Download 6 Heart physiology flashcards

Heart Physiology
1. What does the Bundle of His do to the
electrical signal that is trying to pass
through? Why do we need this?
2. Why is the AV node a slow conductor?
3. What are the two types of fibers in the
heart?
4. What can specialized fibers do?
5. What is the pathway of conduction in the
heart?
6. How can the specialized fibers in the
heart generate their own action
potential?
7. What two things give the heart its rhythm?
8. What neurotransmitter slows the heart
rate? To what branch of the ANS does it
belong?
9. What neurotransmitter speeds up the
heart rate? To what branch of the ANS
does it belong?
10. How does the sympathetic nervous system
speed up the heart rate?
Slows it down to give the atria a chance to finish
contracting before the ventricles start to contract
The cells there have a smaller diameter, and
there are fewer sodium channels
Specialized fibers and contractile fibers
Initiate an action potential without being
stimulated by a nerve.
SA node  AV node  Bundle of His  Bundle
Branches  Purkinje fibers
They cannot maintain a stable resting membrane
potential. It gradually drifts to depolarization
because they gradually increase in permeability to
sodium ions.
The specialized fibers of the heart and the
autonomic nervous system
Acetylcholine (Ach). Parasympathetic division
Norepinephrine (NE). Sympathetic division
By increasing sodium and calcium permeability
and decreasing potassium permeability
11. How does the parasympathetic nervous
system slow down the heart rate?
By decreasing sodium and calcium permeability
and increasing potassium permeability
12. What is the formula to measure cardiac
output (You can use Q or CO to represent
cardiac output)?
13. What is another name for the Ventricular
Ejection Volume?
Q = Stroke Volume × Heart rate
Stroke Volume
(SV)
What is the abbreviation for this?
~ 70ml
What is the approximate amount of blood
released during each ejection?
14. What is the formula for the Ejection
Fraction?
What is the approximate percentage of
blood ejected at rest?
During vigorous exercise?
SV/ EDV
EF is ~ 60% at rest
EF is about 90% during exercise
Heart Physiology
15. What is the End Systolic Volume of blood
left in the heart (at rest)?
16. What does HR stand for?
17. What is the average liter per minute for
cardiac output for an adult?
18. What is the formula for cardiac output?
19. What does SV stand for?
20. What is the definition of blood flow?
21. What is the formula for cardiac reserve?
22. If resting CO = 6 L/min and after exercise it
increases to 21 L/min, what is the cardiac
reserve?
23. What is the definition of EDV?
24. What is the definition of ESV?
25. If the end diastolic volume is 120 ml
And the end systolic volume is 50 ml
What is the stroke volume?
What is the ejection fraction?

26. What is the normal ejection fraction
percent?
27. If heat rate is 80 beats/minute, what is the
cardiac output with average stroke vol?
28. If EDV = 130 ml and ESV = 50 ml:
a. What is the SV?
b. What is the EF?
c. What is the CO if HR is 80 bpm?
29. If EDV = 110 ml and ESV = 60 ml:
a. What is the SV?
b. What is the EF?
c. What is the CO if HR is 75 bpm?
d. Is this heart diseased?
30. What is the equation for Ohm’s Law?
31. What two things influence Flow (Q)
through blood vessels?
32. How is “Pressure” difference related to
blood flow: indirectly or directly?
33. How is “Resistance” difference related to
blood flow indirectly or directly?
34. As the blood flow goes up in arterioles,
50ml
Heart Rate
5 L/min
CO= HR x SV
Stroke Volume
Quantity of blood that passes a given point in the
circulation in a given period of time.
Max CO – Resting CO = Cardiac Reserve
21 – 6 = 15 L/min
EDV (end diastolic volume) is the amount of blood
that has poured into the left ventricle after
diastole (ventricle relaxation)
ESV (end systolic volume) is the amount of blood
left in the left ventricle after systole (ventricular
contraction)
SV = EDV - ESV
SV = 120 – 50 = 70 ml
EF = SV/EDV
EF = 70/120 = 58%
60%
(HR x stroke volume)
80 x 70= 5600ml/min
a. 130 – 50 = 80 ml
b. 80/130 = 62%
c. 80 bpm x 80 ml = 6400ml/min
a. 110 – 60 = 50 ml
b. 50/110 = 45%
c. 75 bpm x 50 ml = 3750ml/min
d. yes, heart is diseased. (EF < 50%)
Q= ∆P/R
Pressure and Resistance
Directly
Indirectly
Resistance of the vessel goes down.
