A)Low Blood Ph Causes Vasodilation
PEW 2002
Physiology
1Regarding pulmonary blood flow
A)low blood pH causes vasodilation
B)at high altitude, generalised vasodilatation causes arise in pulmonary arterial pressure
C)vasoconstriction may occur when the alveolar PO2 is reduced below 55mmHg
D)inhaled nitrous oxide reduces pulmonary vasoconstriction
E)endothelins are potent vasodilatory peptides
2Causes of hypoxic hypoxia include the following, EXCEPT
A)pulmonary shunting
B)morphine
C)pulmonary fibrosis
D)fatigue
E)congestive heart failure
3Regarding buffers of the body
A)initial correction of pH disturbance is achieved by kidneys
B)the phosphate buffer system is the predominant buffer in the blood
C)bones contribute to buffering by taking up HCO3
D)Hb is an important buffer in the blood
E)all of the above are correct
4Regarding ventilation / perfusion differences in the lung
A)in healthy individuals, anatomical dead space is less than physiologic dead space
B)the relative change in blood flow from apex to base is less than relative change in the ventilation
C)ventilation / perfusion differences are due to gravity
D)ventilation perfusion ratio is low at the base
E)all of the above
5Lung compliance
A)is normally 100mL/cm water
B)falls if the lung remains unventilated for a long period
C)rises if the pulmonary venous pressure is increased
D)falls as the lung ages
E)is the area under the pressure-volume curve
6Work of the lung in breathing
A)is increased with larger tidal volumes
B)is increased with higher flow rates
C)in inspiration needs to overcome elastic forces and viscous resistance
D)in expiration needs to overcome airway and tissue resistance
E)all of the above
7The most important short term response to high altitude is
A)hyperventilation
B)polycythaemia
C)chronic mountain sickness
D)acidosis
E)decreased erythropoietin release
8Regarding the alveolar gas equation PAO2 = PIO2 – PaCO2 + F
R
A)this equation gives the value of alveolar PO2 in a given patient
B)R denotes the respiratory rate
C)At sea level, PIO2 = 690mmHg X 0.21 of humidified air
D)At high altitude, PaCO2 can be less than 35mm Hg
E)The alveolar gas equation is only applicable at sea level
9In carbon dioxide transport
A)the HCO3- content of venous blood is reduced compared to arterial blood
B)the osmolarity of RBCs in venous blood is increased compared to arterial blood
C)the haematocrit of venous blood is 3% less than arterial blood
D)the solubility of CO2 in blood is less than O2
E)CO2 does not react with plasma proteins
10With regard to neural control of respiration
A)there are three neural mechanisms regulating respiration
B)the dorsal group of respiratory centre has expiratory neurons
C)the ventral group of respiratory centre are located in the pons
D)the main respiratory control centre is located in the pons
E)voluntary control system is located in the cerebral cortex
11Surfactant
A)is produced by class II pneumocytes
B)is increased in smokers
C)helps keep the alveoli moist
D)decreases alveolar stability in preterm babies
E)maturation is impaired by glucocorticoids
12Regarding the O2 dissociation curve
A)each gram of pure Hb can bind one mole of O2
B)2,3 DPG levels fall at high altitude
C)an increase in the affinity of Hb for O2 in an acid environment is called the Bohr affect
D)a right shift implies a lower PO2is required for O2 binding
E)the P50 is an index of the affinity of Hb for O2
13For the chemical control of respiration
A)the carotid bodies respond to changes of pH, PO2, PCO2
B)the aortic bodies respond to changes of pH, PO2, PCO2
C)PO2 is only detected by the central chemoreceptors
D)Severe hypoxia strongly stimulates the central chemoreceptors
E)The central chemoreceptors respond to changes in plasma pH
14In the kidney
A)K+ is actively reabsorbed in the distal tubule
