Physiology Final Flashcards
The lysosome contains the following bactericidal agents, except: A. Lysozyme B. Lysoferrin C. Lysolecithin D. Acid hydrolase E. None of the above.
C
Answer: C. The lysosomes contain bactericidal agents that can kill phagocytized bacteria before they can cause cellular damage. These agents include (1) lysozyme, which dissolves the bacterial cell membrane; (2) lysoferrin, which binds iron and other substances before they can promote bacterial growth; and (3) acid at a pH of about 5.0, which activates the hydrolases and inactivates bacterial metabolic systems. (Guyton 11th ed, page 20).
What is/are the BEST index/indices of left ventricular pre-load? A. Ventricular enddiastolic volume B. Pulmonary wedge pressure C. Left atrial pressure D. Pulmonary venous pressure E. B and C
A
Answer: A. The best indices of left ventricular preload are ventricular EDV and EDP. Less reliable indices include left atrial pressure, pulmonary venous pressure, pulmonary wedge pressure. (Kaplan Step 1, lecture notes, page71).
Premature ventricular contractions (PVCs) causes the following ECG changes, EXCEPT:
A. QRS complex prolongation
B. Large QRS complexes
C. T-wave inversion immediately after a premature beat
D. None of the above
E. A and C
D
Answer: D. PVCs cause specific effects in ECG, as follows: 1. The QRS complex is usually considerably prolonged. The reason is that the impulse is conducted mainly through slowly conducting muscle of the ventricles rather than through the Purkinje system. 2. The QRS complex has a high voltage for the following reasons: when the normal impulse passes through the heart, it passes through both ventricles nearly simultaneously; consequently, in the normal heart, the depolarization waves of the two sides of the heartﾗmainly of opposite polarity to each otherﾗ partially neutralize each other in the electrocardiogram.When a PVC occurs, the impulse almost always travels in only one direction, so that there is no such neutralization effect, and one entire side or end of the ventricles is depolarized ahead of the other; this causes large electrical potentials. 3. After almost all PVCs, the T wave has an electrical potential polarity exactly opposite to that of the QRS complex, because the slow conduction of the impulse through the cardiac muscle causes the muscle fibers that depolarize first also to repolarize first. (Guyton, 11th ed, Chapter 13, page 151).
The principle that in the spinal cord the dorsal roots are sensory and the ventral roots are motor is known as the: A. Bell-Magendie law B. Maestrini law C. Frank-Starling law D. Polyvagal principle E. Muller law
A
Answer: A. The principle that in the spinal cord the dorsal roots are sensory and the ventral roots are motor is known as the Bell-Magendie law (Ganong, 2003).
The basic rhythm of respiration is generated mainly in: A. Ventral respiratory group, medulla B. Dorsal respiratory group, medulla C. Pneumotaxic center, pons D. All of the above E. A and B only
B
Answer: B. The basic rhythm of respiration is generated mainly in the dorsal respiratory group of neurons. The neurons of the ventral respiratory group remain almost totally inactive during normal quiet respiration. Therefore, normal quiet breathing is caused only by repetitive inspiratory signals from the dorsal respiratory group transmitted mainly to the diaphragm, and expiration results from elastic recoil of the lungs and thoracic cage. They are especially important in providing the powerful expiratory signals to the abdominal muscles during very heavy expiration. The function of the pneumotaxic center is primarily to limit inspiration. (Guyton, page 514).
A normal 25-year old man has a respiratory rate of 14 breaths per minute. What is his alveolar ventilation? A. 6 L B. 5 L C. 4 L D. 7 L
B
Answer: B. Computation is 500ml (normal tidal volume) ﾖ 150ml (normal anatomic dead space, assuming that this subject has 0 physiologic dead space) = 350ml x 14 = 4,900 ml, rounded off to 5L.
Which of the following statements is TRUE regarding voltage-gated sodium ion channels?
A. They are opened when the membrane is hyperpolarized.
B. They pump 3 sodium ions out of the cell and 2 potassium ions inwards.
C. They display a high conductance in the resting membrane.
D. They are virtually closed when the cell is at rest
D
Answer: D. Voltage-gated Na channels are opened during depolarization. NaK ATPase pump is the one pumping 3 Na out and 2 K in. There is virtually minimal/negligible conductance of sodium in a resting membrane.
