Cardio Week 2 Flashcards
1
Q
where are phrenic nerves located
A
descending across lateral borders of pericardium
2
Q
the fibrous pericardium is lined internally by what
A
parietal serous pericardium
3
Q
what covers the anterior surface of heart
A
epicardium (same thing as visceral pericardium) that excretes pericardial fluid
4
Q
where is the pericardial cavity located
A
between the 2 layers of serous pericardium
5
Q
what is cardiac tamponade
A
when pericardial cavity fills with blood and pressure around heart prevents it from contraction
6
Q
what is pericardiocentesis
A
drainage of fluid from pericardial cavity - needle inserted via infrasternal angle and directed superioposteriorly
7
Q
what is the transverse pericardial sinus
A
space within pericardial cavity (lies posterior to ascending aorta and pulmonary trunk) and surgeons use this to identify and isolate great vessels
8
Q
what is the only artery that carries deoxygenated blood
A
pulmonary artery
9
Q
what is the only vein that carries oxygenated blood
A
pulmonary vein
10
Q
what is the coronary sinus
A
short venous conduit (in AV groove posteriorly) which receives deoxygenated blood from most of cardiac veins and drains into right atrium
11
Q
what is the first branch of the aorta
A
coronary arteries as they come off ascending aorta
12
Q
where do coronary arteries course
A
just deep to epicardium - usually embedded in adipose tissue
13
Q
where is the right coronary arteries situated
A
right atrioventricular groove
14
Q
where is the left (main stem) coronary artery situated
A
left AV groove between pulmonary trunk and left auricle
15
Q
are left and right coronary arteries connected
A
yes - via anastomoses
16
Q
what is the consequence of a septal defect
A
hole (mixes arterial and venous blood) - reduces O2 content of systemic arterial blood in aorta - hypoxaemia
17
Q
where is mitral valve located
A
between left atrium and left ventricle
18
Q
where is tricuspid valve located
A
between right atrium and right ventricle
19
Q
what are examples of organic nitrates
A
glyceryl trinitrate (GTN), isosorbide mononitrate, isosorbide denigrate, erythrityl tetranitrate, pentaerythriol tetranitrate
20
Q
when are organic nitrates used
A
angina - decreased myocardial O2 requirement via decreased preload, after load and improved perfusion
21
Q
how do organic nitrates work
A
metabolised to release NO - elevates cGMP (vasodilation)
22
Q
what are examples of ACE inhibitors
A
captopril and enalopril
23
Q
when are ACE inhibitors used
A
chronic heart failure and hypertension
24
Q
how do ACE inhibitors work
A
block conversion to angiotensin II (blocks sympathetic response) and promotes diuresis since it is blocking hormones that cause renal Na+ and water retention
25
give examples of angiotensin II receptor blocker (ARB)
losartan and valartan
26
how do ARBs work
selectively inhibit effect of angiotensin II without affecting bradykinin levels
27
what side effect is present in ACE inhibitors but not ARBs
chronic cough - ACE metabolises bradykinin and substance P whereas ARB does not
28
what can ACEI and ARB cause in pregnancy
renovascular disease and aortic stenosis
29
what are examples of calcium antagonists
verapamil, amiodipine and diltiazem
30
when are calcium antagonists used
hypertension (first line) angina (in combo with GTN) and in dysrhythmias
31
how do calcium antagonists work
prevent opening of L type Ca++ channels so limit increasing Ca2+ - reduced rate of conduction through AVN as well as reducing force of contraction
32
what is the adverse effects of calcium antagonists
excessive vasodilation - hypotension, dizziness and ankle oedema
33
give examples of potassium channel openers (K+ATP openers)
minoxidil and nicrorandil
34
when are potassium channel openers used
minoxidil - last resort hypertension but cause reflex tachycardia and salt and water retention, treat hair lossnicrorandil - NO donor activity, used in angina (side effect - mouth ulcers)
35
how do potassium channel openers work
open channels which causes hyper polarisation which switches off L type Ca2+ channels - less calcium causes vasodilation etc
36
what are examples of a1 adrenoceptors
prazosin and doxazosin
37
when are a1 adrenoceptors used
hypertension
38
how do a1 adrenoceptors work
vasodilation by blocking a1 adrenoceptors - decreases MABP
39
what are examples of diuretics
furosemide, bumetanide, torasemide and ethacrynic acid
40
what are the two different kinds of diuretics
thiazide (inhibit reabsorption in distal tube) and loop diuretics (inhibit reabsorption in thick ascending limb of the loop of hernie)
