Chapter 6 Skin and the Integumentary System

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Chapter 6Skin and the Integumentary System

• (pgs 115-129)

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Introduction

• Lets read about the rare disorder of Katie Maher.
  Pg.115
• What is the name of her disorder?
• Last Chapter 5 on tissues we learned that all
  organs are composed of 2 or more tissues grouped
  together and performing specialized functions

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Membranes

• The thin, sheetlike membranes, composed of
  epithelium and connective tissue covering body
  surfaces and lining body cavities are organs.
• The cutaneous membrane, for example, together
  with certain accessory organs, make up the
  Integumentary System.
• What is the cutaneous membrane?

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4 Major Types of Membranes

• Serous Membranes
• Mucous Membranes
• Synovial Membranes
• Cutaneous Membrane

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Serous Membranes

• These line body cavities that lack openings to
  the outside. They form the inner linings of the
  thorax(parietal pleura) and abdomen(parietal
  peritoneum), and they cover the organs within
  these cavities(visceral pleura and visceral
  peritoneum)
• These consists of a layer of simple squamous
  epithelium and a thin layer of loose connective
  tissue.
• Cells of a serous membrane secrete watery serous
  fluid, which lubricates membrane surfaces.

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Mucous Membranes

• These line cavities and tubes that open to the
  outside of the body.
• These include the oral and nasal cavities and the
  tubes of the digestive, respiratory, urinary, and
  reproductive systems.
• Mucous membranes consists of epithelium overlying
  a layer of loose connective tissue. Specialized
  cells(goblet) within this membrane secrete mucus.

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Synovial Membranes

• These form the linings of the joint cavities
  between the ends of bones at freely movable
  joints(synovial joints).
• These membranes usually include fibrous
  connective tissue overlying loose connective
  tissue and adipose tissue.
• Cells of a synovial membrane secrete a thick,
  colorless synovial fluid in the joint cavity,
  which lubricates the ends of the bones within the
  joint.

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Cutaneous Membrane

• Is more commonly called the skin.

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Skin and its tissues

• Skin is one of the larger more versatile organs
  of the body.
• It is vital in maintaining homeostasis in that it
  is a protective covering, helps regulated body
  temperatures, retards water loss from deeper
  tissues, houses sensory receptors, synthesizes
  various biochemicals and excretes small
  quantities of wastes

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Skin

• Has 2 distinct layers
• Epidermis the outer layer composed of
  stratified squamous epithelium.
• Dermis thicker layer containing fibrous
  connective tissue, epithelial tissue, smooth
  muscle tissue, nervous tissue, and blood.
• A basement membrane that is anchored to the
  dermis separate the two skin layers.
• Beneath the dermis are masses of loose CT and
  adipose tissue that bind the skin to underlying
  organs. These tissues form the subcutaneous layer
  (hypodermis)

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Practice

• Answer the Tan questions 1-4 Pg. 117 in your
  class notebook.
• Draw the layer of skin you see on Pg. 118 (will
  be a grade) Need to familiarize yourself with the
  different layers of the skin.

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Epidermis

• This layer lacks blood vessels since it is made
  up of stratified squamous epithelium.
• However, the deepest layer of epidermal cells,
  called the stratum basale, is close to the dermis
  and is nourished by the dermal blood vessels.
• The outer layer of the epidermis consists of
  cells that are keratinized or hardened. These are
  dead and have replaced their cytoplasm with
  strands of tough, fibrous waterproof keratin
  protein.
• This layer is called the stratum corneum
• Have a student read the tan section pg.118

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Dermis

• It binds the epidermis to underlying tissues. It
  is composed largely of fibrous connective tissue
  that includes tough collagenous fibers and
  elastic fibers within a gel-like ground
  substance.
• These networks give the dermis its strength and
  elasticity
• Dermal blood vessels supply nutrients to all skin
  cells. These vessels also help regulate body
  temperatures.
• Nerve fibers are scattered throughout the dermis,
  motor fibers carry impulses from the brain to
  dermal muscles and glands.
• Other nerve fibers, sensory fibers, function as
  sensory receptors.

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Dermis

• This layer also contains hair follicles,
  sebaceous (oil producing) glands, and sweat
  glands,

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Subcutaneous Layer

• Also, known as the hypodermis, is beneath the
  dermis and consists of loose connective and
  adipose tissues. The collagenous and elastic
  fibers of this layer are continuous with those of
  the dermis. These run parallel to the surface of
  the skin and extend in all directions. No sharp
  boundary separates this layer from the dermis.

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Subcutaneous Layer

• The adipose tissue of the subcutaneous layer
  insulates, which conserves body heat and impedes
  the entrance of outside heat.
• This layer also contains the major blood vessels
  that supply the skin and underlying adipose
  tissue.

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Key Terms

• Play hangman