Physiology 51-100 Flashcards
Which among these is the first step in the process of urine formation A. tubular filtration B. tubular secretion C. glomerular filtration D. tubular reabsorption E. glomerular feedback
C
SIMILAR TO PREVIOUS BOARD EXAM
CONCEPT/PRINCIPLE
A patient who took an overdose of aspirin started having tinnitus, headache, dizziness or vertigo, confusion, tachypnea, metabolic acidosis, nausea, vomiting, dehydration/thirst and hypoglycemia, which of the following physiologic processes is expected to occur
A. shift in hemoglobin dissociation curve to the right
B. decreased baroreceptor stimulation
C. increased intracellular influx of potassium
D. decreased renal reabsorption of bicarbonate
E. decreased ADH secretion
A SIMILAR TO PREVIOUS BOARD EXAM CONCEPT/PRINCIPLE: increase temperature, increase acidity shifts dissociation curve to the right
Which of the following is true regarding the sympathetic nervous system?
A. It is responsible for accomodation of vision to near objects
B. it is responsbile for relaxation of urinary and gastrointestinal sphincters
C. it has short preganglionic fibers and long post ganglionic fibers
D. it only utilizes norepinephrine as neurotransmitter
E. the autonomic ganglia are usually embedded inside the effector organs
C SIMILAR TO PREVIOUS BOARD EXAM CONCEPT/PRINCIPLE, sympathetic has short preganglionic long postganglionic fibers
Which of the following is false of skeletal muscle contraction
A. action potential travels down depolarizing the terminal axonal bouton promoting release of Acetylcholine
B. during membrane depolarization, the inside of the cell becomes positively charged
C. acetylcholine diffuses across the synaptic cleft stimulating muscarinic acetylcholine receptors
D. acetylcholinesterase leads to break down of acetylcholine terminating the synaptic transmission
E. the acetylcholine receptor at the postsynaptic membrane is a ligand gate ion channel
C.
SIMILAR TO PREVIOUS BOARD EXAM CONCEPT/PRINCIPLE, review skeletal muscle contraction and NMJ physiology, post synaptic acetylcholine receptor in the muscle is a nicotinic ligand gated ion channel
24 year old female patient is pregnant at 8weeks AOG presents with intractable vomiting, which potential acid base disturbance can be seen in this patient? A. respiratory acidosis B. compensated metabolic acidosis C. respiratory alkalosis D. metabolic alkalosis E. none of the above
D.
SIMILAR TO PREVIOUS BOARD EXAM CONCEPT/PRINCIPLE, can be as simple as this, intractable vomiting = metabolic alkalosis
A neonate was jaundiced at the 8th hour of life, his mother was RH(-) baby was RH(+), total bilirubin levels were found to be 25mg/dL at the 2nd day of life, patient was deemed at risk for a CNS complication due to these conditions which were most likely to affect which part of the brain? A. basal ganglia B. cerebellum C. medulla D. cerebral cortex E. hypothalamus
A.
SIMILAR TO PREVIOUS BOARD EXAM
CONCEPT/PRINCIPLE, kernicterus
affects the basal ganglia
A 30 year old patient was involved in a motor vehicular accident, he has sustained multiple fractures over the lower
extremities and multiple rib fracturs as well. His initial BP was 80/50 HR 138, he was assessed to have hypovolemic shock,
which of the following parameters are known to increase cardiac output?
A. increased venous capacitance
B. decreased heart rate
C. decreased afterload
D. decreased inotropy
E. decreased left ventricular end diastolic volume
C. CO = HR x Stroke volume, stroke volume is amount of blood pumped by the heart during each contraction influenced by preload which is represented by left ventricular end diastolic volume, afterload and contractility. Decreased afterload increases stroke volume thereby increasing CO, increased venous capacitance decreases preload thereby decreasing stroke volume and CO
Which of the following conditions increases gastric emptying time?
A. decreased cholecystokinin secretion
B. decreased intake of fatty foods
C. increased motilin secretion
D. presence of fat and peptides in the duodenum
E. none of the above
D.
presence of breakdown products fat, peptides, acid in the duodenum delays gastric emptying, fatty meal delays emptying, increase cholecystokinin delays emptying
Assuming equal amounts of glucose were provided, which of the following routes produces a greater increase in pancreatic insulin secretion?
A. oral glucose intake
B. rapid IV glucose infusion
C. sugar tablets underneath the tongue
D. A and B produces equal rises in insulin
E. none of the above
A.
because of incretin effect, oral glucose
causes increased insulin secretion
A 30 year old female patient presents with hypertension, supraclavicular fat pad, multiple abdominal striae, obesity, red flushed skin, history of visual disturbances specifically involving temporal visual fields of both eyes, which of the following laboratory findings is expected?
