uWorld 27 Flashcards
what is the motor and sensory innervation of the tibial nerve
Motor:
foot PLANTAR FLEXION (gastrocnemius, soleus, planters muscles)
INVERION (tibialis posterior muscle)
TOE FLEXION (flexor digitorum longs, flexor hallucis longus muscles)
sensory: plantar foot
lateral 4 toes (posterior tibial nerve)
how does tibial nerve injury (at the popliteal fossa- deep penetrating trauma, knee surgery) often present
calcaneovalgus position (dorsiflexed and everted)
if tarsal tunnel may cause sensory loss over the sole with intrinsic foot muscle weakness (plantar flexion and inversion remain intact)
the femoral nerve dos what motor and sensort
motor:
leg flexion at the hip
leg extension at the knee
sensory: medial leg (saphenous nerve) anterior thigh (femoral nerve)
the superficial peroneal nerve does what motor and sensory
motor:
foot EVERSION
sensory:
dorsal surface (top) of foot
anterolateral leg
the deep peroneal nerve dos what motor and sensory
motor:
foot dorsiflexion
toe extension
sensory:
between first and second toes
what is the T LOOP of the tRNA
contents T(psi)C sequence that is necessary for BINDING of tRNA to RIBOSOMES
refers to the presence of ribothymidine, pseudouridine, and cytidine residues
what is the D LOOP of tRNA
facilitates correct tRNA recognition by the proper AMINOACYL tRNA SYNTEHTASE (with the acceptor stem and anticodon loop)
contains dihydrouridine residues (modified bases)
what is the ANTICODON loop of tRNA
contains sequences that are complementary to the mRNA codon
during translation, the RIBOSOME complex SELECTS the proper tRNA based SOLEY on its ANTICODON SEQUENCE
what is the ACCEPTOR STEM of tRNA
created through the base parking of the 5’-terminal nucleotides with the 3’terminal nucleotides
has the CCA at the 3’ end, with the amino acid bound to the 3’ terminal hydroxyl group
helps mediate correct tRNA recognition by the proper aminoacyl tRNA synthetase
if a patient has decreased breath sounds, hemithroax opacification on one side (right), and deviation of the trachea toward the opacified side are suggestive of what
COLLAPSED LUNG due to BRONCHIAL OBSTRUCTION
complete collapse of a lung usually occurs following obstruction of a MAINSTEM BRONCHUS (central lung tumors in smokers)
alveolar collapse (atelectasis) which causes TRACHEA to DEVIATE TOWARD SIDE of LESION
when does one see COMPLETELY OPACIFIED HEMITHROAX w/ tracheal deviation TOWARD the effected lung
mainstream bronchus lesion causing ATELECTEASIS
loss of radiolucent air combined with shifting of organs into the hemithroax
bilateral fluffy appearing infiltrates in the lungs are typically seen when
pulmonary edema (fluid in alveolar species)
when does one see COMPLETELY OPACIFIED HEMITHROAX w/ tracheal deviation AWAY FROM the effected lung
large pleural effusion
what are the two main enzymes of the non oxidative reaction of the HMP shunt
transketolase (two carbon group transfer) w/ TPP substrate
transaldolase (three carbon transfer)
can synthesize ribose from fructose-6-phosphate
what does the HMP shunt produce from one molecule of glucose
five-carbon sugar, two molecules of NADPH and CO2
two reactions:
oxidative (irreversible)
non-oxidative (reversible)
the oxidative portion of the HMP shunt primarily occurs where
tissues active in reductive biosynthesis
fatty avid and steroid synthesis
CYP450 pathway
generation fo superoxide in phagocytes
what enzymes are necessary for the oxidative part of the HMP shunt
GLUCOSE-6-PHOSPHATE DEHYDROGENASE (RATE LIMITING): glucose-6-phosphate to 6-phosphogluconate
6-phosphogluconate dehydrogenase: 6-phosphogluconate to ribulose-5-phosphate
what does enolase do
convers 2-phosphoglycerate to phosphoenolpyruvate in glycolysis
why does aconite do
catalyzes isomerization of citrate to isocitrate in the TCA cycle
what treatment is being researched for AR SCID
RETROVIRAL VECTORS to “INFECT” patient STEM CELL with the GENE CODING for ADENOSINE DEAMINASE
