Step1 - United State Medical Licensing Examination (Step 1)
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Cells in the pancreas that secrete glucagon and insulin are which of the following?
A and B cells
A 72-year-old male patient has suffered a cerebral infarct affecting the left cerebral hemisphere. On examination of the patient, it is noticed that his verbal output is fluent and paraphasic. His comprehension of speech is normal but repetition is severely impaired. Naming is also impaired, although when given a list, the patient is able to select the correct name. Special consultation with a neurologist results in a diagnosis of conduction aphasia. Which of the following brain structures is affected?
A premature female infant is born about 24 weeks after fertilization and develops rapid, labored breathing shortly after birth. She is immediately transferred to intensive care where she is diagnosed with hyaline membrane disease (HMD). Which of the following is most likely deficient in the infant?
type I alveolar cells
Amember of a college fraternity, who had consumed a large amount of alcohol on a dare, is brought to the emergency room with vomiting and severe abdominal pain. Blood tests reveal that he has elevated serum levels of amylase and lipase. Atentative diagnosis of acute hemorrhagic pancreatitis is formulated. Which cells of the pancreas are directly involved in this condition?
Serous cells are glandular acinar cells that produce a watery, proteinaceous fluid. This cell type is most predominant in which of the following glands?
the parotid gland
In this same patient, the pectineus muscle is also badly bruised. This muscle is innervated by which of the following?
A 15-year-old high school football player is brought to the emergency room. On examination, his right lower limb is deformed and swollen around the knee. At full extension, there is valgus instability, suggestive of knee dislocation. The patient is in great pain and there is a concern for concomitant vascular and nervous injuries. Palpation of the dorsalis pedis artery reveals a normal pulse. However, neurological examination reveals impaired dorsiflexion of the foot with decreased sensation in the space between digits 1 and 2. Which of the following nerves is affected?
deep peroneal (fibular) nerve
Hormone-secreting chromophils in the pars distalis of the adenohypophysis are classified into acidophils and basophils. Which of the following hormones is secreted by the acidophils?
A patient was thrown from a tractor, which partially ran over him and caused injury to the base of the skull. The origin of the internal jugular vein at the jugular foramen was compromised. Which of the following cranial nerves courses through the jugular foramen?
spinal accessory nerve (eleventh cranial) nerve
In the central auditory pathways, second-order neurons are located in which of the following?
Aperilunate fracture dislocation is a devastating closed injury of the wrist. It usually results from a fall where the weight of the body is transferred onto the wrist. The hand is caught in the hyperextended and ulnar deviated position. The fracture dislocation involves rupture of interosseous ligaments, joints, and ultimately dislocation/fracture of the lunate bone. In the anatomical position, which carpal bone lies directly distal to the lunate?
Which of the following normally occupy the dark spaces indicated by the arrows in following figure?
A gang member is rushed to the emergency room suffering from multiple stab wounds made by an ice pick. Athird-year medical student rotating through emergency medicine is puzzled by the sight of a milky white substance exuding from a stab wound just superior to the right sternoclavicular joint. Which of the following structures is possibly injured at this location?
the right lymphatic trunk
A 24-year-old student is brought to the emergency room after being found in a ditch where he had lain overnight after being hit by a car. He complains of severe pain in the left arm and examination reveals a broken humerus. Neurological examination reveals that the patient can extend the elbow but displays inability to supinate the elbow when it is extended. The patient also has wrist drop and very weak hand grasp. The neurological lesion is likely localized at which of the following locations?
radial nerve at the distal third of the humerus
Protein zero (P0) is the predominant protein in myelin in the peripheral nervous system and its function is to stabilize adjacent plasma membranes by interaction with similar P0 molecules. Which of the following cells manufacture P0?
During development, the upper limb buds appear by day 27 and the lower limb buds by day 29. An apical ectodermal ridge at the tip of each limb bud promotes growth. This multilayered epithelial structure interacts with which of the following to direct the growth of the limb?
Arrow 2 in following figure points to which of the following structures?
In the skull, a network of thick-walled vessels named dural venous sinuses drains the cerebrospinal fluid and the venous blood from the brain. These vessels are formed by reflections of the dura mater, which also form partitions between major parts of the brain. Which of the following dural venous sinuses is associated with the falx cerebri?
superior sagittal sinus
A football player was simultaneously tackled from the front above the knee and from the back below the knee. In the emergency room, he displays a positive anterior drawer test which becomes negative if the knee is internally or externally rotated. Which of the following has ruptured?
anterior cruciate ligament
A 28-year-old male patient suffering from head trauma resulting from a car accident is brought unconscious to the emergency room. In performing the pupillary light reflex, you notice that even though the left pupil constricts when you shine a light directly into the left eye, it does not do so when you shine a light into the right eye. This is best explained by a disconnection between which of the following bilateral structures?
Production of specific granules occurs mainly during which stage of granulocyte development?
Which of the following is characterized by an absence of lymphoid follicles and germinal centers?
Desmin is a 53-kDa protein found in skeletal and smooth muscle cells. It plays a role in coordinating muscle cell contraction. Desmin belongs to which type of intermediate filaments?
A 1-year-old infant presents with cardiomegaly and congestive heart failure. She has increased intracranial pressure with hydrocephaly and cranial bruit. A vein of Galen aneurysm, revealed by MRI, is shown to compress the aqueduct of Sylvius, the posterior part of the third ventricle, and the splenium of the corpus callosum. Normally, the cerebral vein of Galen joins with which dural venous sinus?
inferior sagittal sinus
During surgery at the root of the neck, an attending surgeon cautions her resident to locate important structures which need to be protected. One of these is the phrenic nerve, responsible for the innervation of the diaphragm and thus, respiration. The phrenic nerve can be positively identified by which of the following anatomical relationships?
It wraps around the right subclavian artery.
Below figure is a high magnification photomicrograph of the gall bladder. The arrow points to the internal lining that is formed by which of the following?
simple columnar epithelium
A patient has been admitted for hematemesis (vomiting of blood). Endoscopic examination reveals bleeding esophageal varices resulting from portal obstruction. These varices represent anastomoses between branches of which of the following?
left gastric, azygos, and hemiazygos veins
A 45-year-old female patient presents to the emergency room with a headache and complains of abnormal sensations on the left side of her body. She claims that the sensory changes came on rapidly in the last few hours. Her laboratory reports come back normal, a spinal tap reveals normal cerebrospinal fluid (CSF), and her mental ability seems good. You perform a neurological examination and find she has greatly reduced sensation on the entire left side of her body, including her face. The sensory loss includes all modalities. The motor examination is normal, as is her visual examination and hearing examination. Based on the neurological findings, which of the following thalamic nuclei would be involved?
ventral posterior lateral and ventral posterior medial nuclei
A 19-year-old man was in a barroom brawl and was punched squarely in the right eye. He comes to the emergency room the next day and complains of diplopia. An X-ray reveals fracture of the orbital floor. Neurological examination shows loss of sensation of the skin of the right face below the right eye and the upper gums. Which of the following nerves may be injured?
An overworked surgical resident is resecting an acinic cell carcinoma from the inferior aspect of the parotid gland when he makes a careless incision and nicks a branch of the facial (seventh cranial) nerve. Which of the following muscles may be affected by this injury?
A 35-year-old male patient suffering from pulmonary hypertension has been diagnosed with ostium secundum atrial septal defect. Abnormal development of which of the following structures is responsible for this developmental defect?