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Systems Physiology > Cardiology Introduction > Flashcards

Cardiology Introduction Flashcards

1
Q

*Sketch a typical action potential in a ventricular muscle and a pacemaker
cell, labeling both the voltage and time axes accurately. Describe how ionic
currents contribute to the four phases of the cardiac action potential. Use this
information to explain differences in shapes of the action potentials of
different cardiac cells (particularly pacemaker vs non-pacemaker cells).

A

There was

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2
Q

(Explain what accounts for the long duration of the cardiac action potential
and the resultant long refractory period. What is the advantage of the long
plateau of the cardiac action potential and the long refractory period?

A

I am

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3
Q

*Contrast the duration of the action potential and the refractory period in a
cardiac muscle, a skeletal muscle, and a nerve. Sketch the temporal
relationship between an action potential in a cardiac muscle cell and the
resulting contraction (twitch) of that cell. On the basis of that graph, explain
why cardiac muscle cannot remain in a state of sustained (tetanic)
contraction.

A

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4
Q

*Explain the ionic mechanism of pacemaker automaticity and rhythmicity, and
identify cardiac cells that have pacemaker potential and their spontaneous
rate. Identify neural and humoral factors that influence their rate.

A

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5
Q

*Beginning in the SA node, diagram the normal sequence of cardiac activation
(depolarization) and the role played by specialized cells. Predict the
consequence of a failure to conduct the impulse through any of these areas.

A

I will be

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6
Q

*Explain why the AV node is the only normal electrical pathway between the
atria and the ventricles, and explain the functional significance of the slow
conduction through the AV node. Describe factors that influence conduction
velocity through the AV node.

A

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7
Q

*Discuss the significance of overdrive suppression, ectopic pacemaker and
reentry including the conditions necessary for each to occur.

A

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8
Q

*Contrast the sympathetic and parasympathetic nervous system influence on
heart rate and cardiac excitation in general. Identify which arm of the
autonomic nervous system is dominant at rest. Discuss ionic mechanisms of
these effects on pacemaker cells.

A

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9
Q

In the Cardiovascular system, what activity precedes the other? What are the main cellular structures in CV system?

A

IN CV system, Electrical activity precedes mechanical activity.
Arterioles, Venules, capillaries make most of surface area of CV system (heart major organ of course)

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10
Q

Describe the functions of the Cardiovascular system.

How long is the CV system?

A

Functions of CV system: to move Oxygen and nutrients around the body, control body temperature (regulate the flow of blood to cutaneous (skin) ).
CV system usually about 14,000-60,000 miles depending on body size (determines CV length),

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11
Q

What is the function of the right ventricle vs left ventricle in heart?

A

Right ventricle- supplies blood flow to the lungs, pulmonary vein.
Left ventricle- provides blood flow to rest of the body, like the brain, heart, and muscle.

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12
Q

What is required for the heart to function?

What lines the CV system?

A

The heart is a muscle that needs oxygen and nutrients to function. The heart provides a lot of pressure and energy.
ENDOTHELIAL Cells lines the CV system, and all chambers of the heart and blood vessels.
Capillaries- 1 cell thick of endothelial cells

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13
Q

compare and contrast the arterial side vs venous side in the CV system (in terms of resistance, pressure, volume)

A

Venous side: veins are very compliant, and has great stretchiness. The veins are more compliant than arteries. They have HIGH VOLUME at LOW pressure (15 mmHg). they also have higher capacity to store blood at low pressure (variable reservoir)
Arterial side: Arteries are not as compliant as veins, they have MORE RESISTANCE, LESS volume and MORE PRESSURE.
veins- 70-80% of volume, and arteries 20-25% of volume.

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14
Q

Describe how blood is pumped from the RV to LV, and how they are organized.

A

The right ventricle pumps blood to the lungs, which then enters the left atrium into the left ventricle and then to rest of the circulatory system. The 2 pumps in RV and LV are in SERIES with each other.

