uWorld 10 Flashcards
what cells can act as the regenerative source of ciliated cells in the bronchioles
club (clara) cells- conciliated, secretory cells found predominantly in the terminal portions of the bronchioles
what dermatome innervates the anus, which one does the perianal region
pudendal nerve (S2-S4)
anus- S5
perianal region- S4
(anus looks like target of dermatomes with S5 as bullseye going out to L5 at the lateral thigh)
where does the spinal cord end in an adult and what happens if image occurs here
conus medullaris at approx L2 level
conus medullar is syndrome referes to legions at L2-
flaccid paralysis of the bladder and rectum, impotence and saddle (S3-S5 roots) anesthesia
mild weakness of the leg muscle if the lesion spares both the lumbar cord and adjacent spinal and lumbar nerve roots
common causes: disk herniation, tumors, spinal fractures
what is cauda equina syndrome
typically results from massive eruption of an intervertebral disk that is capable of causing compression of two or more of the 18 spinal nerve roots of the cauda equina
can also occur due to train or space-occupyin lesion of the lower vertebral column
symptoms:
low back pain radiating to one or both legs
saddle anesthesia (S3-S5 roots)
LOSS of ANOCUTANEOUS REFLEX (S3-S4)
bowel and bladder dysfunction (S3-S5 roots)
loss of ankle-jerk reflex with plantar flexion weakness of the feet
what is observer bias
investigators decision is affected by prior knowledge of the exposure status
fibroblasts begin synthesizing polypeptide chains that assemble into TRIPLE HELICAL STRUCTURES, followed by fibrils
fibrillar proteins hydrolyzed and separated into constituent amino acids, what amino acid is found in highest quantities in these proteins
GLYCINE
collagen is the most abundant protein in the human body and is synthesized by fibroblasts, osteoblasts, and chondroblasts
collagen is made up of 3 polypeptide ALPHA CHAINS held together by hydrogen bonds, forming a role-like TRIPLE HELIX (collagen molecule)
collagen molecules self-assemble into fibrils, which subsequently crosslink to form collagen fibers
GLY-X-Y IS THE STRUCTURE OF COLLAGEN thus GLYCINE is 33% of the amino acids not matter what
(proline residues are essential for alpha helix formation because there ring configuration
hydroxylysine is necessary for cross linking- which greatly increases tensile strength of assembled collagen fivers)
what causes photoaging of the skin
UVA which can penetrate deeper into the skin producing reactive oxygen species- activating multiple inflammatory cell-surface receptors and nuclear transcription factors
leads to DECREASED COLLAGEN FIBRIL PRODUCTION, and upregulatin of matrix metalloproteinases (collagenases) that degrade type I and III collagen and elastin
what is seen histologically in photoaging
THINNING OF EPIDERMIS
reduction in subcutaneous fat, blood vessels, hair follicles, sweat ducts, sebaceous glands
rete ridges at dermoepidermal junctions become flattened
loss of subcutaneous tissue causes the skin to become atrophic and more vulnerable to damage
what causes wrinkling of photo aged skin
INCREASED CROSSLINKING of collagen, along with desiccation of the stratum corneum,produces the charactpericic drinking of photo ages skin
what is adjustment disorder
increased anxiety, depression, or disturbed behavior that develops WITHIN 3 MONTHS of an IDENTIFIABLE STRESSOR and lasts NO MORE than 6 MONTHS after the STRESSOR ENDS
what is myoglobin and what does its oxygen dissociation curve look like
MONOMERIC protein and the primary oxygen storing protein in the skeletal and cardiac muscle tissue
only found in bloodstream after muscle injury
myoglobin curve is shifted ALL THE WAY TO THE LEFT and is HYPERBOLIC
where in the cell is Vitamin C active during collagen synthesis
ROUGH ENDOPLASMIC RETICULUM
collagen alpha-chains are synthesized by the RER ribosomes and directed to the cisternal of the RER where PROLINE and LYSINE resides are prosy-translationally HYDROXYLATED to hydroxyproline and hydroxylysine by lysyl hydrolyze- VITAMIN C is REQUIRED for this
pt with progressive lethargy w/ loss of appetite, constipation, muscle weakness, and increased thirst and urination for 3 wks
