Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
132 Cards in this Set
- Front
- Back
|
Protoplasm
|
*living substance inside the cell
*also called bioplasm |
|
|
Ergastic Substances
|
*non-living cell components
|
|
|
Divisions of Protoplasm
|
*cytoplasm
*nucleoplasm |
|
|
Tonoplast
|
*large water-filled vacuole enclosed by a membrane
*occupies most of the volume of many plant cells |
|
|
Major Classes of Organic Compounds
|
*hydrogen
*carbon |
|
|
Mitochondria
|
*energy production through formation of ATP
*involved in apoptosis through release of cytochrome C |
|
|
Endoplasmic Reticulum
|
*outer membrane contains ribosomes
|
|
|
Ribosomes
|
*translate mRNA into proteins
|
|
|
Golgi Complex
|
*modifies and transports proteins made in RER
*contains processing enzymes |
|
|
Lysosomes
|
*trash compactors of the cell
*single membrane structure *contains acid hydrolases for breaking down macromolecules |
|
|
Structure of DNA
|
*double helix of sugar phosphate groups held together by hydrogen bonds between the bases
*sequence of bases specifies genetic code |
|
|
Bases of DNA
|
*thymine-cytosine
*adenine-guanine |
|
|
Width of Strand of DNA
|
2 nM wide
|
|
|
Chromatin
|
*unit of DNA packaged into a chromosome
*genes are on chromosome |
|
|
Telomeres
|
*long arrays of bases of varying lengths that protect the terminal ends of chromosomes
|
|
|
Result of Cell Division
|
some telomeric DNA is lost, initiating senescence
|
|
|
Telemorase
|
the rebuilding of telomeric DNA in stem and cancer cells
|
|
|
Phases of Mitosis
|
*prophase
*metaphase *anaphase *telophase *interphase |
|
|
Prophase
|
*cell getting ready to divide
*duplicates DNA *gets centrioles in the right position |
|
|
Metaphase
|
*DNA lines up along a central axis
*centrioles send out specialized tubules that connect to the DNA *chromatin has now condensed into chromosomes *two strands of the chromosome are connected at the center with a centromere *tubules connect to the centromere, not the DNA |
|
|
Anaphase
|
half of the chromosomes are pulled to each side of the cell
|
|
|
Telophase
|
*cell membranes close in and split into two separate cells with half of the original DNA for each cell
|
|
|
Interphase
|
*resting state of the cell
*performing general life functions *duplicating nucleic acids to prepare for prophase again |
|
|
Cell Cycle
|
G1 - S - G2 - M
|
|
|
Production of X-Rays
|
from liberated electrons
|
|
|
Production of Gamma Rays
|
liberated from the nucleus
|
|
|
Mass and Charge of Electrons
|
*negative charge
*small mass |
|
|
Mass and Charge of Protons
|
*positive charge
*larger mass |
|
|
Mass and Charge of Neutrons
|
*no charge
*large mass |
|
|
Mass and Charge of Alpha Particles
|
*positive charge
*very large mass |
|
|
Direct Ionization
|
liberated electron interacts directly with the DNA, causing a strand break
|
|
|
Indirect Ionization
|
liberated electron reacts with water, producing free radicals, which damage DNA
|
|
|
Primary Mechanism X-Rays Use
|
Indirect Radiation
|
|
|
Linear Energy Transfer
|
rate at which energy is deposited in matter
|
|
|
Units of Linear Energy Transfer
|
KeV per micron
|
|
|
High LET Particles
|
*alpha particles
*neutrons |
|
|
Mechanism of Action for High LET Radiation
|
*greater likelihood of producing double strand DNA breaks, which kills cell
*less likelihood of producing single strand breaks, which can be repaired |
|
|
Type of Ionization that High LET Radiation Uses
|
direct ionization
|
|
|
Effect on the Survival Curve of High LET Radiation
|
direct ionization results in the straight initial slope of the survival curve
|
|
|
Relative Biologic Effectiveness
|
quantity used to compare doses of radiation needed to produce the same biologic effect
|
|
|
Standard of Relative Biologic Effectiveness
|
*250 kV
*D250/D |
|
|
Units of Relative Biologic Effectiveness
|
no units, just ratio
|
|
|
Factors Used to Determine Relative Biologic Effectiveness
|
*linear energy transfer
*dose of radiation *number of fractions *dose rate *biologic endpoint |
|
|
How Linear Energy Transfer Influences Relative Biologic Effectiveness
|
high linear energy transfer beams result in greater relative biologic effectiveness
|
|
|
Shoulder for High Linear Energy Transfer Beams
|
small shoulder
|
|
|
How Dose Fractionation Influences Relative Biologic Effectiveness
|
increased dose fractionation results in greater relative biologic effectiveness
|
|
|
How Dose Rate Influences Relative Biologic Effectiveness
|
lower dose rate results in greater biologic effectiveness
|
|
|
How Relative Biologic Effectiveness Influences Repair of Radiation Damage
|