A. decreased serum free cortisol
B. suppression of cortisol secretion following low dose dexamethasone administration
C. decreased urine free cortisol
D. increased ACTH
E. increased urinary metanephrines
D. patient most likely has cushings diease, pituitary ACTH most likely increased, non suppression with low dose dexa, cortisol in serum and urine is expected to be increased as well
The basement membrane of intestinal epithelial cells requires the GLUT2 transporter for absorption of glucose into circulation. Which of following is true about this kind of transport?
A. This transporter will absorb both D-glucose and L-glucose into the circulation.
B. Other similarly structured solutes such as galactose will competitively inhibit the absorption of glucose
C. The transport protein has no maximum transport capability and and is directly
proportional to the gradient at all concentrations
D. This transporter is dependent on ATP
E. None of the above
B GLUT 2 is a facilitated diffusion transporter which is stereospecific, saturable and competitive. Choice B is descriptive of competitive inhibition.
A 22 year old man is noted to have normal secondary sex characteristics but has deficient testosterone levels in the seminifirous tubules and epididymis. Which of the following is most likely dysfunctional? A. Leydig cells B. Anterior pituitary C. Hypothalamus D. Sertoli cells E. A an B
D. Sertoli cells is responsible for secreting the Androgen binding protein which traps and maintains testosterone concentration in the seminiferous tubules. The presence of normal secondary sex characteristics indicates that Leydig cells is functional.
RBC’s in the unoxygenated systemic venous circulation will have which of the following characteristics?
A. Has less H+ bound to hemoglobin
B. The major form of transport of CO2 is via binding to hemoglobin to form carbaminohemoglobin
C. HCO3- enters the RBC’s to recombine with H+ to form H2CO3 and which dissociates into CO2 and H2O
D. Has increased intracellular levels of Cl-
E. All of the above
D. HCO3- is transported out of the RBC in exchange for Cl- in unoxygenated blood. Choices A and C occur in oxygenated blood. The major form of transport of CO2 is via HCO3-.
Absence of T-tubules in skeletal muscle cells will result in:
A. Asynchronous waveforms and calcium release
B. Absence of action potential generation
C. Absence of calcium uptake by the sarcoplasmic reticulum
D. Inability of acetylcholine to bind and activate receptors at the neuromuscular junction
E. All of the above
A.
T-tubules is responsible for the
synchrony of Calcium release.
Which of the following will increase the contraction velocity of a skeletal muscle? A. Decreased afterload B. Decreased myosinactin overlap C. Increased extracellular Ca D. All of the above E. None of the above
A.
Afterload is the load against which the skeletal uscle must contract and is analogous to the afterload of the heart. Decrease in afterload will increase contraction velocity. In skeletal muscles, an increase in extracellular Calcium will lower gradient and decrease contractility
An exercising athlete will have which of the following respiratory responses? A. Increased oxygen consumption B. More evenly distributed V/Q ratio C. No change in arterial pCO2 and pO2 D. A and B E. All of the above
E.
All are correct. Venous pCO2 (but not
arterial pCO2) will increase.
Glucose and insulin levels were measured one hour after a patient is instructed to ingest 75 grams glucose which revealed glucose level of 250mg/dL accompanied by a corresponding rise in insulin secretion when compared to baseline. What is most likely the explanation for this finding?
A. Peripheral insulin resistance
B. Pancreatic beta cell destruction
C. Insulinoma
D. Physiologic glucose mobilization upon insulin release
E. A or B
A.
The scenario shows high glucose levels
despite corresponding insulin release.
A 63 year old presents to the clinic with complaints of dizziness and lightheadedness upon assuming an upright position. His supine blood pressure measurement is 95/65 and his standing blood pressure is 80/60. What will you expect to accumulate in the vascular smooth muscle cells in this patient upon standing. A. cAMP B. cGMP C. NO D. inositol triphosphate E. acetylcholine
D. Constriction of vascular smooth muscles involves stimulation of alpha 1-receptors. The mechanism is via Gq, leading to phospholipase C - mediated release of diacylglycerol and IP3
Conduction velocity measurements were obtained from different parts of the heart. The slowest and fastest conduction velocities respectively will be found in: A. Atrial and ventricular muscle cells B. AV node and atrial muscle cells C. SA node and AV node D. AV node and Purkinje fibers E. Ventricular muscle cells and SA node
D.
Fastest to slowest: Purkinje>atria and
ventricles > AV node
Angiotensin II plays an essential role in regulation of renal circulation. Its action on the efferent arteriole will result in which of the following changes?
