Chapter 4 - Tissue: The Living Fabric

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Chapter 4 - Tissue The Living Fabric

• I. Introduction
• A. General Characteristics
• Tissue group of closely associated cells that
  are similar in structure and perform a common or
  related function
• 1.) epithelial,
• 2.) connective,
• 3.) muscle and,
• 4.) nervous

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Epithelial
Muscle
Connective
Nervous
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Functions

• Cover,
• Support,
• Movement, and
• Control

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II. Epithelial Tissue

• A. Features
• 1. Covers body surface, lines cavities,
  glandular epithelium
• 2. Retain ability to divide throughout life span
  
• 3. 5 functional types of epithelia
• 1. Protective - skin, lining or cavities such as
  mouth
• 2. Exchange - lungs, blood vessels
• 3. Transporting - intestine, kidney
• 4. Ciliated - nose, trachea
• 5. Secretory - sweat and saliva are secreted by
  epithelia, exocrine glands including pancreas
  endocrine including thyroid

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• B. Special Characteristics
• 1. Cellularity close packed cells
• 2. Specialized contacts tight junctions and
  desmosomes
• 3. Polarity apical (free) surface and basal
  surface
• 4. Basement membrane base of the epithelium
• a. a network of fine protein filaments embedded
  in glycoprotein. The filaments hold the
  epithelial cells to the underlying cell layers -
  like adhesive junctions
• 5. Innervated but avascular - contain no blood
  vessels. The cells are nourished by diffusion
  from blood vessels in the underlying connective
  tissue.
• 6. Regeneration - some epithelia are exposed to
  friction or noxious substances

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• C. Classification
• Criteria
• a. Cellular shapes squamous (flat), cuboidal
  (cube) or columnar
• b. Cellular arrangement (layers) simple - 1
  cell thick, or stratified - multiple layers
• c. Classes
• 1) Simple squamous, cuboidal, columnar and
  pseudostratified
• 2) Stratified squamous, cuboidal, columnar and
  transitional named for shape of cells at apical
  surface

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1. Simple Epithelium

• Simple Squamous
• Single layer of flat cells
• filtration kidney
• lungs,
• blood vessels

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Simple Cuboidal

• single layer as tall as wide
• secretion and absorption

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Simple Columnar

• 1) Absorption and,
• 2) Secretion of mucous
• Goblet cells secrete mucus
• Simple ciliated columnar lines uterine tubes and
  some of respiratory tract

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Pseudostratified Columnar

• All cells rest on basement membrane but only
  tallest reach apical surface
• Secretion and absorption
• Pseudostratified ciliated columnar lines most of
  respiratory tract

Basement membrane
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• 2. Stratified Epithelia
• Stratified Squamous
• Most widespread forms external part of skin
  and a short distance into body openings
• Several layers of cells
• So, protective
• Surface cells are
• squamous
• 5. Deeper cells cuboidal

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Transitional

• lines urinary organs(bladder) basal cells
  cuboidal or columnar
• 6 layers when empty and
• 3 layers when stretched

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• D. Glandular Epithelia
• General - Secretory epithelia are composed of
  cells that produce a substance inside the cell
  and release it - a secretion.
• Secretory cells may be scattered or form a gland
• a. Gland one or more cells that make and
  secrete a particular product or secretion
• b. There are 2 types of secretory glands
• endocrine
• exocrine

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Endocrine Glands (endo in)

• a. Ductless glands
• b. Release secretions called hormones into blood

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• Exocrine Glands secrete onto body surfaces
• Produce 2 secretions
• serous - watery secretions that contain enzymes
• mucous - sticky solutions of glycoproteins
• Release secretions into the external
  environment skin surface, epithelial lining.
• Most use open tubes or ducts. Examples - sweat,
  mucous, salivary glands

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• Multicellular Exocrine Glands
• a. Contain a duct and secretory unit with
  secretory cells
• b. Structural classification
• 1) Simple glands single unbranched duct
• 2) Compound glands branched duct
• 3) Tubular secretory cells form tubes
• 4) Alveolar hollow cavity or sac
• 5) Tubuloalveolar both

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Connective Tissue

• Characterized by the cells widely separated from
  each other in a matrix that is produced by the
  cells.
• Tissue protects and supports.
• Cell Matrix composed of two regions
• Ground
• Liquid (sol), Gel, Gum or solid
• Fibers
• Non-elastic ( white or Collagen)
• Elastic ( yellow fibers)
• Types of Connective tissue

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Connective Tissue

• Types
• 1. connective tissue proper ( fat and fibrous
  tissue of ligaments),
• 2. cartilage,
• 3. bone,
• 4. blood

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• Regions
• ground substance,
• fibers, and
• cells
• 1. Ground substance fills the space between
  cells and contains fibers
• 2. Fibers
• a. Collagen fibers primarily collagen
  stronger than steel! white fibers
• b. Elastic fibers long, thin fibers that form
  networks stretch and recoil
• c. Reticular fibers fine collagenous fibers
  continuous with collagen fibers form networks
  around vessels, soft tissues and organs and
  basement membrane

