Disorders of Growth and Differentiation Flashcards
What causes physiological hypertrophy?
It occurs due to normal stimuli like exercise in athletes, leading to an increase in cell size
What is pathological hypertrophy and give an example.
Abnormal increase in cell size due to stress or disease; e.g., right ventricular hypertrophy due to pulmonary hypertension.
What causes physiological hyperplasia?
Increased cell number due to normal adaptation, e.g., adaptation to high altitude.
What is pathological hyperplasia?
Abnormal increase in cell number, e.g., in psoriasis due to autoimmune stimulation
How is hyperplasia involved in tissue repair
It’s essential for processes like angiogenesis, wound healing, and liver regeneration, but can become harmful if excessive (e.g., cirrhosis, hypertrophic scar).
What is physiological atrophy?
Normal decrease in cell size/number, such as in thymus involution or aging.
What causes pathological atrophy?
Injury, lack of blood supply, nerve damage, pressure, or malnutrition (e.g., bedsores, paraplegia).
What genetic mutation is associated with Turner Syndrome?
45, XO – missing one X chromosome. Causes short stature and SHOX gene haploinsufficiency.
What is the role of SHOX in growth
It’s expressed in growth plate chondrocytes and regulates hypertrophy. Mutation reduces skeletal growth.
What are growth-related effects of Down Syndrome?
Trisomy 21 – short stature, hypotonia, heart defects, learning difficulties.
What causes Beckwith-Wiedemann Syndrome?
Increased IGF-II (from paternal allele) and decreased H19 expression → leads to early childhood overgrowth.
What is pituitary gigantism and its cause?
Overgrowth due to excess growth hormone and IGF-1, often from pituitary tumors. In adults, it causes acromegaly.
What causes achondroplasia?
A mutation in FGFR3 (G380R) that makes the receptor constitutively active, suppressing growth in chondrocytes.
What happens when FGFR3 is knocked out in mice?
The mice are larger than normal – showing FGFR3 normally suppresses bone growth in long bones.
Define hypertrophy
Increase in cell size, typically in response to increased workload
Define hyperplasia
Increase in cell number, often in response to a stimulus
Define atrophy
Decrease in cell size or number due decreased use, blood supply or nutrients
What is metaplasia
Replacement of one differentiated cell type with another; a reversible adaption to stress
Give an example of metaplasia
In smokers, respiratory epithelium changes from columnar to squamous cells
Define dysplasia
Disordered cell growth and diffrentiation with abnormal morphology - often premalignant
Define neoplasia
Abnormal, unregulated cell growth that persists after stimulus removal. May be benign or malignant
What is differentiation in pathology?
The extent to which cells resemble their normal counterparts; used to grade tumours
Define agenesis
Complete failure of an organ or structure to form
Define atresia
Failure to develop a lumen in a hollow organ
