CVS Flashcards
1
Q
Where is the heart found?
A
Middle mediastinum
2
Q
What is the heart surrounded by ?
A
Pericardium
3
Q
Describe the pericardium?
A
Fibroserous fluid filled sac surrounding the musclular body of the heart and roots of the great vessels
4
Q
Give the functions of the pericardium
A
Fixes the heart and limits rotation
prevents over filling due to inextensible fibrous layer
lubrication
protection from infection as it acts as a barrier from the lungs which are susceptible to injury
5
Q
Describe the two layers of the pericardium
A
Fibrous layer - continuous with the central tendon of the diaphragm
Serous layer - outer parietal layer and internal visceral layer made up of mesothelium
6
Q
What is the innervation of the pericardium? What are its spinal roots?
A
Phrenic nerve (C3-C5)
7
Q
What clinical relevance does the fibrous pericardium have?
A
During accumulation of fluid - pericardial effusion within pericardial cavity leading to increased pressure and chambers are compressed reducing the CO.
8
Q
What is the clinical relevance of the transverse pericardial sinus? Where is it found ?
A
Can be used to located and subsequently ligate arteries during coronary bypass grafting.
It is a passage through pericardial cavity located posteriorly to ascending aorta and pulmonary trunk, anteriorly to SVC and superior to LA
9
Q
Where does the apex of the heart point?
A
Anterior inferior direction
10
Q
What is the anterior border of the heart?
A
Right atrium
11
Q
What is the posterior border of the heart ?
A
Left atrium
12
Q
What is the inferior border of the heart?
A
Both ventricles
13
Q
What is the right pulmonary border of the heart?
A
Right atrium
14
Q
What is the left pulmonary border of the heart?
A
Left ventricle
15
Q
What are sulci and what do they create?
A
Divisions in the heart which form grooves
16
Q
Where is the coronary sinus and what travels in it ?
A
Transverse around the heart- wall dividing atria and ventricles
Contains vascualture
17
Q
What does the anterior and posterior interventricular sulci divide?
A
Run vertically and separate ventricles
18
Q
What is the formation of the pericardial sulci?
A
Passageways formed in way in which percardium folds around the great vessels.
19
Q
What are the two pericardual sulci? Where are they found ?
A
Oblique pericardial sulci- posterior surface of the heart
Transverse pericardial sulci- superiorly found
20
Q
What are the two things that may happen to a valve?
A
Stenosis and regurgitation
21
Q
If changes occur to a valve what may be heard? Why?
A
Murmur due to tuberlent flow
22
Q
What murmurs caused by valve changes are heard during systole?
A
Pulmonary and aortic valve stenosis
Mitral valve prolapse
Mitral/ tricuspid regurgitation
23
Q
What murmurs caused by valve changes are heard during diastole?
A
Aortic/ pulmonary regurgitation
Mitral/ tricuspid stenosis
24
Q
What forms the IVC?
A
Joining of the two common iliac veins
25
What forms the SVC?
Joining of the two brachiocephalic veins
26
What are the three branches of the aortic arch?
Brachiocephalic
Left common carotid
L subclavian
27
Describe an aortic dissection
Tear in the inner wall which restricts blood flow and causes shearing of the blood vessels layers from each other.
28
Describe an aortic aneurysm
Dilation of artery underlying weakness can lead to rupture and therefore huge haemorhaging causing death.
29
How are the mitral and tricupsid valves shut? What is heard when they shut?
Contraction of small muscles - papilary muscles attached to valves by chordae tendinae . The first heart sound S1 or lub.
30
Describe the aortic valve. What is its significance in terms of filling of the coronary arteries?
Fibrous ring where 3 cusps attach
Opening to the coronary vessels found above L and R cusps so when valve opened these are covered so filling occurs during diastole.
31
What happens to the heart sounds during inspiration?
Inspiration causes blood into the thorax increasing right ventricular pressure leading to the shutting of the aortic valve first
32
How can you tell between the heart sounds S1 and S2?
2nd heart sound higher pitch shorter duration and lower intensity
33
Describe the inner surface of the RA?