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15
Q

Explain how the diameter of the arterial vessel can be varied and how this affects resistance and pressure..

A

Arteries offer the most resistance (hence, high pressure and low volume), but we can vary the diameter.
Dilate an arteriole- you are DECREASING resistance, and there will be LOWER pressure in the aorta.
Constrict an arteriole- INCREASE resistance of arterioles and Increase the flow of aorta, causing pressure to rise.
aorta and arteries- have highest pressure; veins-low pressure.

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16
Q

How are the Arteries arranged in the CV system? What happens if the arrangement changes for arteries? What is the advantage of the original arrangement of arteries?

A

In arterioles, the resistance is arranged in PARALLEL.
If NOT parallel (or if in series), it would cause higher resistance, and the heart would have to do more work to pump blood.
Advantage of parallel arrangement:
-reduces work for heart increase blood flow
-controls blood flow individually through each resistance for each organ
-commits blood flow through different parts of body (important for exercise)

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17
Q

What occurs when you make veins less compliant?

A

When you make veins less compliant- make them more STIFF (not stretchy anymore). This would cause pressure to go up (increase), and there will be a need to force more blood out to RA, increasing Cardiac output.

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18
Q

What is the number 1 killer of American in the U.S?

About 50% of deaths from CV disease are related to what?

A

Number 1 killer in U.S.- Heart (CV)disease

50% of deaths from CV disease are due to CORONARY HEART DISEASE

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19
Q

When was the peak of deaths due to CV disease? What has happened over the years?

A

Peak of deaths from CV disease- during 1980s. Over last 10-`15 years, deaths have decreased (CV is still #1 killer though)
CV disease- major cause of death in both women and men in the U.S.
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20
Q

What is coronary circulation and why is it important? What is a primary disease for coronary circulation?

A

Coronary circulation- process of circulation where blood vessels supply blood and nutrients to heart muscle.
The primary disease for coronary circulation- atherosclerosis (when plaque builds up in vessels or arteries that supply blood to the heart).
The build up of plaque narrows the arteries and decreases blood flow to heart.

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21
Q

Describe the pressure difference in aorta.

A

In aorta: the pressure is 120/80 (max/min)

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22
Q

What are the two main health incidences that increase with age?

A

Prevalence of both CV disease and High blood pressure that increase with age.

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23
Q

Describe what occurs during hypertension in terms of change in pressure and possible complications that occur.

A

Hypertension- aka High Blood Pressure in arteries (pressure of 140/80) . This is a lot more pressure compared to normal (120/80).
With hypertension: the heart has to work harder to acquire higher pressure and pump blood.
This can cause heart hypertrophy and a High blood pressure can lead to heart failure.

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24
Q

Describe the prevalence of heart failure by sex and age, including discharge or other components.

A

Hospital discharges for heart failure have increased overtime due to use of technology that is keeping people from having heart attack, (which damages ventricles and leads to heart failure)
Heart failure increases with age.
-higher rate in women around 80 years old
- higher rate for men in their 60-79 year range.

25
Q

What is commonly used as a remedy for heart failures? What is the current trend of this remedy?

A

remedy for heart failures- heart transplantation
use of heart transplantations have increased over the years and INCREASES for people in their 50s and 60s (highest transplant rate) , when CV disease predominates

26
Q

What is the prevalence of heart attack or fatal coronary heart disease (CHD) by age and sex?

A

higher rate of heart attack or CHD in men (especially in 55-64 years)
women- highest rate of heart attack or CHD at 85+ years

27
Q

What medical conditions does U.S. spend the most money on?

A

U.S spends the most money on CV disease and stroke (billions of dollars)

28
Q

What is the pressure in the aorta?