B)K+ excretion is decreased when H+ secretion is decreased
C)K+ does not compete with H+ in the tubular fluid
D)The rate of K+ secretion is proportionate to the rate of flow of tubular fluid in the distal nephron
E)K+ is reabsorbed and Na+ is secreted in the distal tubules
15In regards to renal handling of Na+
A)Na+ is actively transported out of all parts of the renal tubule
B)Na+ is pumped out of the thin portion of the loop of Henle by a Na+- K+ ATPase
C)The Na+ - K ATPase extrudes one Na+ in exchange for one K+ out of the tubular cell
D)Most of the Na+ is actively transported out of the tubular cell into the lateral intercellular spaces
E)Around 60% of Na+ is reabsorbed back into the circulation
16In the kidney
A)H+ secretion in distal convoluted tube and collecting ducts mainly occurs through Na+ dependent transport mechanism
B)pH of 4.5 in the urine is the limiting pH for H+ secretion
C)for each H+ secreted, 2 of the Na+ ions are reabsorbed
D)the H+ secretion in the proximal convoluted tube is mainly dependent on ATP driven proton pump
E)the carbonic anhydrase inhibitors increase the H+ secretion
17Regarding thyroid hormones in plasma
A)glucocorticoids decrease free plasma T4
B)concentrations of binding proteins are increased in hypertension
C)estrogens decrease total plasma T4
D)free T3 levels are normal in hyperthyroidism
E)plasma TSH is high in hypothyroidism
18The pancreas
A)does not resemble the salivary glands
B)contains digestive enzymes in granules
C)secretes 500mls of pancreatic juice per day
D)secretes trypsinogen which activates phospholipase A2
E)is stimulated by secretin to secrete enzyme rich pancreatic juice which is low in volume
19In the kidney
A)glucose is secreted by the collecting duct
B)the renal threshold refers to glucose resorption from the urine
C)glucose is resorbed by secondary active transport
D)glucose is resorbed by the loop of Henle
E)there is no glucose carrier in the kidney
20Renin secretion is increased by
A)increased Na+ and Cl- re-absorption across the macula densa
B)increased afferent arteriole pressure
C)prostaglandins
D)vasopressin
E)angiotensin II
21ADH secretion is increased by
A)alcohol
B)carbamazepine
C)increased extracellular fluid volume
D)angiotensin I
E)lying supine
22The following is an essential fatty acid
A)linoleic
B)palmitic
C)stearic
D)oleic
E)meralonic
23With regards body fluid compartments
A)intracellular fluid constitutes 60% body weight
B)females in general have higher total body water (as % body weight) compared with males
C)plasma volume is approximately 3500L
D)blood plasma is approximately 20% body weight
E)the ECF volume / intracellular fluid volume ratio is larger in adults than infants
24The following gastrointestinal peptides are all distributed distal to the gastric antrum EXCEPT
A)secretin
B)cholecystokinin
C)gastric inhibitory peptide
D)neurotensin
E)gastrin
25Regarding HCI secretion by the parietal cells, the following are true EXCEPT
A)hydrogen is actively pumped out by ATPase
B)after a meal, the blood pH can rise
C)hydrogen is exchanged for chloride
D)histamine and gastrin stimulates it
E)parietal cells are rich in carbonic anhydrase
26Regarding blood flow
A)blood flow in the blood vessels is normally turbulent
B)turbulent flow is silent
C)the small arteries and arterioles are referred to as the capacitance vessels
D)the average velocity of blood is highest in the capillaries
E)blood flow and resistance in vivo are markedly affected by small changes in the calibre of vessels
27In the cardiac action potential
A)initial rapid depolarisation is due to opening of voltage gated potassium channels
B)phase 2 is due to opening of sodium channels
C)phase 3 is due to the opening of potassium channels
D)extracellular potassium concentration is not important
E)the magnitude is affected by external sodium concentration
