Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cardiology > Physiology > Flashcards

Physiology Flashcards

1
Q

What is the equation for MABP?

A

((2 x diastolic pressure) + systolic pressure)/3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a different equation for MABP?

A

diastolic pressure + 1/3 (systolic - diastolic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the normal range of MABP?

A

70-105 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the minimum MABP required for perfusion of coronary arteries, brain and kidneys?

A

60 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What effect does sympathetic stimulation have on the arterioles and veins?

A

Vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which system controls the short term regulation of mean arterial blood pressure?

A

The baroreceptor reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where are the baroreceptors?

A

Aortic arch

Carotid sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which nerves do the baroreceptor signals travel in to reach the brain and where in the brain do they go?

A

CN IX and CN X

Medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do the baroreceptors respond to a decrease in blood pressure?

A

Decrease firing from baroreceptors
Decrease vagal activity, so sympathetic activity increases
Heart rate and stroke volume increase ergo cardiac output increases
Vasocontriction occurs, so TPR increases
Venoconstriction occurs, so venous return increases and SV increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do the baroreceptors respond to an increase in blood pressure?

A 
Increase firing from baroreceptors
Increase vagal activity
HR decreases, SV decreases, CO decreases
Vasodilatation occurs, so TPR decreases
Venodilatation occurs, so venous return decreases and SV decreases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which receptor regulates the contraction of vascular smooth muscle?

A

L-type Ca2+ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What molecule does the calcium-calmodulin compound activate?

A

Myosin light chain kinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does myosin light chain kinase do that allows contraction?

A

Phosphorylates, and thus activates, myosin light chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What effect does phosphorylation of MLCK have on it?

A

Inactivates it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which enzyme dephosphorylates phosphorylated MLC?

A

Myosin-LC-phosphatase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What molecule activates myosin-LC-phosphatase and this stimulates relaxation?

A

cGMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where are the electrical signals of the heart generated?

A

Within the heart itself - pacemaker cells of the sinal atrial node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where is the SA node located?

A

In the upper right atrium close to where the SVC enters the right atrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the term given to the state where the heart is controlled by the sinal atrial node?

A

Sinus rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the pacemaker potential?

A

The potential that must be taken to threshold potential to generate an action potential in the SA node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What generates the pacemaker potential?

A

It is slow depolarisation caused by a decrease in potassium efflux and a slow sodium influx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the “funny current”?

A

The slow sodium influx of the pacemaker potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What causes the rising phase of the action potential?

A

Activation of voltage gated Ca2+ channels

Rapid influx of Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the falling phase of the action potential caused by?

