test #14 4.2 Flashcards
which n. can be affected by an acoustic schwanomma?
CN VII and CV by proximity
parinaud syndrome (dorsal midbrain syndrome)
paralysis of vertical gaze & pupil issues
germ cell tumors in the brain arise…
in pineal and suprasellar regions
meningiomas are commonly found…
over the lateral hemispheric fissure & parasaggital aspect of the brain convexity
prokaryotic ribosome is composed of…
3 types of rRNA and 50+ proteins
30s ribosomal subunit in prokaryote contains..
16s subunit. essential for INITIATION of protein synthesis.
16S rRNA expresses sequence
complementary to Shrine-Dalgarno sequence in all prokaryotic mRNA. [10bp upstream from AUG]
shrine dalgarno sequence
sequence 10bp upstream AUG on mRNA. binds to 16s rRNA in 30s subunit of prokaryotic ribosome. allows mRNA & 30s ribosomal subunit to bind for protein translation.
when does 50s ribosomal subunit associate?
- mRNA and 30s (w/ 16s rRNA and shrine dalgarno seq). (2) initiator tRNA binds to AUG (3) 50s subunit associates
peptidyl transferase activity of 50s subunit conferred by..
23s rRNA on 50s subunit. facilitates peptide bond formation
energy for translation translocation [where ribosome advances to next mRNA codon to be translated] in prokaryotes
facilitated by elongation factor G, energy by GTP
tissues w/ surface ectoderm origins
rathke’s pouch (anterior pituitary), LENS & CORNEA, INNER EAR SENSORY ORGANS, olfactory epithelium, epidermis, salivary, sweat, & mammary glands
tissues w/ neural crest (ectoderm) origins
autonomic, sensory & celiac ganglia. schwann cell, PIA & ARACHNOID MATER, aorticopulmonary septum & endocardial cushions, BRANCHIAL ARCHES (bones & cartilage), skull bones, melanocytes, adrenal mudella
mesoderm
muscle (skeletal, cardiac, smooth), connective tissue, bone & cartilage, serosa linings (peritoneum), cardiovascular system, blood, lymphatic system, SPLEEN, internal genitalia, kidney & ureters, adrenal cortex
endoderm
GI tract, liver, pancreas, lungs, thymus, parathyroids, thyroid follicular cells, middle ear, bladder & urethra
gastrulation (formation of 3 germ layers) occurs.. initiated by..
3rd wk of embryogenesis. initiated by formation of PRIMITIVE STREAK: thickening of epiblast cell layer that appears caudally and extends cranially. epiblast cells undergo epithelial-to-mesenchymal transition, causing loss of cell-cell adhesion properties– allows migration downward through primitive streak to form mesoderm and endoderm layers. remainder of epiblast = surface ectoderm.
notochord formation
2 days into gastrulation, some epiblasts migrate cranially through the primitive node (cephalic end of primitive streak) to form midline structure –> notochord. which induces overlying ectoderm to differentiate into neuroectoderm & form neural plate –> neural tube & neural crest cells (remainder of ectoderm –> surface ectoderm)
notochord becomes…
nucleus pulposus of intervertebrae disk in adults
clinical manifestation of Edwards syndrome (trisomy 18)
- FACE: microstomia, micropthalmia, cataracts, coloboma (hole in eye), low set & malformed ears, prominent occiput.
- CNS: microcephaly, neural tube defects, holoprosencephaly.
- MUSCULOSKELETAL: CLENCHED HANDS w/ overlapping fingers, rocker-bottom feet, short sternum, hypertonia.
- CARDIAC: VSD, patent duct arteriosus
- GI: Meckel’s diverticulum, malrotation
ultrasound findings suggesting edwards syndrome
intrauterine growth restriction, polyhydramnios, fetus w/ abnormal hand arrangement
direct thrombin inhibitors examples (2)? rx?
lepirudin & agratroban. rx: heparin-induced thrombocytopenia
ticlopidine and clopidergel use (3)
percutaneous coronary interventions (PCI), unstable angina, nonQwave MI
folate deficiency inhibits formation of what substrate?
dTMP (deoxythymidine monophosphate). can reduce erythroid precursor cell apoptosis if supplement thymidine
thymidylate synthase catalyzes what rxn?
methylation of dUMP (deoxyuridine monophosphate) to dTMP (deoxythymidine monophosphate) WHILE converting folate derivative 5-10 methylenetetreahydrofolate (methylene -THF) to dihydrofolate (DHF). de NOVO dTMP production. methylene-THF donates 1 carbon group to dUMP –> dTMP
thymidylate synthase is essential in the supply of which nucleotide precursors?
all 4 precursors of DNA replication (directly – thymidine) indirectly (w/ DHF) – purines
diminished dTMP synthesis w/ folate deficiency can be partially compensated w/
thymidine salvage pathway using thymidine kinase (normally accounts for 5-10% of dTMP synthesis). can use this w/ thymidine supplemenentation
major source of nitrogen in synthesis of nucleotides?
glutamine. i.e. contributes nitrogen atom to biosynthesis of dUMP.
withdrawal symptoms for alcohol & benzodiazepines? exam findings?
