physiology Flashcards
Non nutritent ecoli
Acanthamabea
Enzymes that control translation
Translation is the production of an amino acid sequence from mRNA in the cytoplasm. It is controlled by 2 main enzymes: aminoacyl-tRNA synthetase (which helps join tRNA to its specific amino acid) and by peptidyl transferase which involves the uncoupling of the tRNA from the amino acid and joining of the amino acid to the growing polypeptide chain.
Cells that produce eicosanoids
Prostaglandins, thromboxane and leukotrienes are all eiconsanoids, produced from arachidonic acid. Prostaglandins and thromboxane require cyclo-oxygenase, while leukotrienes require lipoxygenas
Which is the most appropriate imaging modality for a patient with a suspected exacerbation of thyroid eye disease?
T2 with STIR
Where does post transcriptional modifications take place
Nucleus
Translation occurs in
Cytosol
Crossing over occurs in what stage of reproduction
Prophase I
Independent assortment
Genes appear in the same order but different alleles
Genetic linkage is
genes inherited due to close proximity
5 main functional group of the golgi apparatus
cis golgi network
cis golgi
medial golgi
trans golgi
trans golgi netwrok
Function of RER
Lots of ribosome attached to it to give rough appearance
Proteins from cytoplasm processed before reaching Golgi apparatus
Extensively present in cells which produce secretory proteins
Post-translational modification of proteins occur here. Folding of proteins occur here
Adhesion of ribosomes is energy dependent. Ribosome detaches in hypoxic cell injury where ATP/GTP synthesis reduced
Proteins are destined for:
Secretion into extracellular matrix eg: enzymes
Cell membrane eg: channels
Membrane bound vesicles: enzymes of lysosymes
If proteins are not folded properly, a stress response known as unfolded protein response ( UPR) is generated.
UPR and mammalian target of rapamycin ( mTOR) mediate apoptosis, protein translation, autophagy, ATP supply
Function of SER
Smooth endoplasmic reticulum (SER)
Synthesis of phospholipids, steroids
Contain cytochrome p450 for metabolism of drugs and toxin
Storage of glycogen in cell region rich in SER
In muscle, known as sarcoplasmic reticulum
PAX 6
Anirdia, AD foveal hypoplasa
Pax 2
Optic nerve colomba
Pax 3
Waardenberg syndrome
AD cornea dystrophy ?
Meesman dystrophy - Beta 1g- h3 gene
Reiss BUckle - Thiel Buckle
Granular dystrophy - BIGH 3 gene
AD lens and anterior segment?
Marfans fibrillin1 gene
Anirdia PAx6 gene
X linked dominant?
Inconinteima pigmentii
Alport syndrome
A
AD vitroretinal ?
Sticklers, RP (20-25%), Best
Relatationship between gene legnth and x linked retinopathies /
Positive correlation
Percent of females with x linked disorders
13%
CHM?
Loss of REP1 affects rab protein: loss of autoflouresence.
OCT structural changes in RPE
Cells that produce mucus?
Goblet cells
lacrimal acinar cells,
corneal epithelium
conjunctival epithelium
Principal mucin in tears ?
MU5AC - secreted by goblet cells along with TFF1 and TFF3
Accumlation of goblets cells on tarsal conjunctiva and bulbar conjunctiva?
Tarsal - Henles crypts
Bulbar - Manz glands - near limbus
T helper 1 actiavtes?
INFy, IL2 and TNF a and b, intracellular pathogens
T helper 2 activates ?
IL4, IL5 and ail10, Extracellular pathogens and allergic eye conditions
Th17 activates ?
IL7, 21,22,24
associated with retinonit acid receptor related oprhan receptor; receptor alpha
Immunity against extracellular patogens
Defence of mucosal system
Dysregulation with systemic infalmmaotory
Associated with birdshor chroiretinopahty
Treg cell
Express CD4, 35, and FOXP3
2x types ntreg and itreg
activate TGFB and IL10
MMP hypersensitivity ? mechanism ? antigen against what anitbodies?
Type 2.
Antibodies against cell surface in BM zone.
BP 2 against BP120, 230 and lumin 332.
Type 7 collagen and overexpression of il1 and TNFa
Associate with HLA DR4
Direct investgation of MMP ?
Micrscopy: Tissue bond to IgG, IgA and complex c3.
Visulaizes in viv obond immunoreactant along BM zone
Sensitivity 40 -100%
if neg –> biopsy
Most common collagen in sclera?