The triggering mechanism for the genesis of REM sleep depends on neurons that release: A. Acetylcholine B. Serotonin C. Norepinephrine D. Dopamine
A
Answer: A. Physiologically, certain neurons in the brain stem, known as REM sleep-on cells, (located in the pontine tegmentum), are particularly active during REM sleep and are probably responsible for its occurrence. The release of certain neurotransmitters, the monoamines(norepinephrine, serotonin and histamine), is completely shut down during REM. Acetylcholine is released in high levels as a result of wakefulness and alertness, but it is also found in high levels during REM sleep. Its lowest levels have been found in slow wave sleep when there is no cortical arousal, but relaxation. People that have been unfortunate enough to be exposed to organophosphates insecticides, which are ACh agonists, spend more time in REM sleep than individuals who have not been exposed to these toxins. All this evidence suggests that ACh is involved in controlling REM sleep as well as arousa
BB, 35-year old male office worker on his preemployment check-up, showed marked enlargement of bone of the extremities and significant coarsening of his facial feature. His jaw was likewise enlarged and protruding. This condition is most commonly associated with a tumor located in: A. Posterior pituitary B. Adrenal glands C. Anterior Pituitary D. Lungs
C
Answer is C. The patient described has acromegaly, which is a result of increased growth hormone release from the anterior pituitary gland after the epiphyseal plates have already closed. In over 90 percent of acromegaly patients, the overproduction of growth hormones is caused by a benign tumor of the pituitary gland, called an adenoma
What will be the result of prolonged diastole? A. Increase heart rate B. Reduced peripheral resistance C. Reduced stroke volume D. Better filling of the ventricles E. A and D
D
Answer: D. Prolonged diastole permits more time for ventricular filling, hence better filling of the ventricle. Prolonging the diastole will result in decreased heart rate and increased stroke volume. Duration of diastole has no effect on peripheral resistance
The sympathetic nervous system modulates the output of the pacemaker cells of the heart by:
A. increasing cAMP causing a steep rise in phase 4
B. decreasing the activity of L type Ca++ channels and lowering the threshold
C. increasing the activity of the rectifying K+ channels in phase 3
D. increasing the activity of slow Ca++ channels in phase 2
E. All of the above
A
Answer: A. Sympathetic activation, which releases norepinephrine (NE), increases pacemaker rate by decreasing gK+ and increasing slow inward gCa++ and gNa+; the pacemaker current (If) is enhanced. These changes increase the slope of phase 4 so that the pacemaker potential more rapidly reaches the threshold for action potential generation.
The hormone secreted mainly by the corpus luteum is: A. Progesterone B. Testosterone C. Estrogen D. Inhibin E. None of the above
A
Answer: A. Corpus luteum secretes progesterone to start the luteal (secretory) phase of the menstrual cycle.
Following massive hemorrhage during delivery, a 29-year old female was unable to breastfed due to absence of milk secretion. Which of the following is most likely to be associated with this clinical picture? A. Symptoms of hyperthyroidism B. Elevated prolactin secretion C. Cushingﾒs disease D. Decreased gonadotropin secretion E. All of the above
D
Answer: D. The patient is suffering from postpartum pituitary necrosis secondary to massive haemorrhage (Sheehanﾒs syndrome). Therefore, it is expected that all hormones produced by the pituitary gland will be decreased. There will be hypothyroidism, decreased prolactin secretion (reason for inability to produce milk) and decreased gonadotropin secretion
Which of the following is/are one of the principal means by which acclimatization to high altitudes come about?
A. Lower than normal pulmonary ventilation
B. Decreased number of red blood cells
C. Reduced diffusing capacity of the lungs
D. Decreased vascularity of peripheral tissues
E. None of the above
E
Answer: E. The principal means by which acclimatization comes about are (1) a great increase in pulmonary ventilation, (2) increased numbers of red blood cells, (3) increased diffusing capacity of the lungs, (4) increased vascularity of the peripheral tissues, and (5) increased ability of the tissue cells to use oxygen despite low PO2. (Guyton 11th ed, page 539)
The deficiency of what trace element is associated with skin lesions, weakened immune system, and hypogonadal dwarfism? A. Copper B. Chromium C. Cobalt D. Zinc E. Iron
D
Answer D. Patients with zinc deficiency will present with skin ulcer, depressed immune response and hypogonadal dwarfism.
In the sarcomere, which of the following keep/s the myosin and actin in place? A. Titin B. Z disc C. Myofibrils D. All of the above E. A and B only
A
Answer: A. The side-by-side relationship between the myosin and actin filaments is difficult to maintain. This is achieved by a large number of filamentous molecules of a protein called titin (Guyton, 11th ed).
