Dr. Musch Test 3 info Flashcards

1
Q

Mean Arterial pressure is the product of what 2 variables?

A

MAP= Q x SVR

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2
Q

According to the Fick equation, oxygen uptake (VO2) is the product of what two varibales

A

Fick equation= VO2= Q x a-VO2

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3
Q

Cardiac output (Q) is the product of what two variables?

A

Q= HR x SV

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4
Q

The output of the right ventricle is equal to the output of the left ventricle. True or False?

A

True

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5
Q

How much of the total blood volume is found on the venous side of circulation?

A

70%

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6
Q

What are the major differences between the right and left ventricle in regards to structure and function?

A

A. right ventricle- volume pump- pumps to pulmonary circulation
B. Left ventricle - pressure pump- pumps to systemic circulation (thicker)

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7
Q

The electrical potential from one cardiac muscle cell is transferred to another cardiac muscle cell. What structure contributes to this transfer between cells?

A

intercalated disk

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8
Q

cardiac muscle cells can contract on their own without any nerve innervation. Can skeletal muscle cells do the same?

A

NO

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9
Q

What relationship contributes to intrinsic regulation of stroke volume and therefore cardiac output.

A
Q= HR x SV 
SV= the difference between end diastolic volume (EDV) and end systolic volume (ESV)
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10
Q

Explain the anatomical difference between the sympathetic and parasympathetic nerves

A

a. Sympathetic nerves- originate in spine between 1st thoracic (T1) and second lumbar (L2) vertebrae
b. parasympathetic nerves- originate in the cranial nerves

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11
Q

What influence does the sympathetic and parasympathetic nerves have on the heart?

A

a. sympathetic nerves (spinal cord)- NE stimulate B1 receptor in the heart, which increases HR
b. parasympathetic nerves- (cranial nerve, vagus)- ACh, which stimulates the muscarinic receptor in the heart which decreases HR

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12
Q

What is the neurotransmitter of the sympathetic nervous system?

A

Norepinephrine

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13
Q

What type of receptor does NE stimulate in the heart?

A

B1 receptors in the heart

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14
Q

What is the neurotransmitter of the parasympathetic nervous system?

A

ACh - acetylcholine

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15
Q

What type of receptor does ACh stimulate in the heart?

A

Muscarinic receptors

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16
Q

The ECG or EKG can be broken down into three different electrical events. what are they?

A
  1. P wave- atrial depolarization (contraction)
  2. QRS complex- atrial repolarization and ventricular depolarization
  3. T wave- ventricular depolarization
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17
Q

What is the primary factor that determines ventricular end- diastolic volume (LVEDV)?

A

Preload

  • blood volume
  • body position
  • pumping action of the skeletal muscle
  • atrial contribution to ventricular filling-exercise
  • venous tone (venous return)
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18
Q

Baroreceptors are mechanoreceptors and sense changes in stretch due to changes in arterial pressure. True or false?

A

True

  • increasing arterial bp they act to inhibit sympathetic centers, which reduces Q
  • bp drops- less impulses sent to vasomotor center, which decreases the parasympathetic tone and increases sympathetic tone
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19
Q

Baroreceptors are located in 2 different places in the cardiovascular system. Name the 2 different places.

A

1) aortic arch

2) carotid arteries

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20
Q

What are the hearts mechanical events that follow the three different electrical events?

A
p wave (atrial depolarization)
QRS complex ( atrial repol and ventricular depol)
T wave (ventricular repol)
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21
Q

If there is very low pressure in the systemic circulation the baroreceptors sense this low pressure and activates the ________ nervous system.

A

sympathetic nervous system

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22
Q

The activation of the sympathetic nervous system results in increases in 3 different hemodynamic variables that work to bring pressure up back towards normal values. They are:

A
  1. HR - NE stimulates B1 receptors in the heart to increase HR
  2. SV- alpha receptors in venous return - frank starling cause vasoconstriction therefore increasing SV
  3. SVR- alpha receptors cause vasoconstriction in arterioles
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23
Q

What is the mean pressure in the capillaries?

A

30 mmHg

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24
Q

Left ventricular end- diastolic pressure is 5-7 mmHg in normal individuals, but the diastolic blood pressure in the brachial arteries is 80 mmHg. Why are theses diastolic pressures different?

A

pressure decreases due to aortic valve opening and closing, 2/3 time spent in diastole (relaxation)

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25
Q

The cross sectional area of the circulatory system is at its greatest in the capillaries. True or false?

A

True

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26
Q

The velocity of blood is at its greatest in the aorta and at its lowest in the vena cava. True or false?

A

the lowest velocity is in the capillaries

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27
Q

What type of blood vessel has the greatest wall to lumen ratio?

A

wall to lumen ratio is greatest in ARTERIOLES

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28
Q

what blood vessels are known as regulators?

A

arterioles

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29
Q

what is the diameter of a capillary?

A

6 microns

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30
Q

Left ventricular end diastolic pressure is 7-8 mmHg in normal individuals, but the diastolic blood pressure in the brachial arteries is 80 mmHg. What are these diastolic pressures different?