Type 1
A 21-year-old man with insulin dependent diabetes mellitus presents with hypothyroidism. His HLA (human leukocyte antigen) haplotype is most likely to be:
HLA B27
HLA A1 B8 DR3
HLA B51
HLA DR4 and DR1
HLA A1 B8 DR3 is commonly associated with organ specific autoimmune disease. IDDM can also be associated with DR4.
HLA B27 is strongly associated with seronegative arthritis, and HLA B51 is associated with Behcet’s disease.
HLA DR1 and DR4 (or a shared epitope in these class II proteins) is associated with RA (rheumatoid arthritis).
Tyrosine kinase uveitogenic pathway ?
Melanocytes associated with Vogt Kayandi Harda
Recoverin
Calcium binding protein. Target for anticancer
Bovine melanin protein uvetigoenic pathway
Choroidal disease
Retinal S ag protein uvetigoenic pathway
photorecepetor area of retina; pineal gland
Prothrombotic precurosrs
Von Willebrand,
Factor IXa and X
Factor V
Thromboplastin
Antithrombotic Modulators
fPA: plasminogen–>plasmin
Antithrombin 3 –> ianactivates thrombin
Factor XIIa, XIa, Xa, IXa
Thrombomodulin –> protein C–> inactivates V and VII
Muller cells are associated with what Mac Tel ?
Type 2
Cytokine required for the development of each CD4
IL-2/ TGF beta: T reg
IL12: Th1
IL2,IL4: Th2
IL6, IL21, IL23, TGF beta: Th17
Th1 lymphocyte association?
Th1 lymphocytes is involved in classic delayed type hypersensitivity . Associated with sympathetic ophthalmia
Th2 lymphocyte association?
Th2 lymphocytes is associated with parasite induced granulomas . Associated with toxocara granuloma
What MHC complex do CD4 cells respond to ?
Respond to antigen in association with MHC class II self antigen
Method by which mitochondria replicate?
Binary fission
3 functions of cilary body
Accommodation
Production of aqueous humour
Production of collagens and glycosaminoglycans of the vitreous, and lens zonules
Where is aqueous humous produced from?
Production of aqueous humour is from the ciliary process which has a bilaminar cuboidal neuroepithelium of the non pigmented layer
The gap junctions present at the outer pigmented epithelium ciliary body layer?
Histologically, the outer pigmented epithelium layer is held together by punctate adherentes and permeable zonula adherentes. Macromolecules are prevented from passing into the posterior chamber.
Histology of GCA
Histology:
Chronic granulomatous inflammation affecting internal elastic lamina.
Mononuclear lymhpohistiocytic cells
Neutrophils
Eosinophils
3) Healed arteritis histology:
Discontinuous elastic lamina
Fiibrosis of intima/media with focal calcification
4) Atherosclerosis histology can be confounding:
Also has intimal hyperplasia and fragmentation of the lamina
3x different pre translational / post transcription process that are required to convert immature mRNA to mature mRNA
Pre-translational mRNA processing
1) mRNA has to be processed to mature mRNA via several processes
2) 5’ capping-addition of methylated guanine cap to the 5’ end of mRNA
Allows ribosome to recognise this molecule
Protect mRNA from degradation by RNAases
3) Polyadenylation -addition of poly (A) tail to 3’ end of mRNA
Contains adenosine monophosphate to stabilise RNA
4) Splicing-allows for one genetic sequence to code for different protein
Introns removed via spliceosome excision
Exons joined together by ligation
This allows many proteins to be made by one pre-mRNA
Neutrophil (polymorphonuclear leucocytes) antibacterial properties?
Contain antibacterial agents such as:
Free radicals ( eg: hydrogen peroxide)
Enzymes ( eg: elastase, myeloperoxidase)
Peptides ( eg: defensin)
Ion binders ( eg: lactoferrin)
NETS (neutrophil extracellular traps) composed of nuclear DNA material are used to trap bacteria
Have a role in trapping metastatic cells
Involved in the adaptive immune response through release of cytokines, extracellular vesicles
They are not classically thought of to be antigen presenting cells ( Classical APCs include dendritic cells, macrophage, Langerhans cells and B cells)
4 types of inflammation
1) Acute
Suppurative: Neutrophils
Nonsuppurative: Lymphocytes
2) Chronic
Non-granulomatous: Lymphocytes/plasma cells
Granulomatous: Epithelioid histiocytes (3 subtypes)
3) Endophthalmitis
Inflammation of at least one inner coat of the eye and adjacent cavity (NO scleral involvement)
4) Panophthalmitis
Suppurative endophthalmitis with scleral and orbital and involvement
kollners rule
Kollner’s rule is an ophthalmological principle that describes the relationship between different types of color vision deficiencies and the anatomical location of the underlying damage within the eye. According to Kollner’s rule:
Red-Green Defects (Protan and Deutan Defects): These are usually linked to inner retinal or optic nerve issues
Examples include most optic atrophies, optic neuritis, Leber’s, optic nerve compression.