symptoms: tremors, agitation, anxiety, delirium, psychosis. benzo, also: perceptual disturbances (depersonalization), insomnia. exam: seziure, TACHYCARDIA, palpitations
heroin withdrawal symptoms? exam findings?
symptoms: nausea, vomiting, abdominal cramping, muscle aches.
exam findings: DILATED PUPILS, YAWNING, piloerection, LACRIMATION, hyperactive bowel sounds
stimulants (eg. cocaine & amphetamine) withdrawal symptoms? examination findings?
symptoms: increased appetite, hypersomnia, INTENSE PSYCHOMOTOR RETARDATION, SEVERE DEPRESSION (“crash”). no significant findings on exam.
nicotine withdrawal? examination findings?
dysphoria, irritability, anxiety, INCREASED APPETITITE
when does opiod withdrawal occur
as soon as 6-12 hrs after use, peaks 24-48 hrs. vitals usu normal.
drug withdrawal w/ potentially fatal symptoms
ALCOHOL withdrawal. 12-24 hrs after, autonomic hyperactivity (tachycardia, HTN), also seizures
layers of bone from middle to end
diaphysis, metaphysis, epiphyseal cartilage (growth plate), and epiphysis
two effect of estrogen on bone growth
(1) stimulates rapid linear growth (stimulates osteoblasts, inhibit osteoclast), but also (2) encourage closure of epiphyseal plates (fusion of epiphysis and metaphysis).
somatomedin C
also known as insulin-like growth-factor 1 (IGF-1)
IGF-1 / somatomedin C on bone growth
differentiation and proliferation of chondrocytes in epiphyseal growth plate (increase in linear growth). unlike estrogen, does not accelerate epiphyseal closure.
why does precocious puberty –> short stature but excess GH pre-puberty –> gigantism?
(1) excess sex steroids –> premature closure of epiphyseal growth plate –> short. (2) excess GH –> IGF-1 –> chondrocyte differentiate & proliferate in epiphyseal plate, no closure
smoking can induce what change in hemoglobin
formation of carboxyhemoglobin – via inhalation of CO
which cells in kidney increase EPO production in response to hypoxia?
cortical cells in kidney
HELLP syndrome
hemolytic anemia, elevated liver enzymes, low platelets (thrombocytopenia)
triad of pre-eclampsia
(1) hypertension, (2) proteinuria, (3) edema in pregnancy (diagnosis can be made w/o edema). occurs in <10% of pregnancies. typical onset after 20th wk of gestation.
gestational diabetes associated w/ increased rates of
(1) still birth and (2) macrosomia (large baby)
eclampsia vs. pre-eclampsia?
PRE-eclampsia: HTN, proteinuria, edema. ECLAMPSIA: w/ seizures.
pre-eclampsia can progress to..
HELLP syndrome. hemolytic anemia, elevated liver enzymes, and low platelets.
(1) older patient w/ (2) bone pain and (3) increase alkaline phosphatase level
Paget’s disease of the bone
microscopic analysis of bone in Paget’s disease of the bone
increased osteoclastic activity —> increased osteoblastic activity. net result: mosaic pattern of lamellar bone w/ irregular sections linked by cement lines (representing previous areas of bone resorption)
describe areas of bone affected by Paget’s disease
increased fibrous tissue deposition & vascularity (induced by proliferation of fibroblasts & endothelial cells)
increased vascularity in Paget’s bone disease can result in..
arteriovenous shunting that can result in high-output heart failure.
oil/water parition
used to describe pharmacokinetic properties of general anesthetics (relative solubility in oil vs. water)
rx for narcolepsy? 2
1st line: modafinil – non-ampetamine stimulate. unclear mech, increase dopamine signaling.
2nd line: amphetamines
carbamazepine rx (2)
trigeminal neuralgia and seizures
zolpidem
non-benzodiazepine hypnotic used for insomnia
melatonin rx (2)
jet-lag and age-related insomnia
CEA (carcinoembryonic antigen)
inreased in 60-90% of patients w/ colorectal cancer. glycoprotein involved w/ cell adhesion. produced in embryonic pancreas, liver, and intestine. can be detected in healthy people.
why can’t CEA be used to diagnose colon cancer? what can it be used for?
increased in pancreatic, gastric, and breast malignancies. also, benign diseases like inflammatory bowel disease, cirrhosis, and pancreatitis. smokers. sensitive indicator of colorectal cancer recurrence (measure pre-op and during surgery).
tumor grade looks at
degree of tumor differentiation
tumor stage reflects..
extent of spread
most important factor determining survival of patients w/ colon cancer?
STAGE: lymph node involvement & distant mets.
metabolic acidosis in diabetes caused by which 2 substrates?
ketones: (1) beta-hydroxybutyrate and (2) acetoacetate
where can meningococci be isolated from in asymptomatic carriers?
oropharynx and nasopharynx (transmission w/ respiratory droplets)
how does meningococci enter blood from pharynx?
pilus-mediated adherence and penetration of mucosal epithelium (to gain access to circulation). recall n. meningitidis makes IgA protease.
recurrent lobar hemorrhages in elderly patient most likely results from..
cerebral amyloid angiopathy. (beta-amyloid deposited into arterial wall, weakining it, predispose to rupture). related to advanced age (not systemic amyloidosis)