CV I Flashcards
(116 cards)
1
Q
Heart pumps (BLANK) blood to the lungs and then supplies (BLANK) blood to all parts of the body
A
Heart pumps unoxygenated blood to the lungs and then supplies oxygenated blood to all parts of the body
2
Q
The CV consist of what?
A
CV system is composed of the heart and the vasculature that carries blood
3
Q
What controls the normal pumping action of the heart?
A
A complex series of electrical and mechanical events controls the normal pumping action of the heart
4
Q
what provides Unidirectional flow throughout the heart?
A
Unidirectional flow throughout the heart is provided by four valves
5
Q
Does the heart function as a highly efficient pump?
A
Yes, the Heart functions as a highly efficient pump.
6
Q
What spreads electrical activity through the heart?
A
Specialized conduction pathways readily spreads electrical activity
7
Q
Which node delays conduction and enables atrial contraction to prime the ventricle?
A
Atrioventricular (AV) node delays conduction and enables atrial contraction to prime the ventricle
8
Q
What can the heart be divided into? (4 things)
A
Cardiac muscle can be divided into atrial, ventricular, and specialized pacemaker and conducting cells
9
Q
Where is the heart bound to? three things
A
Heart is bound anteriorly by the sternum and the costal cartilages of the 3rd - 5th ribs and inferiorly by the diaphragm
10
Q
Where is the position of the apex of the heart?
A
Positioned with the apex projecting anteriorly and inferiorly toward the left 5th intercostal space
11
Q
Where is the point of maximal impulse?
A
The apex, first heart sound and s3
12
Q
Where is the LV on the cardiac silhouette?
A
- -LV comprises most of the apex and the lower left lateral border**
- -LA appendage lies superior to the LV and to one side of the pulmonary artery
- -Anterior surface almost entirely made up of the RV
13
Q
what is the pericardium?
A
Fibrous double-walled sac that surrounds the heart and roots of the great vessels
14
Q
What are is the pericardium made up with? two layers
A
- -Consists of (two compenents) visceral (think of organ, it is attached directly to the organ) portion and outer parietal portion
- -Visceral and parietal pericardium separated by pericardial cavity (10-25cc)
Pierced superiorly by the aorta, pulmonary trunk, and SVC
15
Q
Where is the base of the pericardium fused with?
A
Base fused with central tendon of diaphragm
16
Q
Which sulcus separates the atria from the ventricles?
A
Coronary sulcus separates the atria from the ventricles
17
Q
What artery lies inside the coronary sulcus?
A
RCA (Right coronary artery)travels within the sulcus
Circumflex artery arises from the L eft C oronary A and travels in the coronary sulcus
18
Q
Which sulcus separate the RV and LV?
A
RV and LV are separated by the interventricular sulci which are composed of an anterior interventricular sulcus and posterior interventricular sulcus
19
Q
what artery lies in the Anterior interventricular sulcus?
A
Anterior interventricular sulcus contains LA antieor D ecending artery, which courses over the interventricular septum and continues in the posterior interventricular sulcus
20
Q
What are is the cardiac skeleton?
A
- -Tough fibrous rings surround the AV valves and act as points of attachment
- -Two additional fibrous annuli develop in relation to the bases of the aorta and the pulmonary trunk
- -Annulus fibrosis is the fixation point for cardiac musculature and plays an important role in the structure, function, and efficiency of the heart
21
Q
describe the atria in comparison to the ventricles
A
The atria are smaller and thinner walled than the ventricles (low pressure)
22
Q
Describe the ventricles in comparison atria
A
Ventricles have a thicker myocardial layer and make up much of the bulk of the heart
23
Q
Which chambers of the heart are the storage units and conduits for blood that is emptied into the ventricles
A
Atria are storage units and conduits for blood that is emptied into the ventricles
24
Q
Where do the ventricles propel blood through?
A
Ventricles must propel blood through pulmonary or systemic circulation
25
Describe the Right atrium?
- RA serves as a reservoir for the RV
- Muscle wall thickness of ~2 mm***
- RA receives blood from SVC, IVC, and coronary sinus**
- RA consists of two parts:
- -Anterior, thin-walled trabeculated portion
- -Posterior, smooth-walled portion
- -Two distinguishing structures
- >Interatrial septum (separates atrium)
- >Fossa ovalis cordis
26
Describe the Right Ventricle?