what bug is associated with fever, headache, and diplopia in immunocompromised people and found in DAIRY (milk, soft cheeses, and ice cream) as well as raw fruits and processed meats
LISTERIA
significant disease in patients with CELL-MEDIATED immunodeficiency
what happens to 2,3-BPG after chronic high altitude adaptation
an organophosphate created in erythrocytes during glycolysis
increase levels of 2,3-BPG decrease hemoglobin O2 affinity , allowing the release of more O2 in the peripheral tissues
curve shifts RIGHT
what happens O2 curve in exercise, severe anemia, and hypoventilation
shifts RIGHT
what is a CROSS-SECTIONAL study
PREVALENCE STUDY
“SNAPSHOT” design that is inexpensive and easy to perform
what happens to cortisol levels in response to stressful situations (infections, surgery) in patients on chronic glucocorticoid therapy
it CANNOT RISE (the adrenal is atrophied)
can result in RELATIVE GLUCOCORTICOID DEFICIENCY even when the patient’s baseline glucocorticoid regime is maintained
can precipitate HYPOTENSION/SHOCK- a higher STRESS DOSE is needed if this happens
what is a rare complication that can happen on first dose of ACE inhibitors
FIRST-DOSE HYPOTENSION
happens in patients with high plasma RENIN levels like in VOLUME DEPLETION (from DIURETIC USE) or HEART FAILURE
prevent this by starting therapy at low doses and slowly titrated upward as needed
in a patient with albuminuria why are they started on an ACE inhibitor
to treat early diabetic neuropathy
what are the etiologies of hypoxemia in a patient with a NORMAL Aa gradient (5-15 mmHg)
HYPOVENTILATION (obesity hypoventialtion syndrome, neuromuscular disorders
LOW INSPIRED FRACTION OF AIR (high altitude)
what are the etiologies of hypoxemia in a patient with a ELEVATED Aa gradient (over 15mmHg)
RIGHT-to-LEFT SHUNT (cardiac septal defects, pulmonary edema)
VENTIALTION/PERFUSION MISMATCH (PE, COPD)
IMPAIRED DIFFUSION (interstitial lung disease)
what is seen in OBESITY HYPOVENTILATION SYNDROME
increase CO2 production due to increased mass and surface area
sleep-disordered breathing
reduced lung volumes and compliance
chronic fatigue, dyspnea, difficulty concentrating, evidence of hypoventilation (PaCO2 over 45 while awake)
what cells are responsible for synthesizing the structurally important collagen isoforms and extracellular matrix of a atherosclerotic plaque
vascular smooth muscle cells (VSMCs)
who is renal blood flow calculated
first calculate renal PLASMA flow using PAH: RPF = (Urine PAH)*(urine flow rate)/(Plasma PAH)
renal blood flow: RBF = RPF/(1-hematocrit)
when placing a chest tube into the 4th or 5th intercostal space in the anterior axillary or MIDAXILLARY line what does the tube traverse
SERRATUS ANTERIOR muscle
intercostal (external, internal, innermost) muscles
parietal pleura
what does serrates anterior do
originated from ribs 1-8 and inserts along the entire length of the medial scapular border
3 parts: superior, intermediate, inferior
infer part of muscle facilitates ARM ELEVATION by PULLING lower end of SCAPULA forward (SCAPULAR ROTATION)
all 3 parts help with respiration by lifting the ribs when the shoulder grille is FIXED
what does pectorals major do
adduct and internally rotate the humerus
arises from anterior clavicle, sternum, costal cartilages, and aponeurosis of the external oblique muscle
attaches to lateral lip of bicipital groove of the humerus
the lateral epicondyle serves as the primary attachment point for what muscles
EXTENSOR CARPI RADIALIS BREVIS (ECRB)
EXTENSOR DIGITORUM
both involved in WRIST EXTENSION
lateral epicondylitis aka tennis elbow is pain over the lateral epicondyle of the humerus due to antiofibrotic tendinosis of the ECRB tendon
what muscles flex the forearm
biceps brachii
brachialis
brachioradialis
L2 radiculopathy leads to what
sensory loss: upper anteromedial thigh
weakness: hip flexion (ILIOPSOAS)
L3 radiculopathy leads to what
sensory loss: lower anteromedial thigh
weakness: hip flexion (iliopsoas), hp adduction, knee extension (quads)
