Lecture 1 Flashcards
What is aging and how is it changing?
Aging is part of the post natal process. The UK population has increase by 3% with over 65s up be 12% and over 85 up by 18%. 55% of UK welfare is spent on pensioners
Name 3 things that characterise development
1) cell communication= cell to cell signalling
2) cell behaviour= proliferation, movement and differentiation
3) genetic program= genetic expression and regulation
Why are model organisms used?
To understand human development in other organisms and manipulate gene functions and expression to better understand congenital disease that arise congenitally
What are the theories of development?
1) preformationism= idea that we arose from a small person in the head of the sperm (preformed organism)- homunculus
2) epigenesis= aristotol proposed the idea that the embryo develops in a step wise process which was rejected at the time
3) predetermination= arose from cell mass that needs to grow and amplify
What did the invention of the microscope prove about cells?
1) cells are the basic unit of structure, function and organisation
2) all cells arise from a pre-existing cell and is the tool for progressive development
3) all organisms are composed of one or more cells
What is the Weissman theory?
Germ cells have a set of determinants and somatic cells only have a subset of those determinants (get divided up). Roux used a hot needle to kill a cell in a two-staged embryo which resulted in only have of the embryo forming
How did Driesch prove the Weissman theory wrong?
He split the embryo in 2 at the 2 and 4 cell stage using string which resulted in 2 separate embryos forming meaning that all cells have all the subsets but decide when to remove them via cell communication
What does asymmetric division do?
generates diversity due to the difference between the two poles of the cell
Give examples of changes in cell behaviour
1) change in cell shape e.g. epithelial to mesenchymal
2) cell adhesion determines if a cell will migrate or not
3) differentiation
4) cell death
5) cell division
Name the 4 ways in which cells can communicate
1) paracrine= secreted ligand binds to a receptor on another cell
2) autocrine= ligand binds to a receptor in the same cell
3) juxtacrine= the ligand is tethered to the membrane
4) endocrine= hormonal
What are the requirements of cell signalling?
1) a permissive environment
2) all the signal transduction proteins
3) ligand and receptor
4) signals need to be instructive or permissive