A

pressure decreases due to the aortic valve opening and closing

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31
Q

the cross-sectional area of the circulatory system is at its greatest in the capillaries. True or False?

A

TRUE. cross sectional area of the circulatory system is greatest in capillaries

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32
Q

The velocity of blood is at its greatest in the aorta and at its lowest in the vena cava. True or false?

A

False

Velocity of blood is greatest in aorta, and lowest in the capillaries

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33
Q

What blood vessel has the greatest wall to lumen ratio?

A

arterioles

34
Q

what is the diameter of a capillary?

A

6 microns

35
Q

What hemodynamic parameter is extrinsic regulation closely associated with (MAP=Q x SVR)?

A

neural control directed toward maintaining blood flow/ sympathetic nervous system

36
Q

Describe autoregulation of blood flow by graphing blood flow and blood vessel diameter as a function of perfusion pressure (MAP)

A

Autoregulation- intrinsic regulation- for autoregulation to occur the smooth muscle of the resistance vessel must relax as the arterial blood pressure decreases and vice versa

37
Q

In the peripheral circulation what type of receptors does norepinephrine stimulate to cause vasoconstriction?

A

alpha 1 receptors

NE stimulate alpha receptors to vasoconstrict

38
Q

where are alpha receptors found?

A

in the blood vessels

39
Q

in the heart, what type of receptor does norepinephrine stimulate to cause and increase in HR?

A

Beta 1

40
Q

in the peripheral circulation what type of receptors does epinephrine stimulate to cause vasodilation?

A

beta 2

E stimulates beta 2 to cause vasodilation

41
Q

What organ does epinephrine come from?

A

adrenal gland (medulla)

42
Q

EDRF or Nitric Oxide (NO) is released from endothelial cells and stimulates the increase in cGMP in vascular smooth muscle. True or false?

A

TRUE

43
Q

Increases in cGMP in smooth muscle cells results in smooth muscle relaxation with the result being vasodilation in a blood vessel. True or false?

A

True - vasodilation mechanism

44
Q

Prostacyclin (PGI2) is released from endothelial cells and stimulates the increase in cAMP in smooth muscle cells. True or false?

A

TRUE

45
Q

Increases in cAMP in smooth muscle cells results in smooth muscle relation with the result being vasodilation in a blood vessel. True or false?

A

True

46
Q

ACh will stimulate what type of receptor on endothelial cells and result in the increase in NO and vasoilation of the blood vessels?

A

Muscarinic receptors

47
Q

Besides NE, what other two substances will produce a vasoconstriction in a blood vessel? Do these other substances play a significant role in controlling blood flow to the working muscles during exercise?

A
  1. AT2
  2. Endothelin (EDCF)

No they do not play a significant role during exercise. AT2 and endothelin plays a role in disease. NE is used during exercise

48
Q

The cardiovascular centers in the brain control sympathetic outflow to the body. Name the 4 different feedback systems that can influence sympathetic outflow via afferent input into the cardiovascular centers.

A
  1. arterial barorecetptors
  2. heart and lung receptors
  3. chemoreceptors
  4. muscle receptors (mechanoreceptors)
49
Q

A fight between vasoconstriction and vasodilation continually occurs in skeletal muscle. The vasoconstrictor arm is mediated by the sympathetic nervous system. Name the different vasodilator mechanisms discussed in lecture.

A
  1. autoregulation
  2. beta 2 receptors
  3. vasodilator metabolites
  4. prostaglandins
  5. emotion (releases ACh)
  6. histamine containing cell
  7. endothelial cells (EDRF= NO, PGI2, EFHF)
50
Q

in both skeletal muscle and heart, tissue metabolites will produce a vasodilation. Who are the primary players and who is the big dog of the tissue metabolites?

A
  1. Primary players have an early influence

2. Late influence Big Dog is adenosine

51
Q

In the coronary circulation there are two different neural pathways that can influence blood flow. What are the two different neural pathways? What are their neurotransmitters?

A
  1. parasympathetic- ACh stimulates muscarinic receptors

2. sympathetic - NE stimulates B1 receptors

52
Q

What are the potential pathways of vasodilation found in the organs of the splanchnic region?

A
  1. autoregulation
  2. gastrointestinal hormones
  3. endothelial cells ( EDRF (NO) and PGI2 (prostacylclin))
53
Q

What are the pathways of potential vasodilation found in the kidneys?

A
  1. autoregulation

2. endothelial cells (EDRF= NO and PGI2)

54
Q

Increases in shear stress in a blood vessel will result in vasodilation of that blood vessel via an increase in NO in the endothelial cell. True or false?

A

TRUE

55
Q

What is the enzyme that catalyzes the reaction of L arginine to citrulline and NO?

A

NOS - nitric oxide synthase

56
Q

The role of NO is significantly different in different types of muscle fibers during exercise. It contributes significantly in _________ muscle fibers and very little in _______ types of muscle fibers as far as blood flow regulation.

A

NO plays a significant role in Type 1 oxidative muscle fibers.

It does not play a role in glycolytic muscle fibers p< .001

57
Q

When performing calculations with the fick equation, one has to remember to change oxygen content (either arterial or mixed venous) from ml O2/100 ml of blood to ml O2/liter of blood. True or false?

