Human Biology

Deterministic

Radiation response increases with severity with an increase in radiation dose; non-stochastic

Stochastic

The incidence of the radiation response increases with increasing radiation dose; probabilistic

Radiobiology

The study of the effects of ionizing radiation on biologic tissue

Cell theory

In all plants and animals, cells are the basic functional units

Macromolecule

Very large molecules that sometimes consist of hundreds of thousands of atoms, such as proteins, lipids, carbohydrates, and nucleic acids

Organic molecule

Life-supporting macromolecules containing carbon, such as proteins, lipids, and carbohydrates

When an atom is ionized: Its ____ binding properties may change

Chemical

When an atom is ionized: it may result in ____ of the molecule

Breakage

When an atom is ionized: it may result in ____ of an atom within the molecule

Relocation

Most human responses have been observed to occur after exposure to rather large doses of radiation

True

Deterministic effects of radiation on humans: Actue Radiation Syndrome:

• Hematologic syndrome

• Gastrointestinal syndrome

• CNS syndrome

Deterministic effects of radiation on humans: Locat Tissue Damage:

• Skin

• Gonads

• Extremities

Deterministic effects of radiation on humans: Hematologic ____

depression

Deterministic effects of radiation on humans: ____ damage

Cytogenetic

Leukemia and life span shortening

Early American Radiologists

Cataracts

Cyclotron workers/ physicists

Bone Cancer

Radium watch-dial painters

Lung Cancer

Uranium miners

Liver Cancer

Thorotrast contrast agent studies

Hydrogen

60%

Oxygen

25.7%

Carbon

10.7%

Nitrogen

2.4%

Calcium

0.2%

Phosphorus & Sulfur

0.1%

Trace Elements

0.8%

What percentage of the body is made up of water molecules?

80%

Which molecule plays a particular role in delivering energy to the target molecule via indirect effect via Radiolysis?

Water molecule

Anabolism (building up) + catabolism (breaking down) =

Metabolism

Protein

• long chain macromolecule consisting of linear sequence of amino acids connected by peptide bonds

• 22 amino acids are used in protein synthesis, the metabolic production of proteins

• they provide structure and support and function enzymes, hormones, and antibodies

Which macromolecule serves as an insulator and fuel for the body providing energy stores and is the structural component of cell membranes?

Lipids (fats)

Which organic molecules chief function is to provide fuel for cell metabolism?

Carbohydrates (sugars and starches)

Which specific nucleic acid carries out protein synthesis?

RNA

Where is the side of protein synthesis?

Ribosomes

Which nucleic acid is the rarest and is considered to be the more critical and radiosensitive molecule in the human body, according to the target theory?

DNA

Ribosomes

Small, dot-like structures that are the site of protein synthesis

Somatic effects

Effects of radiation on the body (self) being irradiated

Genetic effects

Effects of radiation on a germ cell’s genetic code; affect the next generation

Metaphase

Chromosomes align along equator; Mitosis can be stopped, and radiation-induced chromosome damage can be analyzed under the microscope

Meiosis

The process whereby genetic cells undergo reduction division

These are large, bean-shaped structures that are the engine for the cell

Mitochondria

When are cells more radiosensitive?

Inside the human cell (in vivo)

When genetic cells proliferate or divide, they undergo _____

Meiosis

When somatic cells proliferate or divide, they undergo ____

Mitosis

Somatic effects occur during the lifetime of the exposed _____

Individual

Genetic effects of radiation occur on a _______ cell’s genetic code, affecting the next generation, progeny, or offspring

Germ

List the four sub-phased in order of mitosis

Prophase, Metaphase, Anaphase, Telophase

Another name for the process whereby genetic cells undergoes meiosis is called _____ division

Reduction

Meiosis undergoes two division processes, which results in ____ granddaughter cells, each with ____ chromosomes

4, 23

Radiosensitive cells

• Immature cells called undifferentiated calls, precursor cells, or stem cells

• May continually be undergoing mitosis

• Stem cells are more sensitive to radiation than mature cells

• Epithelial tissue and lymphocytes are radiosensitive

Radioresistant cells

• Mature cells or differentiated cells are non-diving or specialized and do not undergo mitosis

• Adult nervous system (ex. neurons and neuroglia)

What cell types have high radiosensitivity?