2 parts divided by the crista terminalis
Posterior - smooth walls from sinus venous
anterior -muscular wall and right auricle from primitive atria
34
Describe the inner surface of LA?
inflow portion smooth from pulmonary veins
| outflow- pectinate muscle and L auricle from atria
35
Describe the atrial septa
Oval shaped depression called fossa ovalis from foramen ovale
36
Describe the inner surface of the RV?
Triangular shape
Anterior border - trabeculae carnae
Inferior inflow -papillary muscles and chordae tendinae
moderator band contains - right bundle branches
37
Describe the LV composition
Increased muscle as needs to generate higher pressure
| papillary muscles contain trabeculae carnae
38
Describe the ventricular septa
Membranous and muscular parts
39
Give a general description of the layers of the heart muscle?
Endo--> myo--> epi cardium
40
Describe the endocardium
Inner most layer - lines cavities and valves of the heart
loose connective tissue and simple squamous epithelial tissue
regulates contractions and aids cardiac embyrological development
41
What are the two main types of endocarditis ?
Infective and non infective
42
What is the subendocardial layer?
joins endo and myocardium - loose fibrous connective tissue and contains the perkinji fibres so if damaged can lead to arrthymias
43
Describe the myocardium
Cardiac muscle - straitated muscle that contracts involuntarily.
44
What is the subepicardial layer?
Joins myo and epicardium
45
Describe the epicardium?
Outer most layer composed of CT, fat and simple squamous epithelia.
46
Where do the coronary arteries arise from?
Aortic coronary sinuses L and R
47
What does the L coronary artery branch into?
Left anterior descending and circumflex and left marginal artery
48
What does the R coronary artery branch into?
Right marginal artery and posterior interventricular artery
49
What areas of the heart does the R coronary artery supply?
RA, both nodes, posterior part of the interventicular septum
50
Where of the heart does the right marginal supply?
RV and apex
51
Where does the posterior interventricular artery supply?
Both ventricles and posterior 1/3 of IVS
52
Where does the L coronary artery supply?
LA, LV, IVS and AV bundles
53
Where does LAD supply?
RV, LV, anterior 2/3 of IVS
54
Where does the left marginal supply?
LV
55
Where does the circumflex supply?
LA LV
56
Where do the cardiac veins drain into ?
Coronart sinus on posterior aspect of the heart
| Some drain directly into the RA
57
What are the tributaries to the coronary sinus and where do the come from?
Great cardiac vein - from apex follows anterior interventricular groove
Small cardiac vein - right side anterior
Middle cardiac vein - posterior surface
58
What valve is found between the RA and RV?
Tricuspid
59
What receptors innervate the cardiac vasculature to cause vasodilation?
B2 adrenoceptors
60
What allows the spread of AP in cardiomyocytes?
Intercolated discs
61
What sets the heart rate usually ? Why ?
SAN
| Because it has the quickest rate of impulse generation
62
How are impulses generated in the SAN?
Funny current allows the threshold to be regularly reached
63
Why can electrical impulses not spread directly to ventricles ?
Insulation from cartilaginous rings of heart
64
How long and where is the action potiental delayed for?
At the AVN for 120ms.
65
What change produces S1?
closing of the AV valves
66
What change produces S2?
Closing of the outflow valves
67
What do s3 and s4 produce?
Gallop rhythm
68
What is the pressure in the RA?
0-8mmHg
69
What is the pressure in the RV during diastole?
0-8 mmHg
70
What is the pressure in the RV during systole?
15-30 mmHg
71
What is the pressure in the LA?
0-10 mmHg
72
What is the pressure in the LA during diastole?
1-10 mmHg
73
What is the pressure in the LA during systole?
100-140 mmHg
74
What is the pressure in the pulmonary artery during diastole?
4-12mmHg
75
What is the pressure in the pulmonary artery during systole?
15-30mmHg
76
What is the pressure in the aorta during diastole?
60-90mmHg
77
What is the pressure in the aorta during systole?
