BSS Physiology Flashcards
Acute phase proteins
CRP procalcitonin ferritin fibrinogen alpha-1 antitrypsin caeruloplasmin serum amyloid A haptoglobin complement
During the acute phase response the liver decreases the production of other proteins (sometimes referred to as negative acute phase proteins)
albumin transthyretin (formerly known as prealbumin) transferrin retinol binding protein cortisol binding protein
ECG - What does P wave represent?
Represents the wave of depolarization that spreads from the SA node throughout the atria
Lasts 0.08 to 0.1 seconds (80-100 ms)
ECG - What does PR INTERVAL represent?
Represents the time between the onset of atrial depolarization and the onset of ventricular depolarization
Time from the onset of the P wave to the beginning of the QRS complex
Ranges from 0.12 to 0.20 seconds in duration
ECG- What does QRS complex represent?
Represents ventricular depolarization
Duration of the QRS complex is normally 0.06 to 0.1 seconds
ECG - What does ST segment represent?
Isoelectric period following the QRS
Represents period which the entire ventricle is depolarized and roughly corresponds to the plateau phase of the ventricular action potential
ECG- What does T wave represent?
Represents ventricular repolarization and is longer in duration than depolarization
A small positive U wave may follow the T wave which represents the last remnants of ventricular repolarization.
ECG- What does QT interval represent?
Represents the time for both ventricular depolarization and repolarization to occur, and therefore roughly estimates the duration of an average ventricular action potential.
Interval ranges from 0.2 to 0.4 seconds depending upon heart rate.
At high heart rates, ventricular action potentials shorten in duration, which decreases the Q-T interval. Therefore the Q-T interval is expressed as a ‘corrected Q-T (QTc)’ by taking the Q-T interval and dividing it by the square root of the R-R interval (interval between ventricular depolarizations). This allows an assessment of the Q-T interval that is independent of heart rate.
Normal corrected Q-Tc interval is less than 0.44 seconds.
ECG features in hypokalemia?
U waves Small or absent T waves (occasionally inversion) Prolonged PR interval ST depression Long QT interval
In Hypokalaemia, U have no Pot and no T, but a long PR and a long QT!
When is the oxygen dissociation curve shifted to the left?
curve is shifted to the left when there is a decreased oxygen requirement by the tissue
Shifts to Left = Lower oxygen delivery HbF, methaemoglobin, carboxyhaemoglobin low [H+] (alkali) low pCO2 low 2,3-DPG low temperature
When is the oxygen dissociation curve shifted to the Right?
Shifts to Right = Raised oxygen delivery raised [H+] (acidic) raised pCO2 raised 2,3-DPG* raised temperature
Triad of Wernicke’s Encephalopathy
Acute confusion
Ataxia
Ophthalmoplegia
When do refeeding symptoms occur?
If patient not eaten for > 5 days, aim to re-feed at < 50% energy and protein levels
High risk for re-feeding problems
ONE of following:
BMI < 16 kg/m2
Unintentional weight loss >15% over 3-6 months
Little nutritional intake > 10 days
Hypokalaemia, Hypophosphataemia or hypomagnesaemia prior to feeding (unless high)
Two of following
BMI < 18.5 kg/m2
Unintentional weight loss > 10% over 3-6 months
Little nutritional intake > 5 days
History of: alcohol abuse, drug therapy including insulin, chemotherapy, diuretics and antacids
Factors stimulating renin secretion?
Hypotension causing reduced renal perfusion Hyponatraemia Sympathetic nerve stimulation Catecholamines Erect posture