L4 radiculopathy leads to what
sensory loss: lower anterolateral thigh, knee, medial calf and medial foot
weakness: hip adduction, knee extension (quadriceps), PATELLAR REFLEX
L5 radiculopathy leads to what
sensory loss: buttocks, posterolateral thigh, anterolateral leg, DORSAL FOOT
weakness: foot dorsiflexion and inversion (tibialis anterior), foot eversion (peroneus), toe extension (extensor digitorum brevis)
S1 radiculopathy leads to what
sensory loss: buttocks, posterior thigh and calf, lateral foot
weakness: hip extension (gluteus maximus), knee flexion (hamstrings), foot plantar flexion (gastrocnemius), ACHILLES REFLEX
what are two causes of radiculopathy and how do they differ (if we are talking about say L5-S1 radiculopathy)
SPINAL FORAMINA STENOSIS:affects the UPPER nerve root that is actually exiting at that level (since the roots exit below)
- so L5 would be affected if L5-S1 neural foramen were affected
HERNIATED DISC: affects the LOWER nerve root
- so S1 would be affected if L5-S1 disc were to herniate
how does Strep Viridans work
ADHEREs to tooth enamel and to FIBRIN-PLATELET aggregates on damaged heart valves due to their ability to produce INSOLUBLE EXTRACELLULAR POLYSACCHARIDES (aka DEXTRANS) using sucrose as a substrate
this colonization of host surfaces contributes to their ability to cause infections
angiotensin-II, oxytocin, and vascular vasopressin (V1) receptors all work through what mechanism
Gq
why is oxalate absorption in creased in Crohns
calcium normally binds oxalate in the bowel to form insoluble salts that promote oxalate excretion
in Crohns calcium binds LIPIDS instead and cannot complex oxalate
OXALTE ABSORPTION is thus INCREASED, promoting formation of OXALATE KIDNEY STONES (enteric oxaluria)
what causes avascular necrosis (osteonecrosis)
THOMBOTI/EMBOLIC OCCLUSION (SICKLE CELL, BENDs)
GLUCOCORTICOIDS
vascular inflammation/injury (vasculitis, radiation)
alcohol abuse
traumatic fracture
what clinical presentation is seen with osteonecrosis (avascular necrosis)
pain on weight bearing
DECREASED RANGE of MOTION
wedge-shaped or geographic zone of necrosis
articular cartilage is viable but may be distorted or detached from underlying bone
necrosis of surrounding adipocytes
dead bony trabecular with empty lacunae
prior MI is associated with lower risk of ventricular free wall rupture, why?
myocardial fibrosis at the site of infarction
development of collateral circulation
what is the TATA box
promoter region located 25 bases UPSTREAM from the beginning of the CODING REGION
when does gene transcription begin
when RNA POLYMERASE II attaches to one of the promoter regions in a process that requires general TRANSCRIPTION FACTORS
in eukaryotes translation initiation requires what
both ribosomal units (60S and 40S) with their associated rRNA, mRNA, initiation factors, initiator tRNA charged with methionine, and GTP
what is adiponectin
cytokine secreted by fat tissue that increases the number of insulin-responsive adipocytes and regulates fatty acid oxidation
increased by PPAR-gamma via thiazolidinediones (glitters)
what does nedocromil do
mast cell degranulation inhibitor (along with CROMOLYN)
long term glucocorticoid use stimulates anabolism where and catabolism where
anabolism- LIVER (stimulation of GLUCONEOGENESIS and upregulate the synthesis of key gluconeogenic enzymes (PEPCK, G-6-phosphatase), increase in GLYCOGEN RESERVES via expression of glycogen synthase)
catabolism- peripheral in the SKELETAL MSUCLE (antagonizing the action of insulin)- provides substrates for gluconeogenesis and glycogenesis in the liver
can manifest as:
muscle weakness (glucocorticoid myopathy)
lipolytic and antilipolyic, altered fat distribution (central obesity, hypertrophy of dorsocervical fat pad)
increased appetite and caloric intake
HYPERGLYCEMIA (gluconeogenesis and insulin antagonism)
what do glucocorticoids do to the skin
inhibition of fibroblast proliferation and collagen formation: thinning stria impaired wound healing easy bruising
