Block 3 Flashcards
How can the lunate bone be identified on a hand X-ray?
It’s the more medial of the 2 carpal bones that articulate with the radius. it lies immediately medial to the scaphoid bone
What is the most common cause of hair loss, demonstrating polygenic inheritance with variable penetrance?
Androgenetic alopecia (male patterned baldness)
What is RF?
Rheumatoid factor is an IgM antibody specific for the Fc component of self IgG. It binds IgG and forms immune complexes that circulate in the serum.
Immune complexes activate complement in those locations –> chronic inflammation
Describe the role of CD4+ cells in rheumatoid arthritis.
CD4+ T-helper cells become activated by the cartilage proteins and release cytokines that mediate chronic inflammation.
CD4+ cells also induce B-cells to become rheumatoid factor-synthesizing plasma cells.
What line does actin bind to? What line is myosin anchored to?
Actin (thin myofilament) binds to Z line. Z-line lies in the center of the lucent region (I band).
Myosin is anchored to M line which is centered on the dark H-band.
“An Interesting Zoo Must Have Mammals”
what kind of receptors does myasthenia gravis involve?
nicotinic receptors
muscarinic overstimulation from myasthenia gravis treatment can be ameliorated by use of what?
an antimuscarinic agent like scopolamine
a form of multinucleated giant cell that plays a role in granulomatous inflammation
Langhans cell
dendritic cells found in the skin that act as professional antigen presenting cells.
these cells are derived from the myeloid cell line and they possess characteristic racquet-shaped intracytoplasmic granules known as Birbeck granules
Langerhans cells
what are Birbeck granules?
characteristic racquet-shaped intracytoplasmic granules in Langerhans cell
an epidermal accumulation of edematous fluid in the intracellular spaces seen with acute eczematous dermatitis (contact dermatitis).
CD4+ T cell response
spongiosis
what receptor acts to initiate the extrinsic pathway of apoptosis?
Fas receptor
mutations in Fas increase risk of autoimmune disorders like SLE
what is the origin and insertion of the sternocleidomastoid?
origin: medial clavicle and manubrium
insertion: mastoid process of the skull
what does the common peroneal nerve do?
dorsiflexion, eversion, sensation over the dorsum of the foot
how is nafcillin resistance mediated?
by alterations in PBPs
what is the embryologic derivative of melanocytes?
neural crest cells
what causes the hypercalcemia associated with squamous cell lung cancer and several other tumors?
the overproduction of parathyroid hormone-related peptide (humoral hypercalcemia of malignancy”
what do enzyme deficiencies of the early steps in porphyrin synthesis (prophobilogen deaminase, ALA dehydratase) cause?
neuropsychiatric manifestations without photosensitivity
what do late step enzyme derangements in the synthesis of porphyrin (uroporphyrinogen decarboxylase) cause?
porphyria cutanea tarda
photosensitivity
“housemaid’s knee,” common in roofers, plumbers, and carpet layers
knee pain, erythema, swelling, inability to kneel on affected side
prepatellar bursitis
what enzyme is responsible for the production of the activated ribose necessary for de novo synthesis of purine and pyrimidine nucleotides
increased activity will lead to more purines, increasing the RISK OF GOUT
PRPP synthetase
what bacteria causes a late-onset food poisoning characterized by a transient watery diarrhea and gastroenteritis caused by toxin formed when large quantities of spores are injested?
C. perfringens
When is glycogen phosphorylase active and what does it do?
Glycogen phosphorylase is active when phosphorylated by glycogen phosphrylase kinase.
It breaks down glycogen
How is glycogen phosphorylase inactivated?
Protein phosphatase dephosphorylates glycogen phosphorylase, making it inactive
how is phosphorylase kinase activated?
it’s phosphorylated by PKA in response to increased cAMP through binding of epinephrine (in muscle) and glucagon (in liver) to Gs-protein coupled receptors
increased Calcium in cytosol activates phosphorylase kinase which activates glycogen phosphorylase
Foreign bodies, like retained sutures, can elicit what kind of immunological response?
granulomatous response
what does etanercept do?
reduces the biological activity of TNF-a by acting as a decoy receptor.
what is the suffix for kinase inhibitors?
kinase inhibitors = -nib
plasma protein that binds free Hb to prevent its renal excretion
haptoglobin
haptoglobin levels decrease with hemolysis (sickle cell)
what virus causes Rubella?
togavirus
a maculopapular rash that begins on the face and spreads to the trunk and extremities along with POSTAURICULAR LYMPHADENOPATHY is suggestive of…
Rubella
Why should PPD skin tests be performed before administration of TNF-a inhibitors?
TNF-a inhibitors used to treat RA could reactivate latent TB
Name 3 causes of acne
- after conversion to DHT, androgens promote both follicular epidermal hyperproliferation and ecessive sebum production –> causing acne
- epidermal growth factor recepotr inhibitors
- lithium
a common side effect of most diuretics other than the potassium-sparing class
hypokalemic metabolic alkalosis
what electrolyte disorder manifests with muscle weakness and cramping?
hypokalemia
what is a xanthelasma?
a cutaneous lesion commonly found on the eyelid that contains lipid-laden macrophages (foam cells)
these papules are typically yellow due to the location of the foam cells in the superficial dermis
associated with hyperlipidemia
what skin finding can chronic cholestatic processes including obstructive biliary lesions and primary biliary cirrhosis cause?
subsequent hypercholesterolemia –> formation of xanthelasmas
