MSK I FA Flashcards
What are the five layers of the epidermis in order from apical to basal?
They all start with stratum: Corneum, Lucidum, Granulosum, Spinosum and Basale. Californians Like Girls in String Bikinis.
Which layer of the epidermis sports desmosomes?
Stratum Spinosum
Which layer of the epidermis supplies stem cells?
Stratum Basale
What are the three types of glands in the epidermis?
Sebaceous, Eccrine and Apocrine
What epidermal gland is targeted by acne drugs.
Sebaceous. These glands are are associated with the hair follicle and drugs reduce holocrine secretion of sebum.
Starting with glucose, what are all of the glycolytic intermediates as it is broken down to pyruvate?
“German gorillas fight french dandies gloriously by proudly pummeling pretty paris.” Gluc, Gluc-6-P, Fru-6-P, Fru-1,6-Bisphosphate, DHA-P and Glyceraldehyde-3-P, 1,3-bisphosphoglycerate, 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, pyruvate
Starting with hexokinase, what are all of the glycolytic enzymes that break down glucose?
“Harry Potter proudly attacks the German Kaiser’s monkeys eating people.” Hexokinase, Phosphoglucoisomerase, PFK-1, Aldolase, Triose Phosphate Isomerase, Glyceraldehyde-3-Phosphate Dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, enolase, pyruvate kinase
What is the rate determining enzyme in glycolysis?
PFK-1
What regulates the rate-determining enzyme in glycolysis?
POSITIVE REGULATORS: AMP and fructose-2,6-BP NEGATIVE REGULATORS: ATP and citrate
How are the molecules necessary for cellular respiration in the heart and liver shuttled into the mitochondrial matrix?
Malate-aspartate shuttle
How are the molecules necessary for cellular respiration in the muscle shuttled into the mitochondrial matrix?
Glycerol-3-P shuttle
What glycolysis reactions require ATP?
Gluc -> Gluc-6-P by hexokinase and Fructose-6-P -> Fructose-1.6-BP by PFK-1.
What glycolysis reactions generate ATP?
1,3-BPG-> 3-PG by phosphoglycerate kinase and PEP -> pyruvate by pyruvate kinase
A patient comes to see you with symptoms consistent with rheumatic fever. He reported having a sore throat two weeks ago. What bacteria is likely causing these symptoms and by what mechanism is it doing so?
Streptococcus pyogenes. It produces the Streptolysin O toxin which degrades cell membranes and lyses RBCs. The host produces ASO antibodies against streptolysin O/M protein, which also attack cardiac tissue and cause rheumatic fever.
A patient comes to the ED in shock with a rash, vomiting, desqumation and fever. What bacterium may be causing these symptoms and by what mechanism?
Staphylococcus aureus. It produces TSST-1 toxin which is a super-antigen that binds MHC II to CD4 cells and causes overwhelming secretion of IFN-gamma and IL-2. OR Streptococcus pyogenes. It produces Exotoxin A which does the same thing as TSST-1.
A parent brings her child to the clinic with scaled skin syndrome. What is causing these symptoms?
Staphylococcus aureus production of exfoliative toxin that disrupts desmosomes in stratum granulosum layer.
The lab runs a gram stain on a sample from a patient and finds gram + cocci. What tests might they run to further specify the bacteria type?
Test for catalase enzyme in H2O2 solution. Staph will be catalase positive and strep will be catalase negative. Staph will also grow in clusters and strep will grow in chains.
The lab runs a gram stain on a sample and finds gram +, catalase +, cluster-forming bacteria. What test might they run to further specify the bacteria type?
See if the bacteria is positive for coagulase and will convert fibrinogen to fibrin in serum, manifested by clot formation. Staph aureus will be coagulase positive and staph epidermidis will be coagulase negative.
The lab runs a gram stain on a sample and finds gram +, catalase -, chain-forming bacteria. What test might they run to further specify the bacteria type?
But the bacteria on a blood agar plate and test for hemolysis. Group A and B strep will be beta (complete) hemolytic. Viridans strep and strep pneumoniae will be alpha (partial and green) hemolytic. Group D strep and nonenterococcus strep will be non-hemolytic.
The lab runs a gram stain on a sample and finds gram +, catalase -, chain forming, beta-hemolytic bacteria. What test might the lab do to further specify the bacteria type?
Ad bacitracin to the plated bacteria to see if they are resistant to the antibiotic. Group A Strep will be bacitracin sensitive and Group B Strep will be resistant.
How does staph aureus evade the host immune response?
Protein A binds the Fc region of IgG. This inhibits opsinization for complement activation or phagocytosis.
Why is staph aureus so good at making abscesses?
It is coagulase positive and can form a fibrin clot around the area of infection, walling itself off.
You are doing an infectious disease rotation at the hospital and you see a patient with a MRSA infection. Why can’t you treat this patient with normal antibiotics?
It is resistant to beta-lactams that break up the peptidoglycan wall because it has expressed an altered penicillin binding protein.
What bacteria is notorious for infecting dialysis patients?
Stpahylococcus epidermidis. It is great at forming biofilms on IV catheters and prosthetic devices. It is a component of our normal flora.
What are the different diseases caused by streptococcus progenies (group A)?
PYOGENIC: pharyngitis, cellulitis and impetigo TOXIGENIC: scarlet fever, toxic shock, necrotizing fasciitis IMMUNOLOGIC: rheumatic fever, acute glomerulonephritis
Your neighbor thinks his friend might have rheumatic fever? What symptoms would you check for to see if his suspicion may be correct?
“PENES”- Polyarthritis, endocarditis, nodules, erythema marginatum and Sydenham’s chorea.
Two patients have secondary infections from the same microbe. One has rheumatic fever and the other glomerulonephritis. What was most likely their primary condition?
Pharyngitis from group A strep (pyogenes)
A patient comes to see you with secondary condition of glomerulonephritis. What will be the first primary condition you suspect? The secondary?
Impetigo most often leads to glomerulonephritis then pharyngitis.
A female tells you she thinks she has scarlet fever. What do you look for before you make a diagnosis?
Scarlet rash on face, strawberry tongue and scarlet throat
A football player has hypopigmented patches on his shoulders upper back and upper chest. KOH prep after a skin scraping shows a spaghetti and meatball appearance. What is his condition and what is causing it?
Tinea versicolor caused my Malassezia furfur. The fungus degrades lipids and produces acids that damage melanocytes and create funky looking pigmentation.
A patient has multiple clear vesicular papules near his mouth and keratoconjunctivits. What virus may have infected this patient and what type of virus is it? How is this transmitted?
HSV-1. Double-stranded, enveloped DNA virus. Respiratory droplets and saliva.
A patient has multiple clear vesicular papules on his genetilia. What virus may have infected this patient and what type of virus is it? How is this transmitted?
HSV-2. Double-stranded, enveloped DNA virus. Sexual contact and perinatal.
What herpesvirus has a vaccine available? How is this virus transmitted?
VZV for chickenpox or shingles. Respiratory droplets
What is the most common cause of sporadic encephalitis in the US?
HSV-1 infection