A

pressure in aorta: 120/80 mmHg; max/min

29
Q

Describe the anatomy of the heart

A

Heart has 4 chambers: left ventricle, left atrium, right ventricle, right atrium.
Mitral valve- LA and LV; have papillary muscles and chordae tendinae
Tricuspid valve between RA and RV; papillary muscles, chordae tendinae.
The Right and left ventricle are in series with one another
pulmonic valve
aortic valve

30
Q

What happens if the right ventricle pumps 1/10 more blood per min than left ventricle?

A

if RV pumps 1/10 more blood per min, it will accumulate in the lungs and cause pulmonary edema (also cause shortness of breath).
Hence, whatever volume in RV, LV will pump in equal volume away from Lungs

31
Q

What does the Frank-Starling Law describe?

A

Frank-Starling Law: as the heart gets more filled up with more blood during diastole (stretching of the ventricle), it contracts harder and pumps out more blood during systole.
the heart is able to move blood in a regulated way that pumps out as much blood as it receives.

32
Q

Define the terms cardiac output, heart rate, and stroke volume. Also explain the relationship between these three terms

A

Cardiac output- the amount of blood your heart pumps each minute.
Stroke volume- the volume of blood pumped out of LV in heart during systolic contraction.
Heart rate- number of times your heart beats per minute
CO= HR x SV

33
Q

Describe the role of pericardium in the heart and the components inside of pericardium.
What happens if there is excess fluid in the pericardium?

A

The heart is surrounded by pericardium (fibrous sac) that covers the surface of the heart.
normally in space between pericardium, there is a pericardial fluid that lubricates the surface of the heart.
If there is excess fluid in pericardial space (pericardial effusion), can result n BLUNT FORCE TRAUMA (result in tears in the atria)
cardiac tampanod: Excess fluid in pericardial sac can also create a pressure that compresses the heart and limit the heart’s ability to fill with blood (lead to sig consequences) and may require surgical repair of atria.

34
Q

Describe where the RV, LV, SA node, and VENA cava are located in the heart; include how heart is positioned in the body.

A

RV- anterior most part of heart
LV- posterior part
heart: oriented in the chest at a 45 degree angle
SA node: where electrical activity starts (it sends electrical impulse to cause atria (upper heart chambers) to contract.
Superior and inferior Vena cava- veins that bring venous blood to RA
Pulmonary artery- takes blood from RV to lungs.

35
Q

Describe the flow of blood in the heart.

A

Vena cava will bring venous blood from systemic circulation to the RA.
RA then pump blood to RV into pulmonary artery
pulmonary artery will bring blood to the lungs.
Lungs supply blood to the pulmonary veins
Pulmonary veins supply blood to the left atrium which recached left ventricle and pumps blood to the aorta.

36
Q

Which chamber in the heart has the most muscle mass? which generates the greatest pressure. How does pressure in atria and ventricle compare?

A

Left ventricle- MOST MUSCLE MASS in the heart
RV has more muscle mass than atria, but less than LV
RA- thin wall chamber (not a lot of muscle)
LV generates GREATEST PRESSURE (creates higher pressure when it contracts)
Atria- LOWEST pressure. RA- lowest pressure in CV system

37
Q

what determines the opening and closing of valves?

A

The CHANGE in PRESSURE determines opening and closing of valves.

38
Q

What are the two main phases of the heart? Compare and contrast the diastole vs systole in the heart.

A

The two main phases of the heart: Relaxation and Contraction.
Diastole- FILLING phase
-Ventricles are filling with blood and mitral/tricuspid valves are open; heart relaxes after a contraction
Systole- CONTRACTILE phase (heart contracts to pump out blood)
-both ventricles contract, pulmonic and aortic valves are open, mitral/tricuspid valves are closed (prevent blood from filling again), chordinae tendineae, papillary muscles are contracting to prevent mitral/tricuspid valve from opening.

39
Q

compare and contrast the mitral valve and the tricuspid valve in the heart, including its functions.

A

Mitral (bicuspid) valve- is between the left atrium and left ventricle. This valve has papillary muscles and chordae tendinous attached to it. it has 2 cusps.

Tricuspid valve - is between the right atrium and right ventricle.

  • 3 cusps (anterior, medial, and posterior)
  • has tendinous structures, chordae tendon that attach to valve leaflets to papillary muscles.
40
Q

How does the pulmonic valve differ from mitral/tricuspid valves?

A

Pulmonic valve- 3 cusps (anterior, right, left)

  • NO CHORDAE or PAPILLARY Muscles
  • 3 semilunar valves connected to pulmonary artery. These valves open and close due to change in pressure
41
Q

What happens when the right ventricle contracts? How does this affect pulmonic valve? What happens if chordae tendinae rupture?

A

When RV contracts, pressure will increase, and blood will try to go back to RA, which will snap the tricuspid valve shut (due to change in pressure : from high to low ).
papillary muscles will also contract, as RV contracts (to generate enough force to overcome pressure)
The pulmonic valve will only open if pressure in RV exceed the pressure of pulmonic valve.
Once this occurs, blood will flow out of the artery.
if chordinae tendinae rutpured, you would have backflow: patient would have heart murmur during contraction (blood flow back to atria, instead of pulmonary artery), creating turbulence

42
Q

When does the mitral valve close?

A

Both mitral valve and tricuspid valve close due to differences in pressure.
When pressure in LV increases, and blood tries to go back to RA, mitral valve closes.
Also,

43
Q

What kind of system is Cardiovascualr system?

A

CV- TRANSPORT and COMMUNICATION system

44
Q

What is the function of right heart, left heart in CV system?

A

Right heart- VOLUME pump; delivers high volumes of blood at low pressures
left heart- PRESSURE pump; energy source for circulatory system

45
Q

What is the function of arterioles, capillaries and venous vessels?

A

Arterioles-RESISTANCE vessels that are variable resistors and regulate flow of blood into capillary beds
Capillaries- one cell layer that separates blood from tissue space; site of nutrient and waste exchange
Venous vessels- Volume reservoir; vessels function in both storage and mobilization of blood

46
Q

Define the function of pulmonary vessels, elastic arteries and muscular arteries, indicating their location.

A 
Pulmonary vessels- function in blood- gas exchange and serve as volume reservoir.
Elastic arteries (aorta) elastic behavior allows them to serve as "surge pump"; energy stored in these elastic fibers during contraction phase (systole) and is released during relaxation (diastole)
Muscular arteries: function as low resistance conduits that rapidly deliver blood to tissues
47
Q

Differentiate between the two types of circulation in CV system

A

Pulmonary circulation: blood flow through the lungs
Systemic Circulation: blood flow through all organs of the body except lungs
operation of heart and vascular conduits are independent.

48
Q

Describe the structure and function of pulmonary valve

When does pulmonary valve close.

A

Pulmonary valve- 3 cusps, no chordae tendinae or papillary muscles.
-3 semilunar valves connected to wall of pulmonary artery
functions opens and closes due to changes in pressure.
Pulmonary valve will only open if pressure of RV exceeds pressure of Pulmonary artery, allowing pulmonary valve to open.
pulmonary valve closes at end of contraction, (when heart relaxes) to prevent blood from coming back from lungs into right atria (lower pressure)

49
Q

When does aorta valve open and close?

A

Aorta valve open: when pressure in LV greater than pressure in aorta, valve opens, allow blood flow out of LV.
when left ventricle relaxes, after SV achieved, direction of blood comes back to LV, pressure lowers snaps Aortic valve shut.

50
Q

What role do endothelial cells play in CV system. What is EDRF? What later forms and how does this affect smooth muscle?

A

endothelial cells- protect platelets from forming with collagen(aggregate in blood clots)
-have receptors that bind to different substances, forming EDRF (endothelium-derived relaxing factor)
EDRF- discovered to be Nitric oxide (NO) which causes vascular smooth muscle to relax.
each time heart beats, blood pulses through vasculature, endothelial cells release NO (relax vascular smooth muscle, decrease resistance)
NO- reduce resistance, lower blood pressure, keep bp regulated

51
Q

What happens when Nitric oxide is released? What produces Nitric oxide? What occurs if drug is used that inhibits endothelial cell function.

