Final Flashcards
What does lentigo mean?
Flat (growing in a linear fashion)
What does nevus mean?
Nest
What characteristics indicate that a nevus may be dysplastic?
Large
Irregular border
Color variation
What can Acanthosis Nigricans be an indication of?
Often associated with hyperinsulinism and obesity, may rarely indicate stomach cancer
What is the sign of Leser-Trelat?
Sudden appearance of multiple seborrheic keratosis lesions
What physical exam tests are used for psoriasis and pemphigus?
Psoriasis: Auspitz sign. Scrape scale, get pinprick bleeding.
Nikolski’s sign: rubbing the skin quickly exfoliates outer layer and forms blister.
What is the relationship of topical steroids and tinea infection of the skin (athlete’s foot)?
There are topical creams that are combination steroid/antifungal, which seem to be overused for treatment of tinea infections.
- Topical steroids may make the infection worse.
- It takes several weeks to treat tinea, so patients treated with combo products are at risk for side effects from prolonged steroid use.
- Combo products are more expensive than antifungals alone.
What is the difference between erythema nodosum and erythema multiforme?
Nodosum: painful nodules on shins, associated with granulomatous dz and strep. Associated with subQ adipose.
Multiforme: vesicles, bullae, and targetoid red lesions, hypersensitivity rxn
What layers are involved in the following skin cancers: SCC, BCC, and melanoma?
SCC: stratum spinosum
BCC: stratum basale
Melanoma: melanocytes in stratum basale
On an H&E stain, which structures are red and which are blue?
Red (eosin) - cytoplasmic proteins
Blue (hematoxylin) - nuclear material
What is the difference between necrosis and apoptosis?
Apoptosis: Programmed cell death. Clean and orderly, everything is broken down and released in vesicles to be cleared by macrophages.
Necrosis: Inflammatory cell death. Cells burst open, giving rise to local inflammation.
What are common causes of cell injury?
Hypoxia, infection, immune reaction, congenital disorders, chemical injury
What diseases arise from deficiencies in the following vitamins:
A, C, D, K, B12, Folate, Niacin
A: squamous metaplasia, immune deficiency, vision problems C: scurvy D: bones K: bleeding B12: anemia, neuropathy Folate: anemia, neural tube defects Niacin: pellagra,
When does cloudy swelling occur?
When cell can no longer maintain ionic and fluid homeostasis.
Where do free radicals come from?
Ionizing radiation, smoking, pollution, inflammation, metabolism
Describe the pathway of injury in a cell that leads from mitochondrial dysfunction to swelling?
Mitochondrial dysfunction Decreased ATP --> higher mito permeability Release of cytochrome C --> apoptosis Na/K ATPase fails Influx of Na/H2O, Efflux of K Cellular swelling
What is anaplasia?
Anaplastic cells completely lack differentiation and divide rapidly.
Cells lose contact inhibition (grow on top of each other) and polarity, nuclei are very large and stain dark. Increased nuclear:cytoplasmic ratio.
What is the difference between primary, secondary, and tertiary intention?
Primary: wound edges approximate neatly, little scarring
Secondary: wound edges do not approximate, healing requires granulation tissue to grow in the gap, scarring and contraction
Tertiary: wound is physically prevented from healing until later, e.g. so it can be cleaned
What is the difference between hypoplasia and agenesis?
Hypoplasia is defective or incomplete development of a structure.
Agenesis is complete failure to develop.
Describe the different kinds of stem cells
Totipotent: give rise to all cells in body, plus placenta; only the first few divisions after fertilization
Puripotent: give rise to all cells in body; all embryonic stem cells
Multipotent: give rise to multiple cells types; adult stem cells, cord blood stem cells
Which basic tissue types have labile, stable, and permanent cells?
Labile: continually dividing; epidermis, mucosal epithelium
Stable: low level of replication; hepatocytes, renal tubule epithelium, pancreatic acini
Permanent: never divide; nerve cells, cardiac myocytes, skeletal myocytes
What are the three stages of fracture healing?
Procallus (anchors bones, but no rigidity)
Fibrocartilate callus
Osseus callus
What is the difference between a traumatic fracture and a pathologic fracture?
Traumatic: due to a force that breaks the bone
Pathologic: secondary to another condition, like cancer
What is a karyotype and what is an ideogram?
Karyotype: the set and appearance of chromosomes, often refers to a picture of the mitotic chromosomes.
Ideogram: the banding pattern on a mitotic chromosome.
**mutations must be larger than 4mb to be seen on a karyotype
What are the parts of a chromosome?
