7 Flashcards
Define autocrine signalling
Same secreting and responding cell
Define paracrine signalling
Secreting cell and responding cell are different
Define endocrine signalling
Endocrine organs synth + release hormones ➡️ blood stream ➡️ target organs
What are the 4 outcomes of signalling?
- Survive (resist apoptosis)
- Divide (➡️ cell cycle)
- Differentiate
- Die (➡️apoptosis)
What are Growth Factors?
Polypeptides that act on cell surface
Stimulate cell prolif
Describe EGF
Epidermal GF
Prod by: keratinocytes / MAC / inflamm cells
Mitogenic (induces mitosis)
Acts on: epithelial cells / hepatocytes / fibroblasts
Binds to EGFR
Describe VEGF
Vascular Endothelial GF
Vasculogensis inducer
Angiogenesis (in tumours)
Define PDGF
Stored in platelet granules
Released @ platelet activation
Prod by: (MEST) MAC / Endothelial cells / SMC / Tumour cells
Cause migration + prolif of fibroblasts / SMC / monocytes (WBC)
Define G-CSF
Granulocyte Colony Stim Factor
Stim bone marrow ➡️ prod granulocytes (esp neut) ➡️ blood stream
Used as chemo treatment to stim poorly function bone marrow
Describe G1 Phase of cell cycle
Cellular contents dup
Not xsomes
Describe the Restriction Point
In G1
Point of no return
p53 comes into play ➡️ apoptosis (G0) or DNA repair
Describe G1/S Checkpoint
Checks DNA damage b4 DNA replication
Describe S Phase of cell cycle
All 46 xsomes dup
Describe G2 Phase of cell cycle
Double check dupd xsomes for error ➡️ repair
Ready to divide
Describe the G2/M checkpoint
Check DNA damage after DNA dup
Then mitosis then cytokinesis
How is the cell cycle controlled
Cyclin Dependant Kinases (CDK)
CDK activated by cyclin ➡️ phosphorylate prot ➡️ drive cell cycle
GF stim cyclin prod and x prod of CDK inhibitors
Define metaplasia
Reversible change between differentiated cells
E.g. PSCE ➡️ SSE in bronchioles of smokers
Define atrophy
Shrinkage of organ tissue bc reduced cell size / number
Physiological: Ovarian Atrophy (post-menopause)
Pathological: Muscle atrophy (disuse / denervation)
Define hypertrophy
Increase in cell size ➡️ increase in organ size
Physiological: Skeletal muscle
Pathological: R Ventricle wall (compensatory)
Define hyperplasia
Increase in cell number
Only stable and labile tissue
Physiological: Endometrium (oestrogen)
Pathological: Eczema
Define aplasia
Complete tissue dev failure
Define hypoplasia
Underdev of tissue
Define dysplasia
Abn cell maturation
Pre-cancerous
Reversible
Define involution
Atrophy w apoptosis
Define atresia
Abn narrowing of lumen
Whats the difference between Regen and Reconstitution
Regen: replacement of loss cells w identical cells
Recon: replacement of a whole body part w lots of diff cells types
