USMLE Step 1 Qs (4)
Anatomy, biology and living organisms are an important part of nature. If you are interested, take up this quiz and find out how much knowledge you have. All the best.
- 1.A 67-year-old woman slipped on a scatter rug and fell with her right arm extended in an attempt to ease the impact of the fall. She experienced immediate severe pain in the region of the right collar bone and in the right wrist. Painful movement of the right arm was minimized by holding the arm close to the body and by supporting the elbow with the left hand. Which of the following is the carpal bone most likely to dislocate anteriorly and cause a form of carpal tunnel syndrome?
- A.
Capitate
- B.
Hamate
- C.
Lunate
- D.
Navicular
- E.
Scaphoid
- 2.A 67-year-old woman slipped on a scatter rug and fell with her right arm extended in an attempt to ease the impact of the fall. She experienced immediate severe pain in the region of the right collar bone and in the right wrist. Painful movement of the right arm was minimized by holding the arm close to the body and by supporting the elbow with the left hand. The fractured clavicle was reduced and the shoulder bandaged. The lunate bone was surgically reduced. After eight weeks the bone had healed, but the patient was found to have persistent loss of hand function. In addition to the region of original paresthesia (palmar aspects of the thumb, index, and middle fingers as well as a portion of the ring finger), which of the following areas should also exhibit paresthesia
- A.
Dorsal aspect of the distal phalanges of the index and middle fingers
- B.
Dorsal web space between the thumb and index finger
- C.
Medial aspect of the fifth digit
- D.
Skin over the central palm
- 3.
A workman accidentally lacerated his wrist as shown in the accompanying diagram. On exploration of the wound, a vessel and nerve are found to have been severed, but no muscle tendons were damaged. From the indicated location of the laceration, which of the following is the involved nerve?- A.
Median nerve
- B.
Recurrent branch of the median nerve
- C.
Superficial branch of the radial nerve
- D.
Ulnar nerve
- 4.
A workman accidentally lacerated his wrist as shown in the accompanying diagram. On exploration of the wound, a vessel and nerve are found to have been severed, but no muscle tendons were damaged. Which of the following thumb movements would be abolished?
- A.
Abduction
- B.
Adduction
- C.
Extension
- D.
Opposition
- 5.On the advice of a lawyer, a 27-year-old casino employee visited her personal physician because she found she could no longer flex her thumb and was unable to deal cards. Examination revealed weakness at the interphalangeal joint of the thumb as well as difficulty in bending the tips of the index and middle fingers. She could make a fist but had some difficulty in pinching with the thumb and index finger. There was some forearm pain but no tingling or numbness. These symptoms indicate damage to which of the following nerves?
- A.
Posterior interosseus branch of the radial nerve
- B.
Palmar branch of the ulnar nerve
- C.
Recurrent branch of the median nerve
- D.
Anterior interosseus branch of the median nerve
- E.
Digital branches of the ulnar nerve
- 6.On the advice of a lawyer, a 27-year-old casino employee visited her personal physician because she found she could no longer flex her thumb and was unable to deal cards. Examination revealed weakness at the interphalangeal joint of the thumb as well as difficulty in bending the tips of the index and middle fingers. She could make a fist but had some difficulty in pinching with the thumb and index finger. There was some forearm pain but no tingling or numbness. What type of joint is the interphalangeal joint?
- A.
Ball and socket
- B.
Ginglymus
- C.
Gomphosis
- D.
Saddle
- E.
Saddle
- 7.A patient experienced a prolonged stay in one position during a recent surgery and postoperative recovery that resulted in compression of the common peroneal nerve against the fibular head. Which of the following motor deficits would be most likely to occur?
- A.
Loss of extension at the knee
- B.
Loss of plantar flexion
- C.
Loss of flexion at the knee
- D.
Loss of eversion
- E.
Loss of medial rotation of the tibia
- 8.A patient experienced a prolonged stay in one position during a recent surgery and postoperative recovery that resulted in compression of the common peroneal nerve against the fibular head. In the above scenario, inversion of the foot is still intact although weakened. Which of the following muscles supplies this action?
- A.
Tibialis posterior
- B.
Plantaris
- C.
Peroneus longus
- D.
Extensor digitorum longus
- E.
Quadratus plantae
- 9.. Primary oocytes have developed by the time of birth. From puberty to menopause, these germ cells remain suspended in meiotic prophase. The oocyte of a mature follicle is induced to undergo the first meiotic division just before ovulation as a result of which of the following hormonal stimuli?
- A.
The cessation of progesterone secretion
- B.
The gradual elevation of follicle-stimulating hormone (FSH) titers
- C.
The low estrogen titers associated with the maturing follicle
- D.
The slow elevation of progesterone produced by luteal cells
- E.