A

Potassium efflux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Which junctions spread electrical excitation from cell to cell?
Gap junctions
26
Where is the AV node located?
At the base of the right atrium, just above the junction between atria and ventricles
27
What is the only point of electrical contact between atria and ventricles?
AV node
28
What structures allow the spread of the action potential to the ventricles?
The bundle of His | Perkinje fibres
29
What is the resting potential of the ventricular muscle cell?
-90mV
30
What is the rising phase of the ventricular muscle action potential caused by?
Fast sodium influx | This is phase 0
31
What is phase 1 of the ventricular muscle action potential caused by?
Closure of Na+ channels | K+ efflux
32
What is phase 2 or the "plateau" phase of the ventricular muscle action potential caused by?
Ca2+ influx
33
What is phase 3 of the ventricular muscle action potential caused by?
Closure of Ca2+ channels | K+ efflux
34
What is phase 4 of the ventricular muscle action potential?
Resting membrane potential
35
What autonomic influence dominates control of the heart under normal resting conditions?
Vagal tone
36
What effect does vagal stimulation have on the slope of the pacemaker potential?
Decreases the slope of the pacemaker potential - takes longer to reach threshold
37
What is the p wave of the ECG?
Atrial depolarisation
38
What is the QRS complex of the ECG?
Ventricular depolarisation masking atrial repolarisation
39
What is the T wave of the ECG?
Ventricular repolarisation
40
What is the PR interval of the ECG?
AV node delay
41
Whatt is the ST segment of the ECG?
Ventricular systole
42
What is the TP interval of the ECG?
Diastole
43
How is cardiac muscle described?
Striated
44
What causes the striation of the cardiac muscle?
Regular arrangement of contractile protein
45
What do desmosomes do?
Provide mechanical adhesion between cells
46
What are myofibrils?
The contractile units of muscle - each muscle fibre contains many myofibrils
47
What is the name given to the thin protein filaments that cause the lighter appearance in myofibrils and fibres?
Actin
48
What is the name given to the thick protein filaments that cause the darker appearance in myofibrils and fibres?
Myosin
49
How is cardiac muscle tension produced?
Actin sliding on myosin
50
What does force generation in the heart depend upon?
ATP-dependant interaction between myosin and actin filaments
51
What covers the binding sites on the actin filaments?
Tropomyosin
52
What controls the movement of the tropomyosin from the actin binding sites to allow cross bridge formation?
Troponin - calcium binding causes troponin to move the tropomyosin away from the sites
53
Where is calcium stored within muscle cells?
Sarcoplasmic reticulum
54
What is the release of Ca2+ from the sarcoplasmic reticulum in cardiac cells dependant on?
Extracellular Ca2+
55
When in the ventricular muscle action potential does release of Ca2+ from sarcoplasmic reticulum occur?
Phase 2 - influx of Ca2+ released more Ca2+ from SR which activates contraction and generates systole
56
What is the refractory period?
A period following an action potential in which it is not possible to generate another action potential
57
What state are the sodium channels in during the plateau phase of the action potential and how does this contribute to the refractory period?
The Na+ channels are closed, which is important for the refractory period to occur as phase 0 of the action potential is caused by Na+ opening and fast sodium influx Ergo, with the Na+ channels closed, the action potential cannot be triggered
58
What state are the potassium channels in during the descending phase of the ventricular muscle action potential and how does this contribute to the refractory period?
The K+ channels are open - the membrane cannot be depolarised
59
What is the stroke volume?
The volume of blood ejected by each ventricle per heart beat
60
How can the SV be calculated?
End diastolic volume - end systolic volume
61
What is the diastolic length of the myocardial fibres determines by?
The volume of blood within each ventricle at the end of diastole - i.e. end diastolic volume The myofibres stretch to accommodate the volume of blood
62
What determines the cardiac preload?
End diastolic volume
63
What is the end diastolic volume determined by?
The venous return to the heart
64
What does the Frank-Starling mechanism describe?
The relationship between venous return, end diastolic volume and stroke volume
65
What does Starling's law of the heart state?
The greater the end diastolic volume, the greater the stroke volume
66
What is the afterload?
The resistance into which the heart is pumping
67
How does the Frank-Starling mechanism partially compensate for decreased stroke volume caused by increased afterload?
When there is increased afterload, the heart is unable to eject the full stroke volume - this results in increased EDV The force of contraction increases by the Frank-Starling mechanism to eject full SV
68
Why does ventricular hypertrophy occur in untreated hypertension?
The force of contraction rises by the Frank-Starling mechanism to overcome the increased afterload The heart is doing more work than it can cope with
69
Where is the main site of TPR?
Arterioles
70
What is the vasomotor tone?
The vascular smooth muscles are partially constricted at rest
71
What causes the vasomotor tone?
The tonic discharge of sympathetic nerves resulting in continuous release of noradrenaline
72
What effect does antidiuretic hormone/vasopressin have on vascular smooth muscle?
Causes vasoconstriction
73
What role does the intrinsic control of vascular smooth muscles play in metabolism?
The control mechanisms match the blood flow of different tissues to their metabolic needs
74
What factors result in vasodilatation?
``` Decreased local PO2 Increased local PCO2 Increased local H+ Increased extra-cellular K+ Release of: histamine, prostaglandins, bradykinin, NO ```

Cardiology (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions