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Pathophysiology > Exam 3 chapter 25 > Flashcards

Exam 3 chapter 25 Flashcards

1
Q

Describe the function of the pericardial membrane

A

o Protection: shields the heart from external trauma and physical shock
o Lubrication: reduces friction as the heart beats by secreting fluid that lubricates the surface of the heart
o Maintenance of cardiac function: helps maintain the proper position of the heart within the chest cavity and helps to maintain its function
o Prevention of infection: acts as a barrier against invading microorganisms

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2
Q

describe the electrical activity/route of the heart conduction system

A
  1. SA node (located in the upper right atrium and acts at the heart’s pacemaker): generates the electrical impulses and sends it to the atria, causing them to contract and push blood into the ventricles
  2. Electrical impulse reaches AV node (located at the base of the right atrium, and acts as the gatekeeper) delays it for a brief moment to allow the ventricles to fill with blood before contracting.
  3. The impulse then travels down the bundle of His, which divides into two branches that transmit the impulse to the ventricles
  4. The impulse spreads throughout the ventricles through a network of fibers called Purkinje, causing the ventricles to contract and pump blood out of the heart and into the arteries.

Mnemonics
“Some Angry Elephants Have Powerful Hearts”
SA node, AV node, bundle of His, Purkinje fibers, heart muscle

Or

SABP

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3
Q

define cardiac output

A

volume of blood flwoing through either the systemic or pulmonary circuit in liters per minute

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4
Q

describe how myocardial hypertrophy compensates for the heart

A
  • Walls of the heart chambers thicken in response to increased workload or pressure. The thickening of the heart muscle allows it to contract with greater force to help maintain cardiac function but it can lead to heart failure
    o Ex: hypertension, heart valve problems
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5
Q

describe the frank-starling mechanism

A
  • Describes the heart’s ability to increase stroke volume in response to increased blood volume
  • The heart chambers can stretch to accommodate increased blood volume. When the chambers stretch, the myocardial fibers are pulled apart, which allows them to contract with more force and push more blood out of the heart with each beat
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6
Q

describe how the sympathetic nervous system affects for the heart

A

release of norepinephrine can increase heart rate, contractility, and conduction which can help maintain cardiac output in response to stress or exercise. it also allows the heart to pump more blood due to increase O2 demands

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7
Q

describe how the renin-angiotensin-aldosterone system (RAAS) compensates for the heart

A
  • Activated in response to low blood pressure or reduced blood flow to the kidneys. It causes the release of renin, which leads to the formation of angiotensin II. Angiotensin II can increase blood pressure and stimulate the release of aldosterone, which can help the body retain salt and water, thereby increasing blood volume
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8
Q

in simple terms, describe the different compensation processes

A

make heart muscle thicker, pump harder, increase the amount of blood the heart pumps out, speed up heart rate

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9
Q

describe the normal cardiac flow

A

o Normal cardiac flow
1. Deoxygenated blood enters the heart through the superior vena cava to the right atrium
2. From the right atrium, the blood flows into the right ventricle. The right ventricle pumps the blood out of the heart and into the pulmonary artery which carries the blood to the lungs
3. The lung picks up oxygen and releases carbon dioxide
4. Oxygen-rich blood flows back to the heart through the pulmonary veins which enter the left atrium
5. From the left atrium, the blood flows back into the left ventricle
6. The left ventricle pumps the blood out of the heart and into the aorta
7. The aorta carries the oxygen-rich blood to the rest of the body’s tissue where the oxygen is used, and carbon dioxide is produced
8. The blood then flows back to the heart through the superior and inferior vena cava and the process starts again

Some – Superior Vena cava
People – pulmonary artery
Enjoy – pulmonary veins
Going – left atrium
Places – left ventricle

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10
Q

what are the three layers of the heart in order from the outermost layer to the innermost layer?

A
  1. pericardium
  2. myocardium
  3. endocardium
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11
Q

which side of the heart has a thicker myocardium?

A

left side

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12
Q

which of the following layers of the heart is the thickest layer and its main function is to generate the force necessary to pump blood throughout the body?

a. pericardium
b. myocardium
c. endocardium
d. exocardium

A

b. myocardium

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13
Q

the main function of the pericardium is to: SELECT ALL THAT APPLY

a. protect and anchor the heart in the chest cavity
b. help blood flow smoothly
c. generate force to pump blood throughout the body
d. physical protection and barrier to infection

A

a. protect and anchor the heart in the chest cavity
and
d. physical protection and barrier to infection

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14
Q

the endocardium lines the ______ and is the ________ layer

A

heart; innermost

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15
Q

the endocardium is exposed to

A

blood and bacteria

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16
Q

how do positive chronotrope and inotropes control the action of the heart

A

increases contraction and heart rate

the sympathetic nervous system also causes the blood vessels to constrict, which increases blood pressure and ensures that blood flow is directed to the vital organs. these responses are part of the body’s “fight or flight” response, which prepares the body for physical activity or stress

*+chronotrope and inotrope

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17
Q

define chronotropic and inotropy

A

chronotropic: refers to the heart rate. A negative chronotrope slows down the heart rate while a positive chronotrope increases it

inotropy refers to the strength of the heart’s contraction. A negative inotrope weakens the force of the contraction, while a positive inotrope strengthens it

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18
Q

How do automaticity, rhythmicity, conductivity, and contractility affect cardiac function?

A

automaticity: generating spontaneous depolarization (enables SA and AV node to generate cardiac output)

rhythmicity: generation of action potential by the heart’s conduction system

conductivity: ability to conduct from SA node through Purkinje fibers

contractility: ability to contra in sequence by means of action potential

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19
Q

what are the beta-adrenergic receptors and what do they do?

A

B1- heart
B2- lungs

they signal the sympathetic nervous system by binding catecholamines (epi, norepi)

20
Q

how does adrenergic receptor function control the heart?

A

the sympathetic system controls heart actions by releasing neurotransmitters called norepinephrine. norepinephrine binds to specific receptors on the heart muscle cells (beta1) which stimulates the heart to beat faster and stronger

21
Q

how does the parasympathetic nervous system affect cardiac function?

A

Parasympathetic: releases acetylcholine which slows down heart rate, and reduces the force of contraction, and reduces conduction resulting in a decrease in cardiac output
a. Also causes vasodilation in the digestive system and other non-essential organs which increases blood flow to these areas and vasoconstriction in the skeletal muscles, which reduces blood flow to these tissues

  • -chronotrope and inotrope
22
Q

how is cardiac output determined?

A

o Cardiac output: HR (beats/min) x stroke volume = cardiac output
 Stroke volume: volume of blood ejected during systole in liters/beat
 Reflects the heart’s ability to deliver oxygen and nutrients to the body’s tissue
* Exercise –> increased cardiac output

23
Q

what factors determine cardiac output?

A

preload
afterload
myocardial contractility
heart rate

24
Q

define preload

A

volume/pressure inside ventricles at the end of diastole

depends on the amount of blood in the ventricles (the amount of stretch during diastole)

25
Q

define the frank starling law and its relationship to preload

A

the frank-starling law of the heart describes the relationship between the end-diastolic volume (preload) of the heart and the stroke volume (the amount of blood ejected from the heart per beat). according to this law, as the volume of blood in the heart increases during diastole (preload), the force of contraction of the cardiac muscle fibers also increases, resulting in an increase in stroke volume. This increased force of contraction allows the heart to pump a greater volume of blood out into the circulation, maintaining adequate cardiac output.

26
Q

in preload, the __________ of the heart-volume at
end-diastole determines the length of the muscle fibers and is directly related to the force of contraction during systole

A

Frank-starling law

27
Q

define afterload

A

the resistance that the heart must overcome to eject blood from the ventricles

depends on the pressure in the aorta

28
Q

afterload is determined by the _____

A

system vascular resistance in the aorta

29
Q

what are the five phases of the cardiac cycle?

A
  1. Atrial systole: Atria
    contract, pushing blood through the open tricuspid and mitral valves into the ventricles. Semilunar valves are closed.
  2. Beginning of ventricular systole. Ventricles contract, increasing pressure within the ventricles. The tricuspid and mitral
    valves close, causing the first heart sound.
  3. Period of rising pressure: Semilunar valves open when pressure in the ventricle
    exceeds that in the arteries. Blood spurts into the aorta and pulmonary arteries.
  4. Beginning of ventricular diastole:
    Pressure in the relaxing ventricles drops below that in the arteries. Semilunar valves snap shut, causing the second heart
    sound.
  5. Period of falling pressure: Blood flows from veins into the relaxed atria. Tricuspid and mitral valves open when the pressure in the ventricles falls below that in the atria.
30
Q

stroke volume depends on the force of contraction which is determined by:

A
  • Preload
  • Inotropic agents (+ epi, norepi, dopamine, thyroid hormone; -acetylcholine)
  • Oxygen levels
  • Severe hypoxia decreases contraction
31
Q

what factors affect peripheral/systemic vascular resistance and blood pressure?

A

○ Blood pressure: chemoreceptors control BP
■ Pressure:
● High pressure to low pressure (fluid moves from atrial side of capillaries to venous side of capillaries)
■ Resistance:
● Opposition of blood flow
● Diameter /radius and length of the blood vessels contribute to resistance (vasoconstriction/vasodilation)
■ Poiseuille law:
● Resistance is directly related to tube length and blood viscosity and inversely related to resistance, the greater the resistance, the lower the blood flow

32
Q

describe how pressure affects blood flow

A

High pressure to low pressure (fluid moves from arterial side of capillaries to venous side of capillaries)

33
Q

describe Poiseuille law

A

Resistance is directly related to tube length and blood viscosity and inversely related to resistance, the greater the resistance, the lower the blood flow

34
Q

what factors affect blood pressure

A

determined by the amount of blood that is pumped by the heart, the resistance encountered by the blood as it flows through the arteries, and the ability of arteries to expand and contract

  1. Cardiac output: increased cardiac output can increase BP
  2. Blood volume: increased blood volume and increase BP
  3. Vascular resistance: the resistance encountered by the blood as it flows through the arteries can affect blood pressure
  4. Arterial compliance: the ability of the arteries to expand and contract can affect blood pressure. Decreased compliance can lead to increased blood pressure
35
Q

A client is diagnosed with increased systemic vascular resistance (SVR). What will be the effect on the heart?

A. Left atrium will be required to pump harder.
B. Right atrium chamber will become enlarged.
C. Left ventricle will be required to pump harder.
D. Right ventricle will become ineffective because of increased pressure.

A

C. Left ventricle will be required to pump harder

36
Q

How would Each of the Following Affect Blood Pressure? (increase or decrease)

* Vasodilation 
* Decreased stretching of baroreceptors 
* Hypoxemia noted by chemoreceptors 
* Inhibiting angiotensin-converting enzyme 
* Beta blockers/ beta adrenergic blockers 
* Alpha-2 agonists 
    * Calcium channel blockers
A
  • Vasodilation - decrease
  • Decreased stretching of baroreceptors - decrease
  • Hypoxemia noted by chemoreceptors - increase
  • Inhibiting angiotensin-converting enzyme – decrease
  • Beta blockers/ beta-adrenergic blockers - decrease
  • Alpha-2 agonists - decrease
  • Calcium channel blockers - decrease
37
Q

Which of the following is an accurate statement regarding blood flow through the heart?

A. Blood flows from the left ventricle through the bicuspid valve.
B. Blood flows from the right atrium through the aortic valve to the right ventricle.
C. Blood flows from the right ventricle through the pulmonic semilunar valve.
D. Blood flows from the left atrium through the tricuspid valve to the left ventricle.

A

C. Blood flows from the right ventricle through the pulmonic semilunar valve.

38
Q

The term used to describe the resistance to the ejection of blood from the left ventricle during systole is known as ____________. however, ________ describes the volume and pressure inside the ventricles at the end of diastole

A. afterload; preload
B. preload; afterload

A

A

39
Q

which of the following can alter blood volume and thus also alter blood pressure? (choose all that apply)

a. antidiueric hormone (ADH)
b. RAA system
c. natriuretic peptides

A

all of the above

40
Q

the right side of the heart pumps blood to the ______; while the left side of the heart pumps blood to the ______

a. lungs; body
b. body; lungs

A

a. lungs; body

41
Q

The internal lining of the heart is known as the __________ and __________

a. endocardium; is continuous with the endothelium that lines all the arteries, veins, and capillaries

b. myocardium; is composed of cardiac muscle

c. myocardium; is continuous with the endothelium that lines all the arteries, veins, and capillaries

d. pericardium,; is the double-walled membranous sac that surrounds the heart

A

a. endocardium; is continuous with the endothelium that lines all the arteries, veins, and capillaries

42
Q

the pulmonary veins carry ________ blood

a. oxygenated
b. unoxygenated

A

a. oxygenated

43
Q

the _______ is known as the pacemaker of the heart

a. sinoartrial (SA) node
b. atrioventricular (AV) node

A

a. sinoatrial (SA) node

44
Q

cardiac output is calculated by using which of the following factors?

a. heart rate
b. stroke volume
c. blood pressure
d. ejection fraction

A

a and b

45
Q

______ contain valves to facilitate one-way flow of blood toward the heart

a. veins
b. arteries

A

a. veins

46
Q

peripheral vascular resistance (PVR) is increased by which of the following?

a. increased blood viscosity
b. increased hematocrit
c. vasoconstriction
d. vasodilation

A

a, b, and c

47
Q

systolic contraction of the heart is stimulated by _______

a. action potentials
b. the sympathetic nervous system
c. the autonomic nervous system
d. the endocrine system

A

a. action potential

Pathophysiology (25 decks)

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