Week 10 - Infection and inflammation Flashcards

Question

What are the 4 skin cell types?

Answer 1

Keratinocytes Melanocytes Langerhans cells Merkel cells

Answer 2

Lentigo maligna Albinism: Lack of melanin due to lack of enzyme required to make melanin: tyrosinase Vitiligo: macules of de-pigmented skin enlarging over time. Cause unknown

Answer 3

Asymmetry Border Colour Diameter

Answer 4

+ surface area from interdigitation between epidermis and dermis Epidermis and dermis adhered by hemidesmosomes Basement membrane between epidermis and dermis

Answer 5

Dense connective tissue: collagen 70% Papillary: conical papillae (rete ridges), richly vascularised (capillaries), lymph and nerve Reticular: Horizontal collagen and elastin fibres Contains hair and gland structures

Answer 6

_Thin skin:_ - Most locations - + eccrine glands and thin keratin layer - Less well defined rete ridges _Thick skin:_ - Fingertips + soles of feet - Thick epidermis and keratin layer and well developed rete ridges - + eccrine glands, no hair _Hairy skin:_ - Thin epidermis and lots of hair follicles and sebaceous glands

Answer 7

Simple Nucleic acids Proteins Lipids No organelles

Answer 8

Metabolically inert Rely on host cell Are obligate intracellular parasites

Answer 9

Independent component part synthesis Can be in separate parts of cell Under separate control Assembly into new particles

Answer 10

DNA --\> double / single stranded, circular / linear, 3kb-200kb RNA --\> ds / ss, ss = +ve / -ve polarity, linear / segmented, 5kb-10kb

Answer 11

Capsid formation --\> symmetry (icosahedral / helical) Attachment --\> specific cellular receptor and viral ligand interaction, determines viral tropism (preference to infect certain cell types) Enzymes --\> macromolecular synthesis enzymes Interference with cell function --\> i.e. stop apoptosis, avoid immune recognition

Answer 12

From host cell membranes Needs to contain external attachment proteins Loss of infectivity if envelope stripped Virus more fragile if enveloped

Answer 13

Nature of genetic material Nature of capsid Enveloped Size / shape Families, genera, strains

Answer 14

Attachment (cellular receptor / viral ligand) Entry (endocytosis, fusion) Uncoating Macromolecular synthesis (multiple viral genome and viral protein copies (requiring +ve ss RNA)) Assembly Release (budding (yielding enveloped virus), cell lysis)

Answer 15

Virion = mature virus particle --\> nucleic acid, protein coat (capsid), lipid envelope -ve polarity = can be translated at a ribosome Viral tropism = specificity of a virus to a specific host cell

Answer 16

Antibodies = block entry and binding to cells, activate intra-cellular degradation via TRIM21 Antibodies + complement = damage enveloped viruses, opsonisation for phagocytosis Antibody bound to infected cells = antibody-dependent cellular cytotoxicity

Answer 17

Recombination between 2 different viruses, forming a totally new one

Answer 18

Type 1 = enhance HLA class 1 protein expression and activate natural killer cells Interferons produced by infected cells bind to receptors on uninfected cells Uninfected cell is resistant to viral cell replication Protein synthesis is inhibited in cell and viral mRNA is degraded

Answer 19

Have CD8 receptors on surface Viral cell proteins degraded by protease, forming peptides Peptides are expressed on infected cell surface HLA class 1 proteins Cytotoxic T cells bind to the HLA class 1 protein and kill infected cell

Answer 20

Have kill activating receptor molecules Have kill inhibition receptor molecules too Binding to normal cell = don’t kill as stronger inhibition signal Abnormal cells = kill signal is dominant

Answer 21

1. The condition sought should be an important health problem 2. There should be an accepted treatment for patients with recognized disease, and treatment should be better at an earlier stage 3. Facilities for diagnosis and treatment should be available 4. There should be a recognizable latent or early symptomatic stage 5. There should be a suitable test or examination 6. The test should be acceptable to the population 7. The natural history of the condition, including development from latent to declared disease, should be adequately understood 8. There should be an agreed-upon policy on whom to treat as patients 9. The cost of case-finding (including diagnosis and treatment of patients diagnosed) should be economically balanced in relation to possible expenditure on medical care as a whole 10. Case-finding should be a continuing process and not a “once and for all” project.

