the SA node

Back 26

1. Pacemaker Potential: Drives the self-generated firing of Pacemaker Cells
Preceding action potential completes ---> cell is hyperpolarized -60mV ---> Na/K channel opens ---> Na comes in fast ---> K goes out slowly ---> slow net depolarization to -40mV threshold
2. Action Potential
-40mV causes Ca2+ channels to open ---> Ca2+ influx causes upward phase of action potential ---> at top of action potential (+20mV) K+ channels open ---> repolarization ---> new cycle begins

Front 27

Explain how the spontaneous SA node depolarization can be modulated

Back 27

1. Epinephrine/Norepinephrine:
- Increases cAMP production
- cAMP keeps Na+ (HCN) channels open
- Faster pacemaker potential

2. Acetylcholine:
- Secreted by parasympathetic neurons
- Opens K+ channels.
- Slows pacemaker potential

Front 28

Describe the path of electrical signals

Back 28

Sinoatrial (SA) node ---> Electrical channels ---> atrioventricular (AV) node ---> Bundle of His ---> Left/Right Bundle Branches ---> Purkinje Fibers (which start at the base and travel up outer walls)

Front 29

Why is the Pacemaker Potential also called the Diastolic Depolarization

Back 29

Because the pacemaker potential represents the non-contracting time between heart beats (diastole)

Front 30

Describe the Myocardial Action Potential

Back 30

- Myocardial cell rests at -85mV
- Action potential from SA node brings MC cell to threshold
- Voltage gated Na+ channels open, potential shoots straight up (undefined slope) to +15mV
- Plateau for 200-300ms due to a balance of Ca influx and K efflux.
- More K+ channels open, repolarization occurs.

Front 31

ACh (parasympathetic stimulation) speeds or slows the heart?

Back 31

slows

Front 32

NE (sympathetic stimulation) does what to the heart?

Back 32

speeds it up

Front 33

what is the primary ion that causes depolarization in cardiac myocytes?

Back 33

sodium (Na+)

Front 34

What is the difference between what happens in the SA node and in other cardiac myocytes?

Back 34

The SA node has a faster action potential: sodium causes slight depolorazation until threshold when Ca+ channels open and Ca+ rushes in causing a very fast depolarization.

Front 35

Membrane potential of pacemaker cells are higher or lower than other cardiac cells?

Back 35

lower

Front 36

what causes repolarization of cardiac myocytes?

Back 36

potassium leaving the cells

Front 37

what is the same about skeletal and cardiac muscle?

Back 37

depolarization caused by sodium entering the cell and repolarization caused by potassium leaving the cell

Front 38

what is different about cardiac muscle cells from skeletal?

Back 38

The plateau phase: the depolarization of the cardiac muscle causes Ca+ channels to open letting Ca+ into the cell (which makes cell go positive) - at the same time, K+ is leaving the cell (which makes cell go negative) - so the movements of these two ions cancel each other out for a time, causing a longer contraction in the cardiac muscle cell.

Front 39

Increased heart rate (by sympathetic stimulation of SA node) is cause by what hormones?

Back 39

epinephrine (E), norepinephrine (NE), and thyroid hormone

Front 40

How does the cardiac myocyte repolarize?

Back 40

after plateau phase, the L-type Ca+ channes close while K+ continues leaving, making the cell more negative (repolarization)

Front 41

describe what the refractory period in cardiac myocytes is and why it is necessary

Back 41

a period of either complete or reduced sensitivity to additional stimulation
Prevents tetanic contraction - allows movement of AP to progress down the heart from the SA node rather than go back up right away.

Front 42

what does the P wave represent?

Back 42

atrial depolarization spreading

Front 43

what does the QRS complex/wave represent? Immediately after?

Back 43

spread of depolarization into ventricles
immediately after QRS is heart sound 1 "Lub"

Front 44

- what does the S-T segment represent?
- what 2 events does the T wave represent?

Back 44

plateau phase of the action potential
ventricle repolarization, heart sound 2 "Dub"

Front 45

which valves are closed during diastole?

Back 45

semilunar valves (bicuspid and tricuspid) - keeps blood that has left the heart from leaking back into the ventricles.