41
when are diuretics used
chronic heart failure and hypertension
42
how do diuretics work
act on kidney to increase excretion of Na, Cl and H2O and exert additional relaxant effects on vasculature
43
what are examples of class I drugs
disopyramide, lignocaine and flecainide (respective IA, IB and IC)
44
how do class I drugs work
block voltage gated Na+ channels
45
characteristics of IA drugs
associate and dissociate moderately - slow rise of AP and prolong refectory periodused in ventricular arrhythmias
46
characteristics of IB drugs
associate and dissociate rapidly - prevents premature beatsused in ventricular arrhythmias after MI
47
characteristics of IC drugs
associate and dissociate really slowly and depress conduction used for prophylaxis of paroxysmal atrial fibrillation
48
give example of class II drugs
metoprolol
49
how do class II drugs work
block b-adrenoceptor - decrease rate of depolarisation in SA and AV nodes
50
give examples of class III drugs
amiodarone and sotolol
51
how do class III drugs work
block voltage activated K+ channels - prolong AP duration increased refractory period
52
give examples of class IV drugs
verapamil, dilitazem
53
how do class IV drugs work
block voltage activated Ca2+ channels - slow conduction in SA and AV nodes - decrease force of contraction
54
what classes of drugs act on atria (rate control of supra ventricular tachycardia)
IC (flecainide) and III (amiodarone, sotolol)
55
what classes of drugs act on ventricles
IA, IB and II
56
what classes of drugs act on the AV node (rhythm control of SVT)
adenosine, digoxin, classes II (metoprolol) and IV (verapamil)
57
what classes of drugs act on atria and ventricles AV accessory pathways
amiodarone, sotalol, classes IA and IC
58
what are the four main types of SVT (supra ventricular tachycardia)
atrial fibrillation, paroxysmal supra ventricular tachycardia (PSVT), atrial flutter and Wolff Parkinson white syndrome
59
what is the inner layer
tunica intima (single layer of squamous epithelium - endothelium)
60
what is middle layer
tunica media (smooth muscle, thickness varies)
61
what is outer layer
tunica adventitia (supporting connective tissue)
62
what separates tunica intima from tunica media
internal elastic membrane (external elastic separates TM and TA)
63
largest arteries have their own vascular supply; what is this called
vasa vasorum
64
what are capillaries composed of
endothelial cells and basal lamina - often have pericytes (connective tissue with contractile properties)
65
where are continuous capillaries found
muscle, connective tissue, lung, skin and nerve
66
where are fenestrated capillaries found
mucosa of gut, endocrine glands, glomeruli of kidney
67
where are sinusoidal (discontinuous) capillaries found
liver, spleen and bone marrow - lack basal lamina and have large gaps
68
what is components of vein
tunica intima, thin but continuous tunica media (vena cava/HPV has thick tunica adventitia)
69
what veins have valves
small to medium sized veins - valves are inward extensions of tunica intima
70
what is the role of endocardium
lines entire surface of heart including valves
71
what is the structure of endocardium
endothelium, basal lamina, thin layer of collagen fibres, layer of denser connective tissuesome areas has subendocardium of loose connective tissue containing small vessels and nerves
72
what is the role of myocardium
thick middle layer
73
what is structure of myocardium
bundles and layers of contractile cardiac muscle cells, individual muscle fibres surrounded by delicate, continuous connective tissue with rich capillary network
74
what is the role of intercalated discs in myocardium
attach muscle cells and allow spread of electrical activity
75
what is role of epicardium
outer layer of heart
76
what is structure of epicardium
on surface: single layer of flattened epithelium (mesothelium)contains basal lamina, fibroelastic connective tissue and in some places adipose tissue
77
what are the two parts of pericardium
fibrous pericardium (sac of tough fibrocollagenous connective tissue)serous pericardium (simple squamous epithelium backed by basal lamina and connective tissue)
78
what is the two layers of serous pericardium
parietal serous pericardium - inner surface of fibrous visceral serous pericardium - covers surface of heart
79
what is the fibrous skeleton
formed by thick bands of connective tussle around heart valves which supports the valves but also provides attachment for cardiac muscle fibres
80
what is the structure of valves
