12 Basic Science Flashcards
Mechanism of Type III immune rxns
IgG and IgM complexes deposit in basement membranes of blood vessels resulting in outflow of plasma into tissues, activation of complement, and influx of neutrophils
Mechanism of Type IV immune rxn
overenthusiastic T cell response to an environmental Ag where macrophages damage adjacent tissues
Which cells can antigen present
monocytes, macrophages, dentritic cells, Langerhans cells, B cells
Which subtype of TH cell requires IL-1 to proliferate in response to Ag
TH2
What determines the class of an Ig
The heavy chain
Which Ig prevents parasite infxn
IgE
What immune cell displays CD2, CD16, CD56 and kills some types of tumor cells without depending on prior immunization
NK cells
In which are of the inner ear are immunologically active structures most commonly found and what is the predominant Ig there?
Endolymphatic sac; IgA
What is the concentration of Ig in perilymph vs serum
1/1000th
What is predominant Ig in perilymph
IgG
How long does it take for most acid-fast bacilli to grow
7-10 days
what infectious organisms are eukaryotic
fungi and protozoa
which cell type contains peptidoglycan in its cell wall
prokaryotes
The ability of bacteria to take up extracellular DNA from their environment is known as what
competence
Which bacterial infxn accounts for more deaths than any other vaccine-preventable bacterial dz?
strep pneumoniae
What percent of population is colonized in NP with strep pneumoniae
40%
What are 5 stages of biofilm development
- Initial attachment
- Irreversible attachment
- Maturation I
- Maturation II
- Dispersion
What type of cell receptor do thyroid hormone use
Nuclear
What hormone normally regulates protein synthesis and breakdown
insulin
1/2 life of T4
7 days
Thyroid hormone is stored as _____, the main component of colloid
Thyroglobulin
Most of the circulating thyroid hormone is bound by _______
Throxine-binding globulin
In pts treated for thyroid CA, post-tx thyroglobulin levels are less usefull in the presence of elevated _____
antithyroglobulin antibodies
What hormone receptors are present in JNAs?
Dihydrotestosterone and testosterone
What part of the pituitary gland is derived from Rathke’s pouch?
anterior pit
secretion of TSH from ant pit results in increased or decreased colloid production in thyroid gland?
decreased
what is the major inhibiting hormone of TSH
T3
when during day does growth hormone production peak
2-3 hrs into sleep (stage III or IV)
What is the major inhibiting hormone to growth hormone
somatostatin
what effect do exercise and stress have on growth hormone secretion
stimulate secretion
what is the m/c cause of DI
50% idiopathic
what happens to PTH levels as ppl age
rise
What will happen to reverse T3 and T3 levels during fasting, systemic illness, and acute psychiatric illness
Reverse T3 will increase and T3 will decrease
Which thyroid blood test correlates best with the metabolic state of the pt
Free thyroxine index (fT4I) = t4 x THBR (thyroid hormone binding ratio)
How long does it take for 100% Wallerian degeneration to occur after
- complete nerve transection?
- compressive conduction block?
- 3-5 days
- 14-21 days
B/w which days after injury is the degree of axonotmesis and neurotmesis unclear
6-14
Waht are the 3 types of nerve injury and which result in wallerian degeneration
Neuropraxia (no)
Axonotmesis (yes)
Neurotmesis (yes, more rapid rate of WD)
What is Sutherland’s classification for nerve injury
- 1st degree: reversible conduction block (neuropraxia)
- 2nd: WD occurs but endoneurium intact, recovery usu complete
- 3rd: Endoneurium destroyed but perineurium intact; recovery incomplete
- 4th: epineurium intact; recovery poor
- 5th: complete transsection, recovery not expected
Where is B-2 transferrin found
CSF, perilymph, vitreous humor
Where in the brain is the biological clock
suprachiasmatic nucleus
Which rootlet makes greater occipital nerve
C2
“The parasympathetic nervous system originates in the___ segments of the spinal cord while the sympathetic nervous system originates in the___ segments of the spinal cord
Craniosacral; thoracolumbar
What are the products of plt degranulation
TGF-B and PDGF
T/F: TGF-B stimulates cell proliferation
False, it inhibits it via stimulation of the SMAD proteins
What does p53 do
tumor suppressor gene on 17p that is upregulated in presence of cellular injury and DNA damage. It is supposed to arrest cell cycle at G1/S checkpoint
What is the role of cyclin D1 in H&N CA?
It is a kinase that leads to phosphorylation of RB protein (inactivating it) allowing cell to enter S phase
amplified in up to 1/3 of H&N CA
What is the role of cyclooxygenase (COX-1 and COX-2) in H&N CA?
Upregulation of cyclooxygenase has been shown to increase prostaglandins, decrease apoptosis, and increase angiogenesis via vascular endothelial growth factor in H&N tumors
What happens when epidermal growth factor receptor (EGFR) is bound by EGF or TGF-alpha?
Intracellular tyrosine kinase is activated, leading to inhibition of apoptosis and activation of cell proliferation and angiogenesis.
What is the role of EGFR and TGF-alpha in H&N CA?
Overexpressed in 80-90% of SCCa of the H&N
What is the prognostic significance of EGFR expression?
High levels of EGFR expression are correlated with poor prognosis and resistance to RT
“Autosomal recessive conditions are frequently associated with___ defects whereas autsosomal dominant conditions are frequently associated with___ defects.
enzyme; protein structure
Which type of inheritance pattern has a recurrence risk that varies with the number of affected family members
Polygenic inheritance
Hurler-Scheie syndrome is caused by which gene mutations with which inheritance pattern?
This syndrome is inherited in an Auto Rec pattern with the phenotype a product of 2 different mutations of the IDUA gene (compound heterozygotes)
What is a syndrome
pattern of multiple anomalies pathogenetically related
What is a microdeletion syndrome
Variable phenotypic pattern resulting from duplication or deletion of a small segment of linked chromosome material/genes that are functionally unrelated
What syndrome is caused by a microdeletion in chrom 17 and is a/w MR, broad feet and hands, peripheral neuropathy, HL, and recurrent OM, disturbed sleep patterns, and inserting foreign objects into bodily orifices
Smith-Magenis syndrome
What is a sequence
multiple defects arising from a single structural anomaly where the order of maldevelopment is understood
What is an association
malformations occurring together more frequently than would be expected from chance alone
What is genetic anticipation
a phenomenon seen in d/o caused by unstable trinucleotide repeats where the age of onset of the d/o is younger and the phenotype becomes more severe with each succeeding generation
“A classic example of genetic imprinting is seen with microdeletions of the region 15q11 to 15q13. A microdeletion of the paternal chromosome 15 causes___ and microdeletion of the maternal chromosome 15 causes____.
Prader-Willi syndrome; Angelman syndrome