takes lots of vitamins and minerals for health
stuporous and has dry mucous membranes on exam
whats going on, what other condition do you see this metabolic abnormality
HYPERCALEMIA from taking VITAMIN D supplements
impaired depolarization of neuromuscular membranes (muscle weakness, constipation, mental status changes)
impaired concentration of urine (polyuria/dipsia)
bone pain from bone demineralization
hyervitaminosis D is also seen in GRANULOMATOUS disease (sarcoidosis, TB) b/c activated macrophages express 1-alpha hydroxylase)
glucagon works by stimulating what in what organ
Gs in HEPATOCYTES increasing GLYCOGENOLYSIS (breakdown of glycogen) and GLUCONEOGENESIS (production of glucose from noncarb sources glucagon-induced glycogenolyiss is the predominant initial means of rapidly increasing blood glucose levels during hypoglycemia
what enzymes does glucagon stimulate
activation of key glycogenolytic enzyme- GLYCOGEN PHOSPHORYLASE
stimulates gluconeogeneiss by activating- pyruvate carboxylase, phosphoenolpyruvate carboxykinase
decreased intracellular fructose-2,6-bisphosphate levels (inhibiting glycolysis)
when does gluconeogenesis in the renal cortex become an important source of glucose
when hypoglycemia is sustained
epinephrine is more effective than glucagon in stimulating renal gluconeogenesis
the presence of acid in the duodenum and jejunum causes release of what from the mucosa and what does the stimulate
SECRETIN
stimulates secretion of bicarbonate from the submucosal glands and pancreas
where and why is barcyrbonate secreted in the ileum and the colon
to neutralize acid produced by colonic bacteria
epithelial cells in bill in the ileum and crypts in the colon
no glands
what are the carboxyhemoglobin, PaO2, and methemoglobin values in CARBON MONOXIDE poisoning
carboxyhemoglobin: increased
PaO2: NORMAL (ONLY DISSOLVED OXYGEN)
methemoglobin: normal
decreased oxygen-carrying capacity and OXYGEN CONTENT but not the amount of oxygen dissolved in the plasma, which is PaO2
what is a malformation and what is an example of it
primary intrinsic defect int he cells or tissues that form a structure, leading to a chain of downstream defects
HOLOPROSENCEPHALY is a MALFORMATION characterized by a spectrum of fetal anomalies due to incomplete division of the foreign (or prosencephalon)
74 yr old pt hospitalized with catheter and IV antibiotics after intubation and extubation develops fever and right jaw pain
swelling of pot auricular area on the right side extending to the angle of the mandible
what is it? what serum marker is most helpful?
SUPPURTIVE PAROTITIS
serum AMYLASE is elevated (parotid secretes amylase)
MCC is staph a
risk factors: DEHYDRATION, INTUBATION, medications that decrease salivation (Anti-ACh), salivary flow obstruction, recent intense teeth cleaning
pre/post auricular SWELLING that extends to MANDIBLE
trismus, dysphagia, systemic findings (fever, chills)
what drugs are used to treat spasticity in MS
BACLOFEN
TIZANIDINE
what is and what can cause pulses parvus et tardus
LV outflow tract obstruction (aortic stenosis)
slow-rising, low-amplitude pulse due to diminish stroke volume (pulses parvus) and prolonged LV ejection time (pulses tardus)
pt tachypneic w/ prolonged expiration and prominent bilateral wheezing, heart sounds normal, CXR shows normal sized heart but hyper inflated lungs with a flattened diaphragm
Echo shows no intrapericardial fluid accumulation or pericardial thickening
whats he got? whats gna provide immediate relief to this patient?
patient has exacerbation of OBSTRUCTIVE PULMONARY DISEASE (COPD or asthma)
treat w/ BETA-ADRENERGIC AGONIST- relaxes bronchial smooth muscle by stimulating beta-2
Gs receptor that INCREASES INTRACELLULAR cAMP concentrations
what type of error is the probability of concluding there is no difference between groups when ne truly exists
type II error (BETA)
pt w/ colon cancer has generalized edema, protein excretion of 4.g/day
glomerular capillary wall thickening without an increase in cellularity
when stained with silver methenamine, irregular spikes protruding from the glomerular basement membrane are seen
what this patient got?
