3/29 - UW 32 Flashcards
What sensory receptors detect muscle tension? Where?
Golgi tendon organs (GTO) at the junction of muscle and tendon
What sort of change is detected by Golgi tendon organs? What nerves innervate them?
Increases in tension, transmitted by group 1b sensory axons
What purpose does the Golgi tendon organ serve?
Negative feedback to the alpha motor neurons, turning off muscles when tension is too high, preventing damage
What are the fast and slow mechanoreceptors that mediate touch, proprioception, and vibration? What type of fibers innervate them?
Fast: Pacinian corpuscles
Slow: Ruffini’s end organs
Innervated by myelinated A-beta fibers
What is the condition that has decreased ability to repair DNA following UV damage? Its inheritance?
Xeroderma Pigmentosum (“dry, pigmented skin”), AR
How does retinoblastoma (Rb) gene suppress tumors?
Arrests cell cycle in G1, defect leads to retinoblastoma and osteosarcoma
How does ras protein suppress tumors?
G-protein that regulates signal transduction, cell division, apoptosis, cell adhesion
What type of DNA repair is impaired in Hereditary Nonpolyposis Colorectal Cancer (HNPCC or Lynch syndrome)?
DNA mismatch repair
CD14 is a surface marker for what cells?
Monocyte-macrophage lineage
What are the two factors that enhance diuresis by loop diuretics?
- Blocks Na-K-2Cl symporters, preventing reabsorption of Na, Cl, and water in the loop
- Stimulates renal prostaglandin release, which are vasodilatory, increasing RBF and GFR
What are the foregut structures? What vessel supplies them?
From esophagus to UPPER duodenum, including liver, gallbladder, and pancreas. Supplied by Celiac Trunk.
What are the embryologic midgut structures? What vessel supplies them?
From the LOWER duodenum to the PROXIMAL 2/3 of the transverse colon. Supplied by the SMA.
What are the hindgut structures? What vessel supplies them?
DISTAL 1/3 of transverse colon to the sigmoid colon. Supplied by the IMA
During which weeks of fetal development are the midgut structures outside the abdomen?
6th - 10th weeks
What is the toxin found in poisonous mushrooms? MOA?
Amatoxins are concentrated in hepatocytes, where they bind RNA polymerase II (mRNA synthesis)
What lung pathology is seen in Goodpasture syndrome?
Focal necrosis of alveolar walls and intra-alveolar hemorrhages, with hemoptysis
Does Churg-Strauss cause restrictive or obstructive pulmonary pathology?
Obstructive: severe asthma with bronchial wall thickening and eosinophilic infiltrates
What is the only RNA that contains thymidine? What is on its 3’ end?
tRNA, with CCA on the 3’ end
What are two causes of diastolic heart failure?
Impaired myocardial relaxation (eg from ischemia)
Increased intrinsic ventricular wall stiffness (eg from amyloid deposition)
Which branchial arch regresses completely?
5th
What are the structures derived from the 1st branchial arch?
(Associated with CN V)
Neural crest (bones): maxilla, zygoma, mandible, vomer, palatine, incus, malleus
Mesoderm (muscles): muscles of mastication, anterior digastric, mylohyoid, tensor tympani, tensor veli palatini
Muscular elements derived from any branchial arch are from what layer? Bony elements are from what cells?
Muscle: mesoderm
Bones: neural crest cells that migrate in
What are the structures derived from the 2nd branchial arch?
(Associated with CN VII)
Neural crest (bone): styloid, lesser horn of hyoid, stapes
Mesoderm (muscles): muscles of facial expression, stylohyoid, stapedius, posterior digastric
Which branchial arches form the cartilaginous structures of the larynx?
4th and 6th (5th arch regresses completely)
Why might the aortomesenteric angle (between the SMA and aorta) decrease?
Anything that decreases mesenteric fat, pronounced lordosis, or after surgical correction of scoliosis. This may occlude the transverse duodenum
What are the levels of serum Ca and PTH in primary ostoporosis?
Both normal!
What is the pathophys of Henoch-Schonlein purpura?
Ag exposure causes IgA immune complexes to deposit on vessel walls, causing inflammation, which manifests cutaneously as a leukocytoclastic vasculitis with palpable purpura (seen in ages 3-10)
What syndrome is suggested by colon cancer at young age (<50) and FH of colon and other cancers? Inheritance?
Hereditary non-polyposis colon cancer (HNPCC) or Lynch syndrome, AD.
What is the mutation that leads to cancer in HNPCC (Lynch syndrome)?