28Cardiac muscle contraction
A)is in its absolute refractory period in the latter half of phase 3 and phase 4
B)shows a decrease in the number of cross bridges between actin and myosin (during descending limb of starling curve)
C)shows greater inotropism when catecholamines act on 1 adrenergic receptors
D)shows increased contraction when digoxin stimulates Na+/K+ APTase
E)In Duchenne’s muscular dystrophy, shows hypertrophy but does not lead to cardiac failure
29In the cardiac cycle
A)right ventricular contraction occurs before left
B)phase II commences with the opening of the AV valves
C)phase IV is isovolumetric relaxation
D)during inspiration, the pulmonary valve closes before the aortic
E)the duration of systole is more variable than diastole
30Regarding the heart sounds
A)the third heart sound is heard 1/3 of the way through diastole in many young normal individuals
B)a fourth heart sound can be heard in some individuals with low atrial pressure
C)the first heart sound is loud when the heart rate is slow
D)the interval between the aortic and pulmonary valves is decreased during inspiration
E)the second heart sound is normally lower pitched and longer than the first
31Cerebral circulation
A)is highly variable with posture
B)is constant across approximately 100-200mmHg
C)is variable due to the “closed-box” nature of the cranium
D)is approximately 750ml/min
E)has the same flow/weight ratio as the kidney
32Regarding the ECG
A)the U wave is believed to be due to papillary muscle repolarisation
B)the PR interval is the time taken for atrial repolarisation
C)lead III is the vector between right arm and left leg
D)left bundle branch block is defined by cardiac axis > 30°
E)lead V5 is placed in the 4th intercostal spine, midclavicular line
33Increased baroreceptor discharge
A)inhibits GABA secreting neurons in the medulla
B)inhibits vagal stimulation of the heart
C)inhibits tonic discharge of vasoconstrictor nerves
D)is inversely proportional to pressure change
E)passes via efferent nerves in glosopharyngeal and vagus nerves
34Myocardial contractility is increased by
A)vagal stimulation
B)hypoxia
C)acidosis
D)digitalis
E)loss of myocardium
35Cardiac output is increased by
A)sleep
B)moderate changes in environmental temperature
C)eating
D)rapid arrhythmias
E)sitting or standing from lying position
36Myocardial contractility is decreased by
A)acidosis
B)quinidine
C)hypoxia
D)hypercapnia
E)all of the above
37Coronary blood flow
A)occurs predominantly in systole
B)is increased with rising venous pressure
C)is 20% of total cardiac output
D)is most likely to be compromised subendocardially
E)is increased by CO2/H+/k+ and cyanide
38Muscle spindles
A)lie in parallel with extrafusal muscle fibres
B)are the only effector organs in the monosynaptic stretch reflex
C)do not have a motor supply of their own
D)consist of up to 100 muscle fibres
E)can be divided into five types in mammalian muscle
39Large dense vesicles in the synaptic knob contain
A)acetylcholine
B)glycine
C)GABA
D)glutamate
E)neuropeptides
40Nerve fibres
A)have decreased conduction speeds with increasing diameters
B)of type A are the smallest
C)of type A conduct modalities of pain and temperature
D)have an increased refractory period with increasing diameter
E)of type C are unmyelinated
41Regarding the resting membrane potential
A)the inside of the cell is positive relative to the outside
B)the Na+/K+ ATPase is electrogenic because it moves 2Na+ and 3K+ across the membrane
C)the membrane is more permeable to K+ than to Na+
D)in nerve cells it is about –120mV
E)K+ moves out of the cell down its electrical gradient
42Visual pathways
A)have P cells that are associated with colour
B)utilise the primary colours “red, yellow, blue”
C)have simple cells which respond to all light stimuli
