Radiation Effects in Tissues & Cells

Transcription

1 Radiation Effects in Tissues & Cells Module Rhodes Neural Cell Cluster of Human embryonic stem cells. Zhang-UWMadison

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3 Determinist effects Stochastic Effects Effects of Fetal Irradiation Review Bushong page 468 Box 29-1 Table 29-1 Populations of exposed humans

4 The study of effects of ionizing radiation on biological tissue Research in field designed to describe the effects on humans and to better use radiation for diagnostic and therapeutic care

5 Atomic 60 % Hydrogen 25.7% Oxygen 10.7 % Carbon 2.4 % Nitrogen 0.2% Calcium 0.1% Phosphorus 0.1% Sulfur 0.8% Trace Elements Molecular 80% Water 15% Protein 2% Lipids (fats) 1% Carbohydrates 1% Nucleic Acid 1% Other

6 Muscles Enzymes Hormones Antibodies

7 Composed of carbon, hydrogen & oxygen Cell membranes Thermal insulation subcutaneous fat Energy stores

8 Carbon, hydrogen & oxygen Sugars & starches Fuel of cell metabolism

9 DNA & RNA Hereditary Information Cell growth & development DNA is the radiation sensitive target molecule

10 4 nitrogen containing bases for rungs Adenine Guanine Thymine Cytosine Sugar Phosphate combinations make the side rails Twisted to make double helix DNA Replication Animation Super Easy 3 min

11 A Human Cell *14 min tour of cell - Bozeman Science A tour of the cell 11

12 Radiation can interfere with sequence of steps necessary for the cell to carry out an operation. The cells inability to complete a process like Protein synthesis could result in cell death. *Through the virtual cell 7 min

13 Single ionizing events at a critical target molecule can disrupt cell reproduction Two types of cells Somatic General cells of the body Genetic Oogonium and spermatogonium Cell division Somatic mitosis Genetic meiosis Nova How cells Divide

14 4 phases Prophase Metaphase Anaphase Telophase Interphase Period of growth S = Synthesis-DNA G1 & G2 Gap/Growth

15 Interphase Prophase Metaphase Anaphase Telophase Interphase *Mitosis ndsuvirtualcell 6 min

16 Need to reduce original 46 chromosomes to 23 The same as somatic through G2 phase Undergoes 2nd division without duplicating DNA Granddaughter cells have 23 chromosomes Meiosis ndsuvirtualcell 5 1/2 min

17 Collections of cells of similar structure Tissues are tightly bound to form organs Organized into organ systems Tissue Abundance In Body Muscle 43% Fat 14% Organs 12% Skeleton 10% Blood 8% Subcutaneous Tissue 6% Bone Marrow 4% Skin 3%

18 Separated by rate of proliferation and stage of development Immature Undifferentiated cells Precursor Stem cells Stem cells are more sensitive to radiation than mature cells

19 Response to Radiation by Cell Type High Intermediate Low Lymphocytes Endothelial cells Muscle cell Spermatogonia Osteoblasts Nerve cells Erythroblasts Intestinal crypt cells Spermatids Fibroblasts 19

20 Level of Sensitivity Tissue or Organ Effect High 2 10 Gy Lymphoid Tissue Atrophy ( Rad) Bone Marrow Hypoplasia Gonads Atrophy Intermediate Skin Erythema Gy GI tract Ulcer ( Rad) Cornea Cataract Growing Bone Kidney Liver Thyroid Growth Arrest Nephrosclerosis Ascites Atrophy Low >50 Gy Muscle Fibrosis (>5000 Rad) Brain Necrosis Spinal Cord Transection Bushong Table 29-3 Page 477