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FunMed PBL > PBL 5 > Flashcards

PBL 5 Flashcards

1
Q

Haematoma

A

an abnormal collection of blood that has clotted outside a blood vessel

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2
Q

Subcutaneous nodule

A

a firm lump under the skin that is often the result of infection and inflammation

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3
Q

Hyper-extensible

A

being able to be stretched to a greater than normal degree

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4
Q

Episiotomy

A

a surgical cut made in the perineum to enlarge the vaginal opening for childbirth

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5
Q

Skin biopsy

A

a small sample of skin is removed and examined under an electron microscope

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6
Q

Name some autosomal dominant diseases

A
  • huntingtons,
  • marfans syndrome
  • classic elhers danlos
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7
Q

Name some autosomal recessive

A

cystic fibrosis and sickle cell

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8
Q

name some X linked dominant

A

Fragile X syndrome

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9
Q

Name some X linked recessive

A

haemophilia

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10
Q

if one parent has elhers danlos then …

A

50% chance that the child will get it

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11
Q

how many people does EDS effect

A

1 in 5000

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12
Q

how many different types of EDS are there

A

10 different types which are classified in 6 major groups

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13
Q

What is ehlers-danlos syndrome

A

A heterogenous group of inherited connective tissue disorders.

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14
Q

who does Ehlers danlos effect

A
  • caucasians more than other races

- usually manifests in young adults as some of the clinical manifestations only develop during early childhood

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15
Q

How is elhers dakloos mis diagnose

A
  • only 5% of suffers receive a diagnosis
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16
Q

what is each type of EDS charactersticed by

A
  • Gene mutation

- inheritance patterna dn symptom

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17
Q

describe the genetics and clinical manifestation of EDS classic (type 1 and type II)

A
  • COL5A1
  • COL 5A2
  • TYPE V COLLAGEN
  • autosomal dominant
    2nd most prevalent type after hyper mobility
  • can arise from de novo - caused by a mutation in a germ cell and occurs in many cases
18
Q

how many individuals does classic EDS occur in

A

1 in 20,000

19
Q

what collagen does classic EDS affect

A
  • affect type V collagen

type I - severe skin involvement
type II - mild to moderate skin involvement

20
Q

What are the clinical features of classic EDS

A 
Skin hyper-elasticity
Atrophic scars
Joint hypermobility
Abnormal bleeding
Bruising
Fragile tissue
21
Q

what do COL5A1 and COL5A2 code for

A

code for collagen type V

22
Q

what does collagen type V do

A

Collagen V regulates fibril formation and co-polymerization of collagen type I.
- regulates the dimatere and assembly of heterotypic type I collagen fibres

23
Q

describe how collagen V affects collagen I

A

In classic EDS, abnormal collagen V production affects collagen I.
Collagen I makes up the majority of collagen in the dermis and a large proportion in cartilage, so EDS indirectly affects this.

24
Q

How does collagen type V form

A

Synthesis of type V collagen begins with three pro-α(V) chains wound around each other to form a triple helix. There are two types of pro-α(V) chains: pro-α1(V) is coded for by the COL5A1 gene, whilst pro-α2(V) is coded for by the COL5A2 gene. Type V collagen can be composed of three pro-α1(V) chains or two pro-α1(V) and one pro-α2(V) chains.
These triple-stranded procollagen chains are secreted from the cell and processed by enzymes to from mature type V collagen which copolymerises with type I collagen
- short fibril intermediates are formed which increase in size through linear and lateral fusion events

25
Q

when does growth of collagen type V stop

A

Fibril growth is stopped by type V collagen when the diameter of the type I collagen fibrils becomes consistent.

