Cardiovascular Flashcards
(117 cards)
1
Q
what is meant by the term myogenic?
A
signals itself
2
Q
what is meant by the term audtorhythmicity?
A
generates its own rhythm
3
Q
where are pacemaker cells located and why are they different from other cells?
A
in the right atrium
they spontaneously generate action potentials
4
Q
how does the heart beat? (initiation and conduction)
A
- pacemaker cells depolarise.
- bundles take this depolarisation message from the SA node to the AV node.
- AV node created delay between atrial and ventricle contraction.
- AV node transmits signal to bundle of HIS
signal travels down left and right bundle (left bundle splits into left posterior fascicle and left anterior fascicle) - right and left bundles split into purkinji fibres at the ape of the heart - they signal the muscles.
5
Q
what is the purpose of bachmann’s bundle?
A
way for depolarisation to move from the right atrium to the left quickly.
6
Q
why can someone not move during an ECG?
A
skeletal muscles cause electrical activity.
7
Q
what does the P wave represent in an ECG?
A
atrial depolarisation
8
Q
what does the QRS complex represent in an ECG?
A
ventricle depolarisation
9
Q
what does the T wave represent in an ECG?
A
ventricle repolarisation
10
Q
what does the PQ interval represent in an ECG?
A
AV node conduction
11
Q
what does the QT interval represent in an ECG?
A
systolic
12
Q
what does the TQ interval represent in an ECG?
A
diastole
13
Q
what does the R-R interval represent?
A
heartbeat
14
Q
why isn’t atrial depolarisation shown on an ECG?
A
because it happens at the same time as the QRS complex.
15
Q
what does the 1st noise on the heart beat from?
A
- tricuspid and mitral valves closing. start of systole
16
Q
what does the 2nd noise on the heart beat from?
A
- pulmonary and aortic semilunar valves closing.
17
Q
what are the 2 figures representing in blood pressure?
A
systolic blood pressure / diastolic blood pressure.
18
Q
what causes arrhythmia?
A
abnormal SA firing causing fast or slow HR
19
Q
what is meant by third degree block arrhythmia?
A
atrium and ventricles are contracting normally but at random.
20
Q
what is meant by the term ventricular fibrillation?
A
heart beats are no longer synchronised and so the blood cannot be pumped efficiently can be deadly.
21
Q
what is meant by the term atrial fibrillation?
A
weakness to heat beats but not deadly as ventricles still contract sufficiently,
22
Q
what part of the ECG represents the 1st sounds in the heart beat?
A
QRS complex
23
Q
what part of the ECG represents the 2nd sounds in the heart beat?
A
end of the T wave.
24
Q
what is meant by the term venous return?
A
blood returning to the heart - passes through the AV valves under its own pressure.
25
what is meant by the term isovolumetric contraction?
ventricles relax, not enough pressure to allow AV valves to open and not enough pressure to maintain semilunar open.
Therefor all valves are shut snd no change in blood volume in ventricles.
26
what is meant by the term ventricular filling?
blood enters ventricles from atria
27
how do you work out pulse pressure?
systolic pressure - disatolic pressure.
28
what could a high pulse pressure indicate?
hardening of the arteries
29
how do you work out mean arterial pressure?
diastolic pressure + (pulse pressure /3)
30
what is end diastolic volume?
volume of blood in the ventricles at the end of diastole.
31
what is end systole volume?
volume of blood in the ventricles at the end of systole
32
what is meant by the term stroke volume?
volume of blood pumped out of the heart.
33
how do you work out stroke volume?
end diastole volume - end systole volume
34
what is meant by the term ejection fraction?
ratio of volume ejected in one beat to volume immediately prior to ejection.
35
how do you work out ejection fraction?
stroke volume / end diastole volume.
36
what causes coronary artery disease?
build up of plaques in coronary arteries.
| reducing blood flow to the heart and causing strain to the heart.
37
what things could cause coronary artery disease?
endothelial dysfunction
fatty streaks
complicated lesions
38
what are the treatments available for coronary artery disease?
Percutaneous Transluminal Coronary Angleoplasty (PTCA)
| Coronary Artery Bypass Graft (GABG)
39
what is a Percutaneous Transluminal Coronary Angleoplasty (PTCA)?
ballon used to stretch blood vessel with plaque in it squashing the plaque and making the vessel open again.
Stent can also be placed after to ensure the vessel doesn't close again.
40
what is a Coronary Artery Bypass Graft (GABG)?
unblocked vein is taken from another area in the body and placed where the blocked vein is through open chest surgery.
but it does involve stopping the heart.