D)pass through the medial geniculate body
E)have a temporal path for motion
43Parasympathetic stimulation causes
A)sweat secretion
B)salivary secretion
C)inhibition of peristalsis
D)increase in heart rate
E)vasoconstriction of abdominal viscera vessels
44With regard to adrenal function
A)the zona fasciculata secretes mainly aldosterone
B)the adrenal medulla is not essential for life
C)ACTH is the prime controller of secretion from zona glomerulosa
D)More than 85% of adrenal medullary secretion is nor-adrenaline
E)Hypernatraemia is associated with mineralocorticoid deficiency
45A sense organ for pain is
A)Merkel’s disc
B)Kranse end bulb
C)naked nerve endings
D)Meissner’s corpuscle
E)encapsulated endings
46Pain transmission
A)is by peripheral B fibres
B)involves cholinergic transmission
C)is produced by over-stimulation of other receptor types
D)can be gated by presynaptic inhibition
E)is via fast C pain fibres
47Co-transmitters released with noradrenalin include
A)vasoactive intestinal peptide and dopamine
B)ATP and neuropeptide Y
C)dopamine and neuropeptide Y
D)tyrosine and ATP
E)acetylcholine and vasoactive intestinal peptide
48The size of the action potential is decreased by
A)decreasing the intracellular calcium concentration
B)increasing the external Na+ concentration
C)decreasing the internal Na+ concentration
D)decreasing the internal K+ concentration
E)increasing the internal K+ concentration
49Skeletal muscle
A)functions as a syncytium and contracts rhythmically in the presence of a pacemaker
B)contractile proteins include myosin II and tropomyosin
C)has a light I band divided by a dark A band
D)has three troponin units – I, T and M
E)myosin II is made up of four heavy chains and two light chains
50Regarding the neuromuscular junction
A)the myelin sheath thickens at the terminal portion of the axon
B)acetylcholine vesicles are evenly distributed throughout the endplate
C)the impulse alters permeability to Ca2+ and Na+
D)myasthenia gravis is a result of antibodies affecting Ca2+ channels
E)each impulse releases about 60 acetylcholine vesicles
Answers Physiology
PEW 2002
1DWest, 6th Edition, Page 39-40
2EGanong 20th Edition, table 37-1
3DLectures notes on Physiology, 4th Edition
4DGanong, Page 636
5BWest. 6th Edition, Page 82-83
6EWest, 6th Edition, Page 101
7AWest, 6th Edition, Page 119-120
8DWest, 5th Edition, Page 69 and 137
9BGanong, Page 638-639
10E
11A Ganong, 19th Edition, Page 624-625
12E Ganong, 20th edition, Page 645-646
13A West, 6th Edition Page 107
14D Ganong, 19th Edition, Page 691
15D Ganong, Page 667
16B Ganong, 20th Edition, Page 694-695
17E Ganong, 20th Edition, Page 312
18D Ganong, 20th Edition, Page 481-483
19C Ganong, 19th Edition, Page 678
20C Ganong, 19th Edition, Page 437
21B Ganong, 20th Edition, Page 235
22A Ganong, 20th Edition Page 298
23C Ganong, 20th Edition Page 2
24E Ganong, 20th Edition Page 469
25C Ganong, 20th Edition, Page 477
26E Ganong, 19th Edition, Chapter 30
27E Ganong, 19th Edition, Page 72
28C Ganong, 20th Edition, Page 72-76
29C Ganong, 20th Edition, Page 546
30A Ganong, 15th Edition, Page 525
31D Ganong, 20th Edition, Page 595-596
32AGanong, 20th Edition, Page 532-533
33CGanong, 20th Edition, Page 582
34DGanong, 20th Edition, Page 554
35CGanong, 20th Edition Page 551
36EGanong, 20th Edition Page 553
37DGanong, 19th Edition, Page 593
38AGanong, 19th Edition, Page 122
39EGanong, 20th Edition, Page 82
40EGanong, 20th Edition, Page 58-59
41CGanong, 20th Edition, Page 57 and others
42AGanong
43BGuyon Pocket, 10th Edition, Page 471
44BGanong, 20th Edition, Page 344
45CGanong, 20th Edition, Page 136
46DGanong, 20th Edition, Page 137
47BGanong, 20th Edition, Page 219
48CGanong, 17th Edition, Page 51
49BGanong
50EGanong, 20th Edition, Page 110-112
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