Dr. Musch Test 3 info Flashcards by Jennica O'Neill

Mean Arterial pressure is the product of what 2 variables?

MAP= Q x SVR

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

Fick equation= VO2= Q x a-VO2

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

Q= HR x SV

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

True

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

70%

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

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

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

intercalated disk

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

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

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

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Explain the anatomical difference between the sympathetic and parasympathetic nerves

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

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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What is the neurotransmitter of the sympathetic nervous system?

Norepinephrine

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What type of receptor does NE stimulate in the heart?

B1 receptors in the heart

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What is the neurotransmitter of the parasympathetic nervous system?

ACh - acetylcholine

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What type of receptor does ACh stimulate in the heart?

Muscarinic receptors

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

P wave- atrial depolarization (contraction)
QRS complex- atrial repolarization and ventricular depolarization
T wave- ventricular depolarization

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

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

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

1) aortic arch

2) carotid arteries

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

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

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

sympathetic nervous system

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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:

HR - NE stimulates B1 receptors in the heart to increase HR
SV- alpha receptors in venous return - frank starling cause vasoconstriction therefore increasing SV
SVR- alpha receptors cause vasoconstriction in arterioles

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What is the mean pressure in the capillaries?

30 mmHg

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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?

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

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

True

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

the lowest velocity is in the capillaries

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

wall to lumen ratio is greatest in ARTERIOLES

what blood vessels are known as regulators?

arterioles

what is the diameter of a capillary?

6 microns

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?

pressure decreases due to the aortic valve opening and closing

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

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

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

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

What blood vessel has the greatest wall to lumen ratio?

arterioles

what is the diameter of a capillary?

6 microns

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

neural control directed toward maintaining blood flow/ sympathetic nervous system

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

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

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

alpha 1 receptors NE stimulate alpha receptors to vasoconstrict

where are alpha receptors found?

in the blood vessels

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

Beta 1

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

beta 2 E stimulates beta 2 to cause vasodilation

What organ does epinephrine come from?

adrenal gland (medulla)

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

TRUE

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

True - vasodilation mechanism

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

TRUE

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

True

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

Muscarinic receptors

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?

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

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.

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

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.

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)

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?

1. Primary players have an early influence | 2. Late influence Big Dog is adenosine

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?

1. parasympathetic- ACh stimulates muscarinic receptors | 2. sympathetic - NE stimulates B1 receptors

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

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

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

1. autoregulation | 2. endothelial cells (EDRF= NO and PGI2)

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?

TRUE

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

NOS - nitric oxide synthase

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.

NO plays a significant role in Type 1 oxidative muscle fibers. It does not play a role in glycolytic muscle fibers p< .001

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?

True

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?

True

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?

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

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

Q= 6000 ml/min a-vO2= 4.6 volume %

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

Q= 25 L/min a-vO2= 15 volume %

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

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

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

sympathetic nervous system

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

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

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

metabolism

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.

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

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

true | atropine blocks muscarinic receptors

the drug atenolol blocks what receptors in the heart?

beta 1 receptors

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

False: beta 1 receptors stimulate an increase in HR atenolol block beta 1 receptors

how do you estimate your HR?

220-age= max HR

What are the 3 primary determinants of stroke volume?

1. preload 2. afterload 3. contractility

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

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

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

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

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?

1. muscle pump - early during exercise | 2. sympathetic vasoconstriction - later during exercise

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?

3.5 x 6= Q HR= 220-age Q= HR x SV plug in the info 105 ml/beat

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

pericardium

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.

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

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

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

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?

- Systolic blood pressure is dependent on Q during exercise | - diastolic blood pressure is dependent on SVR

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

false SVR decreases in a CURVILINEAR fashion

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

false SVR decreases in a CURVILINEAR fashion

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?

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