Item 10 Flashcards
Chapter 13 (read the sections that relate to the lecture slides)
heart
The _ is a muscular pump that drives the flow of blood through blood vessels, and serves sensory and endocrin functions by regulating blood pressure and volume
heart
_ _ conduits through which the blood flows, and are sensory and effort organs, regulating blood pressure and distribution
blood vessels
_ is fluid that circulates around the body carrying materials to and from the cells with the nervous system, acting as a communication link
blood
The heart beats _ times per minute, approximately
80
The heart has 4 _ or atrium
chambers
The _ occupy the bulk of the heart. The arteries and veins all attach to the base of the heart (located at the top)
ventricles
The right and left _ receive blood and hold onto it before being pumped
atrium/atria
The right and left _ are the pumps of the system
ventricle
The _ ventricle is much larger than the right, because the former has further to pump than the latter
left
Superior vena cava receives blood from …
the body in general
The _ takes blood from the left ventricle into circulation
aorta
The pulmonary artery takes blood from the _ ventricle to provide blood for the lungs
right
The atrialventricular valves (which take place between the atria and the ventricles) are a.k.a. cuspid valves, with the bicuspid valve taking place in the _ AV, and the tricuspid valve taking place in the _ AV
left;
right
- shown on the opposite sides of the diagram, which imagines a heart facing me
Cuspid valves ensure the one-way movement of blood from _ to _
atrium to ventricle
Blood moves through the heart from the…
1. right _
atrium
Blood moves through the heart from the…
1. right atrium
2. _ valve
tricuspid
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. _ ventricle
right
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. _ valve
pulmonic
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonic valve
5. pulmonic _
arteries
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonic valve
5. pulmonic arteries
6. pulmonic _
veins
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonic valve
5. pulmonic arteries
6. pulmonic veins
7. _ _
left atrium
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonic valve
5. pulmonic arteries
6. pulmonic veins
7. left atrium
8. _ valve (left AV valve)
mitral
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonic valve
5. pulmonic arteries
6. pulmonic veins
7. left atrium
8. mitral valve (left AV valve)
9. left _
ventricle
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonic valve
5. pulmonic arteries
6. pulmonic veins
7. left atrium
8. mitral valve (left AV valve)
9. left ventricle
10. _ _
aortic valve
Blood moves through the heart from the…
1. right atrium
2. tricuspid valve
3. right ventricle
4. pulmonic valve
5. pulmonic arteries
6. pulmonic veins
7. left atrium
8. mitral valve (left AV valve)
9. left ventricle
10. aortic valve
11. _
aorta
The heart simultaneously pumps to the _ and systemic circuits
pulmonary
The ventricles pump _, enabling an effective and efficient system
simultaneously
In _ capillary beds, O2 moves into the blood and Co2 leaves
pulmonary
In _ capillary beds, O2 leaves the blood and Co2 enters
systemic
Blood first enters the right atrium and enters the right ventricle, which is then pumped into the _ _, removing Co2 and adding O2
pulmonary circuit
Once the blood is oxygenated and removes carbon dioxide through the pulmonary circuit, it re-enters the heart through the left _ and then is pumped using the left _, into the system
atrium;
ventricle
The 4 valves for ensuring one-way flow of blood are the:
1. tricuspid valve
2. pulmonary semilunar valve
3. bicuspid valve
4. _ _ valve
aortic semilunar
The bicuspid valve is a.k.a. _ valve
mitral
_ _ hold the ends of the cusps, and connect them to papillary muscles
chordae tendenae
When the ventricles are relaxed, blood enters the _, pushing the AV valve cusps down into the _, opening the valves
atria;
ventricles
When the ventricles contract, blood presses up against the AV valve cusps, forcing the valves closed. Contraction of the papillary muscles tightens the _ _, preventing the valve cusps from being pushed into the atria
chordae tendenae
Semilunar valves _ when blood rushes past, then when ventricles are relaxed and semilunar valves are _
open;
closed - valves prevent blood wanting to move down from gravity; caught by this, preventing blood going backward, and improving its efficiency