tissues with higher relative biologic effectiveness show repair of radiation damage
|
|
|
Type of Radiation with High Relative Biologic Effectiveness
|
neutrons
|
|
|
Interaction Between RBE and LET
|
relative biologic effectiveness increases as linear energy transfer increases until it reaches a max of 6 at 100 keV per micron
|
|
|
Effect of Linear Energy Transfer of 6 at 100 keV per micron
|
separation between ionizations is almost equal to the diameter of the DNA, increasing the likelihood of double strand breaks
|
|
|
Effect of Linear Energy Transfer of Greater Than 6 at 100 keV per micron
|
no increase in effectiveness as additional ionizations are overkill, as the DNA has already been fatally damaged
|
|
|
Effects of Radiation on Chromosomes
|
*repair is attempted for DNA breaks
*errors result |
|
|
Types of Errors Resulting from Attempts at DNA Repair
|
*deletions
*translocation *abnormal chromosomal formations |
|
|
Lethal Structural Changes As A Result of Radiation
|
*dicentrics
*anaphase bridges *rings |
|
|
Ways Ionizations are Deposited
|
*spurs
*blobs |
|
|
Differences Between Spurs and Blobs
|
*blobs larger than spurs
|
|
|
Width of DNA
|
2 nM
|
|
|
Size of Spurs
|
3 ion pairs that cover 4nM
|
|
|
Division Delay
|
non-lethal event where temporary block exists between G2 and M phases of cell cycle
|
|
|
Factors That Effect the Length of the Division Delay
|
the higher the radiation dose, the longer the division delay
|
|
|
Effect of the Division Delay on Cell Cycle
|
synchronizes cell population by putting more cells into G2 phase at the same time
|
|
|
Apoptosis
|
*mechanism of programmed cell death for some cells including lymphocytes, oocytes, and spermatogonia
*cell dies before undergoing mitosis |
|
|
How Apoptosis Occurs
|
*cell condenses
*produces blebs of cytoplasm |
|
|
Gene Involved in Apoptosis
|
P53 gene
|
|
|
Reproductive Failure
|
inability to divide indefinitely or produce a clone
|
|
|
Most Common Response of Tumors and Normal Tissue to Radiation
|
reproductive failure (clonogenic death)
|
|
|
When Reproductive Failure Occurs
|
*when cell attempts mitosis
*cell often maintains other functions until death |
|
|
Most Effective Response to Radiation
|
reproductive failure
|
|
|
Why Different Tumors Have Different Responses to Radiation
|
reproductive failure in fast and slow growing tumors
|
|
|
How Reproductive Failure Influences Tumor Status
|
*some tumors don't shrink, just stop growing
*why we wait six months to evaluate treatment |
|
|
X Axis of Survival Curve
|
*dose
*exhibited linearly |
|
|
Y Axis of Survival Curve
|
*percent survival
*exhibited as a logarithm |
|
|
N on Survival Curve
|
*extrapolation number
*defines size of the shoulder *where dotted line crosses the y axis |
|
|
Do on Survival Curve
|
*terminal slope
*where survival curve goes from .01 to .0037 |
|
|
Dq on Survival Curve
|
description of the size of the shoulder
|
|
|
Alpha and Beta on Survival Curve
|
*used in linear quadratic model
*assumes some killing *linearly proportional to dose *quadratically proportional to the square of the dose *constants when used in an alpha/beta ratio to describe the shape of the curve |
|
|
Sublethal Damage
|
can be repaired unless additional damage occurs
|
|
|
Experiments that Demonstrate Sublethal Damage
|
split dose experiments where survival of cells exposed to specific dose of radiation increases if dose is delivered in two fractions seperated by time
|
|
|
Result of More Time Between Fractions
|
survival increases as a result of sublethal damage
|
|
|
How Sublethal Damage Influences the Survival Curve
|
more sublethal damage results in a wider shoulder
|
|
|
Potentially Lethal Damage
|
damage that may be expressed depending on the environment
|
|
|
Conditions That Result in Increased Survival Following Radiation Exposure
|
conditions that are poor for growth
|
|
|
Clinical Relevance of Potentially Lethal Damage
|
of little clinical relevance, but may effect some tumors
|
|
|
Law of Bergonie and Tribondeau
|
*poorly differentiated cells are more sensitive to radiation
*rapidly dividing cells are more sensitive to radiation |
|
|
Effect of Dose Rate on Survival Curve
|
*decreased dose rate allows more repair of sublethal damage
*cells with large shoulders on the survival curve have a greater dose rate effect, and thus will benefit from a higher dose rate |
|
|
Oxygen Enhancement Ratio
|
measure of increase radiosensitivity with addition of oxygen
|
|
|
Type of Radiation Most Likely to Exhibit Oxygen Enhancement
|
x-rays
|
|
|
Effect of Hypoxia on Radiation
|
hypoxia increases a cells resistance to radiation, resulting in increased survival compared to aerated cells
