Flashcards in MOD 6-9 Deck (88)
What is pleomorphism?
More mitosis figures and increasing variation in size and shape of cells - seen in malignant neoplasm.
Describe the alterations to DNA which cause neoplasm
Initiators and promoters needed resulting in monoclonal growth which, through progression, accumulates more mutations.
What is lyonisation?
One x is randomly inactivated during early embryogenesis
Distinguish between in situ and invasive malignancy
In situ- no invasion through basment membrane
What is an adenoma?
Benign, glandular origin, epithelioial
What is a papilloma?
Benign tumour which projects out wards
What is a carcinoma?
Malignant tumour of epithelial cells
What is a sarcoma
Malignant, stromal cells
What is the most crucial check point in the cell cycle
The restriction (r) point towards the end of G1
How is the cell cycle controlled?
Check points at the end of each growth phase.
Levels of cyclins regulate processes and control transitions between stages as well as the speed. They act by binding to CDks to form active kinases.
What is the difference between regeneration and reconstruction?
Regeneration is more cells. Reconstruction is the replacement of a lost part of the body e.g. Babies fingers.
How does the body increase the rate of cell proliferation?
Growth factors e.g. Epidermal growth factor.
Binds to receptors which triggers gene transcription. Shortens cell cycle and takes stable cells out of G0. Also affects differentiation, activation, angiogenesis, locomotion ect.
What type of cells does hypertrophy occur?
Mainly permanent but may occur in any
What causes hypertrophy (generally)?
Functional demand or hormone stimulation
Physiological examples of hypertrophy
Skeletal muscle, pregnant uterus, compensatory e.g. Removing a kidney.
Pathological examples of hypertrophy
Ventricular hypertrophy, bladder outlet obstruction-SM hypertrophy.
Give examples of physiological hyperplasia
Endometrium under influence of oestrogen. Bone marrow produces erythrocytes in response to hypoxia.
Give pathological examples of hyperplasia
Goitre and eczema
Give pathological examples of atrophy
Osteoporosis, tissues around a tumour due to ischemia, loss of blood supply, cerebral atrophy in Alzheimer's, loss of nutrients, loss of innervation to muscle, persistent injury - polymyositis (inflammation of muscle), aging
Give a physiological example of atrophy, what can this be called?
Ovarian atrophy in post menopausal women (technically involution - programmed cell shrinkage) thymus
What is hypoplasia?
Underdevelopment of an organ or tissue in the embryonic stage due to inadequate number of cells.
It is congenital - not the opposite of hyper.
What is the difference between aplasia and hypoplasia?
Aplasia is the complete failure of an organ or tissue to develop, hypo is partial.
Aplasia is also used to describe an organ whose cells nolonger proliferate e.g. Bone marrow.
What is metaplasia
Reversible changes of one cell type to another.
Not across germ layers.
Fully differentiated in response to stress.
May lead to cancer
Give examples of pathological metaplasia
Smoking epithelium changed to stratified (bronchial).
Gastric glandular columnar epithelium instead of stratified squamous with persistent acid reflux.
What is atresia?
When a hole doesn't open
Define an atheroma
The accumulation of intra and extracellular lipid in the intima and media of large and medium sized arteries.
Thickening and hardening of arterial walls due to An atheroma
What is arteriosclerosis
Thickening of arterial walls due to DM or hypertension.
Describe the macroscopic appearance of an atheroma
Starts as fatty streak - lipid deposits in intima, slightly raised.
Then becomes a simple plaque - deposits are more widespread with an irregular outline, enlarge and coalesce.
Can become a complicated plaque which involves thrombosis, haemorrhage into plaque, calcification or aneurysm.