DM, 45 year old female, went to you as her physician complaining of weight gain, even though her diet was controlled. Upon physical examination, you found out that she has elevated blood pressure, purple striae on the trunk, growth of fat pads along the collar bone and hirsutism. Laboratory revealed elevated blood sodium levels and low blood potassium levels. Increased production of which hormone would explain her symptoms? A. Insulin B. Cortisol C. Glucagon D. Aldosterone E. Testosterone
B
Answer: B. The patient has a condition called Cushingﾒs syndrome. This is manifested by abnormally elevated levels of cortisol.
A newborn male was held at the NICU because he did not pass out meconium after 48 hours of life. Plain abdominal radiographs showed distended bowel loops with a paucity of air in the rectum. Absence of which of the following is/are expected to be seen in the biopsy of the affected segment? A. Meissnerﾒs plexus B. Auerbachﾒs plexus C. Myenteric plexus D. All of the above E. A and B only
D
Answer: D. Both the myenteric (Auerbach) plexus and the submucosal (Meissner) plexus are absent from the muscular layer of the bowel wall in Hirschprungﾒs disease.
Which of the following is primarily utilized by an athlete during the first 8- 10 seconds of a 100- meter run? A. Glycogen-lactic acid system B. Aerobic system C. Phosphagen energy system D. A and B E. All of the above
C
Answer: C. The phosphagen energy system can provide maximal muscle power for 8 to 10 seconds, almost enough for the 100-meter run. The glycogen-lactic acid system can provide 1.3 to 1.6 minutes of maximal muscle activity in addition to the 8 to 10 seconds provided by the phosphagen system, although at somewhat reduced muscle power. Aerobic system is required for prolonged athletic activity
The concentrating mechanism of the nephron depends upon the maintenance of a gradient of increasing osmolality along the medullary pyramids. Which of the following is/are true regarding the production of this gradient?
A. It is produced by the operation of the loops of Henle as countercurrent exchanger
B. It is maintained by the operation of the vasa recta as countercurrent multiplier
C. It is generated by insertion of aquaporins at collecting tubules as stimulated by vasopressin
D. A and B only
E. None of the above
E
Answer: E. The concentrating mechanism depends upon the maintenance of a gradient of increasing osmolality along the medullary pyramids. This gradient is produced by the operation of the loops of Henle as countercurrent multipliers and maintained by the operation of the vasa recta as countercurrent exchangers. (Guyton, 11th ed)
A 35 year old male from a nearby city was a diagnosed case of pulmonary tuberculosis . Lesion from this kind of infection is usually walled off by a fibrous tissue but if it fails, abscess cavities and multiple areas of fibrosis will develop causing which of the following consequences?
A. Reduced vital capacity
B. Reduced membrane surface area
C. Increased thickness of the surface membrane
D. Abnormal V/Q ratio
E. All of the above
E
All of the choices are consequences of PTB infection.
Jackie Casimiro, a full time teacher, is currently involved in a hunger strike joined by various teachers as a protest for the low compensation given to them by the government. Common to hunger strikes ,hunger contraction causes hunger pangs especially in young healthy individual. Hunger pangs are usually strongest when? A. 1st 12 hours B. 36-48 hours C. on the 3rd-4th day D. on the 2nd week E. None of the above choices
C
Hunger pangs are strongest in the 3rd- 4th day. SIMILAR TO PREVIOUS BOARD EXAM CONCEPT/PRINCIPLE
All of the following lung volume and lung capacities cannot be measured clinically except? A. TV B. ERV C. RV D. FRC E. TLC
A
Which characteristic or component is shared by skeletal muscle and smooth muscle?
A. Thick and thin filaments arranged in sarcomeres
B. Troponin C. Elevation of intracellular Ca for excitation-contraction coupling
D. Spontaneous depolarization of the membrane potential
E. High degree of electrical coupling between cells
C
an elevation of intracellular calcium is
common to mechanism of excitationcontraction
coupling in skeletal
muscles.
Which of the following structures has a primary function to coordinate rate, range, force and direction of movement?
A. Primary motor cortex
B. Premotor cortex and supplementary motor cortex
C. Prefrontal cortex
D. Basal ganglia
E. Cerebellum
E
output of prkinje cells from the cerebellar cortex to deep cerebellar nuclei is inhibitory. This output modulates movement and is responsible for coordination.