Answer 22

1. Screening may produce earlier diagnoses 2. Earlier diagnosis may improve prognosis for those who develop disease 3. In some cases disease may be prevented 4. If treating early is cheaper than treating late, then screening may sometimes save money

Answer 23

1. Screening programmes cost money 2. Screening may induce anxiety in the well 3. Tests my cause harm directly 4. No screening test will detect all disease 5. A screen negative patient may delay presenting symptomatic disease if falsely reassured 6. There will be false positives 7. There will be over diagnosis

Answer 24

Time between when a disease can be detected through screening and when it can be clinicaly detected

Answer 25

Cell death --\> cytolytic or cytocidal infection (Rhinovirus) Chronic infection --\> continuous viral replication in cell, cell survives (Hep B) Latency --\> No replication of virus, no viral protein production, always infected once infected, reactivation of virus replication can occur, primary and secondary infections (herpes) Transformation --\> cell immortalisation (Epstein-Barr virus)

Answer 26

Skin Mucosal surfaces Respiratory tract Gastrointestinal tract Placenta

Answer 27

Skin – vesicles Respiratory tract – droplets Gastrointestinal tract – saliva, faeces Urogenital tract – urine, semen, female genital tract secretions Blood – BBV incl HBV, HCV, HIV Breast milk

Answer 28

Where a cell is destroyed Change in host cell structure caused by viral infection

Answer 29

Increase in the size of cells Can be physiologic/pathologic No new cells-just bigger Cells that don’t divide e.g. Cardiac and skeletal muscle Examples: exercise, hypertension

Answer 30

Increase in the number of cells Breast development at puberty/liver regeneration after resection/wound healing Eg psoriasis leads to thickened skin

Answer 31

Both adaptations individually result in enlargement of tissue Example of both together: Uterine enlargement (hypertrophy) during pregnancy is a consequence of smooth muscle hypertrophy and hyperplasia

Answer 32

Shrinkage in cell size due to loss of cell substance Functionally diminished but alive Eg immobilised or aging limb muscle

Answer 33

Reduction in number of functioning cells Due to reduction in functional demand (myometrium of uterus post partum) Usually by programmed cell death (apoptosis)

Answer 34

Change in type of cell - reprogramming of stem cells Survival mechanism in response to injury e.g. Smoking Specialised function is lost Can predispose to neoplasia Reversible + cancer risk

Answer 35

**A protective mechanism that functions to:** Eradicate cause of injury Remove damaged cellular material Initiate repair process

Answer 36

**1. Vasodilation** Slowing the local blood flow to the area (allowing time for plasma containing mediators to leave and for neutrophils to come into contact with the vessel wall) Enabling cells to contact the capillary endothelium Generating heat and redness **2. Increased vascular permeability** Allowing plasma carrying mediators out Causing swelling (oedema/tumor/turgor) **3. Cellular activation and migration** Neutrophils are activated to migrate from the vessels. They have a great capacity for phagocytosis Short lived so need to be replaced

Answer 37

Resolution --\> minimal damage, normal tissue restored Repair --\> damage too severe (scar forms) Chronic inflammation --\> persistent stimulus Abscess forms

Answer 38

Labile – replicate throughout life --\> i.e. skin (resolve) Stable – Non-dividing in normal circumstances but capable of regeneration --\> i.e. liver and kidney (resolve or scar) Permanent – non-dividing cells --\> i.e. neurons and heart (always scarring)

Answer 39

Granulation tissue --\> macrophages + fibroblasts + new blood vessels Fibrosis + scar formation --\> matrix laid down by fibroblasts, + collagen laid down forming scar to strengthen tissue Remodelling --\> reduction in number of vessels so pale scar remains

Answer 40

Inflammatory phase --\> macrophages producing growth factors for next phase Proliferative phase --\> granulation tissue, fibroblasts secrete matrix components + growth factors for angiogenesis, regrowth of epithelial cells over wound Remodelling --\> - vascularity, wound contraction

Answer 41

- Mediators of repair - Stimulate cell proiliferation, differentiation and maturation

Week 10 - Infection and inflammation Flashcards

(69 cards)