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Usmle > Block 14 > Flashcards

Block 14 Flashcards

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USMLE® Step 1 flashcards
1
Q

Nucleus vs nucleolus

A

-Nucleus contains euchromatin(electron lucent), and heterochromatin (electron dense- typically around periphery of nucleus).
- nucleolus: dense structure, in direct contact with the rest of nucleoplasm, with no interveening membrane.
contain ribosomal proteins that are translated in the cytoplasm from mRNA. Its primary function is synthesis and assembly of immature 60S and 40S ribosomal subunits that are exported from the nucleus to fully mature in the cytoplasm.

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2
Q

Annular pancreas is a result of which embryological defect

A

Abnormal migration of the ventral pancreatic bud.

The dorsal and ventral are fused, but the ventral bud is constricting the dudenum

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3
Q

Pancreatic ventral and dorsal bed gives rise to

A 
Ventral= uncinate process and main pancreatic duct
Dorsal= tail, body, and the remainder of head.
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4
Q

Pancreas divisum

A

Usually assymptomatic , its a failure of ventral and dorsal parts of pancreas to fuese
Increase risk of acute and chronic pancreatitis.

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5
Q

Rotator cuff muscles

A

SITS

  1. Supraspinatus:–> abduction (30˙)
  2. Infraspinatus–> external rotation
  3. Teres minor –> adduction and external rotation
  4. Subscapularis –> Adduction and internal rotation
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6
Q

Cornybacterium diphteriae aquires virulance

A

A bactriophage mediated infection with Tox gene, which codes for AB diphteria exotoxin . The bacteriophage responsible is called cornyphage beta.

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7
Q

NNRTI’s
Mechanism
Example

A

-prevent synthesis if viral DNA form RNA template (nonnucleoside reverse transcriptase inhibitor) dont require activation via intacellular phophorylation .
The most common are Nevirapine and efavirenz.

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8
Q

Adverse effect of NNRTI

A

1, rash, SJS
2. Hepatotoxicity
3. Neurophycatric effect
E.g (efavirenz and nevirapine)

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9
Q

Pioglitazone

A 
Anti diabetic (thiazolidinediones) 
- it acts on intracellular nuclear receptos, activates the transcription of regulator PPAR-¥ --> increase FA uptake, increased adiponectin production, increase insulin sensetivity (mainely due to increase adiponectin ) and decreased leptin and TNF-å production
AE: fluid retention and weight gain
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10
Q

GABA-A receptor

A

Inotropic receptor ( part of an ion channel) the regulates the flow of negatively charged cholride ion across the neuronal cell membrane.

  • drug that activates GABA-A will increase the conductance of Cl- ions, causing passive transport down the concentration gradient into the cell interior.
  • this cause membrane to become hyper-polarized –> -75 mV (refractory action potential)
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11
Q

Bitemporal hemianopsia and hypogonadism : –> usually indicates

A

Along with increased prolactin, prolactinoma (low GnRh -> low LH–> low testosterone/estrogen

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12
Q

HPV associated with which type of malignancy

A
  1. Cervix
  2. Vulva
  3. Penis
  4. Anus
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13
Q

HIV and HPV correlation

A
  • AIDS increase host susceptibiliy to HPV infection and more severe infections
  • HIV positive men who have sex with men are at increased risk of developing anal squamous cell carcinoma, and HIV positive women are more prone to developing cervical SCC.
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14
Q 
Changes in the oxygen content ,PaO2, PaCO2
CO poisoning 
Cyanide
Anemia
Polycythemia
High altitude
A
  • the total oxygen in the body is determined primarily by the amount of hemoglobin in the blood and its percentage of O2 saturation.
    1. CO poisoning= PaO2 normal, SaO2 decreased, and decreased O2 content
    2. Cyanide = all normal
    3. Anemia=normal PaO2 and SaO2 and decreased O2 content
    4. Polycythemia= normal PaO2 and SaO2 with increased O2 content
    5. High altitude= all are decreased .
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15
Q

Acute hepatitis A infection
Clinical
Biopsy findings

A

Clinical: prodrome of fever,malaise,anorexia,nausea/vomiting, and right upper quadrant abdominal pain. After several days, signs of cholestasis such as jaundice, pruritus, dark-colored urine and alcoholic stools.
- biopsy shows: spooty necrosis with balloning degeneration, councilman bodies and mononuclear cell infiltrates.

