Chapter 5 Tissues

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Chapter 5 Tissues
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Introduction

• Cells are arranged in tissues that provide
  
  specific functions for the body.
• Cells of different tissues are structured
  differently, which leads to their differences in
  function.
• The tissues of the human body include four major
  types.
• Epithelial
• Connective
• Muscle
• Nervous

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Epithelial

• Function
• Protection, secretion, absorption, excretion
• Sensory reception
• Location
• Covers your body surfaces, covers and lines
  internal organs, compose glands
• Characteristics
• Lack blood vessels, readily divide, cells are
  tightly packed
• Anchored to a basement membrane
• Replaced frequently

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Epithelial

• Epithelium- tissue that constitutes the outermost
  layer of the skin.
• Carcinoma is a cancer originating from epithelium
  tissue.
• About 90 of all cancers originate from
  epithelium tissue.

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Types of Epithelium

• 1) Simple Squamous
• 2) Simple Cuboidal
• 3) Simple Columnar
• 4) Pseudostratified Columnar
• 5) Stratified Squamous
• 6) Stratified Cuboidal
• 7) Stratified Columnar
• 8) Transitional
• 9) Glandular

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Simple Squamous Epithelium

• Made up of a single layer of thin, flattened
  cells.
• Suited for diffusion
• Exchanges gases in the lungs
• Lines
• Blood and lymph vessels
• Body cavities
• A basement membrane forms between epithelial and
  connective tissues

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Simple Squamous Epithelium
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Simple Cuboidal Epithelium

• Consists of a single layer of cube-shaped cells
  with a centrally located nuclei.
• It functions in secretion and absorption in the
  kidneys, and in secretion in glands.

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Simple Columnar Epithelium

• Cells are longer than they are wide
• Single layer of cells
• nuclei are located near the basement membrane
• May be ciliated
• It lines
• The uterus, stomach, and intestines
• It also protects underlying tissues, secretes
  digestive fluids, absorbs nutrients

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Simple Columnar Epithelium

• Inner lining organs of the digestive system
  contain this type.
• Goblet Cells
• Secrete Mucus
• Embedded within the tissues
• Unicellular gland.
• Have microvilli
• Increases the surface area for available for
  absorption.

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Pseudostratified Columnar Epithelium

• Appear Layered (but are not truly layered)
• Varying positions of the nuclei
• Cilia may be present
• Also, Goblet Cells
• Function to line and sweep debris from
  respiratory tubes.
• Commonly found forming the inner lining of the
  respiratory passages.

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Stratified Squamous Epithelium

• Made up of layers of flattened cells
• Designed to protect underlying layers.
• Where is it found?
• It makes up the outer layer of skin.
• It lines the mouth, throat
• Outer layers of cells undergo keratinization
• Does not occur where tissues remain moist
• throat

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Stratified Cuboidal Epithelium

• 2-3 layers of Cuboidal Cells
• Several layers of cells provides more protection
  than one single layer.
• Lines
• Sweat glands
• Salivary glands
• Pancreas
• Mammary glands

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Stratified Columnar Epithelium

• Several layers of cells- stratified
• Where is it found?
• Vas deferens
• Parts of the male urethra
• Parts of the pharynx

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Transitional Epithelium

• Designed to distend and return to its normal size
• Lining of the urinary bladder
• Provides distensibility
• Keeps urine from diffusing back into the internal
  cavity

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Glandular Epithelium

• Produces and secretes substances into ducts or
  into body fluids
• Exocrine- glands that secret products into ducts
• Endocrine (ductless) - glands that secret
  products into body fluids and blood

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Glandular Epithelium

• Gland classification way product is secreted
• Merocrine Glands
• Release fluid products exocytosis
• Apocrine Glands
• Lose portions of their cell bodies during
  secretion
• Ex. Mammary glands
• Holocrine Glands
• Release entire cells
• Ex. Sebaceous glands

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Connective

• Function
• Bind, support, protect, fill spaces, store fat,
  produce blood cells, serves as framework, protect
  against infection, repairs tissue damage.
• Has an abundant matrix (unlike epithelial)
• Intercellular material
• Has good blood supply (except cartilage)
• Location
• Widely distributed throughout the body
• Characteristics
• Mostly have good blood supply cells are farther
  apart then epithelial cells with extracellular
  matrix between

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2 Major Types

• 1. Liquid or Vascular Connective Tissue
• 2. Solid Connective Tissue

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Vascular Tissue

• Blood
• Red blood cells (carry oxygen)
• White blood cells (fight infection)
• Platelets (cell fragments used for agglutination)
• Plasma (fluid intracellular matrix)