how do glucocorticoids decrease bone mass (causing osteoporosis and avascular necrosis)
decreased GI calcium absorption
increased renal calcium excretion
direct inhibitor of osteoblast activity
high levels of what are rewired for spermatogenesis
testosterone
inhibin B
how do beta blockers mask hypoglycemia
the neurogenic symptoms of hypoglycemia are caused by SYMPATHOADRENAL ACTIVATION and are mediated via norepi/epi and acetylcholine via sympathetic POSTganglionic fibers
symptoms of norepi/epi are tremulousness, palpitations, and anxiety/arousal
cholinergic symptoms: sweating, hunger, paresthesias
NON-SELECTIVE BETA BLOCKERS will block the norepi/epi mediated compensatory reactions leaving the CHOLINERGIC SYMPTOMS UNAFFECTED
blocking beta-2 also stops hepatic gluconeogeneiss, and peripheral glycogenolysis and lipolysis
if beta-blocker therapy is needed in a diabetic what is prefered
selective beta-1 blockers
beta-blockers with intrinsic sympathomimetic activity (PINDOLOL, ACEBUTOLOL)
what causes the hypervitaminosis D in sarcoidosis
activated MACROPHAGES expression of 1-alpha-hydroxylase
this causes 1,25-dihydroxyvitamin D to be produced and increased INTESTINAL ABSORPTION of CALCIUM
vimentin (an intermediate filament) is a marker for tumors of what origin
mesenchymal tissue
neuron-specific enolase and chromogranin A are markers for what
neuroendocrine tumors
what kind of receptor is HER2/neu
EPIDERMAL TRANSDUCTION PATHWAY that control EPITHELIAL GROWTH and DIFFERENTIATION
what is derived from surface ectoderm
Rathe's pouch (anterior pituitary) lense and cornea inner ear sensory organs olfactory epithelium nasal and coral epithelial linings epidermis salivary, sweat, and mamary glands
what is derived form neural tube
brain and spinal cord
POSITERIOR PITUITRARY
PINEAL GLAND
RETINA
what is derived form the neural crest
autonomic, sensory, celiac ganglia schwann cells pia and arachnoid mater aorticopulmonary septum and endocardial cushions branchial arches (bones, cartilage) skull bones melanocytes adrenal medulla
what is derived from mesoderm
muscles (skeletal, cardiac, smooth), connective tissue, bone, and cartilage serosa lining (peritoneum) cardiovascular system blood lymphatic system spleen internal genitalia kidney and ureters adrenal cortex
what is derived form the endoderm
GI tract liver pancreas lungs thymus parathyroids (???) thyroid follicular cells (????) middle ear bladder and urethra
when do the three germ layers form
GASTRULATION during week 3 go embryogenesis
initiated by formation of primitive streak (thickening of epiblast cell layer that appears at caudal end of the embryo and grows cranially)
what happens 2 days after gastrulation begins
some epiblast cells migrate cranially though the primitive node (the cephalic end of the primitive streak) to form a midline cellular cord known as the NOTOCORD
notochord induces overlying ectoderm cells to differentiate into neuroectoderm and form the neural plate
neural plat ogives rise to neural tube and neural crest cells, the rest of the ectoderm becomes the surface ectoderm
the notochord becomes what in adults
nucleus pulpous of intervertebral discs
what is seen in von Hippel-Lindau
AD disorder
HEMANGIOBLASTOMAS in the RETINA and/or CEREBELLUM
congenital CYSTS and/or NEOPLASMS of the kidney, liver, and pancreas
increased risk for renal cell carcinoma (BILATERAL)
what is seen in Sturge-Weber syndrome (encephalotrigeminal angiomatosis)
cutaneous facial angiomas as well as leptomeningeal angiomas
skin involvement in V1 and V2 distributions of the trigeminal nerve
mental retardation
seizures
hemiplegia
skull radiopacies w/ “TRAM TRACK” calcifications
what is seen in tuberous sclerosis
AD syndrome kidney, liver, and pancreatic cysts cordial and subependymal HAMARTOMAS cutaneous angiogibromas (adenoma sebaceous) visceral cysts varieties of other hamartomas renal angiomyolipomas cardiac rhabdomyomas SEIZURES