A. Decreased GFR, No change in RPF, Decreased Filtration fraction (FF)
B. Increased GFR, Decreased RPF, Increased FF
C. Decreased GFR, Decreased RPF, No change in FF
D. Decreased GFR, Decreased RPF, Decreased FF
E. None of the above
B.
Contriction of efferent arteriole will
decrease RPF and increase GFR and FF
Unmyelinated nerve fibers is best exemplified by?
A. Preganglionic autonomic fibers
B. Postganglionic autonomic fibers
C. A-delta touch and pressure nerve fibers
D. Muscle spindle afferents
E. Golgi tendon nerve fibers
B.
Unmyelinated: postganglionic
autonomic, slow pain
The resting membrane potential of an isolated cell is found to be -70. Which of the following solutes is most likely responsible for this? A. Sodium B. Potassium C. Calcium D. Sodium and Calcium E. Sodium and Chloride
B.Resting membrane potential approximates that of potassium which is -85
What is responsible for an HCO3- rich alkaline intestinal content?
A. Pancreatic ductal stimulation by a duodenal hormone
B. CCK-mediated gallbladder contraction
C. Sympathetic nerve stimulation
D. Somatostatin-mediated inhibition
E. None of the above
A.
Secretin release by duodenal cells
A 33 year old woman presents to your clinic complaining of excessive sweating in the axillary region. Destruction of which of the following structures will prevent the said complaint? A. Vagus nerve B. Cervical sympathetic ganglion C. Thoracic sympathetic trunk D. Sacral sympathetic plexus E. None of the above
C. Though mediated by acteylcholine, the thoracic sympathetic is responsible for sweating. Cervical symphatetic for head and neck
What is the mechanism by which thyroid hormone act on its target tissues?
A. Gs-mediated activation of protein kinase A
B. Gq-mediated release of Ca
C. Binding to intracellular cytoplasmic receptor
D. Binding to intracellular nuclear receptor
E. Binding to a transmembrane receptor with intrinsic tyrosine kinase activity
D.
Thyroid hormone - nuclear receptors;
adrenal steroid hormones -
cytoplasmic receptors
You assess a 72 year old male patient who comes into your clinic complaining of chest tightness and dyspnea usually precipitated by exertion. Upon physical examination, you hear a murmur immediately after the 2nd heart sound when the patient is in a left lateral position. You conclude that what you hear is the third heart sound and that it occurs during which part of the cardiac cycle? A. isovolumic ventricular relaxation B. atrial systole C. rapid ventricular filling D. rapid ventricular ejection E. reduced ventricular filling
C.
S3 - rapid ventricular filling; S4- atrial
systole
The most significant airway resistance is in what part of the respiratory system? A. Primary bronchi B. Small brionchioles C. Alveolar ducts D. Trachea E. Medium-sized bronchi
E.
Small bronchioles have decreased resistance due to its parallel arrangement
A 53 year old woman who wants to prevent osteoporotic fractures takes excessive amounts of Vitamin D. Which of the following will be expected?
A. Increased Phosphorus, Decreased Ca, Increased PTH
B. Decreased Phosphorus, Increased Ca, Increased PTH
C. Increased Phosphorus, Increased Ca, Decreased PTH
D. Increased Calcium and Decreased PTH, No change in Phophorus
E. None of the above
C.
Vit D increases Ca and P levels
A cardiac patient asks you to discuss to her in great detail the physiology of cardiac action potential. You tell her that Phase 2 of SA node action potential is:
A. caused by inward Na current
B. the plateau of the action potential
C. due to a transient increase in Ca conductance
D. does not occur
E. None of these is correct
D.
Phase 2 occurs in ventricular, atria, and
Purkinje but NOT in SA node
A patient who presents with hyperventilation at the ER will have which of the following changes in the hemoglobin-O2 dissociation curve A. Shift to the left B. Decrease in P50 C. Increase in P50 D. A and B E. A and C
D.
Dec in pCO2, temp, 2,3 BPG and Inc in pH - shift to the left and Dec in P50
Which of the following is true regarding pulmonary blood flow when a person is standing?
A. It is equal between the apex and the base
B. It is higher in the apex owing to the effect of gravity on arterial pressure
C. It is higher in the base due to a greater difference between arterial and venous pressure
D. It is lower in the base because that is where alveolar pressure is greater than arterial pressure
E. None of the above
C.
the distribution of blood flow in the lungs is affected by gravitational effects on arterial hydrostatic pressure. Thus blood flow is greatest in the base, where arterial hydrostatic pressure is greatest and the difference between the arterial and venous pressure is greatest.
