cardiovascular system Flashcards
(135 cards)
1
Q
What are the components of the cardiovascular system?
A
Heart, blood vessels, and blood
2
Q
What is the primary function of the cardiovascular system?
A
Transport of nutrients, gases, water, and chemical signals to and from all parts of the body
3
Q
What is the overall function of the cardiovascular system?
A
Maintenance of homeostasis
4
Q
What is the size and weight of the human heart?
A
Size of a fist, 250-350 grams
5
Q
Where is the heart located in the body?
A
Ventral organ in the mediastinum
6
Q
What are the three layers of the heart?
A
- Pericardium
- Myocardium
- Endocardium
7
Q
What is the role of the fibrous pericardium?
A
Offers protection and anchorage, prevents overfilling
8
Q
What is cardiac tamponade?
A
Compression of the heart by abnormal accumulation of fluid in the pericardial cavity
9
Q
What is the outer layer of the heart called?
A
Epicardium
10
Q
What is the thickest layer of the heart?
A
Myocardium
11
Q
What is the inner layer of the heart called?
A
Endocardium
12
Q
What is the function of the fibrous skeleton of the heart?
A
- Reinforces the myocardium
- Point of insertion for cardiac muscle fibers
- Surrounds valves to prevent overstretching
- Acts as an electrical insulator
13
Q
What are the two types of circulation in the cardiovascular system?
A
- Pulmonary circulation
- Systemic circulation
14
Q
What is the function of the right atrium?
A
Receives deoxygenated blood from the body via venae cavae and coronary sinus
15
Q
What is the function of the left atrium?
A
Receives oxygenated blood from the lungs via left and right pulmonary veins
16
Q
What is a common atrial defect known as?
A
Septal defect or ‘Hole in the Heart’
17
Q
Why is a septal defect a problem?
A
Can lead to mixing of oxygenated and deoxygenated blood, causing chronic fatigue and shortness of breath
18
Q
Which ventricle has thicker muscle, right or left?
A
Left ventricle
19
Q
What is the function of the valves in the heart?
A
Ensure one-way flow of blood
20
Q
What structures assist the atrioventricular valves?
A
- Chordae tendineae
- Papillary muscle
21
Q
What are semilunar valves characterized by?
A
Pocket-like cusps
22
Q
What is the significance of bioengineered heart valves?
A
They can grow with the recipient, offering a long-lasting solution for pediatric heart surgery
23
Q
What is pulmonary circulation?
A
Right side of the heart receives oxygen-poor blood and pumps it to the lungs
24
Q
What is systemic circulation?
A
Left side of the heart receives oxygenated blood and pumps it throughout the body
25
What are the three main types of blood vessels?
Arteries, Capillaries, Veins
26
What tissue layers can blood vessels have?
Endothelium, Connective tissue (elastic - elastin), Smooth muscle, Connective tissue (non-elastic – collagenous fibres)
27
What are the three distinct layers of artery and vein walls?
1. Tunica interna/intima 2. Tunica media 3. Tunica externa/adventitia
28
What is the function of arteries?
Arteries carry blood away from the heart under high pressure
29
Name the structural adaptations of arteries that relate to their function.
* Narrow lumen * Thick elastic tissue * Thick smooth muscle * Thick collagen and elastic fibres
30
What is the function of capillaries?
They allow exchange of materials between the blood and the tissue fluid
31
Describe the structure of capillaries related to their function.
* Very narrow lumen (7um) * Single layer of flattened endothelial cells * Gaps between endothelial cells
32
What is the function of veins?
Veins carry blood towards the heart under low pressure
33
List the structural adaptations of veins related to their function.
* Wider lumen * Thinner elastic tissue * Thinner smooth muscle * Thinner collagen and elastic fibres * Presence of valves
34
What is the role of precapillary sphincters?
They can regulate blood flow in some capillary beds
35
What is coronary circulation?
The supply of blood to and from the tissues of the heart
36
Why do heart chambers provide little nourishment to heart tissue?
The blood flowing through the heart chambers does not supply enough oxygen and nutrients
37
What are the two main coronary arteries?
Left coronary artery, Right coronary artery
38
What is the coronary sinus?
It empties venous blood into the right atrium
39
What is the most common cause of compromised coronary circulation?
Coronary artery disease (CAD)
40
What is myocardial infarction often called?
Heart attack
41
What are common symptoms of a myocardial infarction?
Centre/left chest pain travelling to shoulder, arm, back, neck or jaw
42
What are cardiac troponins (cTnT and cTnI) used for?
They are biomarkers for diagnosing myocardial infarction
43
What does myoglobin indicate in relation to myocardial infarction?