Mutation in genes responsible for DNA mismatch repair
What is the most common enteric parasite in the US? Route?
Giardia lamblia, by contaminated water
How to treat Giardiasis?
Metronidazole
What causes bacterial vaginosis? What causes chronic diarrhea from contaminated water? Tx for both?
Vaginosis: Gardnerella
Water: Giardia
Tx: Metronidazole
Treatment for roundworms? MOA?
Mebendazole, acts on microtubules
Treatment for tapeworms (Echinococcus)?
Albendazole
What do you give Albendazole for?
Echinococcus (tapeworm), which causes hyatid cysts, which can cause anaphylactic shock
What do you give Mebendazole for?
Round worm infx (Ancylostoma, Ascaris, Enterobius)
What nitrate has the greatest PO bioavailability?
Isosorbide MONOnitrate (mono in your mouth bitch!)
How is amyl nitrate administered?
Inhalation
How is sodium nitroprusside administered? Use? Major toxicity?
IV (for hypertensive emergency, can cause cyanide toxicity)
Dopamine is tricky! What receptors does it act on with different doses?
Low dose: D1 agonist in kidneys (and mesentery), increasing RBF, GFR, and Na excretion
Medium dose: add B1 agonist in the heart, increasing inotropy, pulse pressure, sBP (no change in dBP)
High dose: add a1 agonist in systemic vasculature, increasing vasoconstriction and afterload, decreasing CO
What receptor does clozapine act on? What ADR is most concerning?
D4 (as opposed to D2 of traditional antipsychotics), so no DAergic side effects like pseudoparkinsonism, tardive dyskinesia, hyperprolactinemia.
Causes granulocytopenia, need to monitor CBC. Also seizures…!
What disease commonly presents in women aged 20-40 with dypnea and exercise intolerance and a positive FH?
Familial Pulmonary Arterial Hypertension (PAH)
What is the definitive tx for Pulmonary Arterial Hypertension?
Lung transplant
What is an effective symptomatic tx for Pulmonary Arterial Hypertension?
Vasodilators, particularly Bosentan (endothelin-receptor antagonist)
What type of thyroid neoplasm is seen in MEN 2A and 2B?
Medullary thyroid cancer
What type of cells produce Medullary thyroid cancer? How do they appear histologically?
Parafollicular C (calcitonin) cells, appear uniform polygonal or spindle shaped cells with extracellular amyloid deposits that stain with Congo red
In what type of thyroid cancer can you see follicular hyperplasia with tall cells forming intrafollicular projections?
Papillary thyroid cancer
What are 2 causes of drug-induced body fat redistribution (Cushing syndrome or lipodystrophy)?
HAART (protease inhibitor) or glucocorticoids
What are the unidirectional enzymes in glycolysis? (Cannot be reversed for gluconeogenesis)
- Hexokinase (glucokinase)
- Phosphofructokinase 1 (PFK-1)
- Pyruvate kinase
High levels of Fructose-2,6-bisphosphate drives which reaction, glycolysis or gluconeogensis?
Glycolysis
Conversion of F6P to F2,6P is driven by what enzyme? (Thereby promoting the PFK-1 mediated conversion of F6P to F1,6P)
PFK-2, driven by insulin!
What are the lab findings of DIC?
- Prolonged PT, PTT, and bleeding time.
- Low platelets fibrinogen, factor V, and VIII
- Elevated D dimer (fibrin split product)
Vegetations in bacterial endocarditis are composed of what cells?
Fibrin and platelet deposition at a site of bacterial colonization
Where do hepatic adenomas typically arise? What drugs are they associated with?
Solitary mass in the right lobe, associated with oral contraceptives and anabolic steroids.
Hepatic angiosarcomas are associated with what exposure?
Vinyl chloride, arsenic, or Thorotrast
Very aggressive!
In addition to focal headache and craniofacial pain/claudication, what other sx can present with temporal arteritis?
Polymyalgia rheumatica (axial joint pain and morning stiffness)
Sudden vision loss…give prednisone stat!
What is Ewing sarcoma?
Undifferentiated neoplasm of neuroectodermal cells, commonly in the long and flat bones of children and adolescents
Where are neuroblastomas most commonly found?
Adrenals
Oxalate crystals and acute onset renal failure are signs of what?
Ethylene glycol poisoning
Phenelzine MOA?
MAOI, irreversibly binds MAO A and B
Sertraline MOA?
SSRI
Why is coadministration of Phenelzine and Sertraline contraindicated?
Coadministration of an MAOI and SSRI can cause Serotonin Syndrome