|
|
|
Effect of Increased Oxygen on Radiation
|
increased radiosensitivity
|
|
|
Way the Cell Cycle Influences the Oxygen Enhancement Ratio
|
*increased oxygen enhancement ratio in S phase
*decreased oxygen enhancement ratio in G2 phase |
|
|
Oxygen Effect with High LET Beams
|
no oxygen effect as there is no shoulder
|
|
|
Oxygen Effect with Large Tumors
|
*large tumors outgrow blood supply and are hypoxic
*more cell survival with large tumors |
|
|
Effect of Mitosis on Radiosensitivity
|
highly mitotic cells are very radiosensitive, as mitosis is the most radiosensitive phase
|
|
|
Least Sensitive Phase of Cell Cycle
|
G2
|
|
|
TD 5/5
|
dose where 5% of the population irradiated will develop the complication at 5 years
|
|
|
TD 50/5
|
dose where 50% of the population irradiated will develop the complication at 5 years
|
|
|
Systemic Response of Hematopoietic System
|
-bone marrow stem cells
-very sensitive -acute anemia and thrombocytopenia -no chronic effects |
|
|
Systemic Response of Skin System
|
-epithelial cells
-very sensitive -acute erythema and desquammation -chronic ulceration, fibrosis, and telangietasis |
|
|
Systemic Response of Digestive Tract
|
-crypt cells of jejunum
-very sensitive -acute shortening of villi and diarrhea -chronic small bowel obstruction and hematochezia in rectum |
|
|
Systemic Response of Reproductive System
|
-spermatogonia and oocytes
-very sensitive -acute azospermia -chronic infertility |
|
|
Systemic Response of Respiratory System
|
-type II pneumocytes
-sensitive -acute pneumonitis -chronic fibrosis |
|
|
Systemic Response of Urinary System
|
-tubule cells
-very sensitive -acute nephritis, hypertension, proteinuria, and uremia -chronic hypertension and nephropathy |
|
|
Systemic Response of Nervous System
|
-oligodendrocytes and possibly neurons
-sensitive -acute Lhermitte's sign -chronic myelopathy |
|
|
Examples of Early Responding Tissues
|
-skin
-hair |
|
|
Examples of Late Responding Tissues
|
-spinal cord
-muscle |
|
|
Shoulder on Survival Curve for Early Responding Tissues
|
smaller shoulder than late responding tissues
|
|
|
Alpha/beta ratio for Early Responding Tissues
|
higher alpha/beta ratio
|
|
|
Tolerance Dose for Spinal Cord
|
4500 cGy
|
|
|
Tolerance Dose for Small Bowel
|
4500 cGy
|
|
|
Tolerance Dose for Lens
|
500-1000 cGy
|
|
|
Tolerance Dose for Lung
|
1500-2000 cGy
|
|
|
Tolerance Dose for Partial Brain
|
6000 cGy
|
|
|
Tolerance Dose for Whole Brain
|
4500-5000 cGy
|
|
|
Somatic Effects
|
-seen in exposed individual
-acute or late |
|
|
Genetic Effects
|
-seen in progeny of exposed individual
-result of mutation that occurred that was not lethal to cell -also called hereditary effects |
|
|
Stochastic Effects
|
-no threshold dose (except zero)
-dose will not predict severity, but will predict likelihood of occurence |
|
|
Example of Stochastic Effect
|
secondary malignancy
|
|
|
Deterministic Effects
|
-threshold dose
-severity is determined by dose of radiation |
|
|
Example of Deterministic Effects
|
cataracts
|
|
|
Defining Characteristics of Radiation Induced Malignancy
|
-not a recurrence of original tumor
-within the radiation field -occurs after a latent period of years, usually 8-10 years -all types of tumors may be seen |
|
|
Exposure Required to Induce Hematopoietic Syndrome
|
2.5-10 Gy
|
|
|
Prodromal Stage of Hematopoietic Syndrome
|
nausea and vomiting
|
|
|
Latent Stage of Hematopoietic Syndrome
|
no overt symptoms, but decline of hematologic indicators
|
|
|
Illness Stage of Hematopoietic Syndrome
|
-begins about 3 weeks after exposure
-fever, chills, sweats, epilation, hemorrhage, bleeding, infection |
|
|
LD50 for Hematopoietic Syndrome
|
4 Gy
|
|
|
Supportive Measures for Hematopoietic Syndrome
|
-fluids, transfusions, and antibiotics for doses below 5 Gy
-bone marrow transplant may be attempted for doses between 8-10 Gy -GI syndrome will be fatal at doses above 10 Gy |
|
|
Four Rs of Radiobiology
|
-repair
-reoxygenation -repopulation -redistribution |
|
|
Repair
|
-sublethal damage is repaired
-fractionation takes advantage of repair in normal tissues |
|
|
Reoxygenation
|
-hypoxic cells are aerated
-fractionation takes advantage of reoxygenation of the tumor cells, as hypoxic parts of the tumor are oxygenated and become more radiosensitive |
|
|
Redistribution
|
-cells are synced into more radiosensitive part of the cell cycle
-fractionation takes advantage of tumor cells being redistributed so they are more radiosensitive |
|
|
Regeneration
|
-repopulation with new cells
-fractionation takes advantage of regeneration of healthy tissue |