It is released rapidly from infarcted myocardium and can be detected as early as two hours after an MI
44
What are the limitations of using myoglobin as a biomarker?
It has high sensitivity but poor specificity
45
What is the significance of hPSC-derived cardiomyocytes?
They have potential for regenerative medicine applications
46
What challenge is associated with transplanting cardiomyocytes?
Poor survival rate and risk of arrhythmias
47
Fill in the blank: The coronary arteries encircle the heart 'like a _______'.
crown
48
What is the main muscle type that makes up the bulk of the heart?
Myocardium
## Footnote
Myocardium is also referred to as cardiac muscle.
49
What are the two types of cardiac cells?
* Contractile cardiomyocytes
* Autorhythmic cells (pacemaker cells)
50
How do cardiac muscle cells differ from skeletal muscle cells?
* Striated
* Short and branched
* One or two nuclei per cell
* Autorhythmic
* No tetanus possible
51
What is the intrinsic pacemaker of the heart?
SA node
## Footnote
The SA node sets the heart pace at around 75 bpm in healthy adults.
52
What is the function of the AV node?
Delays the impulse by 0.1 seconds to allow atrial contraction before ventricular contraction.
53
What is the role of the AV bundle (bundle of His)?
It is the only electrical connection between the atria and ventricles.
54
What are the Purkinje fibers responsible for?
Allow ventricles to contract forcefully from the apex to the top.
55
How do action potentials differ between pacemaker cells and cardiomyocytes?
Pacemaker cells have a pacemaker potential; cardiomyocytes have a resting potential.
56
What is the significance of Ca2+ during cardiomyocyte contraction?
It plays a role in the plateau phase and ensures a long refractory period.
57
How does the action potential in cardiac muscle prevent tetanus?
The refractory period prevents a second contraction before the heart fills again.
58
What are the phases of action potentials in cardiomyocytes?
* Rapid depolarization
* Plateau
* Repolarization
59
What factors affect heart rate?
* Hormones (e.g., epinephrine, thyroxine)
* Ions (e.g., calcium, sodium, potassium)
* Physical factors (age, gender, exercise, body temperature)
60
What does an ElectroCardioGram (ECG) measure?
The electrical activity of the heart.
61
What is represented by the P-wave in an ECG?
Atrial depolarization (contraction).
62
What does the QRS complex indicate in an ECG?
Onset of ventricular depolarization (contraction).
63
What is the T-wave in an ECG associated with?
Ventricular repolarization (just before ventricles start to relax).
64
What can an enlarged P wave indicate?
Enlarged atrium.
65
What is Long-QT syndrome?
A genetic problem that causes repolarization abnormality and rapid heartbeats.
66
What is the function of β-blockers in heart treatment?
They block β adrenoceptors to decrease electrical impulse through the AV node.
67
What is arrhythmia?
Irregular heart rhythm due to defects in the conduction system.
68
Name a serious type of heart block.
Conduction system slowed or blocked, commonly at AV node.
69
What does ventricular fibrillation lead to?
Quick death as blood is not ejected from ventricles.
70
What does the ST segment in an ECG represent?
The period when the entire ventricular myocardium is depolarized.
71
What is the significance of the P-Q interval in an ECG?
Lengthened P-Q interval indicates scar tissue or coronary artery disease.
72
Fill in the blank: The heart's average resting pulse rate is _______.
[75 bpm]
73
What is haemodynamics?
The study of how blood flows through the cardiovascular system.
74
What are the three types of blood vessels and their functions?
* Arteries: pressure reservoirs
* Arterioles: resistance vessels
* Veins: capacitance vessels
75
What determines blood flow in the cardiovascular system?
* Blood pressure
* Resistance to flow
76
What is a pressure gradient?
Blood flows down a pressure gradient, from a region of high pressure to a region of low pressure.
77
What is driving pressure?
The pressure created in the ventricles as blood is forced out.
78
What is the relationship between resistance and blood flow?
Flow is inversely related to resistance; an increase in resistance results in a decrease in flow.
79
What factors affect resistance in blood vessels?
* Radius of the tube
* Length of the tube
* Viscosity of the fluid
80
What happens to blood flow during vasodilation?
Resistance decreases and blood flow increases.
81
What is blood pressure?
The pressure that blood exerts against blood vessels as it is pumped by the heart.
82
Where is systemic blood pressure highest and lowest?
Highest in the aorta, lowest in the venae cavae.
83
What is systolic pressure?
Pressure generated by ventricular contraction, approximately 120 mmHg in healthy adults.
84
What is diastolic pressure?