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Major Cell Types

• Fibroblast Cell
• Most common
• Fixed, star-shaped cell
• Large
• Secretes Fibers
• Macrophages (wandering)
• Function
• Scavenger cells
• Defend against infection

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Major Cell Types

• Mast Cells
• Large
• Located near blood vessels
• Release
• Heparin (anticoagulant)
• Histamine (promotes inflammation)

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Connective Tissue Fibers

• Collagenous Fibers
• (white fibers)
• Made of
• Collagen
• Add Strength (for holding body parts together)
• Elastic Fibers (yellow fibers)
• Made of
• Elastin
• Stretchy
• Add Flexibility to certain types of connective
  tissues

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Connective Tissue Fibers

• Reticular
• Thin collagenous
• Form supportive networks
• Osteocytes (bone cells)
• Arranged in concentric circles around the
  osteonic or Haversian Canals

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Loose Connective (areolar) Tissue

• Forms
• Delicate, thin membranes
• Binds body parts together
• Skin and underlying organs
• The majority of the cells are fibroblasts that
  are separated by a gel-like intracellular
  material that contains collagenous and elastic
  fibers.

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Adipose Tissue

• Loose connective tissue
• Stores fat
• Where is it found?
• Beneath the skin
• Around joints
• Padding the kidneys, and internal organs
• Abdominal membranes

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Adipose Tissue
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Dense Connective Tissue(Fibrous Connective
Tissue)

• Densly packed collagenous fibers
• Very Strong!
• Lacks a good blood supply
• Where is it found?
• Tendons and Ligaments

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Cartilage

• Rigid connective tissue
• Provides a supportive framework
• Enclosed within Perichondrium
• Lacks a vascular system
• Healing takes longer
• Chondrocytes- cartilage cells
• Lie within the lacunae
• Small chamber within a gel-like fluid matrix

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Cartilage

• Hyaline Cartilage
• Most common
• White
• Abundant fine collagen fibers
• Where is it found?
• Ends of bones
• Function?
• Supports respiratory passages
• Trachea is composed of Hyaline Cartilage

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Cartilage

• Elastic Cartilage
• Elastic Fibers
• Forms Framework
• Ex. External Ears Parts of Larynx
• Fibrocartilage
• Collagenous Fibers
• Tough- Tissue
• Shock- absorbing
• Ex. Intervertebral Disks of Backbone
• Disks separate individual parts of backbone
• Ex. Knees, Pelvic Girdle

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Bone

• Most Rigid Connective Tissue
• Matrix Contains
• Deposits of Mineral Salts
• Collagen
• Functions
• Internally Supports the Body
• Forms Muscle Attachments
• Site for Blood Cell Formation
• Osteocytes- Bone Cells
• Found in Lacunae
• Arranged in Osteons (concentric circles)
• Around osteonic canals interconnected by
  canaliculi

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Bone

• Bone has a good blood supply, enabling rapid
  recovery after an injury.

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Bone
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Blood

• Composed of red and white cells
• Suspended in plasma
• Liquid matrix
• Function
• Transport substances throughout body

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Muscle

• Function
• Movement
• Location
• Attached to bones, in the walls of hollow
  internal organs, heart
• Characteristics
• Able to contract in response to specific stimuli

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3 Major Types of Muscle Tissue

• 1) Skeletal
• 2) Smooth
• 3) Cardiac

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Skeletal Muscle Tissue

• Attached to bone
• Controlled voluntarily
• Muscle Fibers
• Long, striated, cylindrical, many nuclei
• Major Characteristic
• Ability to contract from nervous impulse
• Least likely cell type to reprodue

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Smooth Muscle Tissue

• Lacks Striations
• Uninucleate
• Spindle-shaped cells
• Involuntary Muscle
• Found in the walls of internal organs
• Ex. Stomach, Digestive Tract, blood vessels,
  urinary bladder

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Cardiac Muscle Tissue

• 1. Cardiac muscle tissue is found only in the
  heart and consists of branching fibers that are
  connected to each other with intercalated disks.
  This is the band that occurs where two cardiac
  muscle cells join.
• 2. This involuntary muscle has a single nucleus
  in each cell but appears striated.
• 3. When cardiac muscle cells are damaged by a
  heart attack, they are usually replaced by
  connective tissue cells

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Nervous Tissues

• A. Nervous tissues are found in the brain,
  spinal cord, and nerves.
• B. Neurons, or nerve cells, conduct nervous
  impulses while helper cells, or neuroglia,
  support and nourish the neurons.
• C. Generally nervous tissue conducts nerve
  impulses from one neuron to another and it
  coordinates body activities.

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Nervous

• Function
• Transmit impulses for coordination, regulation,
  integration, and sensory reception
• Location
• Brain, spinal cord, nerves
• Characteristics
• Cells connect to each other and to other body
  parts

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