Histology & Cell Biology Flashcards
Define “neoplasm”
Neoplasm=new growth
Define “benign neoplasm”
Grow slowly and remain localized to site of origin
Define “malignant neoplasms”
Cancers
- grow rapidly
- abnormal growth
- unregulated rapid cell proliferation
Define “carcinoma”
Malignant tumor growing from EPITHELIAL tissue
*most of human cancers are carcinoma
Define “sarcoma”
Malignant tumor growing from connective tissue
Define “benign”
Not invasive
Grows locally
Resembles cell of origin
Relatively uniform
Define “malignant”
Invasive
May metastasise
Cells vary in shape and size
Define “metastasis”
Distant spread of the tumor cells into other tissues of the body.
Necrosis
Cell death, not orderly. May cause content to lyse.
Apoptosis
Physiological programmed cell death. Cell shrinkage.
Caspase cascade activation.
ie Normal embryological development (developing digits)
Mitochondrial enzyme which is released into cytoplasm in apoptosis
Cytochrome C is released from mitochondria.
Tumor progression
Genetically unstable
Apoptosis pathways: Extrinsic
Binding of ligand to death receptor
Recruitment of death domain adaptor proteins
Death inducing signaling complex
Caspase cascade
Apoptosis pathways: Intrinsic
Death signal
Proapoptotic proteins upregulated (ie Bax)
Release cytochrome c from mitochondria
Apoptosome formation Caspase cascade
Interphase
G1-Cell growth, synthesize RNA and proteins
S- DNA synthesis/replication
G2-Cell preparation for division, cell growth
G1 Phase-Checkpoints
G1 DNA damage checkpoint
G1 Restriction checkpoint-mediated by retinoblastoma (Rb) protein
S Phase-Checkpoints
S DNA damage checkpoint
G2 Phase-Checkpoints
Unreplicated DNA checkpoint
G2 DNA-damage checkpoint
Mitotic (M) Phase-Checkpoints
Spindle assemby checkpoint
Chromosome Segregation checkpoint
Mitosis stages
Prophase Prometaphase Metaphase Anaphase Telophase
Cytokinesis
Centromere
holds sister chrmatids together
site of kinetochore formation
Kinetochore
Large protein complex
Attach chromosome to mitotic spindle
Centrosome
Microtubule organizing center.
Location of spindle fiber poles.
Mitotic Spindle
Centrosomes
Microtubules (Overlap, kinetochore, astral)
Motor proteins (Dynein-, kinesin+)
