Cardiovascular System Flashcards
1
Q
What does haemostasis mean?
A
Stops bleeding
2
Q
What is circulation time?
A
Time for a drop of blood to pass from right atrium through pulmonary circulation, back to left atrium, through systemic circulation down to foot and back to right atrium. At rest it take about 1 minute
3
Q
What order does blood flow through CVS?
A
Veins- heart - arteries
4
Q
What is the pericardium?
A
Double-walled sac enclosing heart, to isolate and give room for expansion and to resist compression
5
Q
Why does the pericardial cavity contain fluid?
A
It lubricates for heart to beat without friction
6
Q
What is the layer of the sac that covers the heart?
A
Visceral pericardium
7
Q
What is the outer layer of the sac that covers the heart?
A
Parietal pericardium
8
Q
What does fluid within pericardium cause?
A
Cardiac tamponade
9
Q
What is cardiac tamponade?
A
Compression of heart by abnormal accumulation of fluid on pericardial cavity
10
Q
What are the 3 layers of the heart wall?
A
Outer epicardium, middle myocardium and the inner endocardium
11
Q
What is the epicardium made out of?
A
Visceral pericardium of simple squamous epithelium
12
Q
What is the myocardium?
A
Thickest layer made of cardiac muscle
13
Q
What makes up the endocardium?
A
Simple squamous epithelium that forms the inner lining of the chamber
14
Q
What is the fibrous skeleton?
A
Dense connective tissue of heart, surrounding valves and forms foundation to which heart valves are attached
15
Q
What structure prevents over-stretching of valves?
A
Fibrous skeleton
16
Q
What 3 veins does the right atrium receive blood from?
A
Superior vena cava, inferior vena cava and coronary sinus
17
Q
What is the RA and LA separated by?
A
Interatrial septum
18
Q
Where does blood to go from RA?
A
To RV through tricuspid valve (R atrioventricular valve)
19
Q
Where does blood go to from RV?
A
Leaves heart through pulmonary semilunar valve to pulmonary trunk (large artery) and then to either left or right pulmonary artery
20
Q
What order does blood flow through CVS?
A
Veins- heart - arteries
21
Q
What is the pericardium?
A
Double-walled sac enclosing heart, to isolate and give room for expansion and to resist compression
22
Q
Why does the pericardial cavity contain fluid?
A
It lubricates for heart to beat without friction
23
Q
What is the layer of the sac that covers the heart?
A
Visceral pericardium
24
Q
What is the outer layer of the sac that covers the heart?
A
Parietal pericardium
25
What does fluid within pericardium cause?
Cardiac tamponade
26
What is cardiac tamponade?
Compression of heart by abnormal accumulation of fluid on pericardial cavity
27
What are the 3 layers of the heart wall?
Outer epicardium, middle myocardium and the inner endocardium
28
What is the epicardium made out of?
Visceral pericardium of simple squamous epithelium
29
What is the myocardium?
Thickest layer made of cardiac muscle
30
What makes up the endocardium?
Simple squamous epithelium that forms the inner lining of the chamber
31
What is the fibrous skeleton?
Dense connective tissue of heart, surrounding valves and forms foundation to which heart valves are attached
32
What structure prevents over-stretching of valves?
Fibrous skeleton
33
What 3 veins does the right atrium receive blood from?
Superior vena cava, inferior vena cava and coronary sinus
34
What is the RA and LA separated by?
Interatrial septum
35
Where does blood to go from RA?
To RV through tricuspid valve (R atrioventricular valve)
36
Where does blood go to from RV?
Leaves heart through pulmonary semilunar valve to pulmonary trunk (large artery) and then to either left or right pulmonary artery
37
Where does blood go to from LA?
Through bicuspid ( L atrioventricular valve) to LV. Then blood leaves heart through aortic semilunar valve to aorta (largest artery of body) and goes to either coronary arteries or arch of aorta to body
38
What do heart valves do?
Ensures 1-way flow of blood
39
What do AV valves involve?
Chordae tendineae (strings of connective tissue) and papillary muscle
40
What are the 3 layers of walls of arteries and veins?
Tunica interna/intima, tunica media and tunica externa/adventitia
41
What percentage of circulating blood does heart use in coronary circulation to meet its own demands?
5%
42
What can fatty deposits or blood clots lead to?
MI which is a sudden death of patch of tissue as it is deprived of blood flow
43
What is a heart bypass?
Rerouting blood around clogged coronary arteries
44
How do anastomoses protect against MI?
Union of branches of 2 or more arteries supplying same region so there is an alternative route is blocked
45
Why does the heart continuously beat?
Due to an inherent and rhythmical electrical activity
46
Do veins have more or less bp than arteries?
Less
47
What is the source of stimulation for the heart?
Network of specialised cardiac muscle fibres called autorhythmic cells because they are self-excitable. They repeatedly generate spontaneous action potentials that trigger heart contractions
48
What is an action potential?
Electrical signal along membrane of muscle fibre (rapid change in membrane potential involves depolarisation followed by polarisation)
49
What effect to nerve impulses from autonomic nervous system and blood-borne hormones have on heartbeat?
They modify it but do not establish the fundamental rhythm
50
What do autorhythmic cells do?
Act as pacemaker setting rhythm for entire heart
Form conduction system
Are found in specific locations
51
How can hormones and neurotransmitters speed or slow pacing of heart?
By SA node fibres
52
What effects does acetyl choline from parasympathetic division of ANS have on AP/min of a person at rest?
Decreases AP/min from 90-11 to 75
53
Where is ectopic pacemaker site?
