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RadioBiology HUMAN BIOLOGY What is Radiobiology? Radiobiology is a branch of science concerned with the action of ionizing radiation on biological tissues and living organisms. The job of radiologic...

RadioBiology HUMAN BIOLOGY What is Radiobiology? Radiobiology is a branch of science concerned with the action of ionizing radiation on biological tissues and living organisms. The job of radiologic technologists is to produce high quality x- ray images with minimal radiation exposures. Early effect of Radiation / Deterministic Effect Radiation response increases in severity, occurs within minutes or days after exposure Late effect of Radiation / Stochastic Effect Radiation response is observed for 6 months or longer after radiation exposure. Radiation response increases in incidence.  Cell Theory He was responsible for Robert Hooke, 1655 discovering bacteria, free- living and parasitic tiny He discovered numerous protists, sperm cells, blood tiny pores, which he cells, microscopic nematodes described as “cells”. and rotifers, and many other organisms. His contribution to microbiology revealed a whole new realm of microorganisms in the study of biology. Antonie Van Leeuwenhoek 1674 Cell Theory Schleiden and Schwann, 1838 Schwann offered the notion that animals’ and plants’ bodies are made up of cells and cell products based on this Therefore, the cell theory was proposed by Schleiden and Schwann Deoxyribonucleic acid (DNA) In 1953, Watson and Crick described the molecular structure of DNA as the genetic substance of the cell. Molecular Imaging made a significant contributions to human health  COMPOSITION OF THE HUMAN BODY The human body is composed of atoms. 85% of the human body consists of hydrogen and oxygen ATOMIC COMPOSITION Determines the character and degree of radiation interaction that occurs. 60% Hydrogen 0.2% Calcium 25.7% Oxygen 0.1% Phosphorus 2.4% Nitrogen 0.1% Sulfur 10.7% CArbon 0.8% Trace Elements Molecular Compositions Five Principal Types of Molecules Organic Molecules Molecules containing carbon were assumed to point towards organisms, and hence were called organic molecules. Macromolecules These are very large molecules that sometimes consist of hundreds of thousand of atoms. Proteins, Lipids, Carbohydrates and Nucleic Acids are examples of Macromolecules. Water The most abundant molecule in the body, and it is the simplest. It plays a particularly important role in delivering energy to the target molecule, thereby contributing to radiation effects. They provide some form and shape, assist in maintaining body temperature, and enter into some biochemical reactions. Consist of two atoms of hydrogen and one atom of oxygen (H2O) Homeostasis the self-regulating procedures that help an organism maintain stability while adjusting oneself to suitable environmental conditions Metabolism Anabolism anabolic processes of sum of all biochemical reactions that take place in an metabolism are those in organism in order to maintain the living condition of which simple molecules the cells within it are changed to complex molecules Catabolism catabolic processes are those in which complex molecules are broken down into simple molecules and energy is released. Protein Proteins are long chains of components known as amino acids consisting of layered structures. The first level is known as the primary structure, which is the order of amino acids in every chain Are long chains macromolecules that consist of a linear sequence of amino acids connected by peptide bonds. Twenty-two AA are used in protein synthesis, the metabolic production of proteins. GROW, GROW, GROW!!!  Enzymes complex proteins that are produced by living cells and act as catalysts in biological reactions (such as digestion). Hormones chemical-signaling molecules that are produced by endocrine cells and act to control or regulate particular physiological processes such as growth, development, metabolism, and reproduction. Antibodies constitute a primary defense mechanism of the body against infection and disease. An antigen is a foreign substance that enters your body and antibodies fight off these antigens LIPIDS General formula: CnHnOn Composed of two types of smaller molecules -- glycerol and fatty acid. Each lipid molecule is composed of one molecule of glycerol and three molecules of fatty acid. They are present in all tissues of the body and are the structural components of cell membranes. They also serve as fuel for the body by providing energy stores. Carbohydrates The ratio of the number of hydrogen atoms to oxygen atoms in a carbohydrate molecule is 2:1 the same with water. Glucose is a common carbohydrate whose formula is C6 H12 O6.. Carbohydrates are made up of carbon (carbo-) and water(-hydrate), and their name comes from this combination. Glucose is the ultimate molecule that fuels the body PROVIDE FUEL FOR CELL METABOLISM Simple and Complex Carbohydrates Complex carbohydrates are a Simple vital source of energy for your body’s operations. They supply Simple carbohydrates your body with the long-term include natural sugars. energy required for exercise, They originate from fruit, daily activities, and even sugar, and anything else relaxation and recovery. sweet. These substances can be easily broken down by the human body, which causes various issues. Complex  FOUR TYPES OF CARBOHYDRATES MONOSACCHARIDES - Simple sugars DISACCHARIDES - simple sugars that are soluble in water OLIGOSACCHARIDES - composed of 3–10 monosaccharide units in a saccharide polymer POLYSACCHARIDES - a lengthy chain of monosaccharides connected by glycosidic linkages (poly- Meaning “many”) NUCLEIC ACID Are very large and extremely complex macromolecules. The most critical and radiosensitive target molecule. TWO PRINCIPAL TYPES: 1. Deoxyribonucleic acid (DNA) 2. Ribonucleic acid (RNA) DNA is the control center for life.  