41
what happens if you have cyanotic congenital heart disease?
blood to systemic circulation have reduced level of O2 - darker blood colour (blueish)
42
what happens if you have septal defect congenital heart disease?
blood is able to flow from right to left in the heart.
43
what happens if you have ventricular septal defect?
incomplete development of the the septum - oxygenated and deoxygenated blood can mix.
44
what happens if you have coarctation of the aorta?
narrowing of the aorta, so reduced flow meaning that the left ventricle has to pump harder and you have a highter blood pressure.
45
what happens if you have patent ductus arteriosus?
the ductus arteriosus allows O2 exchange in utero - if blood vessel between pulmonary trunk and aorta remain open, blood destined for aorta flows to lower pressure pulmonary trunk, increasing trunk blood pressure and overworking the ventricles.
46
what happens if you have Tetralogy of Fallot?
- ventral septal defect
- stenose pulmonary valve
- enlarger right ventricle.
meaning little blood reaches pulmonary circulation so cyanosis occurs - Blue Baby.
47
how can you work out cardiac output?
heart rate X stroke volume.
48
what does darcy's law state?
resistance = pressure difference between 2 points.
pressure is a lot lower into the right atrium.
49
what are the 3 patterns of blood flow through the body?
- laminar flow (normal arteries/veins)
- turbulent flow (ventricles+ascending aorta)
- single-file flow (in the capillaries)
50
how can total resistance in a circuit increase?
add more units (eg increase length)
51
how can total resistance in a circuit be decreased?
adding parallel units (more avenues for blood to travel)
52
what also increases when distending pressure increases?
volume increases
53
why do veins have higher compliance that arteries?
due to their thin walls and that they can be stretched easily.
54
how is wall tension increased in arterial/venous/capillary walls?
internal pressure and vessel radius.
55
how is wall tension decreased in arterial/venous/capillary walls?
increasing wall thickness.
56
why do large arteries need thicker walls?
due to higher transmural pressure and increase in vessel radius.
57
why are vein walls thinner?
low transmural pressure and increase vessel radius.
58
where is rupture risk greatest?
elastic arteries (eg aorta)
59
what is metabolic control?
relationship between rate of metabolism and the rate of blood flow.
when rate of metabolism increases so does blood flow.
60
what happens when the metabolic rate of a tissue increases exceeding local O2 consumption?
local hypoxia - causing relaxation of nearby arteriolar smooth muscle,
61
what effect does Nitric oxide have on blood flow
increases blood flow by relaxing smooth muscle causing blood vessels to dilate. It has been used in angina meds.
62
what effect does myogenic control have on the blood?
increases pressure gradient so therefor increases in resistance if the flow is constant.
causes the fibres/cells of smooth muscle to stretch.
63
what causes long-term autoregulation?
nutritional and or oxygen demands of a tissue chronically exceeding delivery.
due to increase in number of microcirculatory vessels supplying blood to the tissues and enlargement of existing vessels.
64
how do hydrophilic solutes cross through the capillarys via transcellular route?
via intercellular clefts in the cell walls
65
how do lipohilic solutions enter/ leave the capillary?
via transcellular route (single celled walls)
66
where is pressure greatest in the capillaries? and why is this?
at the arterial end and then lowest at the venous end.
| this is to drive fluid out of the tissues.
67
what is net fluid balance?
the lost fluid from circulation is returned with any leaked plasma protein to the circulation via the lymphatic system.
68
what is the main role of the cardiovascular centre?
maintain a steady MAP - ensuring adequate blood flow to the vital organs.
69
where are arterial baroreceptors found?
outer layer of the arterial walls in the carotid sinus and aortic arch.
70
what is the purpose of the arterial baroreceptors?
detect pressure - send messages via cranial nerves to CV centre.
71
which is more sensitive to pressure, atrial+pulmonary stretch receptors or arterial baroreceptors?
atrial+pulmonary stretch receptors
72
what is the main role of atrial+pulmonary stretch receptors?
regulate blood volume.
73
what happens if there is a loss of nerve supply to the atrial+pulmonary stretch receptors?
MAP will increase
74
what do chemoreceptors detect in blood?
changes in levels of O2, CO2 and H in arterial blood
75
what effects do the chemoreceptors have on the body?
increase rate and depth of breathing
| increase tidal volume so increase heart rate and a small vasodilation. so increases MAP
76
how do you work out cardiac output?
heart rate X stroke volume.
77
what are the 2 automatic peripheral nervous system branches?
- sympathetic and parasympathertic.
