Physiology & Shock Flashcards
Define sinus rhythm
Heart controlled by the SA node
Put in order:
Purkinje fibres, A/P fascicles, Bundle of His, AVN, bundle branches, SAN
SAN > AVN > Bundle of His > bundle branches > Purkinje fibres > A/P fascicles
Vagal tone:
parasympathetic or sympathetic?
what does it act on?
what does it do?
Parasympathetic action on SAN + AVN at rest, increases AVN delay
Sympathetic supplies what part of the hearts? What is its function?
To beta adrenoceptors in SAN + AVN + myocardium
Increases HR + contraction
B1 adrenoceptors where
B2 adrenoceptors where
B1 heart
B2 GI/resp/kidney
Define stroke volume
Volume ejected by each ventricle per beat
Define cardiac output
Volume ejected per minute
CO = SV X HR
Ventricles contract in ____ and relax in ____
Contract systole, relax diastole
AV valves shut when…
AV valves shut when ventricular pressure greater than atrial pressure
S3 or S4 - which is always pathological and which is physiological in a young person?
S4 always pathological
S3 physiological in a young person
Heart gets perfusion during diastole or systole
Diastole
slower heart rate = more diastole
Formula for maximum heart rate
220 - age
Coronary arteries arise from …
Aorta
Pulmonary circulation is low or high resistance
Low resistance
Formula for MAP
MAP = (2X diastolic + systolic) / 3
MAP = diastolic + 1/3(systolic -diastolic)
Where are baroreceptors
In carotid sinus and aortic arch
Function of atrial natriuretic peptide
Decreases BP vasodilates
RAAS
- What is the rate limiting step?
- Renin is released from _____, it stimulates the release of _____ from _____, which stimulates the release of _____. _____ converts _____ to _____, which stimulates the release of _____ from the _____
- Function
The rate limiting step is renin release
Renin is released from KIDNEY, it stimulates the release of ANGIOTENSINOGEN from LIVER, which stimulates the release of ANGIOTENSIN 1. ACE converts ANGIOTENSIN 1 to ANGIOTENSIN 2, which stimulates the release of ALDOSTERONE from the ZONA GLOMERULOSA OF THE ADRENAL
Function to >BP (by retaining Na and increasing plasma volume)
ADH
- Where is it made?
- What is it also called?
- Function?
Hypothalamus
Vasopressin
Concentrates urine to increase BP
Name the drug
Side effects include dry cough and teratogenicity
Contraindicated in severe CKD
ACEI eg lisinopril
Angiotensin receptor blockers are teratogens - T or F
True
Atenolol, metoprolol, propranolol, bisoprolol
Which are B1 selective?
Which are B1 + B2 non-selective?
Atenolol B1 selective
Metoprolol B1 selective
Propranolol B1 + B2
Bisoprolol B1 selective
B-blockers are contraindicated in ____ and known to worsen ____
B-blockers are contraindicated in ASTHMA and known to worsen DIABETES
Hypokalaemia is a side effect of which antihypertensive?
Loop diuretics
Which antihypertensive functions by blocking sodium reabsoprtion?
Thiazide diuretics
What is the mechanism of spironolactone?
Potassium sparing aldosterone receptor antagonist
Which antihypertensives have gynaecomastia as a side effect?
Spironolactone and digoxin
Avoid calcium channel blockers in heart failure except which one …
Amlodipine
Why can’t verapamil be combined with a BB?
Both slow heart rate
Name 4 calcium channel blockers
Amlodipine, nifedipine, verapamil, diltiazem
Ankle oedema is a common side effect of antihypertensives that …
Vasodilate - such as nifedipine
Grey skin and hypothyroidism are side effects of which drug?
Amiodarone
Atropine mechanism
Inhibits muscarinic M2 receptors that decrease HR - to increase HR
Aspirin mechanism
Antiplatelet - cyclooxygenase inhibitors - that produces thromboxane A2
In what type of shock would you see J waves on an ECG?
Hypothermia
Name 3 causes of obstructive shock
PE
Cardiac tamponade
Tension pneumothoax
MIs and arrhythmias cause _____ shock due to decreased contractility, a drug to combat this is a _____
MIs and arrhythmias cause CARDIOGENIC shock due to decreased contractility, a drug to combat this is a INOTROPE
Spinal cord injuries cause ____ shock due to decreased ____ drive
Spinal cord injuries cause NEUROGENIC shock due to decreased SYMPATHETIC drive
Bleeding, vomiting and burns can all cause what type of shock?
Hypovolaemic shock
What are the 3 components of Virchow’s triad
Endothelial injury
Venous stasis / turbulent flow
Hypercoagulability