DNA Located in the nucleus of the cell. It serves as the command or control molecule for cell function. It contains all the hereditary information that represents a cell and, of course, if the cell is a germ cell, all the hereditary information of the whole individual. Sugar Component: Deoxyribose Base Component: Thymine Configuration: Double Helix NOTE: DNA is the radiation sensitive of target molecule.  RNA Located principally in the cytoplasm, RNA also is found in the nucleus. THREE TYPES OF RNA 1. Message RNA (mRNA) 2. Transfer RNA (tRNA) 3. Ribosomal RNA (rRNA) : It is the main constituent of ribosomes and helps in establishing bonds between amino acids during protein synthesis. These molecules are involved in the growth and development of the cell through PROTEIN SYNTHESIS.  RNA Located principally in the cytoplasm, RNA also is found in the nucleus. Sugar Component: Ribose Base Component: Uracil Configuration Single Helix  Nitrogen Base In nucleic acid, the nitrogen atom acts as a base as it gives electrons to various molecules that results in the formation of new molecules. Ring structures are of two types: purines (double rings) and pyrimidines (single rings) Pyrimidines consist of cytosine, thymine, and uracil while purines consist of adenine and guanine. Purines are larger than pyrimidines, this size difference helps in determining the pairings in the strands of DNA. The base sugar-phosphate combination is called a nucleotide, and the nucleotides are strung together in one long-chain macromolecule. Human DNA exists as two of these long chains attached together in ladder fashion. The said rails of the ladder are the alternating sugar- phosphate molecules, and the rungs of the ladder consist of bases joined together by hydrogen bonds. This produces a molecule with the double-helix configuration.  RNA is also known as ribonucleic acid that consists of a single-stranded structure and is found inside the cell of various life forms. Structurally, RNA resembles DNA. In RNA, the sugar component is ribose rather than deoxyribose, and uracil replaces thymine as a base component. In contrast, RNA forms a single helix, not a double helix.  Prokaryotic Prokaryotic Dispersed genetic material Lack a defined nucleus in the cytoplasm. Plant Types Cellulose cell wall; chloroplasts and vacuoles. of Cells Animal Rigid cell wall; may have flagella. Eukaryotic Have a defined nucleus Protist They can have a cell wall, without differentiated tissues. Fungal Chitin Cell Wall; they are heterotrophs.  Composed of several fundamental components Cell membrane Nucleus Ribosome Rough endoplasmic Golgi Apparatus reticulum. Lysosome and Mitochondria Chloroplasts peroxisome Centriole Microtubules  Cell membrane The cell membrane surrounds the cell and is a selective barrier between the interior and the exterior. Its primary role lies in regulating the passage of substances, including nutrients and waste materials.  Cell nucleus An organelle that houses DNA, located in the center of eukaryotic cells. Its primary function is to store and safeguard genetic information, controlling gene expression and DNA replication. It also contains the nucleolus, which is most RNA located.  Cytoplasm It makes up the bulk of the cell and contains great quantities of all molecular components except DNA. It plays a crucial role in biochemical reactions, energy production, and substance transport. Essential for cellular metabolism, it provides structural support to the cell.  Endoplasmic reticulum A network of interconnected membranes that extends from the nuclear membrane to the cell membrane. It plays a fundamental role in the transport, processing, and distribution of proteins and lipids within the cell.  Ribosome Ribosomes are essential organelles for cellular functioning and survival. They synthesize proteins using the genetic information from messenger RNA (mRNA), which is crucial for cellular structure, function, and regulation. Ribosomes are located in the cytoplasm and the rough endoplasmic reticulum. The site of protein synthesis.  Golgi apparatus Key in the processing and packaging of proteins and lipids produced in the endoplasmic reticulum. It synthesizes carbohydrates and lipoproteins and is essential for maintaining the cell's internal balance and facilitating communication with the outside.  Mitochondria Present in eukaryotic animal and plant cells. Their primary function is energy generation through cellular respiration (ATP production). The double membrane of mitochondria allows for the organization of various stages of the respiratory chain, making it crucial for cellular function and survival.  Protein Synthesis Building and repairing cellular structures, regulating biological processes, and expressing specific characteristics of each organism.  