A

True

58
Q

The avO2 measured at rest is ~ 4-5 ml O2/100 ml of blood or ~40-50 ml O2/liter of blood. True or false?

A

True

59
Q

How is the a-vO2 difference increased in going from rest to exercise? What happens in the arterial (CaO2) and mixed venous (CvO2) O2 contents?

A
  1. CaO2 stays the same from rest to exercise
  2. CvO2 decreases in a curvilinear fashion
  3. avO2 increases in a curvilinear fashion
60
Q

Assuming that you are a normal college student, what are approximate values for Q and a-vO2 measured at rest?

A

Q= 6000 ml/min

a-vO2= 4.6 volume %

61
Q

Assuming that you are a normal college student, what are the approximate values for Q and a-VO2 measured at VO2 max?

A

Q= 25 L/min

a-vO2= 15 volume %

62
Q

what organs receive a very large amount of blood flow when compared to oxygen uptake?

A

splanchnic organs (24)
renal (69)
skin (100)

63
Q

splanchnic organs, renal organs, and skin organs are highly dependent upon the _______ in controlling blood flow and oxygen delivery to their respective tissues.

A

sympathetic nervous system

64
Q

what organs receive a low amount of blood flow when compared to their oxygen uptake?

A

heart muscle (9)
cerebral (16)
muscle (17)

65
Q

heart muscle, cerebral, and muscle are highly dependent on ______ in controlling blood flow and oxygen delivery to their respective tissues

A

metabolism

66
Q

cardiac output increases in a linear fashion as a function of exercise intensity or workload. Draw the HR and SV response in going from rest to exercise.

A

HR- increases linearly

SV- goes up linearly until it reaches 45% VO2 max then levels off due to the limitation of the heart (pericardium)

67
Q

the drug atropine blocks muscarinic receptors found in the heart. true or false?

A

true

atropine blocks muscarinic receptors

68
Q

the drug atenolol blocks what receptors in the heart?

A

beta 1 receptors

69
Q

Blocking beta receptors in the heart produces an increase in heart rate. True or false?

A

False: beta 1 receptors stimulate an increase in HR

atenolol block beta 1 receptors

70
Q

how do you estimate your HR?

A

220-age= max HR

71
Q

What are the 3 primary determinants of stroke volume?

A
  1. preload
  2. afterload
  3. contractility
72
Q

what hemodynamic parameters can be measured that are indicators of preload afterload and contractility (primary determinants of SV)?

A
  1. preload indicators: LVEDV and LVEDP
  2. afterload indicators : systolic BP
  3. contractility - LV Dp/Dt
73
Q

in going from the condition of rest to max exercise, what happens to preload afterload and contractility?

A

they all increase, but afterload has a negative effect. preload and contractility have a positive effect overriding the negative effect so SV goes UP

74
Q

name two contributors to increases in SV by increasing preload. Which one increases early during exercise and which increases at workloads greater than 45% of VO2 max?

A
  1. muscle pump - early during exercise

2. sympathetic vasoconstriction - later during exercise

75
Q

an undergrad student in kin is 20 years old and has a measured VO2 max of 3.5 liters/min. Assuming a Q to VO2 ratio of 6:1, what is the estimated maximal stroke volume of this individual?

A

3.5 x 6= Q
HR= 220-age
Q= HR x SV

plug in the info
105 ml/beat

76
Q

what anatomical structure is thought to be the primary determinant of maximal stroke volume? It restricts LVEDV.

A

pericardium

77
Q

from the transition from rest to max exercise there is a significant increase in the a-vO2. This is due to the decrease in CvO2 as CaO2 stays relatively constant. Name 3 factors that contribute to the decrease in CvO2.

A
  1. amount of muscle mass being recruited
  2. capillaries (longitudinal recruitment)
  3. mitochondrial oxidative capacity
78
Q

associated with capillary longitudinal recruitment, there are increases in both RBC flux and capillary hematocrit. True or false?

A
True
Longitudinal recruitment
-increased capillary RBC flux
-increased capillary hematocrit
-increased SA for exchange
-increased diffusive O2 transport and exchange
79
Q

systolic blood pressure is dependent on what cardiovascular variable during exercise? What cardiovascular variable contributes to the maintenance or the reduction in diastolic blood pressure during exercise?

A
  • Systolic blood pressure is dependent on Q during exercise

- diastolic blood pressure is dependent on SVR

80
Q

systemic vascular resistance decreases in a linear fashion in going from resting condition to max exercise. True or False?

A

false

SVR decreases in a CURVILINEAR fashion

81
Q

systemic vascular resistance decreases in a linear fashion in going from resting condition to max exercise. True or False?

A

false

SVR decreases in a CURVILINEAR fashion

82
Q

vasodilation occurs I the skeletal muscle during the transition from rest to exercise. What are thought to be the 3 major contributors to vasodilation in the muscle during the transition? When are they believed to become active contributors?

A

1) EDRF (Nitric Oxide) : early
2) Epi stimulates beta 2 receptors (associated with fight or flight) : early
3) Adenosine (BIG DOG) : later