N116 Unit 1 Lesson 2

-changes in the internal environment
-increased work + other demands
-appropriate stimulus and cease once the need for adaptation has ceased

decrease in cell size

-disuse: immobility
-denervation: neuro-myo stimulation (loss of nerve function -> related muscle group may atrophy)
-loss of endocrine stimulation: androgens
-inadequate nutrition: malnutrition, starvation
-ischemia/decreased blood flow

increase in individual cell size and amount of functioning tissue MASS (not number of cells)

increase in muscle mass associated with exercise

result of disease conditions such as heart failure, hypertensive cardiomyopathy

increase in the number of cells in an organ or tissue capable of mitoic division (epidermis, intestinal epithelium, gladnular tissue)

in response to an appropriate stimulus and ceases after the stimulus has been removed (e.g. callus)

reversible change in which one adult cell type (epithelial/mesenchymal) is replaced by another cell type

in response to chronic irritation and inflammation and allows for substitution of cells that are better able to survive
(e.g. chronic gastric irritation with lower esophageal cells transforming into columnar epithelium, pre-cancerous condition)

deranged cell growth of a specific tissue, results in cells that vary in size, shape, and organization
-adaptive as may be reversible after the irritating cause has been removed
-implicated as a precursor of cancer

-process of cell division
-inherent adaptive mechanism for replacing body cells

-process of specialization
-new cells acquire the structure and function of cells they replace

form of programmed cell death to eliminate unwanted cells

reserve cells that remain quiescent (dormant) until there is a need for cell replenishment
-with division, one daughter retains stem cell characteristics and the other becomes a progenitor cell that proceeds through to terminal differentiation

produced by the fertilization of egg; can differentiate into embryonic and extraembryonic cells

can differentiate into the three germ layers of the embryo

give rise to only a few cell types

give rise to one type of differentiated cell, but retain the property of self-renewal

-muscle satellite cell
-epidermal stem cell > skin, organ lining, vessel lining
-spermatogonium
-basal cell of the olfactory epithelium

interval between each cell division
-genetic information is duplicated

appropriately aligned for distribution between two genetically identical daughter cells

provide opportunities for monitoring the accuracy of DNA replication
-cyclin, cyclin-dependent kinase, cyclin-dependent kinase inhibitors

-disorder of altered cell differentiation and growth, results in neoplasia (new growth)
-solid and hematologic
-growth is uncoordinated and relatively autonomous
-lacks normal regulatory controls over cell growth & division
-tends to increase in size and grow after stimulus ceases or needs of the organism are met

solid tumors (breast cancer, prostate cancer), arise from organ or tissue type and are manifested as a mass

Cancer that begins in blood-forming tissue, such as the bone marrow, or in the cells of the immune system.
-Affects the production and function of blood cells.
-e.g. leukaemia, lymphoma, and multiple myeloma.

-heredity
-hormones
-immunologic
-radiation
-oncogenic viruses

-transformation to oncogenes
-stimulating cell division
-inhibiting cell differentiation
-preventing apoptosis

-restrain inappropriate cell growth and division, stimulate apoptosis
-DNA repair processes, "brakes" to stop cells in their tracks before they can take the road to cancer

-intrinsic pathway: cell kills itself because it senses cell stress
-extrinsic pathway: cell kills itself because of signal from other cells

-number of cells that are actively dividing/moving through the cell cycle
-duration of the cell cycle
-number of cells that are being lost compared with the number of new cells being produced
-growth fraction: the ratio of dividing cells to resting cells in a tissue mass
-doubling time: the length of time it takes for the total mass of cells in a tumor to double

-direct invasion and extension: mass goes beyond areas where it is expected to be, growth invades other tissues, presses on other normal masses (symptoms of pain when tumor mass is pressing onto a nerve, organ, etc.)
-seeding of cancer cells in body cavities: e.g. ovarian cancer, many mass seedlings found in peritoneum, beyond surgical removal
-metastatic spread through the blood or lymph pathways

cure, control (targeted agents), palliative

-radiation can interrupt cell cycle process, kill cells, or damage DNA in the cells

produce stranded breaks in DNA to kill a cell, owing to the high capacity of cells for repairing single stranded breaks

drugs that selectively attack malignant cells without causing harm to normal cells

altered molecules and signalling pathways that allow cancer cells to grow and spread in an uncontrolled manner

small molecules that block specific enzymes and growth factors involved in cell growth

-influenced by the organs and tissues included in the treatment field, type of radiation administered, daily fractional and cumulative radiation dose, and age at treatment.
-Organ dysfunction (lung, cardiac, muscle, vascular)
-RT-induced cancers
-brain 'fog'
-neurotherapy
-infertility