Nscu 302 wk 7 1
Transcript of Nscu 302 wk 7 1
Levels of Organization
28.1 Levels of Organization
KEY CONCEPT The human body and other organisms have five levels of organization.
28.1 Levels of Organization
A. Levels of Structural Organization
AtomMoleculeCellTissueOrganOrgan SystemOrganism
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Examples:
≈ carbon≈ phospholipid≈ nerve cell≈ nervous tissue≈ brain≈ nervous system≈ human
Atom
Molecule
Cell
Tissue
Organ
Organ System
Organism
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1. Atoms combine to form molecules
Atoms Molecule
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2. Molecules form cells
Molecules Cell
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a. Specialized cells develop from a single zygote.
• Organisms are made up of specialized cells.
red blood cell nerve cell
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• Zygotes first divide into embryonic stem cells.
• Stem cells develop in two stages. – determination, or
committing to become one cell type
– differentiation, or acquiring specialized structures and functions
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3. Cells form tissuesSimilar cells with a
common function form tissues
• There are 4 basic tissue types:• Epithelial• Nervous• Muscular• Connective
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cell
4. Specialized cells function together in tissues, organs, organ systems, and the whole organism. • Specialized cells perform specific
tasks. • Tissues are groups of
similar cells working together.
tissue
– epithelial tissue – connective
tissue – muscle tissue – nervous tissue
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5. Tissues form organs• Two or more tissue types form
an organ
An organ is a structure that performs a specific function for the body
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6. Organs form Organ Systems• A group of organs which
work together for a common purpose is an organ system
Brain, Spinal Cord, etc. Nervous System
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B. Body Systems1. Integumentary SystemSkin is the only organ
Protects from injury Regulates body temperature Receptors for temperature, pain,
and pressure
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2. Skeletal SystemBones, cartilage, ligaments, and
joints Supports body Protection Storage for minerals (calcium)
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3. Muscular SystemMuscles contract (shorten)
to cause movement• Skeletal muscles are large,
fleshy, and attached to bone
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4. Nervous SystemBrain, spinal cord,
nerves, & sensory receptors
• Responds to
irritants or stimuli
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5. Endocrine System
Releases hormones to control: Growth Reproduction Food use
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6. Circulatory SystemMade of 2 organ systems:
Cardiovascular System:- Heart and blood vessels- Transport oxygen, etc.
Lymphatic System:- Cleanses blood, immunity
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7. Respiratory System• Nasal passages,
pharynx, larynx, trachea, bronchi, lungs
Supplies body with oxygen
Removes carbon dioxide
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8. Digestive System• Mouth, oral cavity, pharynx,
esophagus, stomach, small intestine, large intestine, rectum
Breaks down food and delivers nutrients to blood for cells in the body
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9. Urinary System• Kidneys, ureters, bladder, and
urethra• Removes Nitrogen-containing
wastes from the blood and flushes them from the body in urine
Regulates:– Water balance– Salt balance– pH (acid-base) balance
28.1 Levels of Organization
10. Reproductive SystemFunctions to produce offspring• Male testes produce sperm
Male Structures: scrotum, penis, accessory glands, duct system
• Female ovaries produce eggs Female structures: uterine tubes,
vagina, uterus (where fetus develops)
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All of the organ systems form the organism