have outer endothelial layer with basal lamina with layer of collagen and elastin fibreshave a core of dense connective tissue called lamina fibrosa in continuity with fibrous skeleton
81
the leaflets of the valves separating atria from ventricles are anchored to papillary muscles in wall of ventricles by what
chord tendineae (which merge with lamina fibrosa)
82
what is the structure of pacemaker cells
smaller than myocytes and embedded in more connective tissueappear pale because of paucity of organelles few myofibrils, little glycogen and no proper T tubule system
83
what is the structure of purkinje fibres
larger than myocytes, found in subendocardial layer, abundant glycogen, no T tubules, no intercalated discsappear pale and very pale/clear centre
84
what is the structure of lymphatic vessels
no central pump but smooth muscle in walls, hydrostatic pressure in tissue and the compression of vessels by voluntary muscle combined with valves in vessels, produce flow
85
how do sympathetic signals reach organs
exit spinal cord at one of T1-L2/3 and then travel either superiorly or inferiorly in sympathetic chain to another ganglion and synapse
86
what are the cardiopulmonary splanchnic nerves
postsynaptic fibres from cervical and upper thoracic sympathetic chainssympathetic nerves to heart and lungs
87
how do parasympathetic signals reach organs
via cranial nerves III (oculomotor nerves) VII (facial nerves), IX (glossopharyngeal nerves) and X
88
what is the role of CN V (vagus nerve) in parasympathetic signals
presynaptic parasympathetic fibres in vagus nerves then synapse onto postsynaptic neurones
89
AP's arriving at postcentral gyrus of parietal lobe (somatosensory) bring what sensations into consciousness
body wall (somatic)
90
AP's arriving at pre central gyrus of frontal lobe (somatomotor) bring what sensations into consciousness
contractions of body wall (somatic) skeletal muscle
91
what is the source of sharp central chest pain by herpes zoster (shingles)
patient with shingles developing in T4/T5 - pain precedes blisters
92
what could be the source of sharp central chest pain by muscle, joints or bones
pectorals major or intercostal muscle strain, dislocated costochondrial joint, costovertebral joint inflammation, slipped thoracic disc
93
what could be the source of sharp central chest pain by parietal pleura and fibrous pericardium
pleurisy and pericarditis
94
what would be the source of dull central chest pain by the trachea
tracheitis
95
what would be the source of dull central chest pain by aorta
ruptured aneurysm of aortic arch
96
what would be the source of dull central chest pain of the abdominal viscerae
gastritis, cholecystitis, pancreatitis, hepatitis
97
what would be the source of dull central chest pain of the heart
angina and myocardial infarction
98
how do pain signals from organs reach brain
visceral afferent APs pass bilaterally to thalamus and hypothalamus then diffuse areas of the cortex
99
what is an example of pain signals from organs reaching brain
ischaemic chest pain: cardiopulmonary splanchnic nerves plus visceral afferents from chest organs
100
if pain is originating in a somatic structure then where is the radiation felt
along the affected dermatome
101
is the pain is originating in the heart then where is the radiation felt
the dermatome supplied by the spinal cord at levels which the cardiac visceral afferents enter sympathetic chain
102
what is referred pain due to
afferent (sensory) fibres from soma and afferent (sensory) fibres from viscera (visceral afferents) entering spinal cord at same levels brain chooses to believe pain from organ is actually coming from soma
103
where is cardiac pain referred to
upper limbs (esp left) or from back, neck or jaw
104
what are the common sites of coronary atherosclerosis
anterior inter ventricular branch (LAD) of LCA, RCA, circumflex branch of LCA, left main stem coronary artery
105
what happens in coronary artery bypass grafting
grafts anastomosed proximally to ascending aorta
106
what is the main artery used for grafting
left internal thoracic (mammary artery) used - not disconnected from patient but instead cut distally and attached to coronary artery
107
what is the other arteries used for grafting
bilateral internal thoracic artery, gastroepiploic and radial arteries
108
what is shock
an abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation
109
how does hypovolaemic shock (also known as haemorrhage shock) occur
loss of blood volume - decreased venous return - decreased EDV - decreased SV - decreased CO and BP.- inadequate tissue perfusion
