Lecture 15 Flashcards
What does C14 content indicate?
how old tissue is
What is apoptosis?
Programmed cell death
- not released into the extracellular milieu
What is necrosis?
Bursting cells as a consequence of severe cell damage
- intracellular constituents are released into the extracellular milieu causing inflammation
Function of Apoptosis
Safety system to remove cells that lost normal communication and control
What are trophic factors?
Survival signals
Why is apoptosis important in neuronal development?
matching the number of developing nerve cell to the number of target cells
What is lost during apoptosis?
Asymmetrical lipid distribution
What two things occur during apoptosis in lipid membrane?
- asymetry is not maintained and PS is exposed on the surface
- PS on cell surface signals to macrophages to phagocytose the cell
What occurs during DNA fragmentation during apoptosis?
- apoptosis activates nucleases that cleave the DNA
What is apoptosis executed by
capases
Activation of initiator - caspase occurs by what
Aggregation of the procaspases with the help of adaptor proteins
Aggregated initiator procaspase cleave each other which results in what
Formation of active caspase
What initiates the apoptotic pathway?
Cytochrome C release from the mitochondria
What causes p53 to activate apoptosis
prolonged DNA damage stress
What is the pathway that activates apoptosis form outside of the cell?
extrinsic pathway
What is the apoptosis pathway?
Regulator — Adapter — Effector
What part of the mammalian instestine have a high turnover rate and therefore must constantly be replaced by new cells?
villi
In mammalian intestine, new cells are produced where?
At the bottom of the crypt by a set of stem cells
Cells born at the bottom of the epidermis differenetiate into what?
keratin containing skin cells, die and shed
What is a tissue
are groups of cells that act together to perform a specific function
What is the role of gap junctions
directly link the cytoplasm of neighboring cells (allow for exchange of ions and small molecules)
Secreted proteins and polysaccharides form what?
strong network between the cells
What links the cells to collagen of the ECM?
integrin
Roles of epithelial tissues
Protection, secretion, absorption, excretion, filtration, diffusion, and sensory reception
