Tissues: Living Communities

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Tissues Living Communities

• Chapter 4

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Introduction

• Since cells are differentiated, they have lost
  ability to perform all metabolic functions
  required to sustain life as an isolated entity.
• Cells exist in cooperative communities in
  multicellular organisms
• Cells of similar type and function cluster
  together to form _____________.
• Tissues cluster to form organs.

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Classification of Tissues

• Epithelial tissue
• Covers and lines
• Connective tissue
• Provides support
• Muscle tissue
• Enables movement
• Nervous tissue
• Controls work
• Most organs contain all 4 tissue types.
• The study of microscopic structures of tissues
  and organs is called _________

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Epithelial Tissue

• Composed of sheets of cells that cover and line
  other tissues.
• Lines bladder, mouth, blood vessels, thorax, etc.
• Have an exposed surface that affords access to
  the surrounding environment or to the inner
  openings of chambers and ducts.
• Functions
• ____________, covers, lines
• ____________ of biochemical substances
• May be _____________
• May play an important role in ____________ input
• ____________ and ____________ of biochemical
  substances
• Glandular epithelia
• Individual glandular epithelial cells are goblet
  cells, groups are referred to as glands.

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Characteristics of Epithelia

• Organized into tightly packed groups that form
  _________ of tissue.
• Can be composed of single layer or multiple
  layers depending on _________.
• Epithelial cells share the following
  characteristics
• ________ - Each epithelial cell has an apical
  surface and a basal surface
• Apical surface faces the lumen or body cavity
• Basal surface faces the underlying connective
  tissue
• Lateral surfaces are connected to neighboring
  cells by ________________ complexes
• Epithelial cells are avascular
• Rely on underlying connective tissue for oxygen
  and nutrients
• Most epithelial cells are innervated

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• Between the cell membranes of adjacent epithelial
  cells are channels that carry nutrients to the
  cells and wastes away from them.
• Junctional Complexes specialized attachments
  between epithelial cells at their plasma
  membranes. Give epithelial tissue strength.
• Tight junctions
• Nothing can penetrate
• Prevent ____________
• Bladder, GI tract
• Desmosomes
• Welded plaque
• Tough, resist __________ and
• stretching (like Velcro). Consist of
• intermediate fibers (tonofilaments)
• Skin, heart, uterus
• Gap junctions
• Cytoplasm continuous
• Linked by tubular channel proteins called
  _______________.

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Epithelial Cells Basement Membrane

• Foundation of epithelial cells and made by
  epithelial cells
• Meshwork of fibers that cements epithelial cell
  to underlying _____________________ tissue (CT)
• Its strength and elasticity help to prevent the
  epithelial cell from being torn away
• Also called basal _________
• Varies in thickness
• Oxygen and nutrients diffuse through the basement
  membrane from the connective tissue. Absorbed
  substances and waste products produced by
  epithelium diffuse through basement membrane to
  the connective tissue.

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Surface Specialization

• Surfaces vary depending on location in body and
  function
• May be smooth or contain ___________(fingerlike
  projections) or _______(hairs)
• Cilia found in respiratory and reproductive
  tracts
• Microvilli in intestines and urinary tract
• If the cell contains microvilli, it is said to
  have a __________ border.
• Brush border helps to increase surface area,
  which aids in absorption. (can add up to 20 times
  of surface area).
• Epithelial cells of the skin are filled with a
• waterproof called __________.
• Accumulate as cell matures

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Classifications of Epithelia

• Classified according to 3 characteristics
• Number of cell layers.
• Single layer is called __________
• Found in protected parts of body where they
  provide minimal protection to underlying
  structures
• More than one layer is called __________
• Thicker and stronger and are on parts of body
  that are subjected to mechanical or chemical
  stress.
• Shape of cells
• Based on shape that is on exposed or _________
  surface
• Squamous, cuboidal, and columnar
• Presence of surface specializations
• Keratinized, ciliated, etc.

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Simple Squamous Epithelium

• Fragile and thin
• Flat and smooth reduce friction
• Found lining surfaces involved in the passage of
  either _____ or ________
• lining of lungs, kidneys
• ______thelium lining of chest (pleura), abdomen
  (peritoneum), and pericardium
• ______thelium lining of blood vessels

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Simple Cuboidal Epithelium

• Single layer of cubical cells
• Round, dark-staining nuclei
• aligned in a single ______
• Occurs in areas of the body
• where ___________ and ______________ take place
• Surface of ovaries, glands, lining of ducts of
  liver, kidneys, pancreas
• Found throughout the ____________ system

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Simple Columnar Epithelium

• Elongated and closely packed together thick and
  protective
• Nuclei aligned in a row (not central) at the base
  of the cell near the basement membrane
• Also found in areas of absorption and secretion
• Line the _____ tract from stomach to rectum
• ____________ cell- apical surface is blanketed by
  dense microvilli that maximize absorption by
  increasing surface contact with nutrient-filled
  lumen.
• __________ cell- manufacture and store mucus for
  lubrication
• Also found in many excretory ducts
• ________ in respiratory tract and uterus

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Stratified Squamous Epithelium

• Multilayered
• Continually being _____ away or __________ off
• Replaced by cells from deeper layers
• _________ cells are attached to the basement
  membrane. As they mature, they are pushed to the
  surface away from nutrients.
• Lose their cytoplasm and nuclei and become
  squamous
• Occur in areas of the body subject to __________
  and ___________ stresses
• Mouth, esophagus, vagina,
• rectum
• Skin (keratinized)

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Stratified Cuboidal Epithelium

• Usually ______ layers of cuboidal cells
• Provides protection to deeper, delicate tissues
• Found primarily along large excretory ducts
• Salivary glands, mammary glands, sweat glands

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Stratified Columnar Epithelium

• Rare
• Basal cells are _________
• Function in secretion and protection
• Found only in select parts of the respiratory,
  digestive, reproductive systems and along some
  excretory ducts

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Pseudostratified Columnar Epithelium

• _______ stratified truly simple epithelium
• Cell nuclei are found at different levels across
  the length of the tissue
• Some cells do not reach luminal surface, but all
  attach to basement membrane.
• Usually ________ and often associated with ______
  cells.
• Found in respiratory tract and in portions of
  male reproductive tract

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Transitional Epithelium

• Stratified epithelium
• Basal layer of cuboidal or columnar cells
• Superficial layer of cuboidal or squamous cells
• Ability to _______ - found in areas
• where changes in volume occur
• __________ tract
• As epithelia stretches, layers often thin
  depending on how much volume is present
• Forms a _____-proof barrier