Heart Physiology
what happens to the resistance?
35. Is the pressure in the aorta higher or lower
than the pressure in capillaries?
36. As the blood flow in the aorta goes up,
what happens to the pressure difference?
37. Ohm’s Law is a formula to show the
relationship between cardiac output, blood
pressure, and peripheral resistance. Write
the formula to solve for cardiac output (Q),
and the formula to solve for blood pressure
(P), and the formula to solve for peripheral
resistance (R).
38. Using P=RQ, calculate P if:
a) R is 25 and Q is 5
b) R is 10 and Q is 5
c) R is 50 and Q is 5
39. Using R= P/Q, calculate R if:
a) P is 100 and Q is 5
b) P is 80 and Q is 5
c) P is 125 and Q is 5
40. The patient presents with high blood
pressure, normal CO: Is peripheral
resistance high or low?
41. The patient presents with low blood
pressure, normal CO: Is peripheral
resistance high or low?
42. The patient presents with high CO, normal
blood pressure: Is peripheral resistance
high or low?
43. The patient presents with low CO, normal
blood pressure: Is peripheral resistance
high or low?
44. The patient presents with high CO, normal
peripheral resistance: Is blood pressure
high or low?
Higher
The pressure difference also goes up.
Q = P/R
P = QR
R = P/Q
a) P = 125
b) P = 50
c) P = 250
a) R = 20
b) R = 16
c) R = 25
high blood pressure, normal CO, peripheral
resistance high
low blood pressure, normal CO, peripheral
resistance low
high CO, normal blood pressure: peripheral
resistance low
low CO, normal blood pressure, peripheral
resistance high
high CO, normal peripheral resistance: blood
pressure high
45. The patient presents with normal CO, low
peripheral resistance: Is blood pressure
high or low?
normal CO, low peripheral resistance: blood
pressure low
46. The patient presents with normal CO, high
peripheral resistance: Is blood pressure
high or low?
normal CO, high peripheral resistance: blood
pressure high
Heart Physiology
47. The patient presents with low CO, normal
peripheral resistance: Is blood pressure
high or low?
48. The patient presents with high blood
pressure, normal peripheral resistance: Is
cardiac output high or low?
49. The patient presents with normal blood
pressure, low peripheral resistance: Is
cardiac output high or low?
50. The patient presents with normal blood
pressure, high peripheral resistance: Is
cardiac output high or low?
51. The patient presents with low blood
pressure, normal peripheral resistance: Is
cardiac output high or low?
52. What three main factors affect cardiac
output (blood flow), and what are their
effects?
53. What’s the most important regulator in
blood flow?
54. Which of the following are vasodilators,
and which are vasoconstrictors?
Epinephrine
Norepinephrine
Bradykinin
Nitric oxide
Carbon dioxide
Vasopressin (ADH)
Potassium/hydrogen ions
Thromboxane
Lactic acid
Elevated temperatures
Adenosine/ ADP
Histamine
Angiotensin
Caffeine
55. In what three ways is the brain involved in
short term blood pressure control?
56. What organ is responsible for long term
control of blood pressure?
57. What vessels do sympathetic nerve fibers
low CO, normal peripheral resistance: blood
pressure low
high blood pressure, normal peripheral
resistance: cardiac output high
normal blood pressure, low peripheral resistance:
cardiac output high
normal blood pressure, high peripheral
resistance: cardiac output low
low blood pressure, normal peripheral resistance:
cardiac output low
Blood viscosity (high viscosity decreases CO)
Vessel length (longer vessel decreases CO)
Vessel diameter (larger increases CO)
Vessel Resistance (larger diameter has less
resistance than smaller diameter vessel)
• Vasodilators
Bradykinin
Histamine
Nitric oxide
Elevated temperatures
Potassium/hydrogen ions
Lactic acid
Carbon dioxide
Adenosine/ ADP
• Vasoconstrictors
Norepinephrine
Epinephrine
Angiotensin
Vasopressin (ADH)
Thromboxane
Caffeine
Vasomotor (causes arteriole constriction when
blood pressure is too low, and arteriole dilation
when BP is too high)
Cardioinhibitory (Vagus nerve signals heart to
decrease rate; parasympathetic)
Cardioacceleratory (sympathetic branch of the
ANS speeds up heart rate).