100-140 mmHg
78
Describe the pathway of vessels from the heart back to the heart
```
Large elastic arteries
Medium arteries
arterioles
metarterioles
capillary beds
post capillary venules
venules
medium veins
large veins
heart
```
79
What is the function of the fluid between the visceral and parietal layers of the serous pericardium?
lubrication
80
Describe cardiac tamponade
Pericardial effusion- accumulation of blood or pus leading to insufficient filling and obstructive shock as decreased filling presents with Becks Triad
81
What is pericardiocentesis?
Drainage of fluid in cardiac tamponade.
| Wide bore needle inserted L 4/5th intercostal space near sternum
82
Describe the changes that would be noticed on examination of a patient with pericarditis
Chest pain
ST elevation in ALL leads
Rustle on ausculation - serous layer can become roughened and fibrosed.
83
Where do you listen to the aortic valve?
2nd intercostal R sternal edge
84
Where do you listen to the pulmonary valve?
2nd intercostal L sternal edge
85
Where do you listen to the triscupid valve?
4th intercostal space L sternal edge
86
Where do you listen to the mitral valve?
5 th intercostal space midclavicular line L
87
Give the equation for cardiac output
CO=SV x HR
88
Give the equation for Blood pressure
BP= CO x TPR
so
BP= SVxHRxTPR
89
What is stenosis?
Narrowing when opening
90
What is regurgitation ? What is it also called?
Not closing
| incompetence
91
What is atresia?
Valve not present or fused
92
What does the ANS and CNS regulate?
HR, BP, temp
93
When is sympathetic nervous system dominante?
Under stress
94
When is the parasympathetic nervous system dominante ?
Basal conditions
95
Describe the parasympathetic input of the heart?
Preganglia at CNX synapse with postganglia on epicardium or within walls of the SA or AV node
96
What parasympathetic receptors are present in the heart? What neurotransmitter is released?
Ach at M2 receptors
97
What is the effect of activation of the parasympathetic nervous system at the heart?
Decrease heart rate ( negative chronotropic response)
98
Describe the sympathetic input of the heart?
Post ganglia via paravertebral chain innervate the nodes and myocardium
99
What sympathetic receptors are present in the heart? What neurotransmitter is released?
Release nor adrenaline on the alpha 1 adrenoceptors
100
What is the effect of activation of the sympathetic nervous system at the heart?
Increase HR and force of contraction
101
Explain the mechanism behind the changes that occur on activation of the parasympathetic nervous system at the heart
Increased K+ conductance leading to decreased cAMP levels and decreasing the pacemaker potential
102
Explain the mechanism behind the changes that occur on activation of the sympathetic nervous system at the heart
Increased Na+ conductance leading to increased cAMP levels and increasing the pacemaker potential.
Activated PKA phosphorylates Ca channels leading to increased Ca entry and increased contraction force- CICR
103
What receptors are found in most arteries and veins? What is there action?
alpha 1 adrenoceptors - contract with circulating adrenaline
104
What is special about the coronary and skeletal muscle vasculature?
Have B2 adrenoceptors which cause dilation during increased stress due to increased adrenaline - over ride a1
105
How is change in condition detected and converted into a change in pressure?
Baroreceptors in the carotid sinus and aortic arch detect high pressure send increased AP due to increased sensitivity to stretched
Low pressure detected by atrial receptors
106
Define flow
Volume of fluid per unit of time passing a given point
107
Define velocity
Rate of movement of fluid particles along a tube
108
What is the equation for pressure?
Pressure = flow x resistance
109
What does poiselles law state?
Increase in resistance with R to the power four
110
What is Becks Triad?
Hypotension,raised JVP and distant muffles of examination
111
Where is blood flow fastest?
Total cross sectional area is at its least- capillary bed
112
How long is a cardiac action potential ? What does this relate to ?
280-300ms
| Ventricular systole
113
Describe the conduction pathway of the heart?
SAN
Over atrial- atrial systole
AVN- delayed for 120
spreads down IV septum to apex and ventricles contract from apex upwards forcing blood out of the outflow valves
114
Describe the development of a CVA or TIA
Thrombus forms on wall of LA ( can occur in atrial fribrilation) can break off and pass into artery suppling the brain resulting in CVA or partial occlusion would lead to TIA
115
What is a consequence of aortic valve stenosis ?