- -RV ejects blood into the pulmonary arteries for oxygenation and removal of CO2 by the lungs
- -Tricuspid valve RA to RV
- -Pulmonary valve RV to Pulm
- -Muscle wall thickness 4-5 mm***
- -Papillary muscles have attachments to the ventricular walls and chordae tendineae
- -Chordae tendineae are attached to the cusps of the tricuspid valve
- -Chordae tendineae and papillary muscles help to prevent the eversion of the tricuspid valve
27
Describe the Left Atrium?
- LA acts as a reservoir for oxygenated blood from pulmonary veins and a pump during ventricular diastole
- Provides a 20 - 30% increase in left ventricular end-diastolic volume (LVEDV), atrial kick***
- Compromised patients rely on this kick to maintain an adequate CO
- LA located superiorly and posteriorly to other cardiac chambers
- Muscle wall thickness ~3 mm
- Mitral valve connects LA to LV
- Atrial wall is smooth, may contain a central depression
28
Describe the Left ventricle?
- LV ejects blood into the aorta
- LV wall thickness is ~8 to 15 mm (think of the pressure)
- Ventricular septum separates the RV and LV cavities
- Upper third of septum smooth endocardium
- Remaining two thirds of septum and rest of ventricular wall covered with trabeculae carneae
- Present in the LV are two large papillary muscles
- Chordae tendineae of each muscle are attached to the cusps of the mitral valve
29
What are the three distinct layers of the cardiac musculture?
Epicardium, Myocardium, Endocardium
30
Describe the myocardium?
--Middle muscular myocardium consists of two layers***
(superficial/deep)
--Layers provide strength during contraction
31
Describe the endocardium?
Inner endocardium consists of endothelium and a layer of connective tissue
32
Describe the cardiac valves?
- --Cardiac valves ensure a one-way flow of blood through the heart**
- --Open and close in response to pressure gradients that exist above or below the valves**
- --AV (Tri/bi) or semilunar (pulm/aortic)
- --Calculation of valve area accurate way to determine valvular pathology
- -Echocardiography used in the diagnosis of valvular disease
33
Describe the tricuspid valve.
---Situated within the right AV orifice
--Three leaflets of unequal size:
Anterior
Septal
Posterior
---Leaflets attached to chordae tendineae, which are attached to papillary muscles
--Normal tricuspid valve area is 7 cm2
34
describe the mitral valve
- --Situated in the left AV orifice
- --Two major leaflets connected by commissural tissue:
- Anteromedial
- Posterolateral
- ---Normal mitral valve area is 4 – 6 cm2 ******
- ---Has papillary muscles and chordae tendineae attached to the leaflets
35
What are the semilunar valves?
- --Aortic and pulmonary valve configuration is similar
- --The cusps of the aortic valve are slightly thicker due to being subjected to higher pressures
- --Semilunar valves situated within the outflow tracts of their corresponding ventricles
- --Each valve is composed of three cusps
- --Above the aortic valve is a dilation known as the sinus of Valsalva** (so it wont occlude the coronary arties, aortic valve is closed during diastole which is when the coronary arties fill)
- --Normal valve area of the aortic valve is 1-3 cm2***
- --Reduction to a 3rd to a half is associated with increased in symptoms of valvular disease ****
36
In coronary circulation, the heart depends on a constant supply of what to meet its high metabolic demand?
Heart depends on a constant supply of OXYGEN to meet its high metabolic demand
37
The coronary circulation contains an extensive arterial and venous network to ensure that what type of cells are adequately supplied with oxygen
Contains an extensive arterial and venous network to ensure that MYOCYTES are adequately supplied with oxygen
38
In the coronary circulation the Arterial system consists of what two types of vessels
Arterial system consists of epicardial and subendocardial vessels
39
Significant obstruction of about how much can result in myocardial ischemia or infarction ?
Significant obstruction (about 50%) can result in myocardial ischemia or infarction
40
Myocardial blood supply is derived entirely from the right and left coronary arteries,
Blood flows from what kind of blood vessels?
Myocardial blood supply is derived entirely from the right and left coronary arteries,
Blood flows from epicardial to endocardial vessels
41
In the coronary circulation, After perfusing the myocardium blood returns to the right atrium via which sinus and what veins?
After perfusing the myocardium blood returns to the right atrium via the coronary sinus and the anterior cardiac veins
42
In the coronary circulation,A small amount of blood returns directly into the chambers of the heart by way of the which vein?