When the ventricle _, blood in the aorta and pulmonary artery presses down against the valve cusps, forcing them to close
relaxes
Damaged mitral valve is a type of _ disease
cardiovascular
Damage to the mitral valve can lead to the heart…, as an indicator of heart failure because when it changes its function, it has to constantly adapt to inefficient function, leading to cardio dysfunction
changing shape
_ can help with calcification of the mitral valve, which otherwise would have inefficient function
drugs
T or F: mitral valves (left AV valve) can be replaced to prevent heart dysfunction
true
Many valve designs exist that enable one-way flow, some of which are purely mechanical, others are _
biological
e.g., pig valves
Electrical activity in the heart starts with the SA node _
depolarizing
The SA and the AV nodes contain _ cells which automatically set the rhythm of the heartbeat
pacemaker
The _ node is autorhythmic; it works at its own pace
SA
The internodal pathway of the heart is through the walls of the _
atria
Electrical activity goes rapidly to the AV node through the walls of the atria, i.e., _ pathways
internodal (between the nodes - from SA to AV)
Depolarization of the SA node spreads QUICKLY/SLOWLY across the atria, and conduction QUICKENS/SLOWS through the AV node, creating a 0.1 second delay before conduction continues
slowly;
slows - it is slow to allow a delay before conduction to happen, otherwise it would be fast
The only electrical connection between the atria and the ventricles is the Bundle of _
His - why it’s a man not a woman is beyond me
Depolarization of the right atrium moves QUICKLY/SLOWLY through a ventricular conducting system to the apex of the heart, namely the Bundle of His
quickly - men like to do things quickly
Electrical activity in the heart starts with:
1. the SA node depolarizing
2. electrical activity going rapidly to the AV node via internodal pathways/atrial walls
3. depolarization spreads more slowly across the atria, with conduction slowing through the AV node, creating a 0.1 second delay
4. depolarization moves rapidly through the ventricular conducting system to the apex of the heart through the Bundle of His
5. depolarization wave spreads upward from the apex, through _ _, the entire wall of the ventricle
Purkinje fibres
Electrical activity in the heart starts with:
1. the SA node depolarizing
2. electrical activity going rapidly to the AV node via internodal pathways/atrial walls
3. depolarization spreads more slowly across the atria, with conduction slowing through the AV node, creating a 0.1 second delay
4. depolarization moves rapidly through the ventricular conducting system to the apex of the heart through the Bundle of His
5. depolarization wave spreads upward from the apex, through Purkinje fibres, along the entire wall of the ventricle
6. …
the entire heart returns tot he resting state, remaining there until another action potential is generated in the SA node
The SA node depolarizes at a wave that is strong enough to dictate the heart rate, usually _ beats per minute
100
The AV node depolarizes AFTER/BEFORE the SA node
after
Once the AV node is activated by the SA node, it goes into a short delay, a _ _, preventing the AV node from initiating its own “extra” beat
refractory period
The SA node has a HIGHER/LOWER beating frequency than the AV node, which overrides the AV node’s beating frequency
higher
The short delay after the AV node is activated, as well as its lower beating frequency enables the SA node to…
govern the actions of the AV node, not the other way around
T or F: it’s possible for one node to beat the heart, although it’s less effective and would not be able to do so indefinitely
true
Cardiac pacemaker cells automatically initiate each cardiac _ (heart muscle cell)
myocyte
That which is initiated by the heart itself is considered _genic, whereas by the nervous system is _genic
myogenic;
neurogenic
Heart muscle cells can depolarize on their own, therefore they have _
autorhythmicity
The pacemaker cell is really the _-type cell, whereas the cardiac myocyte is the _-type cell
electric;
contract
Pacemaker cells are communicated to cardiac myocytes through _ cells
conducting
T or F: pacemaker cells and cardiac myocytes have the same type of action potential
false - they both can do action potentials, but they’re different/location specific
