-replication of chromosomes into 2 complete sets -lining up of chromosomes in the center of the cell -splitting of the cell into 2 daughter cells, each with complete set of new chromosomes
Proliferation is tightly regulated in both children and adults and occurs only to:
-heal a wound -replace cells that are lost -for normal growth in children
Most adult cells are not dividing which is called
Proliferation in Adults: Wound Healing
-for most tissues, cells that fill wound are function cells of that tissue -for heart muscle and nerve cells (which cannot divide under ordinary circumstances), tissue fibroblasts fill the wound--> scar tissue
Proliferation in Adults: Epithelial tissues
skin, glandular ducts, respiratory epithelium -constantly renewing bc of dividing cells at the bottom of the epithelial layer -They give rise to non-dividing cells that migrate upward to perform the barrier function of the epithelium, die and slough off
Proliferation in Adults: bone marrow
-hematopoietic stem cells constantly divide to give rise to the RBCs, platelets, and WBCs
the process of becoming specialized tissue cell
Since all cells in the body are derived from the fertilized ovum the fertilized ovum is ..
able to differentiate into any cell type
As cells differentiate into specialized tissue cells, they lose their .. and what is an example
pluripotency -liver cells can't become heart cells
however, if a tissue is damaged there has to be a way to heal the wound..
-many cell types can proliferate -some tissues have tissue-specific stem cells that are proliferating constantly -some tissue cells are terminally differentiated- their cells can't proliferate under ordinary circumstances (heart muscle)
new abnormal growth that can benign or malignant
where do neoplasms arise from?
tissue cells and grow inappropriately when they shouldn't
cells in neoplasm may resemble the cells in the tissue of origin =
cells in a neoplasm may look different from the cells in the tissue of origin =
-cells remain within the bounds of the tissue origin -do not invade nearby issues or metastasize to distant sites
one exception to benign neoplasms:
Malignant Neoplasms (CANCER)
-solid tumors, hematopoietic, and CNS -For solid tumors, single criterion that differentiates benign from malignant -less well differentiated than benign neoplasms -growth is unremitting
ability to invade nearby tissues and possible metastasize to nearby sites
Carcinoma in situ (noninvasive cancer)
-when neoplastic cells look like carcinoma cells, but the lesion is still confined and hasn't invaded nearby tissues -benign condition, since the malignant-appearing cells have no invaded nearby tissues -considered a pre-malignant condition
carcinoma in situ is frequently treated with
Solid tumors that invade nearby tissues (are malignant) have access to ..
blood and lymphatic vessels
Metastatic tumors composed of cells that spread from the primary tumor like breast cancer spreads to the brain it is ...
it is not a brain tumor but a metastatic breast tumor
The cells resemble the original tumor's cells and behave similarly so they are treated according to ..
their origin, not the metastatic site
cancers without a significant solid component that arise in the bone marrow from a blood cell precursor
Erythroleukemias arise from
red blood cell precursors
Monocytic leukemias arise from
Lymphocytic leukemias arise from
leukemic cells may infiltrate .. but not
may infiltrate organs but not solid tumors
Leukemic cells pathogenesis
-cause inflammation in the organ -fill up the bone marrow cavity and crowd out normal blood cell precursors -few normal blood cells due to crowding -increase bleeding secondary to thrombocytopenia -anemia secondary to lack of RBCs -immunosupression secodary to leukopenia
cancers of lymphocyte precursors with solid components -B cell or T cell lymphomas
Lymphocytes are mobile cells in the body = may spread to ..
multiple lymph nodes quickly -this is not really metastasis and does not mean that the prognosis is bad
How does cancer kill? -rob normal tissues of blood and nutrients via
Leukemias or metastic tumors can fill up the bone marrow and prevent growth of normal blood cell precursors-->
leukopenia, anemia, thrombocytopenia
How does cancer kill? can grow into blood vessels and cause
Diagnosis of Cancer: Screening
submitting the general population to a test to see if they have cancer in a particular organ
-Screening is only done for relatively common cancers for 2 reasons:
-it is expensive to screen large numbers of people for rare cancers, since the cost/case of diagnosed cancer would be prohibitively high -screening tests engender morbidity and mortality themselves, so the risk/benefit ratio is unacceptably high for uncommon cancers
A good cancer screening test has:
- high specificity (no false positives) -high sensitivity (no false negatives) -test has been shown to improve outcomes
Screening Tests: Effective
-Cervical cancer: pap smears -colon cancer: fecal occult blood test, colonoscopy, or sigmoidoscopy -breast cancer: mammography -long: helical CT for those at high rsik
Screening Tests: Ineffective
-prostate cancer: PSA levels -Ovarian, pancreatic: no screening test
-piece of tissue removed for pathologist to examine -needle core -incisional
Biopsy Dx is based on:
appearance of cells, location in tissue, presence of invading cancer cells in nearby or distant sites
Lymph node biopsies may contain
lymphomas or metastatic cells
Bone marrow biopsy:
hematopoietic cancer or metastatic cancer that has traveled through bloodstream from solid tumor
-2 ways to determine severity of cancer -used to predict prognosis and determine treatment options
leads to staging and grading
-based on histologic appearance- how normal do they look?
What does tumor grading take into account?
-degree of differentiation -appearance of nuclei -number of mitoses in sample
low grade ?
(good) -well differentiated with small, regular nuclei and few mitoses --> good prognosis
high grade ?
(poor) poorly differentiated, lack normal cellular structure, large number of mitoses--> poorer prognosis
-determines extent of cancer: size and if it has spread
What is the common grading system to determine the stage of cancer?
TNM (I, II, III, IV)
tumor size -ranges from 1-4, with 1= smallest T0= primary/ main tumor cannot be found Tis= carcinoma in situ
number of nearby lymph nodes that contain tumor cells -ranges from 1-3, with higher number = increasing lymph node involvement -No = no lymph node involvement
presence or absence of distant metastases M0= no metastases detected M1= distant metastases detected
genetic changes (mutations) from agents that cause chemical changes in DNA