Animal Systems

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Animal Systems

• Organization and Homeostasis

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Organization in Living Things

• Cells are organized into tissues
• Tissues are organized into organs
• Organs are organized into systems
• Systems form an organism

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Four tissue types

• Epithelial
• Connective
• Nervous
• Muscular

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Epithelial tissue

• Epithelial cells form the outer covering, line
  the internal cavities, and make up the glands.
• Examples Skin, mucous membranes.

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Connective tissue

• Consists of living cells in a secreted matrix.
• Examples bone, cartilage, blood.

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Muscular tissue

• Specialized protein fibers allow these cells to
  contract.
• Examples skeletal muscle, smooth muscle, cardiac
  muscle.

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Nervous tissue

• Neurons have the ability to pass an electrical
  signal from one cell to another, or to target
  cells (muscles, glands, organs).

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Tissues form organs

• The skin is an example of an organ made up of
  multiple tissues epithelial, muscular, nervous,
  and connective tissues.

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Homeostasis

• Homeostasis is the act of keeping the internal
  environment of a living organism within an
  acceptable range of conditions.
• Homeostasis controls temperature, pH, blood
  volume, oxygen levels, blood sugar levels, and
  other conditions.
• Negative feedback maintains homeostasis.

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Negative Feedback

• Negative feedback keeps conditions within an
  ideal range.
• As conditions exceed the limits of the ideal
  range, chemical signals (hormones) regulate
  conditions. Most often this is controlled by the
  hypothalamus in the brain.

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Positive Feedback

• Positive feedback takes a condition out of the
  normal range, often to some end point.
• During labor, oxytocin increases contractions,
  which stimulate more oxytocin production, until
  birth occurs.

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Maintaining Temperature

• Ectotherms are animals that derive body heat from
  the environment. Their body temperature may vary
  widely.
• Endotherms rely on metabolic reactions and
  physiological systems to maintain a steady body
  temperature.

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Maintaining Temperature
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Blood Glucose Regulation