Which of the following gastrointestinal hormones inhibits gastric emptying time ? A. Gastrin B. Secretin C. Vasoactive intestinal peptide D. Cholecystokinin E. Gastric inhibitory peptide
D.
CCK is the most important hormone for
digestion and absorption of dietary fat.
In addition to causing conraction of the
gallbladder, it inhibits gastric emptying
time As a result chyme moves more
slowly from the stomach to the small
intestine , thus allowing more time for
fat absorption
Which of the following is an INCORRECT statement regarding the effect of polycythemia on the circulatory system?
A. The increased viscosity promotes a sluggish blood flow
B. There is a decreased rate of venous return to the heart
C. Majority of the hemoglobin is in the oxygenated state
D. Blood pressure is normal in most individuals
E. All of the above
C. Due to the sluggish blood flow in polycythemia, most of the hemoglobin is in the deoxygenated state. The blue color of the deoxygenated Hb masks the red color of the oxygenated Hb. Therefore a person with polycythemia ordinarily has a ruddy complexion with a bluish (cyanotic) tint to the skin.
Which of the following conditions would not have an elevation of the plasma renin level? A. Congestive Heart Failure B. Conn's syndrome C. Renal artery stenosis D. Hemorrhagic shock E. Liver cirrhosis
B. Conn's syndrome is characterized by the overproduction of the mineralocorticoid hormone aldosterone by the adrenal glands. This will produce a negative feedback and thus suppress renin secretion. The rest are causes of secondary hyperaldosteronism wherein a decrease in the intravascular volume would stimulate the RAA axis.
A patient with chronic asthma is started on glucocorticoid therapy. The treatment may result in bone loss through what mechanism ?
A. Suppress vitamin D activation
B. Increase production of osteoblast
C. Inhibition of bone formation
D. Inhibition of bone resorption
E. Increase calcium absorption from GI tract
C.
Glucocorticoid therapy enhances bone loss by inhibiting bone formation and increasing bone resorption.
A 78 year old man visited his physician because he finds it difficult to hold his hand steady when painting. Physical examination reveals rest tremor and rigidity. The patient's neurological signs are most likely related to a lesion within which of the following ? A. Vestibular nucleus B. Substantia nigra C. Premotor area D. Caudate nucleus E. Hippocampus
B.
This is a case of Parkinson’s disease characterized by resting tremor, rigidity and akinesia. It is caused by destruction of the dopamine secreting neurons within the substantia nigra
A 2D-echo was performed on a 66 year old male with aortic regurgitation to assess ejection fraction and ventricular hypertrophy. Which of the following would be present in a patient with aortic regurgitation? A. A decrease in diastolic pressure B. A decrease in pulse pressure C. Systolic murmur D. Bradycardia E. Decrease in heart size
A.
blood leaks from the aorta into the LV during diastole in patients with AR producing a diastolic murmur. The rapid flow of blood into the LV during diastole also cause an increase in end diastolic volume which results in a larger stroke volume and therefore a larger pulse pressure.
The affinity of hemoglobin for oxygen is increased by which of the following? A. Metabolic acidosis B. Carbon monoxide poisoning C. Anemia D. Hypoxemia E. Exercise
B.
A 17 year old male who is being treated with erythromycin complains of nausea, intestinal cramping and diarrhea. The side effects are the result of stimulation of enteric nerves and smooth muscle cells that recognize which hormone? A. Secretin B. Cholecystokinin C. Gastrin D. Motilin E. Enterogastrone
D.
Motilin is the GI peptide hormone associated with initiation of migrating motor complexes during the interdigestive period. The hormone stimulates increased contractions by a direct action on smooth muscle and by activation of excitatory enteric nerves. Macrolides antibiotics show an ability to excite motilin like receptors on enteric nerves and smooth muscle
A 64 year old man with a history of renal insufficiency is admitted to the hospital after taking a large amount of ibuprofen. His BUN was elevated at 150 mg/dL. Which of the following is the most likely cause of the elevated values?
A. An increased synthesis of urea by the liver
B. An increased reabsorption of urea by the proximal tubules
C. A decrease secretion of urea by the distal tubules
D. A decrease in the GFR
E. An increased renal blood flow
D.
NSAIDs inhibit synthesis of prostaglandins. PG mediate afferent arteriole vasodilation. Therefore the absence of PG will decrease blood flow through the afferent arteriole and thus decrease the GFR, causing elevation of BUN
A 16 year old medical student was brought to the ER in shock. Which of the following findings would favor anaphyactic shock rather than hypovolemic shock?