• lymphocytes

• spermatogonia

• erythroblasts

• intestinal crypt cells

What cell types have intermediate radiosensitivity?

• endothelial cells

• osteoblasts

• spermatids

• fibroblasts

What cell types have low radiosensitivity?

• muscle cells

• nerve cells

• cartilage

Which tissue or organs have a low level of radiosensitivity?

Muscle, brain, and spinal

A radiation response that occurs within minutes or days after radiation exposure is classified as?

Early effects of radiation

A radiation response that is not observed for month or even years is called?

Late effects of radiation

Late effects of radiation on humans include leukemia, shortening of life span, and genetic damage

True

Early effects of radiation on humans include acute radiation syndrome, local tissue damage, and hematologic depresssion

True

Macromolecules

Very large molecules that sometimes consist of hundreds or thousands of atoms

Lipids make up ___ of the human body

2%

Proteins make up ___ of the human body

15%

Water makes up ____ of the human body

80%

Carbohydrates make up ___ of the human body

1% (sugars and starches)

Nucleic acids make up ___ of the human body

1% (RNA or DNA)

Anabolism

The production of large molecules from small molecules

Catabolism

The breaking down of larger molecules into smaller units

Proteins are long-chain macromolecules consisting of a linear sequence of amino acids connected by ____ bonds

Peptide

The chief function of carbohydrates in the body is to:

Provide fuel for cell metabolism

DNA is the most _____ molecule in the human cell

Radiosensitive

RNA

Nucleic acid that carries out protein synthesis

This connection to the double-walled nuclear membrane controls the passage of molecules, particularly RNA, from the nucleus to the cytoplasm

Endoplasmic reticulum

Mitochondria

Energy source of the cell

Ribosomes

Site of protein synthesis

Lysosomes

Contains enzymes capable of digestive cellular fragments

Golgi apparatus

“Packing center” for secretion from the cell

Somatic cells undergo:

Mitosis and cell proliferation

Genetic or reproduction cells undergo:

Meiosis

Prophase

Nucleus swells

Metaphase

Chromosomes align along equator

Anaphase

Chromosomes split at centromere and move to opposite poles

Telophase

Closing off of the nuclear membrane

Following reduction division, the granddaughter human cells have only ____ chromosomes

23

When genetic cells proliferate or divide, they undergo:

Meiosis

Which of the following best describes the stochastic (late) effects of radiation?

• The incidence of the radiation response increases with increasing radiation dose

• Also described as probabilistic effects

Which of the following human populations have demonstrated lung cancer as a result of exposure to ionizing radiation?

Uranium miners

List the following cell types in order from most radiosensitive to least radiosensitive: muscle cells, spermatogonia, endothelial cells, fibroblasts

1. Spermatogonia

2. Endothelial cells

3. Fibroblasts

4. Muscle cells (myocytes)

What occurs during metaphase?

• Chromosomes appear

• Chromosomes align along the equatorial plane

• Radiation-induced chromosome damage can be analyzed under a microscope during this phase

According tot he table entitled Relative Radiosensitivity of Tissues and Organs Based on Clinical Radiation Oncology, tissues and organs with an intermediate level of radiosensitivity include:

Skin

Cell Theory states that in all plants and animals, cells are the basic functional units

True

The idea of one key radiosensitive molecule (DNA) in the human body best defines:

Target Theory

What best describes radiosensitive cell types?

• Epithelial tissue and lymphocytes

• Immature of undifferentiated cells

• Stem or precursor cells

According to the box entitled Human Response to Ionizing Radiation, the four deterministic (early) effects of radiation on human include?

• Acute Radiation Syndrome

• Local Tissue Damage

• Hematologic depression

• Cytogenetic damage