… have a ver long low phase and then a later action potential
cardiomyocytes
Pacemaker action potentials are UN/STEADY; they fire at threshold which is roughly -_mV (goes up to roughly +20 m’V) and going back to normal is when they return to -_mV
unsteady;
-40 mV;
-60 mV
Pacemaker cells action potentials occur with:
1. ‘funny’ leak channels open allowing_ in, across membrane
Na+
Pacemaker cells action potentials occur with:
1. ‘funny’ leak channels open allowing Na+ in, across membrane
2. some _ channels open, ‘funny’ leak channels close
Ca2+
Pacemaker cells action potentials occur with:
1. ‘funny’ leak channels open allowing Na+ in, across membrane
2. some Ca2+ channels open, ‘funny’ leak channels close
3. action potential starts, with lots of _ channels opening
Ca2+
Pacemaker cells action potentials occur with:
1. ‘funny’ leak channels open allowing Na+ in, across membrane
2. some Ca2+ channels open, ‘funny’ leak channels close
3. action potential starts, with lots of Ca2+ channels opening
4. at its apex, the Ca2+ channels open, _ channels open
K+
Pacemaker cells action potentials occur with:
1. ‘funny’ leak channels open allowing Na+ in, across membrane
2. some Ca2+ channels open, ‘funny’ leak channels close
3. action potential starts, with lots of Ca2+ channels opening
4. at its apex, the Ca2+ channels open, K+ channels open
5. near -_mV, K+ channels close
-60 mV
Pacemaker cells action potentials occur with:
1. ‘funny’ leak channels open allowing Na+ in, across membrane
2. some Ca2+ channels open, ‘funny’ leak channels close
3. action potential starts, with lots of Ca2+ channels opening
4. at its apex, the Ca2+ channels open, K+ channels open
5. near -60 mV K+ channels close
6. funny channels _ until an action potential may start
open
_ stimulation with SA node pacemaker activity would create more rapid depolarization, stimulating more action potentials by changing funny channels by opening faster, allowing more Na+ influx, and therefore a steeper depolarization
sympathetic - fight-or-flight
- more beats per minute, due to increase in funny channels
_ stimulation with SA node pacemaker activity involves later closing of the funny channel, less Na+ influx, and shallow depolarization.
Also, there is longer opening of K+ channels causing greater K+ efflux (hyperpolarized)
parasympathetic - rest and digest
T or F: parasympathetic stimulation with SA node pacemaker activity starts with an even lower membrane potential, which dramatically slows heartrate
true
How are pacemaker and contractile cells electrically connected?
through intercalated disks with gap junctions with cardiomyocytes
Tor F: heart cells contract at the same time
true
Cardiac myocytes have a long plateau at -90 mV which is UN/STEADY; a swift depolarization that goes to about +20 mV, and then repolarization and later dehyperpolarization
steady
Cardiac myocyte action potentials start with:
0. opening of _ channels, creating _ influx with an opening of more _ channels, and voltage increases to as high as +30 mV (or as low as - 40 mV)
Na+!!!
Cardiac myocyte action potentials start with:
0. opening of Na+ channels, creating Na+ influx with an opening of more Na+ channels, and voltage increases to as high as +30 mV (or as low as - 40 mV)
1. action potential occurs with Na+ channels closing, with opening of Ca2+ channels, and _ of K+ channels (prevents potassium from leaving)
closing
Cardiac myocyte action potentials start with:
0. opening of Na+ channels, creating Na+ influx with an opening of more Na+ channels, and voltage increases to as high as +30 mV (or as low as - 40 mV)
1. action potential occurs with Na+ channels closing, with opening of Ca2+ channels, and closure of K+ channels (prevents potassium from leaving)
2. with the slow plateau phase, K+ channels are still closed and Ca2+ are still open creating Ca2+ influx, and with Ca2+ influx greater than K+ efflux (going out), cell is _
depolarized
Cardiac myocyte action potentials start with:
0. opening of Na+ channels, creating Na+ influx with an opening of more Na+ channels, and voltage increases to as high as +30 mV (or as low as - 40 mV)
1. action potential occurs with Na+ channels closing, with opening of Ca2+ channels, and closure of K+ channels (prevents potassium from leaving)
2. with the slow plateau phase, K+ channels are still closed and Ca2+ are still open creating Ca2+ influx, and with Ca2+ influx greater than K+ efflux (going out), cell is depolarized
