Module 2: Genetics and environment + integumentary system Flashcards
What are the nucleotide pairs?
Adenine - Thymine, Guanine - Cytosine
What are chromosomes?
Condensed DNA templates
What is DNA?
Individual coding molecules
What are genes?
Protein-specific DNA sequence code
What are the proteins used in DNA replication?
- DNA helicase (template unzipping)
- DNA polymerase (nucleotide addition and proofreading)
- DNA ligase (seals off the new DNA)
List the DNA mutations by the severity of protein alteration
Missense mutation (specific mispairing)
Nonsense mutaiton (codes the stop codon)
Frameshift mutation (insertion or deletion of a pair)
What are the differences between diploid somatic cells and haploid gametes?
Diploid are body cells, n=46, go through mitosis
Haploid are sperm and egg cells, n=23 (individual chromosomes), go through meiosis
What is polyploidy and aneuploidy?
Ploy: multiple of 23 chromosomes
Aneu: not a multiple of 23 chromosomes (ex trisomy 21 has 47 chromosomes)
What are the characteristics of Turner syndrome?
X chromosome anomaly, n=45, 1% of fetuses survive, loss of paternal X chromosome
- Short stature
- Abnormal female genitalia
- Exogenous estrogen for secondary sexual development
What are the characteristics of Klinefelter syndrome?
X chromosome anomaly, n=47, extra X chromosome
- male appearance & sterile
- small testes and female breast development
- Increased physical and mental alterations
What are the 4 types of chromosome breakage?
- Deletion (smaller chromosome, loss of information ex Cri du chat syndrome)
- Duplication (duplication of a section of the chromosome ex Huntington’s disease)
- Inversion (swapped info)
- Reciprocal translocation (2 chromosomes that swap a part of each other ex Chronic Myeloid Leukemia)
What is a phenotype?
The expression of a trait (outward appearance of organism)
Genotype + environment
What are alleles?
Variants of genes (ex pair of alleles BB or Bb or bb)
What is a genotype?
Refers to the pair of alleles, the genetic constitution of a person
What is a polymorphism?
the presence of 2 or more variant forms of a specific DNA sequence that can occur among different individuals (ex CYP2D6)
What happens when a red and a white flower have incomplete dominance alleles?
pink flower! (heterozygotes)
What happens when a red and white flower have codominance?
Red and white flower!! (heterozygotes)
Give an example of incidence
New cases of breast cancer in Quebec is 20/100 000 in 2018
(# of new cases in a timeframe, within a population)
Give an example of prevalence
Number of smokers in Québec is 17% in 2018
(ratio of affected individuals at a specific time, based on existing and new cases added up)
What is the difference between monozygotic and dizygotic twins?
Mono have 1 sperm and one egg, so they are genetic clones (identical twins)
Di have 2 sperms and 2 eggs (fraternal twins)
What is epigenetics?
It modifies the expression pattern of some genes. It is influenced by environmental factors. Some epigenetic modifications can be transmitted to offspring
What is the main constituent of skin, hair and nail cells?
Keratin
What is continuous turnover of skin cells?
The time it takes for a cell to go from stratum basale all the way up and then shed
What is found in the dermis?
Hair shaft, nerves, sweat and sebaceous glands, lymphatic and blood vessels, mast cells/macrophages/fibroblasts
What is found in the hypodermis?
Adipose tissue and blood vessels. It connects the skin to muscles
What causes male-pattern alopecia?
androgen-sensitive follicles
What is alopecia areata?
A T-cell mediated autoimmune disease causing the chronic inflammation of hair follicles
What could indicate hirsutism?
Endocrine disorders like polycystic ovaries, adrenal hyperplasia or tumours
What is paronychia?
Infection of the cuticle
(abcess may develop, moisture increased risk of infection. caused by strepto or staph)
What is onychomycosis?
Infection of the nail plate
(hyperkeratotic debris within the plate, shows yellow and elevated nail. caused by a fungal or dermatophyte infection)
Explain the 4 degrees of frostbite
1st: superficial freezing of the epidermis
2nd: full thickness freezing (hypodermis and dermis)
3rd: deep and full-thickness + subcutaneous freezing (hypodermis, dermis and subcutaneous)
4th: Deep and full-thickness + subcutaneous freezing + gangrene (cells undergoing necrosis)
What happens to hair with aging?
Lower count of melanocytes (responsible for pigmentation) and Langerhans cells (specialised macrophages) which lead to the loss of protection and hair color
What happens to skin with aging?
Loss of elastin, collagen and fibroblast leads to the loss of elasticity and increases wrinkles
What are the 4 stages of pressure injuries?
1: irritation of the skin
2: down to the soft tissues (fatty tissues, dermis)
3: reaches the muscles or other structures
4: bone is exposed
What is the pathophysiology behind allergic contact dermatitis?
allergen contact on skin -> triggers immune cells -> T-cell activation + cytokines release -> inflammation
What is the pathophysiology behind irritant contact dermatitis?
skin barrier compromised -> exposition to irritant -> inflammation in response to injury (injury is proportional to irritant concentration and exposure)
What is the pathophysiology behind psoriasis?
Th17/IL-23 pathway hyperactivation -> extensive/constant skin inflammation -> keratinocyte hyperplasia + vasculature -> plaque formation
What are the 4 risk factors for acne vulgaris?
Hyperkeratinization, increase of sebum production (from increased androgen/testosterone levels), increase proliferation of P. acnes bacteria, rupture of sebaceous follicle
What is the pathophysiology behind acne vulgaris?
risk factor -> skin pore obstruction -> inflammation
What is the pathophysiology behind acne rosacea?
chronic abnormal vasodilation -> erythema
What are the common hallmarks of acne rosacea?
Photosensitivity, fibrosis and telangiectasia (flushing) and sebaceous hypertrophy
What is the pathophysiology behind discoid lupus erythematosus?
UV light + altered immunity -> activation of self-reactive T&B cells -> formation of autoantibodies immune complexes (AIC) -> skin damage + vasculitis
What is the pathophysiology behind herpes simplex?
virus infects epithelium cells -> latency in local dorsal root ganglion -> viral reactivation -> skin lesions
What is the pathophysiology behind herpes zoster & varicella?
virus infects epithelium cells -> latency in local root ganglion -> viral reactivation -> skin lesions
What is the pathophysiology behind Kaposi sarcoma?
immunosuppression -> latent HSV-8 opportunistic infection -> multilocal lesions & inflammation at blood vessels -> characteristics purple plaques & nodular lesions
What is the pathophysiology behind Lyme disease?
tick bite -> bacterial invasion of tissues -> localized erythema migrans (T-cell mediated) -> systemic spreading -> secondary erythema migrans + complications
What are the 3 stages of infections for Lyme disease?
1: localized erythema migrans (days after bite)
2: spreading of illness with neuralgias and neuritis/carditis (weeks)
3: late persistent can lead to encephalopathy and heart failure
