USMLE Step 1: Biochemistry & other
Biochemistry
Biochemistry
Set of flashcards Details
| Flashcards | 288 |
|---|---|
| Language | English |
| Category | Medical |
| Level | University |
| Created / Updated | 02.03.2015 / 27.03.2020 |
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Which sensory pathway doesn't have a relay nuclei in the thalamus?
Olfaction
Lesion of the ventromedial hypothalamic nuclei –> findings?
secondary obesity due to hyperphagia, aggressive, savage behaviour
Superior mesenteric artery syndrome
- transverse portion of the duodenum is entrapped between SMA & aorta
- occurs when the aortomesenteric angle critically decreases secondary to:
- diminished mesenteric fat
- pronounced lordosis
- surgical correction of scoliosis
Aphasia syndromes
- Broca's
- Wernicke's
- Conduction
- Broca's
- Wernicke's
- Conduction
Portacaval anastomoses (3)
- Esophageal varices
- Hemorrhoids
- Caput medusae
Superior orbital fissure
(Live Frankly To See Absolutely No Insult)
- L: Lacrimal of N. ophthalmicus (V1 of N. trigeminus)
- F: Frontal of N. ophthalmicus (V1 of N. trigeminus)
- T: Trochlear
- S: Superior division of the oculomotor
- A: Abducens
- N: Nasociliary of N. ophthalmicus (V1 of N. trigeminus)
- I: Inferior division of the oculomotor
Imperforate hymen
- congenital disorder
- hymen has no opening
- obstructs vagina
- most often diagnosed in adolescent girls when menstrual blood accumulates in the vagina and sometimes also in the uterus
SVCS vs. brachiocephalic vein obstruction
- SVCS: bilateral
- Shortness of breath
- face swelling
- arm swelling
- Venous distention in the neck and distended veins in the upper chest and arms
- Obstruction of the brachiocephalic vein
- drains the ipsilateral jugular and subclavian veins
- similar symptoms but only ipsilateral
Shoulder injury with flattening of the deltoid muscle
suggests anterior shoulder dislocation
Clasp-knife spasticity
Upper motor neuron lesion
Trochlear nerve palsy affects vision how?
vertical diplopia
Sensory & gustatory innervation of the tongue
- Anterior 2/3
- sensory: mandibular (V3) branch of the N. trigeminus
- gustatory: chorda tympani branche of the N. facialis
- Posterior portion
- sensory & gustatory: N. glossopharyngeus
Syringomyelia
- formation of a cyst or cavity within the spinal cord (=syrinx)
- symptoms:
- severe chronic pain, abnormal sensations and loss of sensation particulary in the hands
- paralysis or paresis temporarly or permanently
- disruption of sympathicus and parasympathicus
- if syrinx is higher up in the spinal cord: vocal cord paralysis, ipsilateral tongue wasting, trigeminal nerve sensory loss
- classically: syringomyelia spares the dorsal column/medial lemniscus of the spinal cord, leaving pressure, vibration, touch and proprioception intact in the upper extremities
Brachial plexus
C5-T1
Gallstone ileus = Bouveret's syndrome
- impaction of a gallstone within the lumen of the small intestine
- diagnosis requires Rx, classic findings: Rigler's Triad
- pneumobilia
- small bowel obstruction
- radiolucent gallstone
Aortic arch vascular derivates
- First
- Second
- Third
- Fourth
- Sixth
Adult derivates
Skull foramina
Anterior cranial fossa
Middle cranial fossa
Posterior cranial fossa
Horseshoe kidney: which artery traps the kidney?
A. mesenterica inferior
Transient central DI vs. permanent central DI
- isolated damage to posterior pituitary –> transient central DI
- damage to the hypothalamic nuclei –> permanent central DI
Pringle maneuver
- surgical maneuver used in abdominal operations
- clamping of the hepatoduodenal ligament –> interruption of the bloodflow through hepatic artery and portal vein
- should bleeding continue, then it's likely that the IVC or the hepatic vein are also traumatized
Germinal matrix hemorrhage
- bleeding into the subependymal germinal matrix with or without subsequent rupture into the lateral ventricle
- the microcirculation in this particular area is extremely sensitive to hypoxia and changes in perfusion pressure
- It is most frequent before 35 weeks gestation and is typically seen in very low birth-weight premature infants
- they lack the ability for auto regulation of cerebral blood flow
- clinical findings:
- cerebral palsy
- mental retardation
- seizures
Structural & regulatory genes of the HIV genome (5)
- gag –> produces p24 & p7
- env -> gp120 & gp41
- pol
- tat & rev –> viral replication
Traumatic aorta rupture
- cause
- most common site
- rapid deceleration in motor vehicle collisions
- aortic isthmus
injury of the posterior urethra associated with ....?
pelvic fractures
Injury to the anterior urethra is most commonly damaged in what kind of injuries?
Straddle injuries
VHL gene deletion associated with what kind of carcinoma?
sporadic & hereditary renal cell carcinoma
N-myc
- = transcription factor
- capable of binding DNA
Tetralogy of fallot: why do patients squat?
increases systemic vascular resistance & decreases R-L_shunting –> increases pulmonary blood flow
4 major causes of hypoxemia
- alveolar hypoventilation
- ventilation-perfusion-mismatch
- diffusion impairment
- R-L-shunting
Most potent cerebral vasodilator
pCO2
decreases cerebral vascular resistance –> increases cerebral perfusion & intracranial pressure
Alcoholics –> hyperesterinism
Clinical findings? (4)
- gynecomastia
- testicular atrophy
- decreased body hair
- spider angiomata
1. What kind of substance is added in blood transfusions and 2. what happens if a patient gets more than one transfusion in 24h?
- Citrate
- citrate chelates calcium & magnesium and may decrease their plasma levels causing parasthesias
What can slow down hemochromatosis in women?
physiologic iron loss through menstruation & pregnancy
Carbonic anhydrase
Carbonic anhydrase
Neurophysin
carrier protein for oxytocin & ADH
Patients with decreased ventricular compliance
abnormal S4
Glucagon stimulates ...? (4)
- glycogenolysis
- gluconeogenesis
- lipolysis
- ketone body production
Insulin:
- stimulates ... (3)
- inhibits...(2)
- increases glucose, aa & potassium uptake by cells
- inhibits ketoacid formation & lipolysis
Allergic asthma: which substances have pharmacologic receptor antagonists that offer clear therapeutic benefit?
- Leukotrienes (LTC4, LTD4, LTE4)
- Acetylcholine
Neurologic degeneration in Wilson's disease?
cystic degeneration of the putamen
