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