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16
Q

Polyuria and polydipsia (water deprivation test, and sodium levels ) DD

A
  1. Normal = sodium normal, urine osmolarity after water deprivation test is increased and urine osmolailty with vasopressin shows no additional increase.
  2. Central DI= high sodium, no change after water restriction, and large increase after vasopressin injection
  3. Nephrogenic DI = same as central with mild increase only after vasopressin
  4. Primary polydipsia = low sodium, increase osmolarity after water deprivation and no additional increase after vasopressin.
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17
Q

Primary polydypsia

A

Psychological disorder characterized by pathological water drinking and is most common in middle aged women and patient with underlying psychiatric disease.
Treated with “water restriction”

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18
Q

Turner syndrome features
Organs
Skin
Genital tract

A
  1. Coarctation of aorta
  2. Bicuspid aortic valve
  3. Streak ovaries, amenorrhea
    4, horseshoe kidney
    5, cubitus valgus
  4. Broad chest with widely spaced nipples
  5. Webbed neck
  6. Short stature
  7. Cystic hygroma
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19
Q

Polyglonal cells with abundant clear cytoplasm (tumor)

A

RCC - can metastasize to the lung
Most common type of clear cell carcinoma
Classic triad is hematuria ,flank pain ,adn palpable abdominal mass.

20
Q

Dyenin arms defeciency results in

A

Kartegner syndrome

21
Q

Kartegner symptoms signs and symptoms

A

AR, disorder.
It results from failure of dynein arms to develop normally.1
- dextocardia( auscultation shows the maximal point of auscultation to be in the right intercostal space (not left) )
-recurrent respiratory infection along with recurrent sinusitis and otitis media.
-infertility in men , ectopic pregnancy in women

22
Q

Immunuglobulin gene rearrangment is impaired in

A

hyper IgM syndrome.

23
Q

(Unilateral)Vesicular rash =

A

VZV,

After a while patient may develop postherpetic neuralgia

24
Q

Lac opero, in E.coli lactose fermentation

A

Consists of regulatory gene, promoter region, and operator region, and 3 structual genes (z,y,a).
The Z gene codes for ß-galactosidase which is primarily responsible for hydrolysis of lactose to glucose and galactose, the y gene codes for permease, –> increase permabilty to cell to lactose.

25
Q

Lac operon )mRNa

A

In prokaryotes, one mRNA transcript contains the sequence for many proteins and a single mRNa molecule can be translated into multiple proteins or polypeptides. For instance, all 3 proteins of the lac operon used for lactose fermentation are synthesized from a single mRNA.

26
Q

S.saprophyticus is a

A

Common cause of UTI, novobiocin resistnat, catalse positive coagulase negative staphylococci.

27
Q

RAS gene codes for

Mutation leads to

A

Family of small G-protein involved in signal transuction in RAS-MAPK pathway.
RAS become activated with Growth factor ligand binds to receptor tyrosine kinase located on the cell membrane, causing autophophorylation of the receptor.
This trigger binding of adaptor proteins that interacts with Ras promoting GDP removal and GTP binding.
-RAS gene mutation leads to decreased intrinsic GTPase activity, this result in constitutively activated RAS protein that causes constant and unregulated cell proliferation. This leads to cancerous tumors specifically colorectal and pancreatic.