Protein Synthesis A series of three base pairs, called a codon, identifies one of the 22 human amino acids available for protein synthesis DNA serves as a template to create messenger RNA (mRNA) during transcription. The mRNA then exits the nucleus and travels to a cytoplasmic ribosome for translation. The genetic code within mRNA is decoded and synthesized polypeptides during translation. One way to simplify these two processes is to remember the foundational element of molecular biology: DNA > RNA > Protein. NOTE: Interference with any phase of this procedure for protein synthesis could result in damage to the cell  Cell Proliferation is the act of a single cell or group of cells to reproduce and multiply in number. The cell proliferation is defined by two well defined time periods: Mitosis (M) where division takes place and the period of DNA Synthesis (S)  Somatic Cell and Genetic Cell. Animals have two basic cell types: somatic cells and germ cells. Somatic cells are formed during asexual reproduction by mitosis, whereas germ cells are formed during sexual reproduction by meiosis. The term vegetal cells refers to cells that are not somatic. The main distinction between somatic and germ cells is that somatic cells are engaged in the construction of multicellular animals’ bodies, whilst germ cells are involved in the synthesis of haploid gametes that are used in sexual reproduction. Because somatic mutations are not engaged in sexual reproduction, they do not pass down across generations. Mutations in germ cells, on the other hand, are passed down through generations via sexual reproduction. Mitosis Mitosis is the cell cycle phase in which newly generated DNA is divided into two new cells with the same number and type of chromosomes as the parent nucleus Cell division is the primary driving force behind cellular reproduction. There are cell division mitosis and meiosis Mitosis is required for both cell development and cell replacement. DNA can be tampered with as a consequence of mitosis anomalies, leading to genetic diseases.  Stages of Mitosis Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Interphase A cell spends a period of its growth in interphase before commencing mitosis When in interphase, it passes through the following phases: G1 Phase: That’s the time preceding DNA synthesis S Phase: That’s the phase in which DNA synthesis occurs G2 Phase: The period between the termination of DNA synthesis and the start of prophase Prophase Mitosis officially begins with prophase. During this phase, the chromatin, which consists of DNA and proteins, condenses into visible chromosomes. Each chromosome consists of two identical sister chromatids joined at a region called the centromere. The nuclear envelope, which surrounds the nucleus, begins to break down, and spindle fibers start to form. Metaphase During metaphase, the chromosomes line up along the metaphase plate, which is an imaginary plane equidistant from the two poles of the cell. This alignment ensures that each daughter cell will receive the same number and type of chromosomes. NOTE: Radiation induced chromosome damage is analyzed during metaphase. Anaphase Anaphase is characterized by the separation of sister chromatids. The spindle fibers attached to the centromeres shorten, pulling the sister chromatids apart and moving them toward opposite poles of the cell. Pole: Spindle Fiber: Spindle Fiber The number of centromere per chromatids is reduced by half and new chromosome migrates towards the spindle. Telophase In telophase, the separated chromosomes reach the poles of the cell, and new nuclear envelopes begin to form around them. The chromosomes start to decondense back into chromatin, and the spindle fibers disassemble. Closing off of the nucleus into two nuclei. Cytoplasm is divided into two equal parts. Meiosis Genetic cells undergo reduction division. No S-phase, therefore no DNA Replication. Two gametes having a haploid set of chromosomes with complete genetic information fuse to form a diploid cell. This diploid cell divides into four new individual haploid cells as the number of chromosomes is reduced by half. This process of division where the number of chromosomes reduce to half of parent cell is called meiosis.. Crossing over/ Crossover- chromatids exchange chromosomal material Tissues - collection of cells of similar structure and function. Organs - Collection of tissue of similar structure and function. Organ System - Combination of tissues and organs. TISSUE COMPOSITION OF THE HUMAN BODY MNEMONICS: My F**king Organ Sucks Blood So Bad, Sh*t TISSUE ABUNDANCE Muscle 43% Fat 14% Organ 12% Skeleton 10% Blood 8% Subcutaneous Tissue 6% Bone Marrow 4% Skin 3% Radiosensitivity of Tissues and Organs 1. Determined by the function of the organ 2. Inherent radiosensitivity of the cell type 3. rate at which cell mature within the organ TYPES OF TISSUE 1. Epithelium - covering tissue may it be exterior and interior 2. Connective and Supporting Tissue - binds organs and tissues together. Highly elastic, high in protein and fibers. 3. Muscle - tissue that can contract; high in protein 4. Nervous - consists of specialized cells called neurons. Parenchymal - part of an organ that contains tissues representative of that organ. Stromal - part of an organ composed of connective tissue that provide structure.  Radiation Response to Cell Type Radiosensitivity Cell Type High Intestinal Crypt Cells ISLE Spermatogonia Lymphocytes Erythroblasts Osteoblasts Intermediate Spermatids OSEF Endothelial Cells Fibroblasts Muscle Cell Low Nerve Cell ANG KATOG MABAWI, ANG GRADO DILI