Disorders of Growth and Differentiation Flashcards
Name four different types of growth
Multiplicative
Auxetic
Accretionary
Combined pattern
What is auxetic growth?
Growth in cell size as opposed to cell number
What is accretionary growth?
A cell secretion to increase the volume of the extracellular spaces.
What is a combined pattern of growth?
A mix of any of the other types of growth
What are the different types of increased growth?
Hyperplasia - An increase in the amount of organic tissue that results from cell proliferation
Hypertrophy - An increase in mass of a cell, tissue, or organ without cellular proliferation
Combined hypertrophy and hyperplasia
What is an example of physiological hypertrophy?
Athletes muscle
What is an example of pathological hypertrophy?
Right ventricular hypertrophy
Abnormal enlargement of the cardiac muscle surrounding the right ventricle - when the heart has to work harder
What is an example of physiological hyperplasia?
Adaptation to altitude
Psoriasis
What is an example of hyperplasia in tissue repair?
- Angiogenesis
- Wound healing
- Liver regeneration
- Heart
Give an example of physiological atrophy?
The thymus goes through regressive alterations with age
Ageing in general
Give an example of pathological atrophy
- Muscle – fractures
- Nerves - paraplegics
- Blood supply – circulatory problems
- Pressure – bedsores
- Diet - anorexia
What is Turner’s Syndrome?
Occurs in females with a missing X chromosome
Puberty will not occur or only partially occur
Females are shorter than average by 20 inches, only 5 with HRT
can live normal lives with regular chechup
What is SHOX?
Short stature homeobox gene present on X and Y chromosomes
If mutated or one is missing it is associated with shortened stature syndrome
Where is SHOX expressed?
SHOX is expressed in chondrocytes of the human growth plate
What gene is linked to Down syndrome?
Trisomy 21
What is Down syndrome associated with?
- Small stature
- Hypotonia
- Heart Defects
- Learning difficulties
How may Down syndrome be identified?
Flattened nose and face, upward slanting eyes
Single palmar crease, short 5th finger that curves inward
Widely separated first and second toes + increased sole skin creases
What is Beckwith-Wiedemann syndrome?
- Inheriting two copies of a chromosome from one (paternal) parent and none from the other is bad news
- Increased expression of IGF-II
- Decreased expression of H19
- Overgrowth in early childhood
What is pituitary gigantism?
• Increased IGF-1
• Increased growth hormone
• Often from pituitary tumours
You grow real big
What are some disproportionate alterations of skeletal growth?
- Achondroplasia (dominant allele)
* FGFR3
What does loss of FGFR3 do?
Loss of FGFR3 increases growth
As
FGFR3 suppresses growth
Where does mutation of FGFR3 have most effect?
Mutation of FGFR3 has most effect in chondrocytes
What is metaplasia?
- Change of differentiated cell type
- Response altered cellular environment
- Often epithelial or mesenchymal cells
Give an example of metaplasia
• Epithelium of trachea and bronchi in smokers
What is dysplasia?
- Increased cell proliferation
- Atypical morphology
- Decreased differentiation
- Often Premalignant
What is neoplasia?
- Abnormal uncoordinated excessive cell proliferation
* Persists after initiating stimulus withdrawn
What are some disorders of differentiation and morphogenesis to do with anomalies of organogenesis?
– Agenesis – Atresia – Hypoplasia – Ectopia/heterotopia – Maldifferentiation
What cause congenital abnormalities in disorders of differentiation and morphogenesis?
Genetic or teratogenic(mutagen but for embryos kinda) causes
What is agenesis?
The failure of an organ to develop during embryonic growth and development due to the absence of primordial tissue
What is atresia?
A condition in which an orifice or passage in the body is closed or absent
What is hypoplasia?
Underdevelopment or incomplete development of a tissue or organ. Although the term is not always used precisely, it properly refers to an inadequate or below-normal number of cells
What is ectopia/heterotopia?
A displacement or malposition of an organ or other body part, which is then referred to as ectopic
What is maldifferentiation?
- Failure of normal differentiation
* Persistence of primitive embryological features
Provide some examples of atresia
Failure to develop a lumen
– Oesophageal atresia
– Duodenal atresia
– Imperforate anus
Failure to close
• Spina bida
• Cleft palate
What is multicystic renal dysplasia (MRD)?
Multicystic renal dysplasia (MRD) is a malformative condition of the kidneys characterized by an abnormal metanephric differentiation and a renal cystogenesis
What is Wilms’ Tumour?
• Developmental malignancy
Tumours can weigh up to 2kg
Can contain cartilage, bone and smooth muscle
