General Physiology Flashcards
1
Q
Accompanying electrolyte disturbance with hypercalcaemia?
A
- Hypomagnesaemia
- Hypophosphataemia
2
Q
Causes of hypercalcaemia?
A
90% - Primary hyperparathyroidism and malignancy
3
Q
What is hypercalcaemia?
A
Ionised calcium > 14mg/dL or 3.5mmol/L
4
Q
Signs & symptoms of hypercalcaemia?
A
- Polyuria
- Polydipsia
- Dehydration
- Anorexia
- Nausea
- Muscle weakness
- Confusion
5
Q
Renal tubular reabsorption of Magnesium is stimulated by what hormone?
A
PTH - Parathyroid hormone
6
Q
Renal tubular reabsorption of Magnesium is inhibited by?
A
Hypercalcaemia
7
Q
Proximal tubular reabsorption of phosphate is inhibited by?
A
PTH - Parathyroid hormone
8
Q
ECG changes relating to hypercalcaemia?
A
- Shorted QT interval
- Osborn waves
9
Q
What is Tumour Lysis Syndrome?
A
This causes massive cellular lysis in cancer.
10
Q
Features of tumour lysis syndrome include?
A
- Hypocalcaemia ( Precipitation with phosphate)
- Hyperkalaemia
11
Q
Management of tumour lysis syndrome?
A
- Hydration
- Rasburicase (Increases the formation of allantoin from uric acid)
12
Q
Causes of TLS-related AKI with renal failure?
A
- Hyperuricaemia
- Hyperphosphataemia
13
Q
Cardiac effect of hypercalcaemia?
A
- Shortening of myocardial action potential
- Shortened QT interval
14
Q
What is pseudo-hypoxaemia?
A
Artifactual condition reported in patients with Leukocytosis & Thrombocytosis. This should be suspected where saturations do not match with ABG saturations.
15
Q
Classification of post-traumatic seizure?
A
- Early PTS - Within 7 days of injury
- Late PTS - AFter 7 days of injury
16
Q
Risk factors for post-traumatic seizures?
A
- GCS < 10
- Subdural, extradural & intracerebral haematoma
- Depressed skull fracture
- Penetrating head injury
- Young age
17
Q
Lactic acidosis is associated with ?
A
- Raised anion gap
- Serum chloride is usually normal
3.
18
Q
Properties of strong ion difference?
A
- Strong ion difference is reduced in acidosis
- Normal value is 42mEq/L
19
Q
D-Lactic acidosis?
A
- It is a rare cause of metabolic acidosis
- Present in short gut syndrome
20
Q
L-lactate acidosis?
A
- Accumulates in humans
21
Q
What is the Henderson-Hasselbalch equation in relation to bicarbonate buffer system?
A
- pH = 6.1 + HCO3-/(0.03 x pCO2)
- 6.1 = pK
22
Q
How do you calculate Strong Ion Difference?
A
- SID = (Na + K) - (Cl + Lactate)
- Normal value = 42mEq/L
- SID in Normal Saline is 0
- SID is reduced in metabolic acidosis
23
Q
Non-volatile acids in the body ?
A
- These acids cannot be excreted by the lungs
- Excretes 80mEq/L of non-volatile acids / day
- Usually from metabolism of protein
- Primarily cleared by the kidney
24
Q
Lactic acid?
A
- About 1,500mmol/day
- Metabolised by the liver
25
Oxidation reactions?
1. The atom losses an electron
2. Example of an oxidising agent: Fluorine - Reduced in the process
26
Reduction reactions?
1. The atom gains an electron
2. Example of a reducing agent: Sodium - Oxidised in the process
27
Hydrogen ion concentration?
1. Present on the ECF
2. Approximately 40nanoEq/L
28
Anion gap?
1. Normal 8-16mEq/L
29
PCT functions?
1. Carbonic acid formation (CO2+H2O)
2. Carbonic acid formation catalyzed by Carbonic anhydrase
3. Dissociates into H+ & HCO
30
Intracellular buffer systems?
1. Protein (Important IC buffer system)
2. Hb accounts for 60-70% of IC buffering
31
Intracellular and extracellular pH?
1. Intracellular pH is slightly lower than ECF pH
2. Venous blood 7.35 (Due to CO2)
3. Arterial blood 7.40
32
Oxyntic cells int the stomach?
1. pH = 0.8
33
ECF anions?
1. Chloride is the most abundant in ECF
34
Glutamine renal metabolism?
1. production of ammonium ion & HCO3
35
Urinary pH
1. The lowest is 4.5
2. Hydrogen ion buffered with PO & NH3 buffer systems
3. There is net addition of HCO3 to blood due to buffer
36
ECF buffer system?
