UWorld_3.1 Flashcards
Osteocytes connected to each other by:
gap jxns
Tight jxn characteristics/locations
- “zona occludens”
- @ apex of glandular cells
- tight jxns = two closely adherent cytoplasmic membranes w/out intervening space
- first component of a jxnl complex
Desmosomes characteristics/locations
- desmosomes = small, circular, adherent patches
- circumferentially placed around cells
- comprise the thirds component of jxnl complex
- common @ stratified squamous epithelium
- contribute to structural cohesion of tissue subject to mechanical stressors
Hemidesmosomes characteristics/locations
- = half desomosomes; extend from basal surfaces of keratinocytes @ stratified squamous epithelium to attach to basal lamina
Intermediate jxns characteristics/locations
- “zona adherens”
- =delicate network of cytoplasmic filaments that radiate from the cell membrane to hold together adjacent cells
- second component of jxnl component
Fxn of 99mmTc-pertechnetate scan
detects presence of gastric mucosa
Characteristics/presentation of Meckel diverticulum
- failed obliteration of omphalomesenteric duct
- e.g. accumulation of 99mmTc-pertechnetate @ right lower abdominal ==> indicates gastric mucosa
- ==> lower GI bleeding
- ==> right lower quadrant pain
- ==> intussusception ==> colicky abdominal pain + “currant jelly” stools
Failure of ventral dorsal pancreatic bud fusion ==>
- formation of pancreas divisum
- usually asymptomatic
Failure of hindgut descent along the inferior mesenteric artery ==>
- hindgut ==> distal third of transverse colon, descending, and sigmoid colon, rectum, upper part of anal canal
- failure of descent ==> various degrees of anal agenesis or imperforate anus
Failure of midgut rotation around the superior mesenteric artery ==>
- ==> intestinal malrotation
- intestine is fixed by fibrous adhesive bands ==> intestinal obstruction
Importance concept in studies looking at risk modigiers
- latent period
- exposure to risk modifiers may occur a significant amount of time before the exposure’s effect on the disease process
- may have to be continued for years
- think about latency when looking at relative risk reductions between groups experiencing a risk modifier for different periods of time
Trisomy 18 presentation
- 2nd most common autosmal trisomy
- face: eye defects, low-set ears, prominent occiput
- CNS: microcephaly, NTDs, Chiari malformation, developmental disability
- MSK: clecked hands + overlapping fingers, rocker-bottom feet, hypotonia
- Cardiac: VSD, PDA
- GI: Meckel’s, malrotation
Deficiency of membrane attack complex ==>
- recurrent infections by Neisseria species
- N. meningitidis
- high-fever, chills
- AMS
- petechial skin rash <== N.-induced small-vessel vasculitis
- esp. @ palms, soles
Factors that form the membrane attack complex + fxn
- C5b - C9
- forms pores @ bacterial cell membrane ==> electrolyte disturbances, inflow of free water, cell lysis
Tx for N. meningitis
- IV ceftriaxone for 2 weeks
Characteristics of Blastomycosis dermatitidis
- dimorphic fungus
- mold form, found in soil, organic matter, and many animals
- ==> pulmonary infections (often chronic) in immunocompetent hosts
- respiratory transmission
- transforms to yeast @ lungs
- granuloma formation
- Dx = sputum stain with KOH ==> round yeast w/thick, doubly refractive walls + single, broad-based buds
- endemic areas
- Great Lakes, Mississippi & Ohio River Basin
Tx of Blastomycosis dermatitidis
itraconazole
Psych:
Reaction formation
Projection
Repression
Identification
Suppression
Displacement
- Rxn form = person does opposite (excessively) of what he/she desires; used to cover up feelings they believe to be unacceptable to society
- Projection = transplant unacceptable impulses to another person/situation
- Repression = unconscious removal of disturbing psych material from conscious awareness
- ID = modeling one’s behavior after someone perceived to be more powerful (e.g. abused child ==> abusing as a parent)
- Suppression = voluntary withholding of unpleasant htoughts or feelings from one’s mind
- Displacement = transfer of impulse or desire toward a safer and less distressful object
Somatostatin from pancreas ==>
suppresion of secretin, cholecystokinin, glucagon, insulin, and gastrin
Somatostatinomas ==>
- somatostatinoma = rare pancreatic cell tumors that arise from “delta cells”
- ==> hyper or hypoglycemia
- ==> steatorrhea
- ==> suppressed cholecystokinin ==> gallbladder stones
Characteristics of acute compartment syndrome
- increased pressure w/in fascial compartment ==> compromised blood circulation and tissue fxn
- develops after significant trauma
- e.g. long-bone fractures of leg or forearm
Characteristics of Dupuytren’s Contracture
- benign, slowly progressive fibroproliferative disease of the palmar fascia
- scarring ==> nodules on palmar fascia ==> loss of finger flexibility ==> contractures that bring the fingers into flexion