All of the following are muscles for inspiration except? A. External Intercostals B. SCM C. Anterior Serrati D. Scalene E. Internal Intercostals
E
Slow waves as an electrical activity of GI smooth muscles are actually not true action potentials. It is a cyclic opening of calcium channel (depolarization) and opening of Na channel (repolarization) which bring undulating changes in RMP by the use of a pace maker (Interstitial cells of Cajal). These waves are found to be slowest in which part of the GI tract? A. Esophagus B. Stomach C. Small intestines D. Colon E. Rectum
B
Slow waves are slowest in the stomach and fastest in the small intestines
Stimulation of gastric acid secretion is potentiated/initiated by all of the following EXCEPT: A. Histamine B. Gastrin C. Acetylcholine D.Secretin
D
Jennifer Arcilla is a professional mountain climber and is used to changes brought about by high altitude. Normally an unacclimatized person can remain conscious up to 50 % of its arterial oxygen is saturated. At 10, 000 feet, arterial oxygenation is at 90 % and drops rapidly as one ascends. What is the most important observed effect to an individual at this level? A. Drowsiness B. Lassitude C. Headache D. Decreased mental proficiency E. Euphoria
D
at 10, 000 feet: most impt effect is Decreased mental proficiency, the rest of the choices can be observed at 12,000 feet
All of the following are characteristics of isovolumetric ventricular contraction phase of the cardiac cycle , EXCEPT:
A. It is a period between closure of the AV valves and opening of Semilunar valves
B. There is an abrupt increase in the ventricular pressure more than the atrial pressure
C. All valves are closed in this phase
D. In this phase, the 1st heart sound is produced
E. End Systolic Volume is involved
E
A-D are correct. End diastolic volume instead of End Systolic Volume is involved in this phase.
In one physiology class, you are tasked to study the cardiac cycle along with the heart sounds and its origin. Which of the following pair of heart sounds and its origin is INCORRECT?
A. S1- closure of AV valves
B. S2- closure of SL valves
C. S3- rapid filling phase (flow of blood from atria to ventricle)
D. S4- atrial systole
E. All of the above choices are correct
E
Which of the following phases of SA nodal conduction is responsible for its automaticity?
A. Phase O-upstroke of action potential (depolarization brought about by increase Ca conductance)
B. Phase 3- repolarization (outward K current)
C. Phase 4- slow depolarization (inward Na current)
D. Phase 5- fast Ca current
E. None of the above
C
Phase 4- slow conduction, inward Na current is respinsible for SA nodal automaticity
All of the following are vasoconstrictors, EXCEPT: A. Serotonin B. Endothelin C. Bradykinin D. Histamine E. C and D
E
Bradykinin and histamine are vasodilators
A 56 year old female was admitted due to uncontrolled DM Type 2. Further work ups revealed that her kidney function is already impaired significantly and she is then already anemic due to lack of production of erythropoietin brought about by kidney damage. Where is erythropoietin produced in a normal kidney?
A. Renal Papilla
B. Fibrous capsule
C. Macula Densa
D. Peritubular Capillaries (Interstitial cells)
E. Lacis cells
D
Which of the following would cause an increase in both glomerular filtration rate and renal plasma flow?
A. hyperproteinemia
B. A ureteral stone
C. Dilation of the afferent arteriole
D. Dilation of the efferent arteriole
E. Constriction of the afferent arteriole
C
A man presents with hypertension and hypokalemia. Measurement of his arterial blood gases reveal a pH of 7.5 and a calculated HCO3 of 32 mEq/L. His serum cortisol and VMA are normal, his serum aldosterone is increased and his plasma renin activity is decreased. Which of the following is the most likely cause of his hypertension? A. Cushing's syndrome B. Cushings's disease C. Conn's syndrome D. Renal artery stenosis E. Pheochromocytoma
C
hypertension, hypokalemia, metabolic alkaLOSIS , ELEVATED ALDOSTERONE AND LOW RENIN ARE ALL CONSISTENT TO CONN’S SYNDROME.
Propagation of the action potential through the heart is slowest in which of the following? A. SA node B. AV node C. Purkinje fibers D. Ventricular muscle E. None of the above
B
slowest= Av node. Fastest= purkinje fibers
Among the following organs, which is most vulnerable to hypoglycemia because of its dependence on the circulating glucose for energy? A. Liver B. Kidney C. Skeletal Muscle D. Brain E. Pancreas
D
Change/s in the lung volumes of capacities of patients with restrictive lung disease:
A. Decrease in TLC
B. Decrease in residual volume
C. Decrease in Functional Capacity
D. Decrease in Expiratory reserve volume
E. All of the above
E
A 23 year old female was admitted due to DHF. Her attending physician requested for bleeding parameters including PT, PTT, CT and BT. Bleeding time is a test of? A. Intrinsic pathway B. Extrinsic pathway C. Platelet Function D. A and B E. All of the above
C