Aortic pressure during ventricular relaxation, approximately 70 to 80 mmHg in healthy adults.
85
What is pulse pressure?
The difference between systolic and diastolic pressures.
86
What is mean arterial pressure (MAP)?
MAP = Diastolic pressure + (1/3 of pulse pressure).
87
How is blood pressure measured?
Using a sphygmomanometer to detect Korotkoff sounds.
88
What defines hypotension?
Low systolic blood pressure, below 100 mmHg.
89
What defines hypertension?
Sustained elevated arterial pressure of 140/90 mmHg.
90
What is cardiac output (CO)?
CO = Heart Rate (HR) x Stroke Volume (SV).
91
What factors affect blood pressure?
* Cardiac output
* Peripheral resistance
92
What is venous return?
The flow of blood back to the heart through veins.
93
What is the role of the respiratory pump?
Pressure changes during respiration help draw blood into the right atrium.
94
What is the role of the skeletal muscle pump?
Skeletal muscle contractions help return blood to the heart through veins.
95
What are baroreceptors?
Sensors that detect changes in blood pressure.
96
What is the effect of the sympathetic nervous system on blood pressure?
Promotes vasoconstriction, which increases blood pressure.
97
What is haemodynamic shock?
Failure of the cardiovascular system to deliver enough oxygen and nutrients to meet cellular needs.
98
What are the types of shock?
* Hypovolemic
* Cardiogenic
* Vascular
* Obstructive
99
What is the homeostatic response to shock?
Activation of renin-angiotensin-aldosterone system and secretion of ADH.
100
What are common signs and symptoms of shock?
* Rapid resting heart rate
* Weak, rapid pulse
* Altered mental state
* Sweating
* Thirst
* Reduced urine formation
* Nausea
* Acidosis
101
What is the duration of one complete cardiac cycle?
800 msec
102
What occurs during systole?
Contract
103
What occurs during diastole?
Relax
104
What are the four phases of the cardiac cycle?
* Ventricular filling
* Isovolumetric contraction
* Ejection
* Isovolumetric relaxation
105
What is the pressure relationship during ventricular filling?
P in atrium > P in ventricle; P ventricle < P aorta
106
What happens during atrial diastole?
Heart is relaxed, pressure in heart is low, AV valves are open
107
What is the role of the AV valves during atrial systole?
They close as the ventricles begin to contract
108
What marks the beginning of ventricular systole?
Atrial systole ends
109
What occurs during the ejection phase of the cardiac cycle?
Intraventricular pressure surpasses the pressure in major arteries, semilunar valves open
110
What is stroke volume?
Volume of blood ejected by each side of the heart per contraction
111
How is stroke volume calculated?
Stroke volume = EDV – ESV
112
What does EDV stand for?
End Diastolic Volume
113
What does ESV stand for?
End Systolic Volume
114
What is the average stroke volume in mL?
70 mL
115
What is the formula for ejection fraction?
(EDV – ESV)/EDV * 100
116
What are the two loudest heart sounds heard through a stethoscope?
* S1 = 'lub'
* S2 = 'dub'
117
What causes heart murmurs?
Abnormal sound indicating valve disorder
118
What is cardiac output (CO)?
Amount of blood pumped by each side of the heart in 1 minute
119
How is cardiac output calculated?
CO = SV x HR
120
What is the typical heart rate (HR) in beats per minute?
75 beats per minute
121
What is the cardiac output of an average healthy adult?
5.25 L/min
122
What is cardiac reserve?
Difference between max CO & rest CO
123
What are the three main factors affecting stroke volume?
* Preload
* Afterload
* Contractility
124
What does preload refer to?
Degree cardiac muscle cells are stretched just before they contract
125
What is the Frank-Starling Law of the Heart?
The higher the preload, the higher the stroke volume
126
What is afterload?
Pressure that the ventricles must overcome to eject blood
127
What factors influence contractility?
* Calcium levels in cardiomyocytes
* ANS modulation
* Inotropic agents
128
What are positive chronotropic factors?
Factors that increase heart rate
129
What are negative chronotropic factors?
Factors that decrease heart rate
130
What role does the autonomic nervous system play in heart rate regulation?
It modulates heart rate and contractility
131
How do hormones like epinephrine and norepinephrine affect heart rate?
They increase both heart rate & contractility
132
What effect does increased body temperature have on heart rate?
Increases heart rate
133
What happens to cardiac output during intense exercise?
Increases to about 19.5 L/min
134
Fill in the blank: Cardiac output (CO) can be affected by changes in _______.
[stroke volume or heart rate]
135
True or False: Mitral valve prolapse is always a serious condition.
False
