chapter 31 - human biology

X-rays have enormous benefits and are considered reasonably safe when using-

ALARA

• as low as reasonably achievable

Human radiation response:

• Effects begin at the:

Atomic level, —> transfer of energy

• this transfer of energy continues through molecules to cells and beyond

Human radiation response

• and nearly every stage in the sequence, It is possible to do what?

It is possible to repair radiation damage, and recover

What are the three human responses to ionizing radiation?

Deterministic effects, stochastic effects, Effects of fetal irradiation

Deterministic effects:

Above a threshold, severity increases with dose

What are examples of deterministic effects?

Acute radiation syndrome, Local tissue damage, Hematologic depression, Cytogenetic changes

Stochastic effects:

Probability of the effect increases with dose, Severity does not

• random

What are some examples of stochastic effects?

Leukemia, Malignant diseases (cancer), Lifespan shortening, Genetic damage

Effects of fetal irradiation (mix)

• what are some expamples

prenatal death, Neonatal death, Congenital malformation, Childhood malignancy, Diminished growth and development

Where did most of the information come from pertaining to human responses to ionizing radiation?

Has been gathered from exposures to very large radiation doses - not diagnostic radiology. We can only extrapolate the data and make assumptions about low doses. Diagnostic radiology follows a very conservative approach

What are the parts of composition of the human body?

Atomic composition, Cell theory, Molecular composition

It’s most basic level the human body is composed of:

Atoms, radiation interacts at the atomic level

Composition of the human body

• Atomic composition contains?

60% hydrogen, 25.7% oxygen, 0.2% calcium, Etc.iug

Atomic composition, How does this Affect differential absorption?

Most of the bodies made of water, So very low atomic #, So not a lot of absorption

Composition of the human body

• Cell theory;

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

Composition of the human body

• Molecular composition: What are the five main molecules?

Water, Protein, Lipids, Carbohydrates, Nucleic acids

Macromolecule definition

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

Composition of the human body

• Molecular composition: Which of the five main molecules are macro molecules?

Proteins, Lipids (fats), Carbohydrates (sugars and starches), nucleic acids

Molecular composition

• Molecule:

A group of atoms bonded together representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Molecular composition

• Water: made of?

Two atoms of hydrogen, and one atom of oxygen

Molecular composition

• ______ % Of body composition is water

80%

Molecular composition

• ______ Contributes to radiation effects (Indirect effects)

Water

Molecular composition

• protein: ___% Of body composition

15

Molecular composition

• Proteins are What??

Long chains of amino acids connected by peptide bonds

• Sequence of AA determines function (AA-AA-AA-AA-AA-)

Molecular composition

• Proteins provide what?

Provide structure and support

Molecular composition

• Proteins also function as:

Enzymes, Hormones, Antibodies

Molecular composition

• Proteins: enzymes:

Allow biochemical reactions

Molecular composition

• Proteins: Hormones:

Regulatory control of growth and development

Molecular composition

• Proteins: Antibodies:

Primary defense mechanisms of infection and disease

Molecular composition

• Lipids (Fat) Present in:

Lipids present in all tissues of the body

Molecular composition

• Lipids (Fat): Component of what?

Component of cell membranes

Molecular composition

• Lipids (Fat) Do what?

are a thermal insulator, also long-term energy storage (Difficult to extract)

Molecular composition

• Carbohydrates provide what

Provide fuel for cell metabolism (Main job) energy

Molecular composition

• Carbohydrates are also called what?

Saccharides

Molecular composition

• Carbohydrates: examples of saccharides and what are they?

Monosaccharides, disaccharides, polysaccharides (all sugars)

Molecular composition

• Carbohydrates also do what besides provide fuel

are the shape and stability of cells

Molecular composition

• Nucleic acids:

Very large complex macromolecules

Molecular composition

• Which two nucleic acids are important to human metabolism

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)

Molecular composition: Nucleic acids

• DNA is ___ sensitive

Radiation sensitive target molecule

Molecular composition: Nucleic acids

• DNA is located primarily where?

In the nucleus

Molecular composition: Nucleic acids

• DNA is the:

Command and control of the cell

Molecular composition: Nucleic acids

• DNA contains the ___ information that represents the cell or whole organism

All hereditary information

Molecular composition: Nucleic acids

• RNA is located where

Primarily in the cytoplasm, some in the nucleus

Molecular composition: Nucleic acids

• what 2 types of RNA are there

mRNA (messenger) and tRNA (transferer)

Both used for protein supynthesis

Molecular composition: Nucleic acids

• Structure: the sides (backbone)

alternating segments of deoxyribose (sugar) and phospahte

Molecular composition: Nucleic acids

• The rungs are made of:

nitrogenous bases (The chemical molecules that pair up across the center to form each rung)

Molecular composition: Nucleic acids

• Structure: Rungs- what are the purines?

Adenine, Guanine

Molecular composition: Nucleic acids

• Structure- rungs: what are the pyrimidines?

Thymine, Cytosine

Molecular composition: Nucleic acids

• Structure: Two long ladders form the_____

double helix

Molecular composition: Nucleic acids

• Stucture: there are sequences (pairs) of ____ and _____

A-T (adenine, thymine) and G-C (guanine, cytosine)

Molecular composition: Nucleic acids

• Structure: RNA is smilar but____

has a single helix & uracil replaces thymine in the sequences

The human cell

• what are the 2 major componets?

Nucleus and cytoplasm

The human cell

• Nucleus does what

houses the DNA

The human cell

• What is inside the nucleus and what does it do?

Nucleolus / Nucleoli: is attached to the nuclear membrane and contains most of the RNA

The human cell

• Cytoplasm is the ___ of the cell

bulk of the cell

The human cell

• what is all contained in the cytoplasm?

Endoplasmic reticulum (ER), mitochondria, ribosomes, lysosomes, cell membrane

The human cell

• Cytoplasm - What is the endoplasmic reticulum (ER)

is attached to nuclear membrane and is channels that allow nucleus to communicate with cytoplasm

The human cell

• Cytoplasm: whats the mitochondria-

powerhouse of cell - digests macromolecules to produce energy (catabolism)

The human cell

• Cytoplasm: Ribosomes are the site of -

proten synthesis