A&P 2-Exam 3

Which side of the heart is in charge of Pulmonary circulation? To where does it pump blood?

Right side, pumps blood to the lungs

Which side of the heart is in charge of Systemic circulation? To where does it pump blood?

Left side, pumps blood out to body

Which chamber of the heart receives blood returning from the body (systemic circulation)? Is this blood fully oxygenated or partially oxygenated?

Right atrium, deoxygenated

Which chamber of the heart receives blood from the pulmonary circulation? Is this blood fully oxygenated or partially oxygenated?

left atrium, fully oxygenated

Which side of the heart has to pump against a large resistance or high pressure?

left

Which side of the heart has to pump against a small resistance or low pressure?

right

List the structures in the correct sequence that a drop of blood would flow through the heart as the blood entered from the inferior and superior vena cava ...

Sup & Inf Vena Cava-Rt Atrium-Rt Ventricle - Pulmonary Artery (Trunk) - Rt & Left Pulmonary Arteries - Lungs - Rt & Lt Pulmonary Veins - to Left Heart (Lt Atrium)

What are the 4 basic properties of cardiac muscle cells/tissue.

1. Excitability - can respond to electrical, mechanical, or chemical stimuli

2. Inherent Rhythmicity - can originate an impulse (autorhythmic, self excitable), some specialized

3. Conductivity - can propagate impulses, rate of conduction varies (intercalated disks with gap junctions)

4. Contractility - can contract, shorten produce tension, ventricular and atrial myocardial cells are best

The term "inherent rhythmicity" (or auto-rhythmicity, or self excitatory) refers to the cardiac cells ability to do what?

initiate contraction itself without external nervous stimulation

So what is spontaneous depolarization?

A pacemaker potential
When it reaches threshold, it triggers an action potential, allowing the two atria to contract at the same time

What is the function of the intercalated discs in cardiac muscle tissue?

Make cardiac muscles contract as a unit, join cardiac muscle cells to allow action potentials to spread throughout a network of cells

What is the correct sequence for the following structures of the conduction pathway in the heart? Atria, Ventricles, AV node, SA node, Purkinje fibers, AV bundle (of His), Bundle branches

SA Node - Atria - AV Node - AV Bundle (Bundle of His) - Bundle Branches - Purkinje Fibers - Ventricles

An electrical gradient exists when there is a difference in electrical charge across the cell membrane. Is the cell depolarized or polarized?

polarized

When the gradient collapses, (goes to zero) is the cell depolarized or polarized?

depolarized

Depolarization is an electrical event of the myocardium. What mechanical event of the myocardium is caused by and follows depolarization?

voltage-gated Na+ channels are open

Why is the SA node "the Pacemaker" (what is a characteristic of the cells)

because it initiates the heart's rhythmic contractions

What is it called when the wave of depolarization is initiated from a site other than the SA node?

Ectopic depolarization

What component of the conduction system provides the only electrical connection between the atria and the ventricles?

AV node/ Bundle of His

The AV bundles and Purkinje fibers stimulate the wave of depolarization to start at the apical (bottom) end of the ventricles and travel upward. Why is this significant?

impulse travels from base of apex of ventricle so that all ventricle contract and there will be effective pumping of blood

Draw a typical ECG wave form and label it.

In a typical electrocardiograph (ECG) waveform the R to R interval represents:

heart rate

In a typical ECG waveform the QRS complex depicts:

Ventricular depolarization

In a typical ECG waveform the P wave depicts:

Atrial depolarization

In a typical ECG waveform the T wave depicts:

ventricular repolarization

The contraction phase of the cardiac cycle is called:

systole

The relaxation phase of the cardiac cycle is called:

diastole

What is the cause of the first main heart sound?

Lubb \= turbulence with closure of AV valves, with ventricular systole

What is the cause of the second main heart sound?

Dupp \= turbulence with closure of SL valves, with ventricular diastole

Which set of valve are open during diastole, and closed during systole?

AV

Which set of valves are closed during diastole, and forced open during systole?

SL

What would happen to blood flow in the heart if the mitral valve didn't close properly during ventricular systole?

blood would flow backwards from the left ventricle to the left atrium, decreasing blood flow

What is an average resting heart rate?

70 bpm

Define Cardiac Output:

the amount of blood pumped to the body by the heart, in 1 minute.

Define Stroke Volume

the amount of blood pumped by the left ventricle in 1 beat.

What is the Equation for Cardiac Output?

Cardiac Output \= Stroke Volume X Heart Rate
CO \= SV X HR

What is an average resting cardiac output ? What would be a reasonable stroke volume for an average sized person (1000 ml \= 1 L)?

