NUR 339 EXAM 22 - Orderly process that provides body with means f...

с

NUR 339 EXAM 22

• What is proliferation?

Orderly process that provides body with means for re- placing cells as needed

• Usually number of cells dying = number of cells proliferating

• What is differentiation?

Process by which proliferating cells are transformed into specialized cell types, which determines cell function

• The more highly specialized a cell, the more likely it will lose its ability to reproduce and

divide

• Stem cells remain incompletely differentiated throughout life
• Highly specialized cells that don't reproduce and divide ->> nerve cells, heart cells

• What is Anaplasia?

Lack of cell differentiation

• What are the Cell Cycle Phases and what happens in each?

G0- resting phase (becomes mitotically dormant)

G1- Gap 1. Cell prepares to make DNA S phase- DNA synthesis actually takes place (most mutations occur in this phase) G2- Prepares for mitosis (cell division) M phase- mitosis occurs

• What is Neoplasms?

Do not obey normal tissue growth/adaption laws 1 / 4

с

• Do not occur in response to appropriate stimulus
• Continue to grow after stimulus has ceased
• Function independently of body's needs (faster growth rate, increase in size at expense of rest

of body's needs, great variation in cell size, shape, arrangement)

• What is Benign Neoplasm?

Composed of well-differentiated cells that resemble cells of tissues of origin

• Slow growth rate
• Remain localized to site of origin without capacity to infiltrate, invade, or metasta- size
• May become encapsulated
• Less blood supply than malignant neoplasm
• Usually do not cause death unless interfere with vital functions because of their location
• Can cause alterations in body function through abnormal alternation of hormones

• What is Malignant Neoplasm?

Atypical cell structure; abnormal nucleus & chromosomes

• Lose differentiation or resemblance to origin cell--more anaplastic (lack cell differ- entiation)
• Not cohesive, irregular growth pattern, no capsule formed, not distinct from sur-

rounding tissue

• Invade adjacent cells rather than pushing aside
• Varying growth rates and do not die within normal timeframe
• More blood supply than normal tissue (angiogenesis)

• Hallmark Sign of malignancy

ability to metastasize or spread to distant sites

• What is Metastasis?

Ability of cancer cells to spread to distant sites 2 / 4

с

• Clumps of malignant cells break off and travel through blood (hematogenic spread) or lymph

(lymphatic spread) to new site - most are killed by body's defense mecha- nisms

• To survive in a tumor you need a host. To metastasize, you need to travel.

• Metastasis in lymph nodes

• In lymph nodes, cancer may die, grow into mass, or remain dormant

Sentinel node initial lymph node to which primary tumor drains (used to determine spread to lymph system)

• Cells in a primary tumor develop that ability to escape and travel in the blood or lymph
• Surviving cancer cells leave lymph nodes and enter venous blood and are carried to major

organs (bone, liver, lungs, brain) Original tumor= primary neoplasm Metastatic site= secondary neoplasm (retains characteristics or primary tumor)

• What is Growth fraction (GF)?

Ratio of dividing cells / G0 cells

• A tissue with a large % of proliferating cells and few cells in G0 has a high growth fraction.
• Chemotherapeutic drugs are much more toxic to tissues that have a high growth fraction than

to tissues that have a low growth fraction

• What is Doubling Time (TD)?

Time to double total mass of cancer cells

• GF and TD are very fast until tumor outgrows blood supply, then slows
• May be influenced by hormones
• High TD is good (takes longer to double in size)

• What are Proto-oncogenes?

Normal genes that regulate cell growth & differentiation & are active for only a short time in 3 / 4

с

cell cycle

• What are Oncogenes?

Gene mutations which become cancer-causing genes; are active continuously & promote unregulated, abnormal & disordered growth

• What is Oncogenesis?

Mechanism by which a normal cell is transformed into cancer cell by random genetic mutation or mutation induced by exposure carcinogens

• Is a monoclonal origin

• What are Tumor Suppressor Genes?

Anti-oncogenes

• Normally inhibit inappropriate cell growth - start senescence and crisis or cell

growth Senescence- cells stop dividing. In response to growth inhibiting proteins like P53 Crisis- cells death

• Abnormal tumor suppressor genes are inherited or mutant genes

• Describe the stages of cancer growth

Initiation

Exposure of cells (especially those actively synthesizing DNA) to enough carcinogens that alter cell's genome-ir- reversible mutation

Promotion

Induction of unregulated accelerated growth by some agent, chemical, or endogenous hormone

• / 4