A

NO- causes smooth muscle to relax, lowers blood pressure.
A drug inhibit endothelial cells, will prevent NO from being produced, blood pressure would increase by about 10 mmHg
Hypertension- endothelial cells not producing NO (which relaxes smooth muscles and regulates bp)

52
Q

What are the Nitric Oxide dilators and constrictors?

A

NO Dilators- Nitric Oxide (reduce pressure, relax smooth muscle and blood vessels), and Prostacyclin (PGI2)- part of prostaglandin that inhibits platelet aggregation, relaxes blood vessels)
No constrictors: endothelin, Angiotensin II

53
Q

Describe the innervation of the heart between the sympathetic and parasympathetic system of Autonomic nervous system

A

sympathetic:
cardiac sympathetic fibers originate in the intermediolateral cell column of spinal cord (T1-T5)
Preganglionic fibers can ascend to stellate, superior or middle level of origin in the paravertebral ganglia
postganglionic sympathetic fibers- distributed to cardiac chambers as epicardial plexus
-Function/Distribution of postganglionic fibers:
-fibers distributed to LEFT side of heart: affect the force of contraction of the heart (contractility)
-fibers distributed to RIGHT side of heart: affect the heart rate (SA node) more than force of contraction
effect of sympathetic fibers on heart- mediated by Beta-adrenergic receptors

Parasympathetic
preganglionic fibers are contained in vagus nerve and synapse with postganglionic fibers within the heart.
parasympathetic stimulation reduces force of contraction and heart rate
right vagus- primarily innervates sinoatrial SA node
left vagus- primarily innervates atrioventricular AV node

54
Q

Describe the special conduction system in the heart

A

Conduction system- transmits electrical activity quickly from SA node (in right atrium) through Atria through AV node to ventricle (through purkinje fibers network)
rapid communication system for electrical impulses within heart muscle.
blood vessel (smooth muscle, fibrous tissue, elastic tissue)

55
Q

Describe the tissue distribution in CV system

A

arterial-rich coat of smooth muscle
microcirculation - where smooth muscle is thickest
capillaries- tube of endothelial cells that allow oxygen and nutrients to diffuse across endothelial membrane to tissue.
arterioles- where pressure drops the most (controls resistance and flow through vessels to capillaries)

56
Q

What is relationship of velocity of blood flow and cross-sectional area of CV?

A

Capillaries- largest cross-sectional area of CV system; Velocity is slowest in capillaries (beneficial for oxygen and nutrient exchange through diffusion
Arterioles- also large cross-sectional area, Not as big as capillaries
the larger cross-section, the slower flow of blood.

57
Q

Where in the CV system is total blood volume greatest?

What is cardiac output? How is it calculated?

A

Total blood volume greatest in Venous side (70-75%)
arterial side (20-25%)
CO= amount of blood heart pumps per unit time (L/min)
CO: Stroke volume (amount of blood pumped/min) x HR (number of beats per min). Each body part gets different percentage of Cardiac output. (heart- 5%, kidneys: 25%; brain: 15%; skeletal muscle: 15
The CO of right heart must = CO of left heart

58
Q

What determines how much blood flows to each organ? what occurs to cardiac output during exercise?

A

how much blood flow goes to body determined by resistance of arterioles
if organs are dilated- more blood flow to that organ
if organs are constricted: less blood flow to organ
exercise- CO increases 3x fold (pump more blood in system to deliver oxygen to body). increase Co from 5 to 15 L per min. most of blood flow goes to skin (produce more heat) and skeletal muscle (high metabolic activity) during exercise (arterioles dilate, more blood flow to body, dissipate heat)

Systems Physiology (19 decks)

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