UWorld_3.2

Question 1

Type I collagen: locations, assoc. diseases

Answer 1

• locations
  
  • dermis
  • bone
  • tendons, ligaments
  • dentin
  • cornea
  • blood vessels
  • scar tissue
• assoc. disease
  
  • osteogenesesis imperfecta

Question 2

Type II collagen: locations

Answer 2

• cartilage
• vitreous humor
• nucleus pulposus = inner core of the vertebral disc

Question 3

Type III collagen: locations, assoc. diseases

Answer 3

• locations
  
  • skin
  • lungs
  • intestines
  • blood vessels
  • bone marrow
  • lymphatics
  • granulation tissue
• assoc. diseases
  
  • Ehlers-Danlos syndrome (types 3 & 4)

Question 4

Type IV collagen: locations, assoc. diseases

Answer 4

• location
  
  • basement membranes
• assoc. diseases
  
  • alport syndrome

Question 5

TATA box =

Answer 5

• promoter region of euk. genes that binds transcription factors and RNA polymerase II during initiation of trxn
• located approx. 25 bases upstream of beginning of coding region

Question 6

Purpose of analysis of variance

Answer 6

• t-test = compare the difference (i.e. is there a true difference?) between the means of 2 groups
• AOV = compares difference between the menas of 2+ groups

Question 7

• Purpose of Chi-square test
• Purpose of Multiple linear regression
• Purpose of Pearson correlation coefficient

Answer 7

• statistical analysis used to check for an association between 2 categorical variables
• MLR = model linear relationship between a dependent variable and 2+ independent variables
• PCC = measure the strength and direction of a linear relations between 2 variables

Question 8

Common finding in MG

Answer 8

• MG ==> m. weakness
  
  • extraocular muscles most commonly affected
  • ==> ptosis & diplopia
  • sx worse w/activity or @ end of the day
• majority found to have thymoma or thymic hyperplasia (“mediastinal mass”)

Question 9

Cholesterol, bile salts, and phosphatidylcholine impacts on gallstone formation

Answer 9

• high cholesterol ==> increased risk
• bile salts + phosphatidylcholine increase cholesterol solubilty
  
  • high bile/phosph ==> lower risk
  • low bile/phosph ==> higher risk

Question 10

V. cholera characteristics

Answer 10

• oxidase-positive, gram (-), comma-shaped; able to grow on high-alkaline media
• ==> diarrhea via enterotoxins or by invading/damaging intestinal epithelium
  
  • does not invade mucosa and cause enterocyte death
• cholera toxin (also @ ETEC) ==> activation of adenylate cyclase ==> increased cAMP production ==> increased chloride efflux and decreased sodium reabsorp ==> watery diarrhea
  
  • “rice water diarrhea” = flecks of mucous and epithelial cells
    
    • no leukocytes or erythrocytes

Question 11

Watery diarrhea: mechanism, stool findings, causes

Answer 11

• mechanism = non-inflammatory (enterotoxin)
• stool
  
  • no leukocytes
  • no red cells (blood)
• causes
  
  • V. cholera
  • ETEC
  • Bacillus cereus
  • S. aureus (pre-formed toxin in early food poisoning)
  • Giardia, other parasites
  • some viruses

Question 12

Dysentery diarrhea: mechanism, stool findings, causes

Answer 12

• mechanism = inflammatory (invasion or cytotoxin)
• stool
  
  • PMNs
  • +/- RBCs (blood)
• causes
  
  • shigella
  • salmonella
  • C. jejuni
  • EIEC
  • Yersinia enterocolitica
  • C. difficile
  • Entamoeba histolytica

Question 13

Enteric fever diarrhea: mechanism, stool findings, causes

Answer 13

• mechanism = penetration and possible dissemination
• stool
  
  • mononuclear leukocytes
• causes
  
  • salmonella typhi (thyphoid fever)

Question 14

~Normal cardiac pressures

Answer 14

• “nickel, quarter, dime dollar”

Question 15

Tx for severe asthmatics

Answer 15

• anti-IgE drugs to help reudce allergy triggers of asthma
• e.g. Omalizumab ==> patients w/mod-severe allergic asthma
  
  • IgG1 monoclonal antibody
  • binds to IgE to prevent action of IgE w/its receeptor on mast cells ,basophils and other cells