Kidney
All vessels except capillaries
Heart Physiology
innervate?
58. What effect do sympathetic nerves have on
arterioles?
59. What are baroreceptors and what do they
respond to?
60. Name two locations where baroreceptors
are found.
61. What cranial nerve transmits signals from
the carotid sinus?
Aortic arch?
62. As pressure increases, it causes an increase
in number of impulses from baroreceptors.
When baroreceptor impulses increase,
what two things happen?
63. What effect does this have on BP?
64. As pressure decreases, it causes an
decrease in number of impulses from
baroreceptors. When baroreceptor
impulses decrease, what happens?
65. What effect does this have on BP?
66. Are baroreceptors important in short term
or long term regulation of blood pressure?
67. What function do baroreceptors have in
the body?
68. Do baroreceptors trigger the sympathetic
or parasympathetic nervous system?
69. Standing up to quickly causes what type of
reaction to a person’s blood pressure, (BP)?
70. What three drugs affect CO?
71. How does ATROPINE work?
How does it affect CO, HR, and BP?
When would a patient need atropine?
72. How does PILOCARPINE work?
How does it affect CO, HR, and BP?
73. How does PROPRANALOL work?
How does it affect CO, HR, and BP?
74. Which drug(s) decreases heart rate?
Causes vasoconstriction, which increases vascular
resistance.
Nerve endings in the walls of arteries that
respond to stretch in a blood vessel. Therefore,
they fire an impulse when the blood pressure is
elevated, since that is what stretches the artery.
When blood pressure is low, they are not
stimulated, and the brain detects that also.
Carotid bifurcation (between common carotid and
internal and external carotid arteries) this area is
called carotid sinus.
Walls of the aortic arch.
Carotid sinus: CN IX (Glossopharyngeal nerve)
Aortic arch: CNX (vagus nerve)
-inhibition of vasoconstriction  vasodilation
-activation of the vagal center (parasympathetic
nervous system)
BP decreases
the vasomotor system becomes stimulated
(sympathetic nervous system).
BP increases
Short term regulation.
They maintain relatively constant pressure
regardless of body position.
Both
It causes a decrease in the central blood volume,
and cardiac output which results in decreased
arterial pressure, (BP).
Atropine, Pilocarpine, and Propranalol
Blocks parasympathetic system (increase in
sympathetic response, so HR speeds up, CO
increases, and BP increases)
A patient whose BP is dangerously low (heroin
drug overdose)
Causes skeletal muscle neurons to release ACH.
Decreases HR, CO, and BP.
Blocks sympathetic effect of heart.
Decreases HR, CO, and BP.
Pilocarpine and Propranalol
Heart Physiology
75. Which drug increases heart rate?
Atropine
76. Which drug blocks the parasympathetic
system?
77. What drug is derived from the foxglove
plant?
78. What effect does Digitalis have on the
heart rate?
79. What effect does Digitalis have on the force
of contraction of the heart?
80. What is the main disadvantage of using
Digitalis?
81. What is edema?
82. List 8 things that may cause edema.
Hints: high or low BP? What 2 types of vein
problems? What 2 types of plasma
problems? What heart problem? What
lymph problem? What parasitic infection?
Atropine
Digitalis
Digitalis slows the heart rate.
Digitalis increases the force of contraction.
It is extremely toxic.
Excessive accumulation of tissue fluid
High arterial blood pressure.
Venous obstruction.
Valve problems
Leakage of plasma proteins into interstitial fluid.
Decreased plasma proteins.
Cardiac failure
Obstruction of lymphatic drainage.
Elephantiasis
NOTE: There are 28 fill in the blank questions on the exam from
the Heart Physiology Homework sheets posted on my website.
The answers to the homework are included on the sheets.
There are another 10 fill in the blanks from the regular Unit 3
flashcards. There will be a total of 100 questions, one point
each. 56 questions are multiple choice, 44 fill in the blanks.