Long arm (q), Short arm (p), centrosome
How many pairs of autosomes and sex chromosomes are present in a normal human cell?
22 pairs of autosomes
XX or XY sex chromosomes
Medical vs general sense of “gene”
General: any functional unit of a chromosome, any trait
Medical: a specific protein-coding sequence on a chromosome
What is a locus?
The exact location of a gene on a chromosome (its address)
What are alleles?
Two or more variants of a particular gene. Different combinations of alleles give rise to normal human variation.
Genotype vs Phenotype
Genotype: the combination of alleles that an individual has
Phenotype: the physical traits expressed in an individual
What is a SNP?
Single nucleotide polymorphism. A mutation in which two homologous sequences of DNA (usually alleles) differ by only one base.
What is the difference between imprinting on the X chromosome and imprinting on autosomes?
In females, one entire X chromosome is turned off with generalized methylation. It shrivels up and is never transcribed.
Imprinting on autosomes refers to the fact that a small number of genes is only transcriptionally active when transmitted by one of the sexes.
This becomes a problem if there is a deletion of the non-imprinted copy of the gene–the individual effectively lacks that gene. Examples are Angelman and Prader-Willi Syndromes.
What are the 5 points of control for gene expression? Which is the most studied for epigenetic influence?
Chromatin stage (most studied in epigenetics)
Transcriptional stage
Translational stage
Post-translational control into cytoplasm
Post-translational modification
Why does DNA naturally wrap around histones?
What epigenetic changes occur to histone tails to encourage or discourage winding/unwinding?
DNA is negatively charged, histones are positively charged.
Methylation and deacetylation of histone tails discourages unwinding, acetylation encourages unwinding.
What is a promoter region on a gene, and why are promoter regions generally not methylated?
The promoter is an upstream sequence that attracts the RNA polymerase complex to the gene.
Promoter methylation results in permanent silencing of the gene.
What is the difference between exudates and transudates?
Exudate: high protein content
Transudate: low protein content
Transudates result in pitting edema.
What is Virchow’s triad, and what are examples of the diseases/conditions contributing to each of the three factors?
The three broad categories of factors thought to lead to thrombosis:
1. venous stasis (atrial fib, left ventricle dysfunction, immobility, varicose veins, venous obstruction)
- vascular injury (trauma, venipuncture, chemical irritation, heart valve dz, atherosclerosis, catheters)
- hypercoagulability (clotting disorders, pregnancy, oral contraceptives, nephrotic syndrome, age, IBD, malignancy)
What is the difference between and embolus and a thrombus?
Thrombus: a blood clot in a vein
Embolus: A mass that travels in the blood vessels until it blocks one (may be a broken off piece of a thrombus)
What are the features of pulmonary embolism?
Often clinically silent, arising from DVTs.
Classic presentation is postop patient who gets out of bed and collapses.
Dyspnea, tachypnea, pleural chest pain, cough + hemoptysis (coughing up blood)
What is the most common outcome of PE?
No sequelae and complete resolution in 75% of cases.
What is the newspaper test?
A quick way to determine if a fluid is transudate or exudate. If you can read a newspaper through it, it’s low-protein (transudate-transparent)
Which countries have the highest incidence of HIV?
South Africa and Botswana (?)
Describe the replication cycle of HIV.
HIV infects CD4+ cells, which includes CD4+ T-cells, macrophages, follicular dendritic cells, and Langerhans cells.
GP120 on virus surface binds CD4, then GP40 binds either CCR5 or CXCR4 for the virus to enter the cell.
Virus from T cells can infect macrophages, virus from macrophages can infect T cells.
Why do 10% of hemophiliacs not progress to AIDS?
Some people with hemophilia have a CCR5 deletion, so they lack the CD4 coreceptor required for the HIV replication cycle.
What are the phases of HIV infection that lead to AIDS?
Acute phase: initial infection, viremia with reduced CD4 count, Mono symptoms + lymphadenopathy, then seroconversion (antibodies against HIV appear, virus population crashes)
Latent phase: asymptomatic/lympadenopathy, low virus in blood, minor opportunistic infections, avg 10 years
What two neoplasms are most commonly seen in AIDS?
Kaposi sarcoma (Herpes 8, endothelial cells/B cells/monocytes, skin/GI/lymph/lungs) Non-Hodgkin lymphoma
What are the diagnostic criteria of AIDS?
HIV infection plus one of the following:
- CD4 count below 200
- CD4 less than 15% of total lymphocytes
- AIDS-defining disease