110
what is the causes of hypovolaemic shock
haemorrhage (trauma, surgery, GI)vomiting, diarrhoea, excessive sweating results in decreased ECFV thus decreased blood
111
what is cardiogenic shock
sustained hypotension caused by decreased cardiac contractility
112
how does cardiogenic shock occur
decreased contractility - decreased SV - decreased CO and BP - inadequate tissue perfusion
113
how does tension pneumothorax (obstructive shock) occur
increased intrathoracic pressure - decreased venous return - decreased EDV - decreased SV - decreased CO and BP - inadequate tissue perfusion
114
how does neurogenic shock occur
loss of sympathetic tone - massive venous and arterial dilation - decreased venous return and SVR - decreased CO and BP - inadequate tissue perfusion
115
how does vasoactive shock occur
release of vasoactive mediators - venous and arterial vasodilation and increased capillary permeability - decreased venous return and decreased SVR - decreased CO and BP - inadequate tissue perfusion
116
what is the treatment for shock
ABCDE, high flow O2, volume replacement, inotropes for cardiogenic shock, immediate chest train for pneumothorax, adrenaline for anaphylactic shock, vasopressors for septic shock
117
what is an example of HDL
apoA1 and apoA2
118
what is an example of LDL/VLDL
apoB-100
119
what is example of chylomicrons
apoB-48
120
what is the role of ApoB containing lipoproteins
deliver triglycerides to muscle for ATP biogenesis and adipocytes for storage
121
where are chylomicrons formed and what is their role
intestinal cells and transport dietary triglycerides - carried in lymph to systemic circulation (subclavian vein) via thoracic duct - exogenous pathway
122
where are VLDL formed and what is their role
formed in liver cells from free fatty acids derived from adipose tissue (during fasting) and de novo synthesis and transport triglycerides synthesised in that organ - endogenous pathway
123
what is lipoprotein lipase (LPL)
lipolytic enzyme associated with endothelium capillaries in adipose and muscle tissueIt hydrolyses core triglycerides to free fatty acids and glycerol which enters tissues
124
what facilitates the binding of chylomicrons and VLDL particles to LPL
ApoCII
125
what are examples of statins
simvastatin and atorvastatin
126
when are statins used
drug of choice to reduce LDL - reduce LDL by 60% and triglycerides by 40%, also increase HDL by 10%other benefits: decreased inflammation, thrombosis and stabilisation of plaquesorally at night
127
how do statins work
competitive inhibitors of HMG-CoA reductase - rate limiting step in cholesterol synthesis decrease in cholesterol causes increase in LDL receptor thus enhances its clearance
128
give examples of fibrates
bexafibrate and gemfibrozil
129
when are fibrates used
pronounced decrease in triglycerides (first line drugs in patient with very high triglycerides)
130
how do fibrates work
act as agonists of nuclear receptor (PPARa) to enhance transcription of genes, including encoding LPL
131
what are adverse effects of fibrates
myositis, best avoided in alcoholics who are predisposed to hypertriglyceridaemias but also rhabdomyolysis other effects (GI symptoms, pruritus and rash) greater than for statins
132
give examples of drugs that inhibit cholesterol absorption
colestyramine, colestipol and colsevelam
133
how do drugs that inhibit cholesterol absorption work
bind to bile acid and cause excretion of bile salts resulting in more cholesterol to be converted to bile salt by interrupting enterohepatic recycling ingested orally, not absorbed from GI tract which prevents reabsorption of bile saltsalso causes decreased absorption of triglycerides and increased LDL receptor expression
134
what is adverse effects of drugs which inhibit cholesterol absorption
GI tract irritation
135
what is a drug which inhibits the transport of cholesterol
ezetimible
136
who do drugs which inhibit the transport of cholesterol work
act to inhibit NPC1L1 transport protein in enterocytes of duodenum, reducing the transport of cholesterol decrease in LDL with little change in HDL
137
when is drugs in inhibit transport of cholesterol work
used in combination with statins when latter alone does not achieve sufficient response orally - metabolised to activate metabolite that undergoes enterohepatic recycling that contributes to long half life (22hr)
138
what are adverse effects of drugs that inhibit transport of cholesterol
diarrhoea, abdominal pain and headache contradicted in breast feeding females