26
Q

what happens in the absence of collagen V

A
  • results in unregulated collagen I assembly
  • absence of or insufficient type V collagen results in unregulated self assembly of type I collagen fibrils which causes irregularities their diameter and shape
27
Q

what is the mutation in Andreas’ case

A
  • C → G in the COL5A1 gene caused a nonsense mutation.
  • Truncated COL5A1 mRNA disrupted collagen V formation.
  • Non-functional collagen V caused collagen I fibrils to become irregular and disordered.
  • Tight packing of collagen I disrupted = Characteristic abnormalities of classic EDS.
28
Q

what are major criteria of classic EDS

A
  • skin hyper extensibility
  • widened atrophic scarring
  • joint hyper mobility
  • positive family history
29
Q

what are minor criteria

A
  • smooth velvety skin
  • subcutaneous spheroids
  • easily bruising
  • manifestation of tissue extensibility and fragility
30
Q

How do you diagnose EDS

A

Physical examination - look for clinical features
Assess hypermobility using Beighton criteria
Major criteria includes arthralgia (joint pain > 3 months) and 5/9 Beighton score)
Skin biopsy for collagen typing
Collagen gene mutation testing

31
Q

What does a physical examination involve

A
  • involves testing the skin
    if the skin feels fragile, soft and velvety
  • hyper extensibility can be tested by pulling the skin and seeing how quickly it returns to its original state after release - EDS has skin that will extend and immediately snap back
  • Beighton score to identify the extent of a patients joint hyper mobility
  • family history
32
Q

How do you test for EDS

A
  • genetic test - determine the base sequence of either COL5A1 or COL5A2 by Sanger sequencing 0 classic EDS will possess a premature stop codon in one of these genes
  • skin biopsy - allows analysis of collagen fibres using gel electrophoresis, abnormal collagen proteins in patients with EDS will migrate in a visibly different way on the gel compared to collagen proteins
33
Q

How to treat EDS

A 
No specific treatment
Measures should be taken to manage symptoms and prevent further damage to skin & joints
Physiotherapy
Painkillers
Vitamin C - reduce bruising
 Avoid contact sports
34
Q

what does the epidermis contain and what cells is it made out of

A
  • in stratified squamous epithelium
  • contains keratinocytes that produce keratin
  • also contains melanocytes and langerhnas cells
35
Q

what are the layers of the skin

A 
Stratum corneum (C) – corny 
Stratum lucidum (L) - lucy
Stratum granulosom (G) –gets 
Stratum spinosum (S) – super 
Stratum basale (B) - baked

Dermis

36
Q

what are the 3 main layers of the skin

A
  • epidermis - is stratified squamous epithelium that is made up of mainly keratinocytes
  • dermis - This layer of skin contains hair follicles and sweat glands, embedded in dense irregular connective tissue (which is made up of collagen and elastic fibres). Fibroblasts and immune cells are abundant in the dermis
  • hypodermis - The hypodermis (also called subcutaneous tissue) forms the lower layer of the skin. It contains blood vessels and adipocytes, which store lipids for energy release.
37
Q

what separates the epidermis and dermis

A

basement membrane

38
Q

How does wound healing take place

A
  1. Haemostasis
    - Forming stable clot
    - enzyme thrombin converts fibrinogen to fibrin, allowing the formation of a fibrin clot at the site of infection
  2. Inflammation
    - High blood supply, release of cytokines and growth factors
    - neutrophils and macrophages migrate to the wound and stimulate inflammation
  3. Proliferation
    - Increased fibroblasts, which begin to lay down new extracellular matrix, including collagen.
    - fibroblasts multiply and secrete collagen fibres into the extracellular matrix
  4. Re-modeling
    - Completion of ECM deposition, healing of epidermis
    - where collagen fibres become organised to form the new, mature tissue
39
Q

what part of wound healing is affected by EDS

A

Stage 4 is effected by EDS:
In normal wound healing, collagen III is deposited largely at first then replaced by collagen I. This does not occur properly in EDS
This has an effect on wound contraction, meaning wounds gape and are atrophic.

. It is this stage that is affected by EDS as the collagen fibres cannot organise themselves into regular structures. Only partial wound contraction occurs, leading to scars that gradually widen.

40
Q

what is child abuse

A

Child abuse = When a parent or caregiver, whether through action or failing to act, causes injury, death, emotional harm or serious risk to a child.
Includes neglect.

41
Q

what are the most common concerns of child abuse

A

Emotional abuse
Neglect
Parental substance abuse

FunMed PBL (7 decks)

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