Q bank

synthesis of secretory, membrane bound, and lysosomal proteins. 

Protein modification, folding, transfer of those same proteins

Well developed in protein secreting cells (i.e. enzyme secreting pancreatic cells)

Synthesize proteins used in the cytosol and cellular organelles

Synthesis of steroid hormones and drug detoxification occurs in the SER

Function in lipid synthesis, carbohydrate metabolism

pulmonary hypoplasia, limb deformities, characteristic facies (suborbital creases, depressed nasal tip, low-set ears, and retrognathia) as a result of oligohydramnios

oligohydramnios - deficiency of amniotic fluid

occurs in fetuses with bilat renal agenesis --> lack of fetal urine causes oligohydramnios

Amniotic fluid is required for proper lung development

Causes of maternal hyperglycemia: gestational diabetes

Complications: increased still birth rates, macrosomia (big baby syndrome), post natal hypoglycemia in infant

Placenta implants over cervical os

common cause of vaginal bleeding during pregnancy

Can be due to deficiency of Vit B12 or folate

Folate deficiency during first trimester is associated with neural tube defects

unconscious belief that people are either wholly good or wholly bad

Hallmark of borderline personality disorder

failure of obliteration of the omphalomesenteric duct. 

Presentation: Lower GI bleeding, RLQ pain

contains ectopic gastric mucosa which produces acid, causing ulceration (possibly) and bleeding

Dx: 99mmTc-pertechnetate scan

failure of neural crest migration into the bowel wall

intestinal obstruction in the first few days of life

number of new cases of a disease per year / total population at risk

benign tumor composed of blood vessels, smooth muscle, and fat

Bilateral renal angiomyolipomas are associated with tuberosclerosis (autosomal dominant condition)

Associated with cortical tubers and subendymal hamartomas

Hamartomas - benign growth of a tissue; resembles a neoplasm, but is not. Same tissue, doesn't grow faster

Primary oocytes develop in female embryos by the fifth month of gestation.

At this point they are arrested in prophase of meiosis I

Menstrual cycle hormones stimulate the primary oocyte to resume meiosis

Secondary oocytes are arrested in metaphase of meiosis II and are released during ovulation

The secondary oocyte remains in metaphase of meiosis II until fertilization

72kD

irreversibly inhibits COX1 and COX2

COX2 is an inducible enzyme that is undetectable in most tissue except during inflammation

Actin filaments are anchored to the Z line of the sarcomere

Z line lies in the center regions of the I band

benzos are sometimes used during the SSRI initiation period if there is a significant increase in anxiety related sx

Triazolam is a benzo that is helpful in treating insomnia in patients who need to be aware during the day due to it's short half life

a microtubule associated ATP motor protein that does anterograde transport of NT containing vesicles down axons to synaptic terminals

pufferfish associated neurotoxin (from microogranisms associated with the fish)

binds voltage gate sodium channels in nerve and cardiac tissue preventing depolarization

MAC (C5b-C9)

results in recurrent Neisseria infections

• Neisseria is a common cause of bacterial meningitis
• Presentation:
• -fever
• -chills
• -altered mentation
• -petechial rash affecting palms and soles (vasculitis)

ie: DiGeorge syndrome (thymic hypoplasia)

pure T cell lymphopenia

Recurrent viral and fungal infections

• X linked
• NADPH oxidase deficiency
• deficient intracellular killing

Recurrent infections with catalase positive organisms (Staph)

-increased risk of disseminated infection in young adults infected with N. meningitidis

-IgA attaches to bacteria and blocks IgM and IgG which would induce C' mediated lysis

-failure of neural tube to close in 4th week of gestation

-most commonly in anterior or posterior neuropores

-folic acid supplementation in early pregnancy decreases risk

Meningocele and menigomyelocele present as cystic masses in lower spine region covered with skin, maybe a tuft of hair present

-Elevated acetylcholinesterase and alpha-fetoprotein on amniocentesis

-exact mechanism unknown

-activation of NMDA receptors by glutamate is believed to enhance morphine tolerance by phosphorylation of opioid Rs and increasing NO levels

-NMDA blockers like ketamine decrease morhpine tolerance

• -autosomal recessive disorder
• -defect in DNA repair genes

-DNA is hypersensitive to ionizing radiation

• Manifestation:
• -cerebellar ataxia
• -oculocutaneous telangiectasias
• -repeated sinopulm infections
• -increased incidence of malignancy

-calcified cystic tumors

-arise from remnants of Rathke's pouch (embryonic precursor to anterior pituitary)

• Presentation:
• -HA
• -growth failure
• -bitemporal hemianopia

measure of how far along an axon an electrical impulse can propagate

-low length constant reduces the distance an impulse can travel

-myelin increases the length constant

-DECREASED IN MS

-additive effects of multiple postsynaptic potentials on a target neuron's membrane potential

***can occur anywhere BUT the axon

Temporal summation: sequential impulses from the same neuron over time

Spatial summation: simultaneous impulses from several different neurons

-time it takes for a change in membrane potential to achieve 63% of the new follow

-lower time constants allow for quicker changes in membrane potential --> increased conduction speed

-myelination reduces the time constant

-INCREASED IN MS!!!

Bilirubin is synthesized (mostly) in the spleen by phagocytic cells metabolizing hemoglobin from old RBCs.

Splenic vein feeds the unconjugated bilirubin into the portal vein, where ~20% is taken up by hepatocytes per pass

Conjugated bilirubin in the blood is only found bc of small, normal reflux from hepatocytes.

• Nl ranges
• -Total bilirubin is <1.2mg/dL
• -direct (conjugated) is <0.2mg/dL
• -indirect (unconjugated) is the difference

-Most bile acid is recycled from the intestine (via sodium-coupled bile acid transporter in the ileum); only 10% is from new synthesis

• Junctional complex relies on homotypic interactions between E-cadherin proteins on adjacent cells
• -Forms the zona adherens, which are then activated to initiate formation of the zona occludens and desmosomes

Gap junctions are formed by Connexin; NOT part of a junctional complex

Desmoglein is a cadherin specific to demsosomes; lack of this protein would affect only desmosome formation

• Systemic lupus erythematous
• -pt must meet 4 of 11 criteria
• 1. malar rash
• 2. photosensitivity
• 3. anemia
• 4. hematologic disorders....
• x. arthritis

• Libman-Sacks endocarditis can affect pts with SLE
• -small, granular vegetations consisting of fibrin develop on either side of the leaflets of the mitral and aortic valves.
• -fragments may detach, resulting in embolism
• -healing leads to distortion of valve leaflets and resultant insufficiency or stenosis

Processus vaginalis is an evagination of the parietal peritoneum of the abdomen that descends through the inguinal canal

The distal end normally remains patent as the tunica vaginalis, the remainder fuses and becomes fibrous

Incomplete fusion leads to cystic structure (hydrocele) of the spermatic cord

ipsilateral ptosis, miosis, anhydrosis

• -characteristic of mitochondrial diseases
• -exclusively maternal inheritance

-variable severity

• -random distribution of normal and mutated mitochondria between daughter cells during mitosis
• --> some cells may have perfectly healthy mitochondria while others contain affected genes

1. Leber hereditary optic neuropathy (bilateral vision loss)

2. Myoclonic epilepsy with ragged-red fibers (myoclonic seizures and myopathy associated with exercise)

3. Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes MELAS (seizure disorder, stroke-like episodes, increased serum lactate levels post exercise and at rest)

-more resistant to outliers

-the most commonly observed data point

• -osteocytes have long intracanalicular processes that extend through the ossified bone matrix
• -these processes send signals and exchange nutrients/waste products with the osteocytes within the neighboring lamellae via gap junctions.
• -osteocytes can sense mechanical stresses and send signals to modulate the activity of surface osteoblasts --> regulate bony remodeling

-increases risk of neural tube defects

-inhibits folic acid absorption

-absence of GnRH secretory neurons in hypothalamus due to defect of migration from olfactory placode

• -central hypongonadism
• -anosmia

-often present with delayed puberty

-depend on disease prevalence in the population

-sensitivity and specificity do not depend on prevalence of disease in population

• Triad:
• -HTN
• -Proteinuria
• -edema

<10% of pregnancies

Onset after 20th week of gestation

Cause unknown, poor placental perfusion thought to contribute

Release of inflammatory factors from hypoxic placenta cause damage to the endothelium

• May progress to HELLP Syndrome:
• -Hemolytic anemia
• -Elevated Liver enzymes
• -Low Platelets

• -translocation 9;22 (Philadelphia chromosome)
• -leads to BCR-Abl fusion protein
• -constituitive tyrosine kinase activity
• -Imatinib tx (TKI)

• -some have chromosomal rearrangement that leads to fusion gene btwn EML4 (echinoderm microtubule associated protein like 4) and ALK
• -constituitively active tyrosine kinase (like CML)

• Exotoxin A:
• -ribosylates and inactivates EF2
• -inhibits host cell prot synth --> cell death

Acts similar to diptheria toxin

-respiratory infection that  can cause severe myocarditis and heart failure

-sx: severe pharyngitis with exudates, cervical lymphadenopathy

-diphtheria toxin = exotoxin that inhibits EF2 (no prot synth and cell death)

• -manifests in patients 40-50 years old
• -enlarged kidneys, HTN, renal failure

-In newborns: kidneys are normal sized and cysts are too small to be detected on U/S

-enzyme deficiencies in early steps of porphyrin synthesis --> Abd pain, neuropsych, W/O photosensitivity

-enzyme deficiencies in late steps --> photosensitivity

Investigator's decision is affected by prior knowledge of the exposure status

-Glucose transport into most tissues occurs by facilitated diffusion (carrier-mediated transport)

-glucose moves from areas of high concentration to low concentration with the help of carrier proteins (GLUT)

-carrier proteins have a preference for D-Glucose (stereoselective)

• GLUT4:
• -insulin sensitive transporter
• -SKM, adipocytes

• GLUT2:
• -export of glucose into circulation
• -iver
• -small intestine
• -kidneys
• -helps control insulin secretion in pancreas

Three cytogenetic abnormalities may cause Down Syndrome:

• 1. Trisomy 21 (95%)
• -almost always maternal origin

• 2. Unbalanced Robertsonian Translocations (2-3%)
• -46 chromosomes
• -chromosome 21 is attached to another chromosome

• 3. Mosaicism
• -patients have two cell lines: one with normal genotype, one with trisomy 21

• Pseudostratified Columnar mucus-secreting epithelium
• -nose
• -paranasal sinuses
• -nasopharynx
• -most of larynx
• -tracheobronchial tree

• Stratified Squamous Epithelium:
• -oropharynx
• -laryngopharynx
• -anterior epiglottis
• -upper half of posterior epiglottis
• -vocal folds (true vocal cords)

• 1. Pro a-collagen transcribed into RER
• 2. Hydroxylation of selected proline and lysine residues
• 3. Glycosylation of selected lysine residues
• 4. Assembly of pro a- chains into triple helix
• 5. Secretion of procollagen into Golgi
• 6. Extrusion into ECM
• 7. N- and C-terminal propeptide cleavage by propeptidase --> collagen fibril (water insoluble)
• 8. Covalent cross links formed btwn collagen fibrils by lysyl oxidase

-rare hereditary disorder

• Sx:
• -hypermobile joints
• -fragile, hyperelastic skin
• -easy bruising (decreased strength of vasculature)

• Mutations:
• -lysyl-hydroxylase (cross links fibrils for form mature fiber)
• -pro-collagen peptidase (cleaves N- and C-termini)

• Pathophys:
• -defective cleavage at N- and C- termini yields formation of a more soluble collagen that does not properly cross link with other collagen molecules

• -most commonly X-linked
• -low levels of circulating B cells
• -low levels of all Ig (including IgA)
• -IgA deficiency --> recurrent respiratory infections and persistent giardiasis
• -B cell markers: CD19, CD20, CD21

• -distal to duodenum occurs due to vascular accidents in utero
• -SMA obstruction: Apple peel atresia (blind-ending proximal jejunum with absence of a long lenth of small bowel and dorsal mesentery)
• -terminal ileum distal to atresia assumes spiral configuration around an ileocolic vessel

• 1. Postpartum Blues
• -2-3 days
• -resolves within 10 days
• -tearfulness, fatigue, depressed affect, irritability
• -tx: reassurance, watchful waiting

• 2. Postpartum Depression
• -lasts 2wks-12months
• -depressed affect, anxiety, worse at night, poor concentration, decreased libido
• -tx: antidepressants, psychotherapy

• 3. Postpartum Psychosis
• -variable
• -delusions, confusion, sleep disturbances, unusual behaviour, emotional lability
• -tx: antipsychotics, antidepressants