Tissues, Organ Systems and Homeostasis

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Tissues, Organ Systems and Homeostasis

• B. L. Krilowicz
• Biology 155
• Winter 2005

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Organization of the Animal Body

• Animals bodies exhibit hierarchical organization
  
• Biological molecules are organized into
  organelles (ex. Phospholipids and proteins are
  arranged into the plasma membrane)
• Organelles are organized into a cell (ex. Nucleus
  plasma membrane cytoplasm proper many
  organelles cell)

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Organization of the Animal Body (continued)

• Hierarchical organization continued
• Groups of similar cells are organized into
  tissues (ex. Cardiac muscle cells are organized
  into the tissue, cardiac muscle) Note that the
  evolution of multicellular living forms required
  development of tissues
• Two or more tissues are organized to form an
  organ (ex. Cardiac muscle tissue connective
  tissue epithelial tissue the heart provides
  force to move blood)

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Organization of the Animal Body (continued)

• Hierarchical organization continued
• Organs are organized into organ systems (ex.
  Heart blood vessels blood cardiovascular
  system function is transport)
• Organ systems are organized into an organism
• (ex. An animal consists of 11 organ systems)

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Embryonic Tissues all adult tissues are derived
from one of three embryonic tissues
Ectoderm outside skin
gut
Mesoderm middle skin
Cross section through embryo
Endoderm inside skin
Animal embryo
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Fate of Embryonic Tissues

• Ectoderm will become the outer covering of the
  body and the nervous system
• Mesoderm will become the muscles and internal
  skeletons
• Endoderm will become the lining of the
  gastrointestinal tract, lungs, vessels and ducts

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Adult Tissues

• Definition groups of cells with similar
  structure, embryonic origin, and function cells
  are bound together by extracellular material and
  function together to perform a specific task
• There are four main types of adult tissues in the
  animal body

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Epithelial Tissues

• Source may be derived from any tissue in the
  embryo
• Function mainly protective, therefore they
  cover all free surfaces of the body can be
  specialized for absorption, excretion, secretion,
  etc.

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Epithelial Tissues (continued)

• Characteristics
• Closely joined cells with little extracellular
  material between the cells
• Presence of a basement membrane secreted by the
  epithelial cells separates the epithelial cells
  from underlying tissues
• One free surface not in contact with other cells

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Epithelial Tissues (continued)

• Classification ask and answer two questions
• How many cell layers above the basement membrane?
• Simple one layer of cells used for exchange
  (ex. Diffusion of gases in the alveoli of the
  lungs, absorption in the small intestine see
  previous slide)
• Stratified more than one layer of cells used
  for protection (ex. the outer layer of the skin
  see board)

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Epithelial Tissues (continued)

• Classification continued
• What shape are the cells? (when viewed from the
  side)
• Flat and thin squamous used to maximize
  diffusion (non-energy requiring exchange where
  things move from an area of high to an area of
  low concentration) ex. Alveoli of lungs,
  capillaries
• Look like squares cuboidal used to maximize
  energy requiring exchange such as absorption and
  excretion (things can move from an area of low
  concentration to an area of high concentration)
  ex. respiratory system
• Tall and thin columnar as cuboidal above ex.
  Small intestine

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Connective Tissues

• Source may be derived from any tissue in the
  embryo
• Function many, but generally holds things
  together in the body can be specialized to give
  structure to and protect body parts

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Connective Tissues (continued)

• Characteristics
• Few cells
• Lots of extracellular material between the cells
  extracellular material is produced by the cells
  and is called matrix
• Matrix consists of
• Protein fibers
• Ground substance non-fibrous proteins other
  molecules
• Fluid

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Connective Tissues (continued)

• Classification ask and answer one question
• What is the nature of the extracellular matrix?
• Fluid tissue is blood, functions in gas
  transport

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(Matrix)
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Connective Tissues (continued)

• Classification ask and answer one question
• What is the nature of the extracellular matrix?
  (continued)
• Solid
• Mainly protein fibers connective tissue proper
  (ex. Loose and dense connective tissues, adipose)
• Protein fibers ground substance special
  connective tissues (ex. Bone and cartilage)

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Muscle Tissues

• Source derived from the embryonic mesoderm
• Function allows movement of the body or
  movement within the body
• Characteristics
• Closely joined cells with little extracellular
  material
• Contain specialized protein fibers capable of
  contraction

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Muscle Tissue (continued)

• Classification
• Cardiac Muscle heart muscle
• One, centrally located nucleus
• Presence of striations
• Short, branched cells
• Presence of intercalated discs
• involuntary

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Muscle Tissue (continued)

• Classification
• Skeletal Muscle
• Many, peripherally located nuclei
• Presence of striations
• long, thin cells
• voluntary

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Muscle Tissue (continued)

• Classification
• Smooth Muscle found in hollow organs
• One, centrally located nucleus
• no striations
• Short, tapered cells
• involuntary

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Nervous Tissue

• Source derived from the embryonic ectoderm
• Function communication
• Characteristics
• Electrically excitable cells (neurons with cell
  body and processes), or
• Cells that support, nourish and protect the
  neurons (glia)
• Classification none

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Animal Organ Systems
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Animal Organ Systems - continued
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Animal Organ Systems - continued
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Animal Organ Systems - continued