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Cells

• Each class of connective tissue has a cell type
  in mature and immature form
• blasts immature and undifferentiated cells
  that secrete the ground substance and the matrix
• cytes mature cells

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Cells

• Cell types in mature and immature form
• Fibroblasts connective tissue proper
• Chondroblasts cartilage
• Osteoblasts bone
• Hemocytoblasts blood
• Macrophages phagocytize foreign materials

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blast bud, forming cyte less active, mature
mode
Connective tissues arise from a common origin -
mesenchyme
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Functions

• 1. Binding and structural support
• 2. Protection
• 3. Insulation
• 4. Transportation

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Types of Connective Tissue

• Loose (Areolar) Connective Tissue
• Dense Connective Tissue
• Adipose
• Cartilage
• Bone
• Blood

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Loose Connective Tissue (Areolar)

• Gel like ground with both elastic and non-elastic
  fibers running though the ground in many
  directions.
• Wraps and cushions organs
• Under the skin

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Dense Regular Connective Tissue

• Nuclei and fibers arranged in parallel rows.
• Tendons and ligaments
• Fibers mostly non-elastic

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Adipose (Fat)

• Function as storage cells for adipose (lipids)
• Adipose cells contain a large vacuole which in
  the live cell contains lipids.
• Cell nucleus and cytoplasm are pushed out to edge
  of cell membrane.

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Cartilage

• Ground of matrix is gum like.
• Cells are found in Lacunae within the matrix.
• Fibers may be elastic or non-elastic, or a form
  of non-elastic called reticular(where the
  non-elastic fibers of very thin)
• Hyaline Cartilage-example on the ends of bones
• Elastic Cartilage- example ear cartilage
• Non-elastic Cartilage- example nose cartilage.

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Hyaline cartilage
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Elastic Cartilage
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Bone

• Ground of matrix is Solid (Calcium carbonate).
• Has blood supply and nerves running through the
  Haversian canal systems.

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Vascular Tissue (Blood)

• Liquid matrix plasma
• 90 water
• 10Plasma proteins, electrolytes, hormones,
  oxygen, glucose etc.
• Formed elements
• Erythrocytes -48billion(female) to 54 billion
  (male) cell / ml of blood in humans. Mammals are
  enucleated while rest of the vertebrates they
  have nuclei
• Leukocytes -about 7.5 million / ml of blood
• Platelets -blood clotting

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Blood
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Muscle Tissue

• Tissue with cells having fibers specialized for
  contraction.
• Skeletal Muscle (Striated, voluntary)
• Parallel elongated cells (fibers)
• multinucleated and each cell is the length of
  the muscle.
• Light meat, Dark meatSlow twitch, fast twitch
  muscle
• Smooth Muscle (Visceral, involuntary)
• Cells are long and tapered.
• Organized into sheets of muscle.
• Cardiac Muscle
• Intercalated disc
• Myogenic
• branched

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Skeletal Muscle
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Smooth Muscle
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Cardiac Muscle
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Nervous Tissue

• Cells specialized to polarize and depolarize.
• Cell is a neuron

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Epithelial Membranes

• Consists of a least two tissue types epithelium
  and connective tissue proper. There are 3 types
  of membranes
• A. Cutaneous
• 1. Skin
• 2. Keratinized stratified squamous attached to
  dense irregular connective dermis

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• B. Mucous Membranes
• 1. Line body cavities that open to outside
  (digestive, respiratory and urogenital)
• 2. Mucosae are stratified squamous or simple
  columnar
• 3. Adapted for secretion and absorption
• 4. Lamina propria loose connective tissue
  under epithelial tissue

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• C. Serous Membranes (Serosae)
• 1. Found in closed ventral body cavities
• 2. Parietal and visceral layers, each of simple
  squamous (mesothelium) on layer of loose
  connective (areolar)
• 3. Serous fluid lubricates between layers
• 4. Pleura, pericardium, and peritoneum

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VII. Tissue Repair

• There are many defenses against damage, but if
  skin is penetrated, inflammatory and immune
  responses are activated
• A. General
• 1. Regeneration replacement of destroyed
  tissue with same tissue type
• 2. Fibrosis scar tissue (fibrous connective)
  forms
• B. Inflammation
• a. Histamine from mast cells, other chemicals
  dilate capillaries and make them more permeable
• b. Allows WBC's and plasma fluid, rich in
  clotting proteins and antibodies to enter.
• c. Clot forms to stop blood, walls off area,
  forms a scab.
• d. Redness, swelling, heat due to above

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• 2. Organization First stage of tissue repair
  blood clot replaced by granulation tissue
  (fragile capillaries from nearby that lay down a
  new capillary bed.
• 3. Regeneration and/or fibrosis epithelium
  regenerates and scar may remain visible

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• C. Factors
• 1. Tissue type skin, epithelial, bone, fibrous
  connective tissues heal well while muscle,
  cartilage are poor at regeneration
• 2. Type of injury and care
• 3. Nutrition
• 4. Blood supply
• 5. Health
• 6. Age