Increased afterload leading to LV hypertrophy
116
Where in the system is pressure high? why ?
arteries to drive the blood through arterioles
117
Where in the system is pressure low? why ?
Venules and veins - low resistance and therefore low pressure needed to drive blood
118
What factors affect the systolic pressure?
Force of contraction, TPR and stretchiness of aorta
119
What factors affect the diastolic pressure?
Systolic and TPR
120
What is the pulse pressure?
Difference between systolic and diastolic pressure
121
How do you calculate an average pressure?
Diastolic + 1/3 pulse pressure
122
Describe reactive hyperaemia
loss of circulation increased metabolites released ( H+, K+, adenosine)- effect dependent on production and removal rate.
Poor perfusion - increased metabolites leads to arterial dilation which washes away increased metabolites .
123
What does an increased in TPR mean?
Decreased need for flow
124
What is central venous pressure ?
Pressure in great veins
125
What does central venous pressure depend on?
Return from the body, pumping of the heart , gravity and muscle pumping
126
Define heart failure
State in which heart cannot maintain adequate perfusion of the body to meet its needs despite adequate filling pressure
127
What are some causes of heart failure?
MI, aortic stenosis, mitral prolapse , hypertension or dilated cardiacmyopathy
128
Draw a SAN action potential and label the ion channel changes
CHECK IN NOTES
129
Draw a cardiac myocytes action potential and label the ion channel changes
CHECK IN NOTES
130
When would you get an upwards deflection on an ECG?
Depolarization towards +ve electrode
| Repolarization away +ve electrode
131
When would you get a downwards deflection on an ECG?
Depolarization away +ve electrode
| Repolarization towards +ve electrode
132
What is the amplitude of a wave on an ECG dependent on?
how much muscle
| how directly towards the electrode excitation is moving
133
Describe the changes that bring about a P wave?
Deploarisation from SA to AV node causing atrial systole
134
Describe why we see a return to normal between the P wave and the Q wave ?
Delay of electrical activity by 120ms at the AVN
135
Describe the changes that bring about a Q wave?
Activity spreads down the bundle of his depolarising the septum
136
What brings about the R and S waves?
R- activity across ventricular walls
| S- up side walls
137
What brings about a T wave?
repolarisation of the ventricle walls
138
Why do we not see repolarization in the atrias on an ECG?
Lost in QRS complex
139
In what plane do the chest leadds view the heart?
Horizontal
140
Where is V1 placed?
4th intercostal R
141
Where is V2 placed?
4th intercostal L
142
Where is V4 placed?
5th intercostal mid clavicular line
143
Where is V6 placed ?
5th intercostal mid axillary line
144
How do you calculate a regular heart rate on an ECG?
300/ number of large squares between sucessive beats
145
What is the cardiogenic region?
Region of mesoderm by the cranial end of the embyro which develops into the heart, BV and blood cells during gastrulation.
146
What effect does lateral folding have on the future heart?
Creates heart tube - endocardial tubes fuse at middle
147
What effect does cephalocaudial folding have on the future heart?
brings the tube into the thoracic region - head and tail tuck around the oropharyngeal membrane putting primative heart in thoracic cavity with pericardial cavity inferior but heart beginning to form within it.
148
What happens to the membrane that suspends the heart is the pericardial sac during embyronic development?
Degenerates
149
How does blood flow in the primtative heart tube?
Caudal to cranial
150
From caudal to cranial what are the layers of the primitative heart?
```
sinus venosus
atrium
ventricle
bulbus cordis
tuncus arteriosus
aortic roots
```
151
Why does looping occur?
Continued elongation results in bending - doesnt fit in pericardial sac as this doesnt grow proportionally to heart
152
In what direction does the cephalic portion move?
Ventrally, caudally and right
153
In what direction does the caudal portion move?
Dorsally, cranially and left
154
What does the looping give?
Transverse pericardial sinus- arteries in front of veins
Puts primordium R ventricle closest to outflow tract
Puts primordium L ventricle - closest to inflow tract
Atrium dorsal to bulbus cordis ie inflow dorsal to outflow
