Cardiovascular Flashcards
What forms intercalated disks
Desmosome
Gap junction
What causes the rapid depolarisation phase of cardiac muscle
Sodium influx
What causes the slow repolarisation phase of cardiac muscle
Calcium Influx
What condition is described as sawtooth pattern on an ECG
Atrial flutter
What condition is no P waves on an ECG
Atrial fibrillation
What is a normal PR interval
> 0.12s - <0.2s
What is a normal QRS complex
<0.12s
What is normal QT interval at 60bpm
<0.42s
What is Standard limb lead 1
RH -
LH +
What is Standard limb lead 2
RH -
LF +
What is Standard limb lead 3
LH -
LF +
What are the possible systolic murmurs
Aortic/pulmonary stenosis
OR
Mitral/Tricuspid Regurgitation
What are the possible diastolic murmurs
Mitral/Tricuspid stenosis
OR
Pulmonary/Aortic regurgitation
What could cause a continuous murmur
Patent ductus arteriosus
How is cardiac output calculated
HR x SV
What is a normal ejection fraction
60%
How is ejection fraction calculated
SV/EDV
How is heart rate regulated
Controlled by pacemaker cells
ANS
- Sympathetic B1 receptors on SA node
- Parasympathetic muscarinic receptors on SA node
What 3 factors affect Stroke volume
Preload
Afterload
Neural - Contractility
What ion allows variable contractility of cardiac muscle
Ca2+
What 5 factors affect venous return
Gravity
Skeletal muscle pump
Respiratory pump
Venomotor tone
Systemic filling pressure
What are the 3 types of capillary
Continuous
Fenestrated
Discontinuous
What 4 things can cause oedema
Raised venous pressure
Lymphatic obstruction
Hypoproteinaemia
Increased capillary permeability
How is mean arterial pressure calculated
CO x TPR
What are the 4 causes of local hyperaemia
Metabolite hyperaemia
Reactive hyperaemia
Pressure autoregulation
Injury response
What is the mechanism of injury response hyperaemia
C-Fibres activated
Release of substance P
Mast cell activation
What is the mechanism of metabolite hyperaemia
Cell metabolites move into blood
Endothelium releases EDRF/NO
Causes dilatation
What is the mechanism of reactive hyperaemia
Decreased blood flow
=> flow increased
Extreme version of pressure autoregulation
What is the mechanism of pressure autoregulation
Increased MAP decreases flow
=> metabolites accumulate
=> NO/EDRF released
Dilatation
What effect does noradrenaline have on systemic arterioles
Vasoconstriction
What receptor does noradrenaline act on in systemic arterioles
Alpha-1
Which 2 areas blood flow is affected by the parasympathetic nervous system
Genetalia
Salivary glands
Where is adrenaline released
Adrenal medulla
What receptor does adrenaline act on in systemic arterioles
Alpha-1
How does hypoxia differ in pulmonary vessels to systemic vessels
Systemic hypoxia - dilation
Pulmonary hypoxia - constriction
What 3 areas have very good blood pressure control
Coronary circulation
Cerebral circulation
Renal circulation
Where are baroreceptors located
Aortic arch
Carotid sinus
What is the function of baroreceptors
Detect changes in blood pressure
What nerve communicates information from aortic baroreceptors
Vagus
What nerve communicates information from carotid sinus baroreceptors
Glossopharyngeal
Where do the vagus and glossopharyngeal nerves communicate information to
Medullary cardiovascular centres
How do baroreceptors work
Releases action potentials when stretched
Which organ controls long term blood pressure control
kidneys
Where is renin produced
Juxtaglomerular (granule) cells
What triggers renin production
Sympathetic innervation of juxtaglomerular apperatus
Renal baroreflex
Decreased delivery of Na/Cl through tubule
What does renin do
Convert angiotensin to angiotensin I
What converts angiotensin I to Angiotensin II
Angiotensin converting enzyme
What effect does angiotensin have systemically
Increased MAP
What 2 substances are released by angiotensin
Aldosterone
Anti diuretic hormone
Where antidiuretic hormone produced
Hypothalamus
Where antidiuretic hormone released
Posterior pituitary
What systemic effects does antidiuretic hormone have
Increased MAP
Where is Atrial Natriuretic Peptide produced
Atria
Where is Brain Natriuretic Peptide produced
Ventricles
What systemic effects do ANP and BNP have
Reduce MAP
What are stage 1, 2 and 3 hypertension classified as
1 - 140/90
2 - 160/100
3 - 180/120
What is the name of the risk calculator for blood pressure
Assign risk calculator
Contradictions to ACEi
Impaired renal function
Hyperkalaemia
Fertile Female
Taking NSAIDS
How is a complicated plaque defined
Plaque rupture/fissuring
Thrombosis
Most important risk factor in atheroma
Hypercholesterolaemia
Signs of hyperlipidaemia
Bloods - LDL, HDL, total cholesterol
Corneal arcus
Xanthelasmata/Xanthomata
Family History
Prevention of atheroma
Smoking cessation
BP control
Weight loss
Diet modification
Exercise
Treatment of atheroma
Cholesterol lowering drugs
Blood thinners
Surgical options
Other risk factors of atheroma
Smoking
hypertension
Diabetes
Male
Elderly
Most common cause of mitral stenosis
Rheumatic fever
4 types of hypoxia
Hypoxic
Anaemic
Stagnant
Cytotoxic
What is hypoxic hypoxia
Due to respiratory causes
What is anaemic hypoxia
Blood cant carry enough O2
What is stagnant hypoxia
Abnormal blood delivery
What is cytotoxic hypoxia
Abnormal O2 delivery at tissue level