3. _ channels open, with high _ efflux and dropping mV, closing Ca2+ channels, and its influx drops and mV declines to baseline
K+;
K+
Cardiac myocyte action potentials start with:
0. opening of Na+ channels, creating Na+ influx with an opening of more Na+ channels, and voltage increases to as high as +30 mV (or as low as - 40 mV)
1. action potential occurs with Na+ channels closing, with opening of Ca2+ channels, and closure of K+ channels (prevents potassium from leaving)
2. with the slow plateau phase, K+ channels are still closed and Ca2+ are still open creating Ca2+ influx, and with Ca2+ influx greater than K+ efflux (going out), cell is depolarized
3. K+ channels open, with high K+ efflux and dropping mV, closing Ca2+ channels, and its influx drops and mV declines to baseline
4. All ions are at resting values, and mV is negative because the membrane is more permeable to _ than to _ or Na+, and mV is closer to E_ (equilibrium potential of _)
K+;
Ca2+;
K+;
K+
T or F: Action potentials for contraction only take place in pacemaker cells
false - only in cardiac myocytes
Heart contraction occurs with:
1. action potential enters from…
adjacent cell
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated _ channels open, with _ entering cell
Ca2+
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a - Ca2+ channel
L-type
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the _ _
sarcoplasmic reticulum
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the sarcoplasmic reticulum
4. local release causes Ca2+ _
sparks (accumulation of Ca2+)
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the sarcoplasmic reticulum
4. local release causes Ca2+ sparks
5. Summed Ca2+ sparks create a Ca2+ _
signal
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the sarcoplasmic reticulum
4. local release causes Ca2+ sparks
5. Summed Ca2+ sparks create a Ca2+ signal
6. Ca2+ ions bind to _ to initiate contraction
troponin (remember, actin and myosin can only work if troponin is pulled away by Ca2+)
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the sarcoplasmic reticulum
4. local release causes Ca2+ sparks
5. Summed Ca2+ sparks create a Ca2+ signal
6. Ca2+ ions bind to troponin to initiate contraction
7. _ occurs when Ca2+ unbinds from troponin
relaxation
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the sarcoplasmic reticulum
4. local release causes Ca2+ sparks
5. Summed Ca2+ sparks create a Ca2+ signal
6. Ca2+ ions bind to troponin to initiate contraction
7. relaxation occurs when Ca2+ unbinds from troponin
8. Ca2+ is pumped back into the sarcoplasmic reticulum for storage, and is also exchanged with _ by the NCX antiporter
Na+ (requires 3 Na+ with Ca2+)
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the sarcoplasmic reticulum
4. local release causes Ca2+ sparks
5. Summed Ca2+ sparks create a Ca2+ signal
6. Ca2+ ions bind to troponin to initiate contraction
7. relaxation occurs when Ca2+ unbinds from troponin
8. Ca2+ is pumped back into the sarcoplasmic reticulum for storage, and is also exchanged with _ by the NCX antiporter
9. Na+ gradient is maintained by the … ATPase
Na+–K+-ATPase
Heart contraction occurs with:
1. action potential enters from adjacent cell
2. voltage-gated Ca2+ channels open, with Ca2+ entering cell through a L-type Ca2+ channel (increases Ca2+ in cell)
3. Ca2+ activates ryanedine receptor channels for Ca2+ to come out of the sarcoplasmic reticulum
4. local release causes Ca2+ sparks
5. Summed Ca2+ sparks create a Ca2+ signal
6. Ca2+ ions bind to troponin to initiate contraction
7. relaxation occurs when Ca2+ unbinds from troponin
8. Ca2+ is pumped back into the sarcoplasmic reticulum for storage, and is also exchanged with _ by the NCX antiporter
9. Na+ gradient is maintained by the … ATPase
Na+–K+-ATPase (enzyme that pumps Na+ out of the cell, maintains membrane polarization of contractile cell of -90, with 3 Na+ being removed with 2K+ entering
The electrocardiogram measures the electrical signals of the heart and how it _
functions
ECG have 5 waves:
P
…
T
Q-R-S
ECG measures _ of the entire heart: ventricles, atria, pacemaker cells, cardiac myocytes
depolarization / electrical activity
Difference in ECG waves depends on the net _ in voltage across the heart
CHANGE!
if there was no change, it wouldn’t be working. how do they change, and what does it mean?