1. HCO3 - Most important
2. pKa of HCO3 = 6.1
37
Hydrogen ion excretion in the renal tubules ?
1. Sodium-Hydrogen exchanger
2. This is an active process
3. Energy is provided by passive diffusion of Na
38
The excretion of Hydrogen ion is increased by ?
1. Metabolic acidosis
2. Respiratory acidosis
3. Aldosterone
4. Angiotensin
5. Hypokalaemia
39
Bicarbonate reabsorption occurs at what sites in the kidney?
1. PCT (80-90%)
2. DCT
3. CD
Occurs in all parts except the descending and thin ascending LoH
40
What is the equation for pH?
pH = -log [H+]
Normal H+ = 0.00000004mEq/L
41
Hydrogen ions in ECF?
It is very low
42
What is the isohydric principle?
All buffers in the body are in equilibrium with the same hydrogen ion concentration
43
Protein C & S?
1. Naturally occuring antocoagulants
2. Vitamin K dependent factors
44
What is a Newtonian fluid?
1. If it has constant viscosity regardless of flow
2. Water is a Newtonian fluid
3. Non-newtonian fluids viscosity varies with flow - Blood is an example
45
Activated clotting time (ACT)?
1. It is done on whole blood
2. It is less sensitive to minor deficiencies in clotting factors
3. Affects the intrinsic and common pathway (Factors < 5% of normal)
4 ACT dose-response relationship is linear with high dose of Heparin
46
APTT ?
1. Performed on plasma
2. More sensitive than ACT for minor deficiencies
3. At high Heparin levels, APTT doesn't have a linear relationship
47
What is the main cause of mitral stenosis?
Rheumatic heart disease in 99% of cases.
48
Epidemiology of mitral stenosis ?
1. 25% pure mitral stenosis
2. Two third are female
3. More common in developing countries
49
What is epidemiology?
This is the distribution, pattern and determinants of health and disease in a defined population.
50
Signs & symptoms of mitral stenosis?
1. Elevated right heart pressures
2. Elevated PAOP
3. Right parasternal heave
4. RVH + RAD on ECG
5. Palpable 1st heart sound apex
6. Pulmonary HTN + Palpable 2nd HS
51
What are the divisions of the bundle of His?
1. Right bundle branch
2 left bundle branch (Ant + Post fascicles)
52
What is bifascicular block?
Combination of right and left hemi-block. It could be left anterior or posterior
Could progress to trifascicular block needing permanent pacemaker
RBBB and LAD indicates bifascicular block
53
Contrast between left anterior and posterior hemiblock.
1. Left ant hemiblock causes LAD on ECG
2. Left post hemiblock causes RAD on ECG
54
Reversal of life threatening bleeding secondary to Warfarin?
1. Prothrombin complex conc
2. FFP can be used in addition
55
Diagnosis of congenital heart disease?
1. Hepatosplenomegally may be an important clue
2. Patent ductus arteriosus is associated with congenital rubella
3. Rate of spontaneous closure of VSD is > 50%
56
What is cholinergic crisis?
This can be induced by overdose of acetylcholinesterase inhibitors (Edrophonium for treatment of myasthenia gravis).
57
Mechanism of action of acetylcholinesterase in cholinergic crisis?
1. Increased acetylcholine at muscarinic receptors.
2. Stimulation of effector organ - (Abdominal colic, sweating, miosis & lacrimation)
58
Mechanism of action of GH?
1. Acts on GH/cytokine/superfamily of receptors
2. Functios via Janus Kinases/signal transducers and activation of transcription pathway (JAK-STAT)
59
How many zones does the adrenal cortex have?
It has 3 zones
1. Zona glomerulosa
2. Zona fasciculata
3. Zona reticularis
60
Secretions of the the adrenal cortex zones ?
Zona glomerulosa: Outtermost layer producing the mineralocorticoid aldosterone
Zona fasciculata produces the glucocorticoids - Cortisone, Corticosterone and deoxycorticosterone
Zona reticularis - Androgens, DHEA, DHEA sulphate and androstenedione
61
What is the most physiologically active glucocorticoid?
Cortisol
62
Adrenal gland?
1. Adrenal cortex
2. Adrenal medula
63
Adrenal medulla?
1. Main secretion - Adrenaline
2. Some noradrenaline
3. Modified post-ganglionic neuron
4. Catecholamine release mediated by pre-ganglionic sympathetic nerve fibres from T5-T11
5. Mediated by cholinergic nicotinic transmission
64
There are to portal venous systems in the body ?
1. Hepatic
2. hypophyseal
65
What is the most abundant store of iron in the body?
Haemoglobin