A. Cardiac output is higher than normal
B. Ventricular contractility is greater than normal
C. Serum creatinine is elevated
D. Total peripheral resistance is greater than normal
E. All of the above
A. Anaphylactic shock is characterized by decreased peripheral resistance and a high cardiac output. Hypovolemic shock is caused by decrease in ECV and arterial pressure. Both types of shock, blood flow is shunted away from the heart, decreasing renal blood flow and GFR leading to an increased Crea. In both hypovolemic and anaphylactic the baroreceptor reflex is stimulated which increases HR and ventricular contractility
The NMDA receptor is activated by which of the following neurotransmitters? A. Glycine B. Acetylcholine C. Substance P D. Histamine E. Glutamate
E
Which of the following characteristics is shared by simple and facilitated diffusion of glucose?
A. Occurs down an electrochemical gradient
B. Saturation
C. Requires metabolic energy
D. Inhibited by the presence of galactose
E. Requires a gradient establised by sodium
A. both types of transport occur down an electrochemical gradient and do not require metabolic energy. Saturability and inhibition of other sugars are characteristic only of carrier mediated glucose transport
A 45 year old male consulted his ophthalmologist because of increasing difficulty in reading the newspaper. His vision problem most likley results from the inability to contract which of the following? A. Iris B. Ciliary body C. Extraocular muscles D. Pupil E. None of the above
B.
contracting the ciliary body increases the refractive power of the eye for near vision. When the ciliary muscle contracts, it pulls the suspensory ligaments toward the cornea, which permits the lens surface to bulge, increasing its refractive power.
Which of the following is the major factor that protects the duodenal mucosa from damage by gastric acid?
A. Endogenous mucosal barrier of the duodenum
B. Duodenal bicarbonate secretion
C. Bicarbonate concentrated in the bile
D. Hepatic bicarbonate secretion
E. Pancreatic bicarbonate secretion
E.
Pancreatic bicarbonate secretion into the small intestine is essential for neutralizationof gastric acid emptied into the small intestine. Unlike the gastric mucosal lining, the small intestine does not have a significant endogenous mechanism. Upon delivery into the proximal small intestine, hydrogen ions stimulate release of secretin which stimulates pancreatic bicarbonate secretion. The acid ouput of the stomach during a meal is matched equallly by the pancreatic output of bicarbonate
Radiation treatment for a pituitary tumor in an 8 year old boy resulted in the complete loss of pituitary function. As a result, the child is likely to experience which of the following signs/symptoms? A. Goiter B. Accerlerated growth spurt C. Absent sexual maturation D. Both B and C E. None of the above
Absence of gonadotropins would cause absence of sexual maturation. Growth stunting is expected due to absence of GH . Goiter is not seen in panhypopituitarism since there would be no TSH present to stimulate excessive growth of the thyroid follicles
A 68 year old female underwent endoscopic ventriculostomy to treat her obstructive hydrocephalus. Intracranial pressure (ICP) increased during the procedure. Which of the following changes in the cardiovascular system can be a result of the increased ICP?
A. A decrease in ventricular contractility
B. A decrease in stroke volume
C. A decrease in mean blood pressure
D. A decrease in heart rate
E. A decrease in total peripheral resistance
D.
Increased ICP stimulated the cushing’s
reflex which causes: hypertension,
bradycardia and apnea
The activity of the central chemoreceptors is primarily stimulated by which of the following?
A. A decrease in PO2 of blood flowing through the brain
B. An increase in the PCO2 of blood flowing through the brain
C. A decrease in the oxygen content of blood flowing through the brain
D. A decrease in the metabolic rate of the surrounding brain tissue
E. An increase in the pH of the CSF
Increased ICP stimulated the cushing’s
reflex which causes: hypertension,
bradycardia and apnea
Which of the following hormones interact with a cytoplasmic receptor and then localizes in the nucleus and directs protein and nucleotide synthesis? A. Cortisol B. Epinephrine C. Insulin D. TRH E. Luteinizing hormone
A
If the patient is unable to hear high frequency sounds, the damage to the basilar membrane is closest to which of the following? A. Oval window B. Helicotrema C. Modiolus D. Stria vascularis E. Spiral ganglion
the portion of the basilar membrane vibrated by a sound depends on the frequency. High frequency sounds produce a vibration of the basilar membrane at the base of the cochlea (near the oval and round window); low frequency sounds produce a vibration of the basilar membrane at the apex of the cochlea (helicotrema). The modiulus is the bony center of the cochlea from which the basilar membrane emerges. the spiral ganglion contains the cell bodies of the auditory nerve fibers, and the stria vascularis is the vascular bed located on the outer wall of the scala media of the cochlea responsible for endolymph secretion