The ECG:
P wave - involves _ depolarization
atrial
The ECG:
QRS complex - involves _ depolarization
ventricular
The ECG:
T wave - involves…
ventricular REPOLARIZATION
When does the atrial repolarization take place?
during the QRS complex, which overtakes any wave, which therefore makes atrial repolarization not measured on ECGs
T or F: P waves don’t do anything unless there is an action potential
true
Ventricular fibrillation shows fluttering of the ventricles, not enabling rhythmic beating, requiring …
atrial defibrillator to reset the heartrate
Sinus bradycardia can be misdiagnosed in…
elite distance athletes because their heart grows significantly larger to require less frequent blood pumping, resulting in ECG waves that are consistent with normal ECG tracings, but at much less frequent amounts
Sinus tachycardia or inverted T wave is the much more frequent beating of the heart, with much more significant voltages over time, causing…
significant wear and tear on the heart
Sinus tachycardia with inverted T wave is likely the result of a…
SA node injury
ECG waves precede specific contractions with:
0. …
ECG must show electrical activity otherwise heart contraction cannot be monitored
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the…
depolarization of the SA node
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the depolarization of the SA node
2. PQ segment shows the continued depolarization of the _ cardiac myocytes, with the _ contracting
atrial;
atria
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the depolarization of the SA node
2. PQ segment shows the continued depolarization of the atrial cardiac myocytes, with the atria contracting
3. Q wave shows the electricity passing…
through the centre of the heart, to the Bundle of His
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the depolarization of the SA node
2. PQ segment shows the continued depolarization of the atrial cardiac myocytes, with the atria contracting
3. Q wave shows the electricity passing through the centre of the heart, to the Bundle of His
4. R wave shows it moving through the _ _ up through the ventricular wall itself
Purkinje fibres
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the depolarization of the SA node
2. PQ segment shows the continued depolarization of the atrial cardiac myocytes, with the atria contracting
3. Q wave shows the electricity passing through the centre of the heart, to the Bundle of His
4. R wave shows it moving through the Purkinje fibres up through the ventricular wall itself
5. S wave shows the whole cardiac myocyte area starts depolarizing from the _ to the _
bottom to the top
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the depolarization of the SA node
2. PQ segment shows the continued depolarization of the atrial cardiac myocytes, with the atria contracting
3. Q wave shows the electricity passing through the centre of the heart, to the Bundle of His
4. R wave shows it moving through the Purkinje fibres up through the ventricular wall itself
5. S wave shows the whole cardiac myocyte area starts depolarizing from the bottom to the top
6. ST segment sees the _ contracting
ventricles
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the depolarization of the SA node
2. PQ segment shows the continued depolarization of the atrial cardiac myocytes, with the atria contracting
3. Q wave shows the electricity passing through the centre of the heart, to the Bundle of His
4. R wave shows it moving through the Purkinje fibres up through the ventricular wall itself
5. S wave shows the whole cardiac myocyte area starts depolarizing from the bottom to the top
6. ST segment sees the ventricles contracting
7. T wave with _ of the cardiac myocytes, dissipating from the ventricles
repolarizing
ECG waves precede specific contractions with:
0. ECG set-up showing electrical waves
1. P wave that coincides with the depolarization of the SA node
2. PQ segment shows the continued depolarization of the atrial cardiac myocytes, with the atria contracting
3. Q wave shows the electricity passing through the centre of the heart, to the Bundle of His
4. R wave shows it moving through the Purkinje fibres up through the ventricular wall itself
5. S wave shows the whole cardiac myocyte area starts depolarizing from the bottom to the top
6. ST segment sees the ventricles contracting
7. T wave with repolarizing of the cardiac myocytes, dissipating from the ventricles
8. …
resetting to baseline
Sinus in ECGs suggest that…
all of the appropriate waves exist, but they are not appearing as normal
Where does the blood go just after it flows through the superior vena cava?
a. right atrium
b. left atrium
c. the body
d. the head
a. right atrium
What is the electrical pathway of the heart, in order?
a. SA node, internodal pathways, AV node, bundle of His, bundle branches, Purkinje fibers
b. AV node, internodal pathways, SA node, bundle of His, bundle branches, Purkinje fibers
c. AV node, internodal pathways, SA node, Purkinje fibers, bundle of His, bundle branches
d. SA node, internodal pathways, AV node, Purkinje fibers, bundle of His, bundle branches
a. SA node, internodal pathways, AV node, bundle of His, bundle branches, Purkinje fibers
What happens during the QRS complex?
a. ventricular depolarization and atrial repolarization
b. ventricular repolarization and atrial depolarization
c. atrial depolarization only
d. ventricular depolarization only
a. ventricular depolarization and atrial repolarization
Which of the following is responsible for the rapid depolarization phase of an action potential within the pacemaker cells?
a. an increase in PCa2+
b. an increase in PK+
c. a decrease in PK+
d. a decrease in PNa+
a. an increase in PCa2+
During repolarization (phase 3) of a contractile cell action potential,
a. only potassium permeability is increased.
b. only calcium permeability is increased.
c. sodium and calcium permeability are both increased.
d. only calcium permeability is increased.
a. only potassium permeability is increased.