The surge of luteinizing hormone (LH) initiated by high estrogen titers
- 10.A 26-year-old man contracted viral influenza with an unremitting fever of 39.5°C (103°F) for three days. Because spermatogenesis cannot occur above a scrotal temperature of 35.5°C (96°F), he was left with no viable sperm on his recovery. Which of the following is the approximate time required for spermatogenesis, spermiogenesis, and passage of viable sperm to the epididymis?
- A.
3 days
- B.
1 week
- C.
5 weeks
- D.
2 months
- E.
4 months
- 11.
Implantation of the conceptus at which site in the accompanying diagram of the female reproductive system could result in excessive, perhaps fatal, vaginal bleeding before parturition?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
- 12.In the developing human embryo, most of the internal organs begin to form in which month?
- A.
First
- B.
Second
- C.
Fourth
- D.
Sixth
- E.
Ninth
- 13.The primitive uteroplacental circulation is established during which period of fetal development?
- A.
First week
- B.
Second week
- C.
Third week
- D.
End of first month
- E.
Second trimester
- 14.Which places the developing heart in the presumptive thoracic region cranial to the septum transversum?
- A.
Gastrulation
- B.
Lateral folding
- C.
Cranial folding
- D.
Neurulation
- E.
Fusion of the endocardial heart tubes
- 15.Which of the following is in direct contact with maternal blood in lacunae of the placenta?
- A.
Cells of the cytotrophoblast
- B.
Extraembryonic mesoderm
- C.
Fetal blood vessels
- D.
Cells of the syncytiotrophoblast
- E.
Amniotic cells
- 16.During which of the following periods is the embryo most susceptible to environmental influences that could induce the formation of nonlethal congenital malformations?
- A.
Fertilization to one week of fetal life
- B.
The second and third weeks of fetal life
- C.
The fourth through eighth weeks of fetal life
- D.
The third month of fetal life
- E.
The third trimester of fetal life
- 17.During a visit to her gynecologist, a patient reports she received vitamin A treatment for her acne unknowingly during the first two months of an undetected pregnancy. Which of the following organ systems in the developing fetus are most likely to be affected?
- A.
The digestive system
- B.
The endocrine organs
- C.
The respiratory system
- D.
The urinary and reproductive systems
- E.
The skeletal and central nervous systems
- 18.Which of the following forms from paraxial mesoderm?
- A.
Adrenal cortex
- B.
Adrenal medulla
- C.
Humerus
- D.
Biceps brachii
- E.
Masseter
- 19.In the developing embryo, the edge of the ectoderm is continuous with which of the following?
- A.
Chorion
- B.
Amniotic membrane
- C.
Yolk sac lining
- D.
Extraembryonic mesoderm
- E.
Adventitia of the umbilical vessels
- 20.Which of the following is primarily responsible for the polyanionic charge on the outer surface of the plasma membrane?
- A.
Cholesterol
- B.
Glycoprotein
- C.
Free saccharide groups
- D.
Peripheral membrane protein
- E.
Integrins
- 21.Glycophorin is a single-pass, transmembrane glycoprotein found in the erythrocyte (RBC). Which of the following is an expected characteristic of this protein?
- A.
It possesses a hydrophilic portion that spans the lipid bilayer
- B.
Hydrolysis of carbohydrate will not affect the glycophorin band on an SDS polyacrylamide gel
- C.
It possesses oligosaccharides on the cytosolic side of the membrane
- D.
The polypeptide chain crosses the lipid bilayer in an alpha -helix conformation
- E.
It may be isolated from the RBC membrane with mild extraction conditions such as altered pH or ionic strength
- 22.Which of the following is the function of the large subunit of the ribosome?
- A.
Bind messenger RNA (mRNA)
- B.
Bind transfer RNA (tRNA)
- C.
Catalyze peptide bond formation
- D.
Link adjacent ribosomes in a polyribosome
- E.
Initiate protein synthesis
- 23.Which of the following events occurs in the rough endoplasmic reticulum?
- A.
Core glycosylation of proteins
- B.
O-linked glycosylation
- C.
Glycogenolysis
- D.
Sulfation
- E.
Protein sorting
- 24.. In Zellweger syndrome, tissue shows the presence of empty peroxisomes. Which of the following findings would you expect in patients?
- A.
Decreased energy production
- B.
Inability to detoxify alcohol
- C.
Decreased exocytosis
- D.
Decreased SER activity
- E.
Decreased lysosomal activity
- 25.Movement of vesicles and organelles from the perikaryon of the neuron to the axon terminus occurs along which of the following?
- A.
Microfilaments (thin filaments)
- B.
Intermediate filaments
- C.
Microtubules
- D.
Thick filaments
- E.
Spectrin heterodimers
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