A small amount of blood returns directly into the chambers of the heart by way of the thebesian veins
43
The right coronary artery normally supplies which cambers of the heart?
RCA normally supplies the RA, most of the RV, and a variable portion of the LV (inferior wall)**
44
In what percentage of individuals, the RCA gives rise to the posterior descending artery (PDA), which supplies the superior-posterior interventricular septum and inferior wall; a right dominant circulation
In 50% of individuals, the RCA gives rise to the posterior descending artery (PDA), which supplies the superior-posterior interventricular septum and inferior wall; a right dominant circulation
45
In what percentage of individuals the PDA is a branch of the LCA; a left dominant circulation
In 10-15% of individuals the PDA is a branch of the LCA; a left dominant circulation
46
In what percentage of individuals of the general population have mixed right and left dominance
Remaining 35-40% of the general population have mixed right and left dominance
47
What parts of the heart does the left coronary artery supply blood to?
LCA supplies the LA and most of the interventricular septum and LV (septal, anterior, and lateral walls)
48
Where does the Left Main Coronary Artery bifurcate into?
LMCA bifurcates into the left anterior descending artery (LAD), which supplies the septum and anterior wall, and the circumflex artery (CX), which supplies the lateral wall
49
In a left dominant circulation, what wraps around the AV groove and continues down the PDA to supply what part of the heart?
In a left dominant circulation, the CX wraps around the AV groove and continues down as the PDA to supply most of the posterior septum and inferior wall****
50
Arterial supply to the SA node may be derived from: what blood vessels in the heart?
Arterial supply to the SA node may be derived from:
RCA (60% of individuals)*
LAD (40% of individuals)*
51
Arterial supply to the AV node by what blood vessels?
AV node supplied by:
RCA (85-90% of individuals)
CX (10-15% of individuals)
52
Arterial supply to the Bundle of His has a dual blood supply from?
Bundle of His has a dual blood supply derived from the PDA and LAD
53
Arterial supply to the Anterior papillary muscle of mitral valve are from what blood vessels?
Anterior papillary muscle of mitral valve; LAD and CX
54
Arterial supply to the Posterior papillary muscle of mitral valve is from what blood vessel?
Posterior papillary muscle of mitral valve; PDA
55
An extensive venous system exists in the heart what are the three major systems for the heart?
```
An extensive venous system exists in the heart
The three major systems include:
Coronary sinus
Anterior cardiac veins
Thebesian veins
```
56
What phase of the cardiac cycle are the LV and RV perfused?
LV is perfused almost entirely during diastole**
| RV is perfused during both systole and diastole
57
Coronary perfusion pressure is usually determined by difference between which two pressures?
Coronary perfusion pressure is usually determined by difference between aortic pressure and ventricular pressure
58
Is Coronary blood flow intermittent or continuous?
Coronary blood flow is intermittent rather than continuous
59
Decreases in which pressure or increases in what pressure can reduce coronary perfusion pressure?
Decreases in aortic pressure or increases in ventricular end-diastolic pressure can reduce coronary perfusion pressure
60
For determinants of coronary perfusion, Increases in what will decrease coronary perfusion?
Increases in heart rate decrease coronary perfusion
61
For determinants of coronary perfusion, Endocardium tends to be most vulnerable to what during decreases in coronary perfusion pressure?
Endocardium tends to be most vulnerable to ischemia during decreases in coronary perfusion pressure
62
Coronary blood flow parallels what demand of the heart?
Coronary blood flow parallels myocardial metabolic demand
63
Coronary blood flow is about how much at rest?
Coronary blood flow is ~250 mL/min at rest (4-5%)
64
Myocardium regulates its own blood flow closely between perfusion pressures of?
Myocardium regulates its own blood flow closely between perfusion pressures of 50 mm Hg and 120 mm Hg
Blood flow becomes increasingly pressure dependent beyond this range
65
Changes in blood flow are entirely due to variations in coronary arterial tone in response to what?
Changes in blood flow are entirely due to variations in coronary arterial tone in response to metabolic demand
66
For myocardial oxygen balance, Increases in myocardial metabolic demand must be met by an increase what?
Increases in myocardial metabolic demand must be met by an increase in coronary blood flow****
67
Myocardium is unable to compensate for reductions in blood flow by extracting more oxygen from what?
Myocardium is unable to compensate for reductions in blood flow by extracting more oxygen from hemoglobin
68
In terms of myocardial oxygen balance, Myocardial oxygen demand is normally the most important determinant of what?