Drug causes: Ethambutol, MAO inhibitors.
Exceptions are AD optic atrophy, glaucoma, and acute demyelinating neuropathy (affect blue-yellow more than red/green).
Blue-Yellow Defects (Tritan Defects): These are typically associated with outer retinal or media abnormalities.
Macular Fluid: Fluid in or under the retina, e.g., macular edema, retinal detachment, or CSC.
Macular disease: AMD.
Peripheral retinal or macular diseases.
Drug causes: Chloroquine, Indomethacin, Phenothiazine, Thioridazine, Digoxin, PDE5 inhibitors.
Exceptions are RPE dystrophies and Cone dystrophies.
Also, cataracts at later stages may affect all colors.
Test used to differenciate acquired veruss inherited color defects?
FM-100 tests are often used to differentiate acquired vs. inherited color defects
Inv for tritan defect
Hardy-Rand-Rittler (HRR) plates are often used to detect Tritan defects.
Tight junctions:
Tight junctions are also known as zonulae occludens. They can be found at the
Blood aqueous barrier of ciliary body
Blood retinal barrier at the apex of RPE cells
3) They have no ‘space’ between the cell membranes and form a barrier to paracellular diffusion of molecules.
4) The major proteins in tight junctions are
Transmembrane protein-occludin , claudins
Signalling proteins-alpha PKC, CDK4
Transcriptional regulators-AP-1
Adaptors-cingulin, MUPPI, ZO-1
Adherens junction description and size of gap
Adherens junctions are also known as desmosomes. The width is 20nm between cells. The two main types of desmosomes are
Spot desmosomes
single site
Belt desmosomes
ring around apex of the cell
also known as zonule adherens
The role of desmosomes is to provide adhesion between cells - stratifies quamous epitelium to cornea
Gap junction size gap and role
Gap junction has a 2nm gap between cells
Occur in cardiac muscle and ocular muscles
Allow passage of larger ions such as Ca2+ and signalling molecules to permit coordinated responses.
Example of enzymes for cutting DNA
Example of enzymes:
Zinc-fingered nuclease ( ZFNS)
Transcription activator like effector-based nucleases ( TALENS)
Meganuclease
CRISPR-Cas9 ( Clustered Regularly Interspaced Short Palindromic repeats with CRISPR associated protein 9)
relationship between alcohol abuse and gluconeogenesis ?
alcohol abuse depletes pyruvate required for gluconeogenesis-leading to hypoglycaemia
The cytokine which induces differncitation of CD4 t cells into T Helper 1 ?
IL12
Cytokine which increases the expression of MHC I and II
INF gamma
How many PCR are reuqired ?
30
Cytokine responsible for inhibiting viral replication ?
INFalpha
Are natural killer cells granulocytes or agrunloyes
They are granuloctes.
Effect against tumour and viral cells
In both innate and adaptive immunity
What aa is histamine derived from ?
Histidine
What is gluconeogenesis ?
Stimulates glucose from no carb souce
What is fibrillin?
Glycoprotein
Dark adaption is measured using ?
Goldmann Weekers adapotmeter
The classical pathway of complement cascade is what ?
Classical pathway
Binding of C1q to antigen antibody complex
Function of vitamin A
Epithelial keratin expression
Synthesis of cell surface glycoproteins
Deficiency leads to keratinization of corneal epithelium
Wound healing
Deficiency can lead to stromal melt ( keratomalacia)
Synthesis of alpha-1 proteinase inhibitor
Alpha-1 proteinase inhibitor protects the avascular corneal tissue against proteolytic damage
Protective effect on corneal endothelial cells
BIGH 3 is involved in what condition?
BIGH-3 mutation is situation on chromosome 5q31-encoding for protein expressed on cornea epithelium; stromal keratocytes. Implicated in adhesion and wound healing.
Associated with corneal dystrophies involving Bowman’s layer ( Reis-Bucklers, Thiel-Behnke); stromal dystrophies ( granular, lattice and Avellino).
Elastin - where it is found ? What secretes it? how is it formed ?
Insoluble protein of extracellular matrix.
Found in deformable tissues such as lungs, lens zonules, blood vessel wall
Secreted from fibroblast, smooth muscle cells.
