Midterm 2 Flashcards
What are some common causes of cell injury?
-inadequate oxygenation
-physical, thermal, or chemical agents
-ionizing radiation
-toxins
-microbes
-inflammation and immune reactions
-nutritional imbalance
-genetic and metabolic defects
-aging
What is meant by an acute mild injury to a cell?
-hydropic change (too much water is cell)
-steatosis (fatty spots in the liver)
-fast and reversible
-reverts to normal when the cause of injury disappears
-brief, visible cell change
-ex. brief hypoxia or anoxia
What is meant by a chronic mild injury to a cell?
-intracellular accumulations
-altered growth and differentiation
-can still be reversible (because it is mild)
Give examples of intracellular accumulations
-cholesterol
-protein
-pigment
-environmental particles
Describe atrophy
-decrease in cell number, cell size, and work output
-adaptation to diminished resources
-often reversible (not always)
What are the causes of atrophy?
-disuse
-denervation (neurogenic)
-hormones
-malnutrition
-ischemia (restricted blood flow)
-aging
Describe hypertrophy
-increase in cell size and work output
-adaptation to increased workload and/or increased endocrine stimulation
-often reversible
-most often seen in muscle tissue as muscle has few stem cells and cannot meet increased demand through growing new cells; it must adapt by cell enlargement
-hypertrophy of the heart muscle cells in the long-term can result in heart failure and death
Describe hyperplasia
-increase in cell number in an organ or tissue
-adaptation to increased workload and/or endocrine stimulation
-often reversible
-when the organ or tissue gets bigger because of an increase in cells
-pregnancy
-most pathologic hyperplasias are due to excessive hormonal and growth factor stimulation
What is the difference between hyperplasia and hypertrophy?
Hypertrophy is an increase in tissue or organ size because the cells adapted to become bigger
Hyperplasia is an increase in tissue or organ size because of an increase in the number of cells
They are stimulated by the same signals and can occur at the same time
What is the difference between hyperplasia and cancer?
Hyperplasia is a strictly regulated adaptation to a particular stressor and is reversible
Cancer is uncontrolled cell proliferation that will not be reversed by the removal of the stressor
Describe metaplasia
-change from one cell type to another
-only occurs in epithelium and mesenchyme (connective tissue)
-often reversible
-caused by chronic injury
-adaptation to an injurious stressor
-may be a precursor to dysplasia and cancer
Describe dysplasia
-abnormal cell growth
-cells vary in size, shape, and organization
-still considered “adaptive” because it is reversible
-means disorder growth
-haphazardly arranged, large, dark nuclei that reflect the chromosomal chaos within
-can become malignant but is reversible
-ex. why we get Pap smears
Remember: dysplasia is an adaptive process and does not necessarily mean cancer, it can revert back to normal structure and function
What are the two types of cell death?
- Necrosis– pathological cell death (disease)
- Apoptosis– programmed cell death (natural suicide)
Describe necrosis
-usually due to ischemia/hypoxia/anoxia
-often occurs in a contiguous block of cells
What are the 4 principle types of necrosis?
- coagulative necrosis
- liquefactive necrosis
- caseous necrosis
- fat necrosis
Although there are technically 6 types we will only look at the 4 most common
Describe coagulative necrosis
-characterized by a gel-like change in blocks of freshly dead cells
-most common type of necrosis
-solid organs like the kidney, liver, and heart are most often effected
-can block arteries which cause ischemia and either a heart attack or stroke
-cell detail is intact
Describe liquefactive necrosis
-happens in organs that don’t have connective tissue (like the brain)
-cell death in which the dead tissue dissolves into fluid
-most often caused by bacterial infection
Describe caseous necrosis
-a variant form of coagulative necrosis with limited liquefication and obliterated cellular detail
-the most common cause is tuberculosis infection
-the dead tissue looks like soft, off-white cheese
Describe fat necrosis
-specialized form of liquefactive necrosis that occurs only in fat
-especially common around the pancreas
-pancreatic disease (ex. trauma) liberates pancreatic digestive enzymes that convert pancreatic fat into glycerol and fatty acids and then the fatty acids combine with calcium to create soap– which makes them look like cancer on x-rays
-look like white, chalky deposits
Describe apoptosis
-programmed natural cell death
-activated by internal forces (like embryological development) and external forces (like disease)
-the cell wants to die so they are activated to die rather than killed
What two heritable properties define cancer cells?
- autonomy
- anaplasia
Describe cell proliferation
the programmed generation of new daughter cells divided from progenitor (parent) cells
-under the control of genes
-types: mitosis and meiosis
Describe autonomy of cancer cells
-altered cellular proliferation (the loss of regulated balance of cell division may result in overproliferation)!!
-cancerous cells exhibit excessive cellular proliferation (they grow and reproduce uncontrollably)– which means they are autonomous
Describe cell differentiation
-the orderly process of cellular maturation to achieve a specific function
-under the control of genes, growth factors, nutrients, and stimulation from the external environment
-a regulated balance of undifferentiated and differentiated cells is needed to maintain homeostasis
Describe anaplasia
-altered cellular differentiation!!
-the loss of regulated differentiation renders the cell incapable of carrying out its designed function
-cancerous cells exhibit a loss of cellular differentiation (lose ability to carry out specific functions and do not die when supposed to– anaplastic)
What is the difference between a tumour and cancer?
tumour refers to new growth (neoplasm) which can be either benign or malignant
cancer is malignant neoplasm
all cancers are tumours but not all tumours are cancers
What is the root cause of cancer? (this question will be on test)
DNA damage (mutation)
What is a carcinogen?
-any substance, radionuclide, or radiation that is an agent directly involved in causing cancer
-ex. sunlight, cigarette smoke, industrial chemicals, human papillomavirus, and contact carcinogens
What is cancer pathogenesis?
the process by which a mutated cell proliferates into an undifferentiated population of cells capable of metastasis
Describe the monoclonal origin theory
-that cancer originates from a single mutated cell
-cancer begins with mutations developing in several genes in a single cell and that cell eventually becoming autonomous and anaplastic
Which genes can cause cancer when altered?
- mutator genes– code for proteins that repair mutated DNA
- oncogenes– code for proteins involved in cell growth
- tumour suppressor genes– code for proteins that prohibit proliferation of cells and regulate apoptosis
Describe initiation-promotion-progression
- initiation– the irreversible alteration of a cancer-related gene
- promotion– the proliferation of the initiated (mutated) cell due to promoter exposure
- progression– the autonomous proliferation of the mutated cells
What size is the smallest detectable mass?
about 1 gram or the size of a grape, which can take 10-20 years
Describe the morphology of a tumour cell
-nuclei often considerably larger than normal
-nuclei often have bizarre shapes
-chromatin is coarse and clumped
-nuclei often contain abnormal numbers of chromosomes (aneuploidy)
-more cells in mitosis than normal
-pleomorphic (variable in size and shape)