5L/min
70mL

What is a reasonable maximal value for cardiac output?

20L/min

At the end of the rest period in between beats, the heart is filled with blood, this volume is called the:

EDV "End Diastolic Volume"

When the ventricles of the heart contract blood is ejected, but not all of it. The amount that is left in the left ventricle after contraction is called the:

ESV "End Systolic Volume"

What is the ejection fraction and what is an average value for rest vs. exercise?

volumetric fraction of fluid ejected from a chamber with each contraction.
A normal ejection fraction is about 50% to 75% and while exercising its about 60 to 80

Why is there a difference in the EF from rest to exercise?

Because when you are exercising your body needs to pump more blood throughout the body faster

Why might SV not be maximal during exercise at very high HRs?

There is not enough time for the left ventricle to completely fill with blood in between each heart beat

What is "Systole"?

contraction

What is "Diastole"?

Relaxation

Define "End Diastolic Volume" (EDV)

amount of blood available for ventricles to eject

Define "End Systolic Volume" (ESV)

Amount of blood left in ventricle after contraction (ventricular systole)

Define "Preload"

The volume of blood filling the relaxed ventricles prior to their contraction.

Define " Afterload"

The force required to open the semilunar valves to eject blood from the ventricles; determined largely by arterial pressure.

Define "Venous Return"

the flow of blood from the periphery back to the right atrium, and except for periods of a few seconds, it is equal to cardiac output.

Will cardiac output be increased or decreased by the following (if HR remains constant): increasing stroke volume

decrease

Will cardiac output be increased or decreased by the following (if HR remains constant): decreasing stroke volume

increase

Will cardiac output be increased or decreased by the following (if HR remains constant): increasing end systolic volume

increase

Will cardiac output be increased or decreased by the following (if HR remains constant):decreasing end diastolic volume

decrease

The Frank-Starling law of the heart indicates that the more you stretch (within limits) the fibers of a heart chamber the greater the force of contraction will be. Which of the following should increase stroke and which would decrease it?

increase in preload, increase in venous return,increase in time for filling, increase in afterload

increase in preload: increase
increase in venous return: increase
increase in time for filling: increase
increase in afterload: decrease

What is bradycardia?

Abnormally slow heart rate

What is tachycardia?

Abnormally rapid heartbeat

Parasympathetic nervous system impulses cause heart rate to: \________Via what nerve is the message sent?

decrease, vagus nerve

Is parasympathetic input the most influential during rest or exercise?

rest

Sympathetic nervous system impulses cause HR to:\________Via what nerve is the message sent?

increase, cardiac accelerator nerves

If the nervous innervation to the heart (sympathetic and parasympathetic) was cut off, would the heart still beat? About how fast? \** Why?

Yes, about 100 bpm because the SA node can sustain life on its own but it can't adjust heart rate or contraction strength based on rest or exercise

As physical activity begins, which type of receptors monitor the positions of limbs and muscles and send signals to the cardiovascular center in the brain, to increase heart rate and BP?

proprioceptors

What type of receptors monitor the O2 , CO2, and pH of blood?

chemoreceptors

What is the effect of increasing or decreasing O2 , CO2, or pH of blood, on HR?

increased CO2 and O2\= increased HR (direct relationship)
increased pH\=decreased HR (indirect relationship)

List the structures in the correct sequence that a drop of blood would flow through as the blood entered the Aorta and went through the body all the way back to the heart.

Aorta, arteries, arterioles, capillaries, venules, veins, inferior superior vena cava

What are the characteristics of the aorta?

The main artery, very elastic and wide
High pressure; tough fibrous walls; 3 layers - tunica interna, tunica media, and tunica externa.

What are the characteristics of elastic arteries?

largest arteries, conducting arteries

What are the characteristics of muscular arteries?

medium sized arteries, distributing arteries

What are the characteristics of arterioles?

small arteries, Big control over blood pressure

What are the characteristics of capillaries?

Smallest-diameter blood vessels, substance exchange, diffusion of gases, capillary beds, extensive in high metabolic tissue, precapillary sphincters, continuous, intercellular clefts: small gaps, fenestrated, fenestrations: small holes, sinusoids, bigger holes or gaps

What are the characteristics of venules?

little veins

What are the characteristics of veins?

low pressure, valves, compliant, blood reservoirs - 60%, returns blood to heart

At rest, in what region of the vasculature is the greatest percent of blood located or contained?

Venous vasculature

What is the heart doing when the pressure in the arteries is the highest?

Contracting, pumping blood to arteries

What is the name given to the pressure in the arteries during contraction?

