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
Spleen function?
Filtration of abnormal blood cells and foreign bodies such as bacteria.
Immunity: IgM. Production of properdin, and tuftsin which help target fungi and bacteria for phagocytosis.
Haematopoiesis: up to 5th month gestation or in haematological disorders.
Pooling: storage of 40% platelets.
Iron reutilisation
Storage monocytes
What does white pulp in spleen do?
Immune function. encompasses approximately 25% of splenic tissue. White pulp consists entirely of lymphoid tissue.
What is the function of Red pulp (spleen)?
Filters abnormal red blood cells.
Definition of lung compliance
Lung compliance is defined as change in lung volume per unit change in airway pressure
More stretchy
Causes of increased lung compliance?
Causes of increased compliance
age
emphysema - this is due to loss alveolar walls and associated elastic tissue
Causes of decreased lung compliance
pulmonary oedema
pulmonary fibrosis
pneumonectomy
kyphosis
Which drugs cause pseudohaematuria?
Rifampicin, phenytoin, levodopa, methyldopa, and quinine
syndrome of inappropriate antidiuretic hormone (SIADH): causes
Malignancy
especially small cell lung cancer
also: pancreas, prostate
Neurological stroke subarachnoid haemorrhage subdural haemorrhage meningitis/encephalitis/abscess
Infections
tuberculosis
pneumonia
Drugs sulfonylureas SSRIs, tricyclics carbamazepine vincristine cyclophosphamide
Other causes
positive end-expiratory pressure (PEEP)
porphyrias
Normal Gap Acidosis: HARDUP
H - Hyperalimentation/hyperventilation A - Acetazolamide R - Renal tubular acidosis D - Diarrhoea U - Ureteral diversion P - Pancreatic fistula/parenteral saline
Causes of a raised TLCO
asthma pulmonary haemorrhage (Wegener's, Goodpasture's) left-to-right cardiac shunts polycythaemia hyperkinetic states male gender, exercise
Causes of a lower TLCO
pulmonary fibrosis pneumonia pulmonary emboli pulmonary oedema emphysema anaemia low cardiac output
KCO also tends to increase with age. Some conditions may cause an increased KCO with a normal or reduced TLCO
pneumonectomy/lobectomy
scoliosis/kyphosis
neuromuscular weakness
ankylosis of costovertebral joints e.g. ankylosing spondylitis
Mnemonic for the causes of hypercalcaemia:
CHIMPANZEES
C alcium supplementation H yperparathyroidism I atrogentic (Drugs: Thiazides) M ilk Alkali syndrome P aget disease of the bone A cromegaly and Addison's Disease N eoplasia Z olinger-Ellison Syndrome (MEN Type I) E xcessive Vitamin D E xcessive Vitamin A S arcoidosis
Somatostatin - function
Somatostatin is produced in the D cells of the pancreatic islets. It is also produced in the gut (enterochromaffin cells) and is found in brain tissue. Those substances that stimulate insulin release will also induce somatostatin secretion. It is an inhibitor of growth hormone, it also delays gastric emptying and reduces gastrin secretion.
It reduces pancreatic exocrine secretions and may be used therapeutically to treat pancreatic fistulae.
Somatostatinomas are rare pancreatic endocrine tumours and will result in the clinical manifestations of diabetes mellitus, gallstones and steatorrhoea.
Actions of adrenaline on ALPHA adrenergic receptors cause?
α adrenergic receptors:
Inhibits insulin secretion by the pancreas
Stimulates glycogenolysis in the liver and muscle
Stimulates glycolysis in muscle
Actions of adrenaline on β adrenergic receptors:
Stimulates glucagon secretion in the pancreas
Stimulates ACTH
Stimulates lipolysis by adipose tissue
Fluid physiology of a physiologically normal adult
The 60-40-20 rule:
60% total body weight is water
40% of total body weight is intracellular fluids
20% of body weight is extracellular fluids
Males typically have more water per unit weight than females, as females have a higher fat content.
Aldeosterone
1) What is it? Where is it produced
2) What activates it?
3) What action does it cause, where does it act
1) Steroid hormone produced by zona glomerulosa of adrenal cortex.
2)Part of RAAS and also ACTH, Hyponatraemia, Hyperkalaemia and hypovolaemia
3) Acts on distial tububle of kidney. Regulates Na+/K+ and H20 balance. Increases Na+ K+ permeability causes Resorption of Na+ and H20 in exchange for K+
Also acts on collecting ducts and secrete H+ ions
Describe JVP wave
ASKME
a Wave - atrial contraction - abscent in AF, prominent in TS, or RV hypertrophy
c wave - Right ventricular contraction + bulging of tricuspid valve on to RA
X descent - Rapid atrial filling due to atrial relaxation (klosed tricuspid) - - Absent in TR
V descent - Maximal atrial filling, prominent in pericarditis
Y - emptying of atrium absent in Tamponade
3 Characteristics of Diabetes insipidus
Polyuria
Polydipsia
Dilute urine