Formed from soluble tropoelastin monomers
Forms random coil, little order to tertiary structure
size of mitochonidria ?
2um
Arrangment of sacroplasmic reticulum in EOM?
Triad?
Most common Glu transporter in the brain and its activity
In contrast with peripheral tissues, the brain is considered an insulin-insensitive organ because GLUT-4 is present at low level and it does not seem to be significantly regulated by insulin
2 things that CD4 activate?
Activate b cell and macrophages
Chromosome that the p53 gene is located on ?
what gene influences if
CHr 17
BAX gene
Xeroderma pigmentosa is an example of what DNA repair?
SS DNA repair - nucleotide excision
T arm is used for ..
D arm is used for ..
T arm - ribosome attachment
D – attracting AA
Distribution of KP is influenced by ?
Inferior - temperature
Alts triangle - herperitic anterior uveitis
Fresh and pigmented KP indicates ?
Viral - hsv, vzv,
Granulomatosis versus non granulomatosis ?
Granulomatosis; chronic; prolonged antigenic stimulation
Non- Granulomatosis; acute;
size of small, medium and large KPs
Small - 15-30 um
Med: 30-100 um
Large40-150 um
Heterotrophic calcification ? Met versus dystrophic
Met; happens in igh calcium staes
Dys; occurs in dead or damaged tissue. Normal serum calcium
ocular response of suture ?
PMMA?
CMO
Silicone plastic tubules
Hyaluronic acid
Silicone oil ?
Sutures - giant cell granulomatous
PMMA - no response
CMO - metastic lens epithelial cells - not for inflammatory rxn
Silicone plastic tubes - minimal inflam response, but bands can be blocked by surrounding fibrous capsules
Hyaluronic acid - inert
Silicone oil ; low grade macrophage after oil is emulsified
Apoptosis intrinsic and extrsnisic pathway ?
Intrinsic - Mitochondia - BCL (anti) and BAK (pro)
Extrinsic
- ligand receptor; expressed on iris, corneal endothelium
Immune cell: Cytotoxic T cell release of perforin and granzyme B
Gene that code for VEGF?
The Chr 6p12, 45kDa
Ranibizumab;
Monoclonal AB - huma FAB VEGF
Afbercept?
Decoy VEGF A recpetor
4 glycosaminoglycan
lumin, keratocan, miecan,decorin
Proteoglycan examples
Type IX;
Aggregcan;
Veriscam,
Fibrillinogenesis;
Fibromoduline;
core protein covalently attached to glycoaminoglycan
Type IX; collagen binding
Aggregcan; cartilage
Veriscam, decorin for fibrillinogenesis; fibroblast
Fibromoduline; Keratocytes
Corneal Transparency
lumin, keratocan, miecan,decorin and collagen VI and XII
The light reaction can be summarised as:
all-trans retinal to 11-cis retinol
11-cis retinal to all-trans retinol
all-trans retinol to 11-cis retinol
11-cis retinol to all-trans retinal
11-cis retinal to all-trans retinol
Drugs that cause IIH
tetracyclines
fluoroquinolones
vitamin A/retinoids
progesterones
corticosteroids
anabolic steroids
amiodarone
lithium
phenytoin
tamoxife
Which portion of the iridocorneal angle is usually the easiest for distinguishing landmarks on gonioscopy?
temporal
nasal
superior
inferior
inferior
The outer capillary plexus of the retina is contained in:
the ganglion cell layer
the inner plexiform layer
the inner nuclear layer
the outer nuclear layer
Inner nuclear layer
The cell bodies of the ganglion cells are located in which retinal layer:
ganglion cell layer
outer nuclear layer
inner nuclear layer
nerve fibre layer
Ganglion cell layer
The outer nuclear layer contains;
layer contains the cell bodies of the photoreceptors (rods and cones).
Inner nuclear layer
The inner nuclear layer contains the cell bodies of bipolar cells, horizontal cells, and amacrine cells, which process visual information.
Nerve fibre layer consists
The nerve fiber layer consists of the axons of ganglion cells that converge to form the optic nerve.
A Maddox rod test is performed on a patient. With the rod held before the right eye, he sees a red line above a point of light.
What is the diagnosis:
right hypophoria
orthophoria
right hyperphoria
right exophoria
right esophoria
right hypophoria
Maddox rod test interpretation:
Line above point: covered eye is hypo-deviated
Line below point: covered eye is hyper-deviated
Line temporal: covered eye is eso-deviated
Line nasal: covered eye is exo-deviated