White blood cells are _cytes and red blood cells are _cytes
leukocytes;
erythrocytes (more numerous in blood than white blood cells)
The superior vena cava delivers blood from parts of the body above the _, whereas the inferior vena cava delivers from parts of the body below it
diaphragm
Most arteries carry oxygenated blood, except for the _ arteries
pulmonary - they bring deoxygenated blood to the lungs, whereas the pulmonary VEINS bring oxygenated blood to the heart
- just to mess with you
Silent myocardial ischemia is a risk for those with _, because of neuropathy of nerves that transmit signals from the heart to the CNS
diabetes
A decrease in blood flow through the coronary arteries can lead to a heart attach or _ _
myocardial ischemia
Digitalis is used to decrease the _ _, as an option for those who have experienced myocardial ischemia
heart rate
_ _ blockers are used to decrease the likelihood of coronary vascular spasma in those with patients at risk for a myocardial infarction
calcium channel
Beta-blockers are used to decrease heart rate and… for patients at risk for a myocardial infarction
cardiac contractility
Chronic myocardial ischemia is subject to …, whereas acute is caused by vascular spasms of the coronary arteries or increased activity of the heart
atherosclerosis, a narrowing of the (often) coronary arteries due to the buildup of plaques
Parallel arrangement of organs in the heart’s systemic circuit is useful for 1) ensuring each organ is fed by a separate artery and receives fully oxygenated blood and…
blood flow to the organs is independently regulated, and can be adjusted to match the constantly changing metabolic needs of organs
- more helpful to ensure homeostasis of the organs and therefore the entire body
Angina pectoris is chest pain caused by a decrease in …
cardiac blood flow to sufficiently provide oxygen and remove metabolites, as a result of myocardial ischemia
Parallel blood flow involves blood flowing from the arteries to the arterioles to an organ’s capillaries and then immediately to the venules, etc., whereas series blood flow involves…
blood flow between two capillary beds
e.g., portal veins of hypothalamus and anterior pituitary or
intestines and liver or kidneys
The heart wall has three layers organized from interior to exterior:
endothelium
epicardium
myocardium
inner to outer:
endothelium - epithelial cells
myocardium - cardiac muscle
epicardium - connective tissue
The liquid that surrounds the heart and for which prevents too much friction (causing pain) as well as encourages the continuing heartbeat (for which it is required to beat autonomously) is the _
pericardium
pericarditis is pain caused by friction from inflammation of the pericardium
Pacemaker cells and _ _ are types of autorhythmic cells
conduction fibres
Conduction fibres are larger in diameter than other fibres therefore they can conduct action potentials FASTER/SLOWER than cardiac contractile cells
faster
(up to 4 metres per second, vs. 0.3-0.5 metres per second)
Between the incalated disks of cardiac muscle cells are gap junctions which permit electrical current to pass in the form of ions from one cell to another and _ , which form a physical bond between disks, resisting mechanical stress and enabling the myocardium to resist stretching
desmosomes
- imagine sliced open hot dogs that are still connected by links which help them resist stretching and mechanical stress
Sometimes a contraction is initiated outside the normal conduction pathway at a site called an ectopic focus. If this site is located in the atrium, it can causea premature atrial contraction (PAC); current will then spread through gap junctions, followed by a ventricular contraction. If the ectopic focus is located in the ventricle, it can cause a premature ventricular contraction (PVC), with no atrial contraction being involved. This extra beat, called an extrasystole, is followed by a skipped beat, leaving a pause between ventricular contractions. Why would the heart skip its next regular beat following an extrasystole?
A premature ventricular contraction results from a depolarization of the ventricle musculature. This depolarization sends the ventricle into a refractory period, such that when the next wave of depolarization comes from the normal conduction pathway, he voltage-gated sodium channels are inactivated and the ventricle cannot be excited to contract. Thus, the next beat is skipped
Minimum aortic pressure during the cardiac cycle is attained
a) Immediately after closure of the aortic semilunar valve.
b) Immediately before opening of the aortic semilunar valve.
c) Immediately before opening of the atrioventricular valves.
d) In mid-diastole.
e) At the end of systole
?