28
Q

Tetanus vaccine, and its effect

A

Circulating antibodies that neutralizes bacterial products. The vaccine elicits humoral immunity specific for tetanus toxin. Tetanus immune globulin can be administered during the acute treatment of tetanus and for tetanus prophylaxis after an injury if the wound is grossly contaminated

29
Q

Signs of tetanus intoxication

A
  1. Masseter muscle spasm - lockjaw
  2. Opisothotonos
  3. Dysphagia
  4. Facial muscle spasm (risus sardonicus)
30
Q

Platelet defects vs coagulopathies

A
  • platelet defects typically manifest with mucocutaneous bleeding, epistaxis, petechiae
  • coaguolopathies present with deep tissue bleeding into joints, muscles and subcutaneous tissues.
31
Q

Wobble hypothesis

A

Multiple different codons coding for same amino acid

32
Q

Etoposide acts on

A

Topoisomerase II

33
Q

Adenosine adverse effect

A
  • its used for treating paroxysmal SVT, and adenosine is the drug of choice for the treatment of this arrhythmia.
  • it can frequently be dependent on a reentrant circuit.
  • adenosine very rapid acting drug with half life of less than 10 seconds
  • act by slowing conduction through AV node hyperpolarizating the nodal pacemaker
  • side effect most common are flushin, chest burning)(bronchospasm), hypotension and high grade AV block
34
Q

Unilateral nasal hemianopia can be caused by

A
  • lesion involving the lateral aspect of the optic chiasm.

- this may occur with aneurysm of internal carotid artery.

35
Q

Partial Lesion involving the retina

A

Focal monocular scotoma

36
Q

Wear and tear lesion

A
  • an insoluble pigment composed of lipid polymers and protein complexed phopholipids, lipofuscin is considered a sign of wear and tear or aging.
  • yellow brown, finnely granular perinuclear pigment is product of the free radical injury and lipid peroxidation.
  • its commonly seen in heart and liver of aging or malnourished ppl
37
Q

Lithium can lead to

A

Nephrogenic diabetes insipidus

Anti ADH in collecting tubules and ducts

38
Q

Lyme disease is treated is using

A

Doxycycline for initial treatment

Ceftriaxone if the patients develops bells palsy can prevent late lyme disease progression.

39
Q

Mallory weiss syndrome

A
  • longitudinal mucosal tears of espohaggastric squamocoulmnar junction
  • due to increased intrabdominal and intraluminal gastric pressure as when happens during retching and vomiting.
40
Q

Acoustic neuroma is located usually at

A

Cerebellopontine angle , most cases are unilateral but bilateral in NF-2

41
Q

Heeslbachs triangle
Floor
Medial lateral inferior

A

Floor : transvalis fascia
Lateral: Inf epigastric vessels
Medial: rectus abdomins
Inferior: inguinal ligament

42
Q

Direct inguinal hernia are covered by

A

External spermatic fascia only unlike indirect which is covered by all 3 spermatic fascial layers.

43
Q

HCM
Clinical
Histology
Features

A

AD, mutation in one of several sarcomeres genes and is charactrized by massive myocardial hypertrophy
Histological features include:
1. Massive myocyte hypertrophy predominantly in septal region
2. Myofiber dissarray
Clinical: assymptomatic mostly, occasional exertion related chest discomfort, and dyspnea, sudden cardiac death

44
Q

CF pancreas, squamous epithelium with keratinization in pancreatic duct is due to

A

Avitamnosis A
Due to pancreatic insuffeciency –> fat soluble vitamins deficiency –> avitaminosis A –> squamous metaplasia –> injured and predisposed to squamous metaplasia by inspissated mucus.

45
Q

Lymphocytes with cytoplasmic projection are seen in

A
  • hairy cell leukemia, B-cell neoplasm that infiltrates the bone marrow and reiculoendothelial system. Bone marrow infiltration and cytokines production cause fibrosis and bone marrow failure resulting in pancytopenia.
  • bone marrow aspirate is usually unsuccefull “dry tap”
  • massive splenomegaly

Usmle (45 decks)

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