Myocardial oxygen demand is normally the most important determinant of myocardial blood flow
69
What do most volatile anesthetics do to the coronaries?
Most volatile anesthetics are coronary vasodilators
70
Volatile anesthetics effects on coronary blood flow is variable due to what three things?
Their effect on coronary blood flow is variable due to:
- Direct vasodilating properties
- Reduction of myocardial metabolic requirements
- Effects on arterial blood pressure
71
Volatile agents appear to exert beneficial effects in what two settings?
Volatile agents appear to exert beneficial effects in the setting of myocardial ischemia and infarction
72
Can potentially be beneficial in patients with patient population because preload and afterload is decreased despite a decrease in myocardial contractility?
Can potentially be beneficial in patients with heart failure because preload and afterload is decreased despite a decrease in myocardial contractility
73
Normal ventricular cell resting membrane potential is what?
Normal ventricular cell resting membrane potential is -80 to -90 mV****
74
Action potential transiently raises myocardial cell membrane potential to what?
Action potential transiently raises myocardial cell membrane potential to +20 mV
75
CARDIAC CONDUCTION SYSTEM
| Conduction system consists of the what following components?
```
CARDIAC CONDUCTION SYSTEM
Conduction system consists of the following components:
SA Node
Internodal tracts
AV node
AV bundle purkinje system
```
76
SA node located along the epicardial surface at the what junction?
SA node located along the epicardial surface at the junction of the SVC and the RA
77
SA node consists of what two cell types?
Consists of two cell types:
P cells (pacemaker cells) (starts here?)
Intermediate or transitional cells
Transitional cells conduct impulses within and away from the SA node
78
Internodal tracts consist of what type of cells?
Contain P cells (spontanous rate of depolerization) and transitional cells
60-80
79
What are the three major internodal tracts?
Three major internodal tracts exist:
Anterior- sends fibers to the LA and then travels down through the atrial septum to the AV node
Middle- curves behind the SVC before descending to the AV node
Posterior- continues along the terminal crest to enter the atrial septum and then passes to the AV node
80
AV node causes a delay in the transmission of what?
AV node causes a delay in the transmission of the action potential (delay to allow for atrial kick)
81
The AV node delay may be attributed to what three things?
Delay may be attributed to:
- Size of the AV nodal cells
- Resting membrane potential
- Paucity of gap junctions
82
There is a greater what? to the transmission of an action potential that exists within the AV node.
Greater resistance to the transmission of an action potential exists within the AV node
83
What is the AV bundle?
```
ATRIOVENTRICULAR BUNDLE 20-40
AV bundle (bundle of His) extends from the lower end of the AV node and enters the posterior part of the ventricle and Purkinje system
```
84
What are the purkinje system?
PURKINJE SYSTEM
| Consists of the bundle branch system and its terminal branches
85
What two events define the cardiac cycle?
Cardiac cycle can be defined by both electrical and mechanical events
86
Which part of the cardiac cycle is considered contraction and which is considered relaxation?
Systole refers to contraction, diastole refers to relaxation
87
Most diastolic ventricular filling occurs how?
Most diastolic ventricular filling occurs passively
88
Contraction of the atria contributes what percent of ventricular filling
Contraction of the atria contributes 20-30% of ventricular filling
89
Preload and afterload depend on what two systems in the body?
Preload and afterload depend on both the heart and vascular system
90
What four factors affect cardiac performance directly?
Four factors affect cardiac performance directly:
- Preload
- Afterload
- Heart rate
- Myocardial contractility
91
What factors affect ventricular preload?
```
Factors affecting ventricular preload:
Venous return
Blood volume
Distribution of blood volume
Heart rhythm
Heart rate
```
92
What is preload?
Preload:
Ventricular preload is end-diastolic volume
When HR is constant CO is directly proportional to preload
this is a DETERMINANTS OF
VENTRICULAR PERFORMANCE
93
What is afterload
Afterload: (SVR)
Commonly equated with either ventricular wall tension during systole or arterial impedance to ejection
this is a DETERMINANTS OF
VENTRICULAR PERFORMANCE
94
What is Heart rate?