The first heart sound occurs when the atrioventricular valves close; thus it marks
a) The end of the ejection period.
b) The beginning of the ejection period.
c) The beginning of systole.
d) The beginning of isovolumetric contraction.
e) Both c and d are true
?
If you know end- diastolic volume, the only other thing you need to know to determine stroke volume is
a) Afterload.
b) Ventricular contractility.
c) End-systolic volume.
d) Heart rate.
e) Cardiac output
?
As a result of Starling’s law, stroke volume should increase following an increase in
a) Mean arterial pressure.
b) Heart rate.
c) Sympathetic activity.
d) Afterload.
e) Preload
?
Sympathetic and parasympathetic input to the SA node influences
a) Ventricular filling time.
b) Ventricular contractility.
c) Afterload.
d) Atrial contractility.
e) All of the above
?
Which of the following contains deoxy- genated blood?
a) The right ventricle
b) The left ventricle
c) Pulmonary veins
d) The aorta
e) Both a and c are true
>
Which of the following is not normally apparent in the EGG?
a) Atrial depolarization
b) Atrial repolarization
c) Ventricular depolarization
d) Ventricular repolarization
e) None of the above
?
The second heart sound occurs when the semilunar valves close; thus it marks
a) The end of the ejection period.
b) The beginning of the ejection period.
c) The beginning of systole.
d) The beginning of isovolumetric contraction.
e) Both c and d are true
?
The QRS complex of the EGG is due to
a) Atrial depolarization.
b) Atrial repolarization.
c) Ventricular depolarization.
d) Ventricular repolarization.
e) Opening of the AV valves
?
As a wave of action potentials travels from the atria to the ventricles, it is momentarily delayed by about
0.1 second as a result of slow conduction through
a) The SA node.
b) The AV node.
c) The atrioventricular bundle.
d) The left and right bundle branches.
e) Purkinje fibers
?
Which of the following is most likely to cause a decrease in the stroke volume of the left ventricle?
a) An increase in mean arterial pressure
b) An increase in end-diastolic pressure
c) An increase in end-diastolic volume
d) An increase in the activity of sympa- thetic nerves to the heart
e) An increase in central venous pressure
?
Left ventricular pressure and aortic pres- sure are virtually identical during
a) Isovolumetric contraction.
b) Isovolumetric relaxation.
c) Diastole.
d) Systole.
e) The ejection period
?
Heart rate is normally determined by the action potential frequency in the (SA/AV) node
?
According to Starling’s law, stroke volume should increase if end-diastolic volume (increases/decreases)
?
Heart rate is determined entirely by the inherent action potential frequency in cells of the SA node, with no external in- fluences, (true/false
?
Blood flow through the systemic circuit is driven by contractions of the (right/left) ventricle.
?
The valve located at the junction between the left ventricle and the aorta is an example of a(n) (atrioventricular/semilunar) valve
?
(Isovolumetric contraction/Ejection) occurs immediately after diastole
?
The maximum aortic pressure during the cardiac cycle is called (diastolic/systolic) pressure.
?
Under normal conditions, pressures in the left and right ventricles are equal dur- ing systole, (true/false)
?
Stroke volume and completely
determine cardiac output.
?
If end-diastolic volume does not change but end-systolic volume decreases, stroke volume (increases/decreases)
>
If end-diastolic volume does not change but end-systolic volume decreases, ejection fraction (increases/decreases).
?
If sympathetic and parasympathetic inputs are constant and end-diastolic volume increases, contractility of the ventricular myocardium increases, (true/false)
?
The period of relaxation of the heart muscle is known as
?
The (P/T) wave of the EGG corresponds to ventricular repolarization
?
Action potentials generated by pacemaker cells are called pacemaker potentials, (true/false)
?