Outwith SA node
54
What does ectopic pacemaker site do?
If abnormal self-excitability develops it can produce extra beats or pace heart for some period of time
55
What can trigger ectopic pacemaker site to kick in?
Caffeine and nicotine
Electrolyte imbalances
Hypoxia
Toxic reactions to drugs
56
What component of the conduction system contains pacemaking cells that establish heart rate?
The SA node
57
Where is the SA node?
Embedded in the posterior wall of the right atrium
58
Where is the AV node?
Within the floor of the right atrium near the opening of the coronary sinus
59
How can hormones and neurotransmitters speed or slow pacing of heart?
By SA node fibres
60
What effects does acetyl choline from parasympathetic division of ANS have on AP/min of a person at rest?
Decreases AP/min from 90-11 to 75
61
Where is ectopic pacemaker site?
Outwith SA node
62
What does ectopic pacemaker site do?
If abnormal self-excitability develops it can produce extra beats or pace heart for some period of time
63
What can trigger ectopic pacemaker site to kick in?
Caffeine and nicotine
Electrolyte imbalances
Hypoxia
Toxic reactions to drugs
64
What component of the conduction system contains pacemaking cells that establish heart rate?
The SA node
65
Where is the SA node?
Embedded in the posterior wall of the right atrium
66
Where is the AV node?
Within the floor of the right atrium near the opening of the coronary sinus
67
What is normally the only electrical connection between the atria and the ventricles?
Bundle of His
68
What is tetanus?
Maintained contraction
69
What would happen is tetanus occurred in cardiac muscle?
Blood flow would cease
70
How come tetanus does not occur in cardiac muscle?
Because of refractory period with is the time interval during which a 2nd contraction cannot be triggered. In cardiac muscle it lasts longer than contraction itself
71
In ventricular action potentials what does depolarisation lead to?
Contraction
72
In ventricular action potentials what does depolarisation lead to?
Relaxation
73
What happens when Na enters the cell?
Depolarisation
74
What happens when Ca enters the cell?
Initiation of contraction
75
What happens when K exits the cell?
Repolarisation
76
What is an electrocardiogram (ECG)?
Recording of electrical changes that accompany AP propagation that can be detected at surface of body
77
What are the 3 states an ECG can be taken at?
Resting, stress or ambulatory
78
What does an ECG do?
Amplifies heart electrical activity. Compares records with different places in the body and with normal recordings to determine is conduction pathway is abnormal, if heart is enlarged and if certain regions are damaged
79
Is P wave on electrocardiograph is larger what does that mean?
Enlarged atrium of heart
80
If Q on electrocardiograph is enlarged what does this mean?
MI
81
If R on electrocardiograph is enlarged what does this mean?
Enlarged ventricles
82
If T in electrocardiograph if flatter what does this mean?
Insufficient oxygen eg. Coronary artery disease
83
If P-W interval on electrocardiograph is lengthened what does his mean?
Scar tissue either from coronary artery disease or rheumatic fever is present
84
Is S-T segment of electrocardiograph is elevated what does this mean?
Acute MI
85
Is S-T segment of electrocardiograph is depressed what does this mean?
Insufficient oxygen
86
If Q-T interval of electrocardiograph is lengthened what Dow this mean?
Myocardial damage or coronary ischaemia or conduction abnormalities
87
What is long Q-T syndrome?
Rare genetic problem where there is a repolarisation abnormality so individual is prone to very rapid heart beats therefore poor supply of oxygen to the brain
88
How do beta-blockers work?
Block beta receptors and decrease electrical impulse that passes through AV node and prevents sudden increase in heart rate
89
How does a defibrillator work?
Depolarises entire myocardium simultaneously then hopefully after repolarisation the SA node will be 1st to reach threshold
90
What is an arrhythmia?
Irregular heart rhythm as defect in conduction system
91
What are causes of arrhythmia?
Caffeine, nicotine, alcohol, drugs, anxiety, hyperthyroidism, K deficiency and certain heart diseases
92
What are 4 examples of arrhythmia?
Heart block, atrial flutter, atrial fibrillation and ventricular fibrillation
93
What is heart block?
Conduction system slowed or blocked at AV node
94
What is atrial flutter?
Abnormal rapid atrial contraction
95
What is atrial fibrillation?
Asynchronous contraction of atrial fibres this chamber fails to pump blood as effectively
96
What is ventricular fibrillation?
Quick death as blood is not ejected from ventricles
97
What is long Q-T syndrome?
Rare genetic problem where there is a repolarisation abnormality so individual is prone to very rapid heart beats therefore poor supply of oxygen to the brain
98
How do beta-blockers work?
Block beta receptors and decrease electrical impulse that passes through AV node and prevents sudden increase in heart rate
99
How does a defibrillator work?
Depolarises entire myocardium simultaneously then hopefully after repolarisation the SA node will be 1st to reach threshold
100
What is an arrhythmia?
Irregular heart rhythm as defect in conduction system
101
What are causes of arrhythmia?
Caffeine, nicotine, alcohol, drugs, anxiety, hyperthyroidism, K deficiency and certain heart diseases
102
What are 4 examples of arrhythmia?
Heart block, atrial flutter, atrial fibrillation and ventricular fibrillation
103
What is heart block?
Conduction system slowed or blocked at AV node
104
What is atrial flutter?
Abnormal rapid atrial contraction
105
What is atrial fibrillation?
Asynchronous contraction of atrial fibres this chamber fails to pump blood as effectively
106
What is ventricular fibrillation?
Quick death as blood is not ejected from ventricles