MEMBRANOUS GLOMERULOPATHY
the presence of NEPHROTIC SYNDROME and his UNDERLYING MALIGNANCY suggests membranous glomerulopathy
one of most common nephrotic syndrome in adults
what is seen on biopsy of membranous glomerulopathy
uniform, diffuse thickening of the glomerular capillary wall on light microscopy without an increase in cellularity
EM shows thickening caused by irregular, dense deposits laid b/w basement membrane and epithelial cells
protrusions resemble “spikes and domes” when stained with silver
Immunofluorescence shows IgG and C3
what happens to ED50 when given a noncompetitive antagonists with an agonist
ED50 does not change
distinguishing characteristic of noncompetitive antagonism
in a patient with A-Fib what physiologic factor most likely determine the ventricular contraction rate
atrioventricular node refractory rate
each time AV node is excited it enters a refractory period where additional impulses cannot be transmitted to the ventricles- consequently majority of atrial impulses never reach the ventricles
ventricular be a is 90-170 in A-Fib and is irregular with no set intervals b/w contractions and narrow QRS complexes
what is seen and what causes cri du chat
de novo partial deletion of short arm of ch 5 (59)
round face, cat like cry, microcephaly
what are the complications of diabetes during pregnancy
premature delivery
fetal macrosomia (big body)
congenital malformations (neural tube defects, CV anomalies, caudal regression syndrome)
respiratory distress
transient hypoglycemia (resolves in 3-7 days)
polycythemia and hyperviscosity
neonatal hyperthyroidism can be caused by what maternal issue
Gaves’ disease during pregnancy can cause neonatal hyperthyroidism by placental transfer of matron thyroid-stimulating antibodies
12 yr old AA male in ER w/ high fever, chest pains, dyspnea
prior hospitalization for abdominal pain, which resolved with analgesics and hydration
hematocrit is 23% and reticulocyte count of 9%
patient dies several hours after being admitted
SPLEEN IS FIRM AND BROWN- what caused this
person has “ACUTE CHEST SYNDROME” (ACS) due to sickle cell
this is a VASO-OCCLUSIVE CRISIS localized to the pulmonary vasculature- commonly precipitated by pulmonary infection
faso-occlusive crisis can also cause SPLENIC infarcts and over time spleen is shrunken, discolored and fibrotic
THIS IS THE AUTOSPLENECTOMY SEEN IN ADULT SICKLE CELL PTS
recurrent episodes of abdominal pain that resolve with hydration = sickle cell
pt with progressive pain beneath right scapula and in high right arm for last several months (no longer received by OTC analgesics)
numbness in his right forearm extending up to the tips of the fourth and fifth fingers
persistent nonproductive cough but now blood streaked
history of HTN, GERD, osteoarthritis
smokes 2ppd for 40 years but now only 4 or 5 per day
whats he got???
smoking history with hemoptysis and shoulder pain is likely LUNG CANCER
PANCOAST TUMOR is at lung apex and often arise in the SUPERIOR SULCUS (groove formed by the subclavian vessels)
what do pan coast tumors (Superior sulcus tumors) present with
SHOULDER PAIN radiating toward axilla and SCAPULA C8, T1, T2 distribution (MOST COMMON presenting sign)
arm paresthesias, weakness, and muscle atrophy
HORNER SYNDROME
SPINAL CORD COMPRESSIOn and paraplegia can result from tumor extension into the intervertebral foramina
upper extremity edema may be due to compression of subclavian vessels