Systolic pressure

What is the heart doing when the pressure in the arteries is the lowest?

Relaxing between beats

What is the name given to the pressure in the arteries during relaxation?

Diastolic pressure

What is the driving pressure of the heart pushing the blood through the vessels called?

Blood hydrostatic pressure

What is the pressure pushing outward against the walls of the blood vessels called?

Transmural pressure

What is a typical/average Blood pressure value?

120/80

What is Mean Arterial Pressure and how is it calculated? What would MAP be for a BP of 118/72

The average arterial pressure throughout one cardiac cycle, systole, and diastole.
add the diastolic pressure to one-third of the pulse pressure
MAP\=(DBP + 1/3 (SBP - DBP))
MAP\= 72+1/3(118-72)\=87

What would be considered Hypertension? And what are the main health "drawbacks" of this?

130/80
main health drawbacks: heart attack or stroke, aneurysm, heart failure, weakened and narrowed blood vessels.

What would be considered Hypotension? And what are the main health "drawbacks" of this?

90/60
dizziness, weakness, fainting, risk of injury due to falling, strokes

What is acute orthostatic hypotension? (Blood rush)

a form of low blood pressure that happens when you stand up from sitting or lying down. This can make you feel dizzy or lightheaded, and maybe even cause you to faint

Why do people sometimes faint when they stand at attention for a while or in the heat?

Heat causes the blood vessels to expand (dilate), so body fluid moves into the legs by gravity, which causes low blood pressure and may result in fainting.

The pulse pressure is the difference between force with which you are pushing the blood into your arteries and is represented by the systolic blood pressure and Resistance with which the total arterial vasculature is exerting represented by the diastolic blood pressure. So how does this represent the amount of blood "flow" that move through the vessels?

What would the pulse pressure be for a blood pressure of 120/80?

40 mm Hg

What would the pulse pressure be for a blood pressure 130/80 or 110/60?

130/80\=50 mm Hg
110/60\=50 mm Hg

Which pulse pressure would represent the greatest amount of "flow" (120/80, 130/80, or 110/60)?

120/80

How do these hormones affect/regulate blood pressure: (and from where are they secreted ) (Renin-Angiotensin- Aldosterone system)

secreted by kidneys, increase blood pressure by contracting vessels; causes vasoconstriction (blood pressure increases and increase blood volume)

How do these hormones affect/regulate blood pressure: (and from where are they secreted) Epinephrine and Norepinephrine

secreted by adrenal glands, aid body during stress by raising heart rate, blood pressure, and respiration (blood pressure increases and increase blood volume)

How do these hormones affect/regulate blood pressure: (and from where are they secreted )Antidiuretic Hormone (ADH)

secreted by posterior pituitary gland, works on kidneys and tells them to keep water in the blood (blood pressure increases and increase blood volume)

How do these hormones affect/regulate blood pressure: (and from where are they secreted )Atrial Natriuretic Peptide (ANP)

secreted from right atrium, reduces blood pressure, inhibits drinking, and promotes the excretion of water and salt at the kidneys

Give an example of how blood pressure and pulse pressure would change with dynamic continuous type exercise where you need to increase the total amount of blood flow... so cardiac output has to increase. For example: jogging. Does SBP increases or decrease? Does DBP increase or decrease?

SBP Increases, heart is contracting more

DBP Stays the same, slight increase

Why does the DBP increase blood pressure increase with static type exercise (like weight lifting, or shoveling snow).

mean arterial pressure increases as a result of an increase in heart rate and thereby cardiac output with no significant change in stroke volume or systemic vascular resistance

How does DBP increasing blood pressure increase with static type exercise affect the blood flow? What does your heart have to do to over come this? So then what happens to SBP?

blood flow decreases, Heart increases contractility and HR to improve cardiac output, SBP increases

What are the three main factors that affect resistance to blood flow?

h \= viscosity of blood
L \= length of vessel(s)
r \= radius of vessel

So would it be easier to drink a thick milkshake through a straw with a diameter of 3 mm, or 6 mm? Why?

6mm because it is wider and less restrictive

Would it be easier to drink the thick milkshake or just plain milk through any given straw? Why?

Milk because of the decrease in fluid thickness

Would it be easier to drink the milkshake through a straw that was 7 inches long or one that was 10 inches long? Why?

7 inches because the straw is shorter with less resistance

Which factor is most significant in determining resistance to blood flow? Briefly explain how changing this factor would affect resistance.

vessel radius, the larger the radius the easier it is to move blood through it
Small change in vessel radius has a large influence on flow, due to it being raised to the 4th power.Example: if you decrease the diameter by 50%, 4th power turns into 16th power