Arteries/aorta leave the heart, whereas veins lead to the heart. Pulmonary veins, however, are the only veins which carry _ _, whereas all other veins do not
oxygenated blood
Atrial myocardium and ventricular myochardium are anchored to and separated by a layer of fibrous conective tissue called the _ _ of the heart, which forms rings that anchor the heart valves in place
fibrous skeleton
The equivalent to the aorta (sends blood to systemic organs) is the _ _ (sends blood to the lungs)
pulmonary trunk
Prolapse occurs when the increased ventricular pressure…
exerts an upward force against the AV valve, causing one or more valve cusps (specific to the mitral/right/bicuspid valve)
Prolapse of the AV valves is normally prevented by…
chorae tendineae (strands of connective tissue) that extend from the edges of the cusps to the papillary muscles, which protrude from the ventricular wall. During ventricular contraction, papillary muscles contract which exert tension on the chordae tendineae which then pull downward on the valve cusps and help seal them shut
A pacemaker cell is able to fire action potentials in the absence of any external stimulus because… (i.e., pacemaker potentials)
after an action potential, it immediately begins to depolarize slowly and continues to do so until its membrane potential reaches threshold, triggering another action potential
IN pacemaker and other cardiac muscle cells, electrical signals are caused by changes in…
plasma membrane ion permeability brought about by the opening and closing of special types of ion channels
it’s always about the ion movement, changing the chemical (and thereby electrical) charges that cause graded potentials, and eventually action potentials
As a membrane’s permeability to a particular ion increases relative o that of other ions, the membrane potential…
moves toward the equilibrium potential of that ion
i.e., during pacemaker potential slow depolarization, the membrane potential starts at -70 (close to K+ equilibrium potential), and then slowly rises to -50, the threshold for an action potential
The equilibrium potential of _ is +130 mV, whereas that of K+ is _, and _ is +60 mV
Ca2+;
-94 mV;
Na+
Increased _ permeability tends to make a membrane potential become more positive, whereas potassium permeability tends to make heart muscle cells more negative
Na+ or Ca2+
Funny channels open after the cell _ and allow sodium and potassium ions to cross the plasma membrane. They are oopen only for a brief time, closing when the membrane potential approaches -55 mV, 5 mV short of the threshold to generate an action potential
repolarizes
if they are used to depolarize the cell, then it makes sense that they come in after the cell has been repolarized
Much like muscle contraction, voltage-gated _ channels raise permeability to _, which depolarizes the cell to threshold (alongside funny channels - although these are specific to heart muscle cells)
calcium (both)
The two types of calcium channels that open during depolarization before and after threshold respectively are: _-type and _-type channels
T (transient);
L (long-lasting)
The opening of L-type voltage-gated calcium channels allows some _ to flow into the cell, increasing P_ and adds to the depolarizing effect.
Na+;
Na
The opening of L-type voltage-gated calcium channels allows some sodium to flow into the cell, increasing PNa+ and adds to the depolarizing effect. This depolarization triggers the opening of _ channels and, consequently, a rise in P_ that occurs shortly after the increase in P_
K+;
K;
Ca2+
The opening of L-type voltage-gated calcium channels allows some sodium to flow into the cell, increasing PNa+ and adds to the depolarizing effect. This depolarization triggers the opening of K+ channels and, consequently, a rise in PK+ that occurs shortly after the increase in PCa2+. The subsequent fall in potential removes the stimulus for _ channel opening, allowing these channels to begin closing
calcium
The cardiac action potential involves _ cells, not _ cells
cardiac contractile;
pacemaker
During a typical cardiac (contractile cell) action potential, PK _creases as a result of the action of a certain type of voltage-gated _ channel that closes in response to depolarization
potassium (both)!
pacemaker and other excitable issues usually see PK INCREASING during an AP bc they would open in response to depolarization, however in cardiac contractile cells it is the influence of CALCIUM that screws up this dynamic - its high + extracellular activity requires K+ at a different time, during rest to keep it hyperpolarized
During a cardiac action potential, depolarization causes the open of voltage-gated _ channels, which not only affects the membrane potential but also is instrumental in triggering muscle cell contractions, prolonging the AP for cardiac contractile cells
CALCIUM
mOST cardiac contractile cells are _ muscle cells
ventricular
they have to do most of the heavy lifting
Cardiac contractile cells have UN/STABLE resting potentials, unlike pacemaker cells
STABLE
pacemaker cells keep on going, therefore they can’t rest; they are always holding a graded potential that keeps working (autorhythmicity)
There are 5 phases of cardiac contractile cell permability:
0 - _ _, caused by similar events to neuronal ones
action potential (not rest, but starts first with an AP)