78
what does the parasympathetic neurotransmitter input to control heart rate?
acetylcholine
79
what does the sympathetic neurotransmitter input to control heart rate?
noradrenaline and adrenaline
80
what effect does adrenaline have on heart rate?
increases action potential at SA node so increases heart rate.
81
what is starlings law of the heart?
when the rate which blood flows into the heart from the veins changes, the heart automatically adjusts its output to match the inflow so end diastolic matches stroke volume.
82
what is end diastolic pressure determined by?
the pressure of blood inside the heart before contraction.
83
what is preload determined by?
fill time and atrial pressure.
84
what is afterload?
arterial pressure placed on the myocardium after contraction starts.
85
if arterial pressure increases what effect does this have on stroke volume?
decreases.
86
what is the outer structure of blood vessel walls called?
tunica adventitia
87
what is the middle structure of blood vessel walls called?
tunica media
88
what is the inner structure of blood vessel walls called?
tunica intima
89
what are the 3 types of arteries? and what is the difference between them?
- Elastic arteries
(larger diameter, low resistance, can hold large amounts of pressure)
- Muscular arteries
(take blood to specific organs, more smooth muscle)
- Arterioles
(take blood to capillary beds - mostly smooth muscle.
90
where are fenestrated capillaries found? and why?
found in small intestine and kidney.
| they are much more permeable to fluids and small solutes.
91
why is capillary blood pressure low?
otherwise fragile capillary walls will rupture.
92
what are the 2 ways in which venous return is 'pumped' back to the heart?
- respiratory pump (inspiration increases abdominal pressure which compresses the abdominal veins)
- skeletal muscle pump (these muscles contract, compressing deep veins pushing blood towards the heart)
93
what is the metarterioles and where is it found?
it is a vascular shunt found in most capillary beds.
| allows blood to bypass the true capillaries.
94
how is capillary flow regulated?
precapillary sphincter - ring of smooth muscle fibres.
95
what is the pathway for the sympathetic nervous system from the brain to the body?
- hypothalamus
- sympathetic division of ANS
- perganglionic nerve endings
- adrenal madulla
- release of adrenaline and noradrenaline.
96
what effect does the sympathetic nervous system have on the body?
- increase heart rate and increase stroke volume causing an increase in cardiac output.
- increase constriction of blood vessels causing an increase in blood pressure.
- blood diverted from non essential organs to brian, heart and skeletal muscles.
- increased ventilation
- sweating.
97
where are the adrenal glands located?
above the kidneys.
98
what does the adrenal medulla secrete?
adrenaline and noradrenaline.
99
what effect does noradrenaline have on the body?
vasoconstrictor for a1 receptors. (most potent on peripheral vasoconstriction and blood pressure)
100
what effect does adrenaline have on the body?
vasodilation in skeletal muscles (receptors a2)
| most potent on the heart and metabolic activities
101
what do adrenaline and noradrenaline inhibit? and what does this result in?
they inhibit the release of insulin so cause an increase in blood glucose.
102
what does familiar emotional stress cause the increase of in the body?
increase Noradrenaline
103
what does unfamiliar stress cause the increase of in the body?
increase adrenaline
104
what is a phaechromocytoma? and how is it treated?
benign tumor - needs to be surgically removed,
105
what causes a phaechromocytoma? and what are the effects of it?
caused by growth of adrenaline producing cells.
| symptoms = hypertension, increased heart rate, increases blood glucose and sweating .
106
what is releases as a long lasting response to stress?
Cortisol.
107
where is cortisol secreted from?
adrenal cortex.
108
what are the effects of cortisol on the body?
- increase blood glucose
- increase in fats.
- increase in blood pressure
- increase in heart rate
- anti-inflammatory response.
109
why is cortisol used in some angina meds?
for its anti inflammatory response to the blood vessels.
110
what is crushing's disease? and what causes it?
hyper-secretion of cortisol due to a tumour of adrenal cortex
111
what are the symptoms of crushing's disease?
- moon face
- buffalo hump
- hyperglycemia
- increase blood pressure
- thin limbs
- increased infection.
112
what is the tx for crushing's disease?
surgical removal of tumor.
113
what is Addison's disease and what causes it?
hyposecretion of cortisol
| - caused by damage to the adrenal corect
114
what are the symptoms of Addison's disease?
- lower blood pressure
- hypoglycaemia
- susceptible to debilitating effects of stress
115
what is the tx for Addison's disease?
replacement of cortisol.
116
is fainting a sympathetic or parasympathetic response?
parasympathetic
117
what causes an individual to faint?
- caused vasovagal syncope due to eg emotional stress, phlebotomy , sight of blood, acute pain.
- loss of blood due to a transient fall in perfusion pressure to the brain.