Heart rate:
-CO is generally directly proportional to HR
-HR is an intrinsic function of the SA node but is modified by autonomic, humoral, and local factors
-Normal intrinsic rate of the SA node in young adults is about 80-100 beats/minute, but decreases with age according to the following formula:
Normal Intrinsic HR = 118 beats/min – 0.57 x age
this is a DETERMINANTS OF
VENTRICULAR PERFORMANCE
95
What is myocardial contractility?
```
Myocardial contractility:
Stroke volume (volume of blood ejected during systole) depends on myocardial contractility
```
this is a DETERMINANTS OF
VENTRICULAR PERFORMANCE
96
what are two major factors that influence contractility
Two major factors influence contractility:
- Preload
- Alterations in sympathetic activation of the ventricles
this is a DETERMINANTS OF
VENTRICULAR PERFORMANCE
97
What is cardiac output?
cardiac Output: (4-8L)
Volume of blood pumped from the heart per minute
CO = SV x HR
98
What is cardiac index?
Cardiac Index: (2-4)
Compensates for variations in body size
CI = CO/BSA (body surface area)
99
What is ejection fraction?
ejection Fraction: (60-70%)
| EF = (SV/EndDiastolicVolume) x 100
100
What is SVR?
SVR: (800-1200)
Relationship among CO, preload, and afterload
SVR = (MAP - CVP)/CO x 80
101
What is ventricular compliance contraction abnormalities?
Contraction abnormalities:
- Hypokinesis (decrease contraction)
- Akinesis (failure to contract)
- Dyskinesis (paradoxyl bulging?)
102
What is ventricular compliance wall motion abnormalities?
Wall motion abnormalities:
| When the ventricular cavity does not collapse symmetrically or fully, emptying becomes impaired
103
Valvular dysfunction can lead to what?
Valvular dysfunction:
| Can lead to stenosis, regurgitation, or both
104
What can happen in stenosis in an AV valve or semilunar valve?
Stenotic lesions:
- Stenosis of an AV valve reduces stroke volume primarily by decreasing ventricular preload
- Stenosis of a semilunar valve reduces stroke volume primarily by increasing ventricular afterload
105
What happens to stroke volume with a regurgitant lesion?
Regurgitant lesions:
| Effective stroke volume is reduced by the regurgitant volume with every contraction
106
describe arteries
Arteries:
- Transport blood to tissues under high pressure
- Average diameter 4 mm and wall thickness 1 mm
- Have a thick layer of elastic tissue, smooth muscle, and fibrous tissue
107
Describe arterioles
Arterioles:
- Last small branches of the arterial system
- Act as control valves for the release of blood into capillary beds. Structurally similar to arteries
- Average diameter 30 μm and wall thickness 20 μm
108
describe capillaries
capillaries: (one cell thick)
Exchange of fluids, nutrients, electrolytes, hormones, and other substances occurs between the blood and the interstitial fluids in the capillaries
Average diameter 8 μm and wall thickness 1 μm
109
describe venules
- Collect blood from capillaries and gradually and progressively become larger veins
- Average diameter 20 μm and wall thickness 0.5 mm
- Contain a thin fibrous layer
110
describe veins
Veins:
- Serve as conduits for the transport of blood back to the heart
- Act as a large reservoir because they are very distensible*
- Average diameter 30 mm and wall thickness 1.5 mm
111
How much blood is held in the venous system, arteries, and tissue?
The venous system holds about 60% of the blood volume
The arteries contain about 20% of the blood volume
The rest is in the tissue, 20%
112
What are the factors that influence blood flow in the vascular tree?
Multiple factors influence blood flow in the vascular tree:
- Local and metabolic control mechanisms (autoregulation)
- Endothelium-derived factors
- Autonomic nervous system (sympathetic, primarily)
- Circulating hormones (catecholamine)
113
in the systemic circulation, what is arterial blood pressure?
Arterial blood pressure:
- Systemic blood flow is pulsatile in large arteries, when it reaches the systemic capillaries, it is continuous
- Directly related to SV and inversely proportionate to the compliance of the arterial tree
114
What is the immediate control of arterial blood pressure?
CONTROL OF ARTERIAL BLOOD PRESSURE
Immediate control: (min to min)
-Primarily the function of the autonomic nervous system reflexes
-Peripheral baroreceptors (in aortic arch and common carotids)
115
What is the intermediate control of arterial blood pressure?
intermediate control:
| Activation of the renin-angiotensin-aldosterone system (water follows Na)
116
What is the long term control of arterial blood pressure?
Long-term control: (take several hours or days)
| Slower renal mechanisms
