Lab 2- Body Tissues rev 7011

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Lab 2- Body Tissues rev 7011

• Tissue group of cells that are similar in
  structure and perform a common or related
  function
• 4 primary tissue groups
• Epithelium
• Connective
• Muscle
• Nervous

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Lab 2-Tissues

• Tissues combine to form Organs
• Organs combine to form Organ Systems
• organ systems combine to form the Organism
  (humans)

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Lab 2-Tissues

• Epithelial Tissue--sheet of cells that covers a
  body surface or lines a body cavity helps form
  boundaries between different body environments
• examples skin, lining of mouth, lining of
  digestive tract, etc.
• Epithelial tissues also
• protect underlying tissues

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Lab 2-Tissues

• reduce friction because they are smooth
• epithelial tissue lines the blood vessels and
  thus helps blood flow more easily
• absorb epithelium
• filter which lines the
• excrete kidneys perform
• secrete all these functions
• sensory reception

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Lab 2-Tissues

• Some epithelial tissues form glands
• glands are epithelial tissues that are
  specialized to synthesize and secrete a product
• Characteristics of Epithelial Tissue
• 1. Cells are packed closely together
• 2. One surface of the tissue is free while the
  other surface is attached to the underlying
  connective tissue by the basement membrane

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Lab 2-Tissues

• 3. Epithelial tissues tend to be given 2 names-
• first name indicates the number of cell layers
  present
• one layer of cells is called simple epithelium
• typically found where absorption and filtration
  occur and a thin epithelial barrier is desirable
• many layers--stratified epithelium
• common in high-abrasion areas where protection is
  important i.e. lining of the mouth, skin surface
• second name describes the shape of the cells

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Lab 2-Tissues

• 4. Cells occur in 3 types
• squamous--thin and flat cells
• forms the thinnest possible layer for diffusion
  filtration
• look like a pancake when viewed from the side
• mostly found in air sacs of lungs, kidney
  glomeruli, lining of heart, blood vessels, and
  lymphatic vessels
• cuboidal--cube or rounded cells (about as tall as
  are wide)
• major function is secretion but may also be
  involved in absorption
• line the ducts of many glands
• has round shaped nucleus which stains very darkly

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Lab 2-Tissues

• columnar--cylindrical cells (tall and column
  shaped)
• tall cell with oval shaped nucleus
• mostly associated with absorption, secretion of
  enzymes and mucous, and movement of materials
  (ciliated cells)
• line the stomach, small and large intestines and
  a few ducts
• these tissues may also have microvilli, cilia, or
  goblet cells (secrete mucus--a thick fluid which
  lubricates tissues and traps bacteria, viruses
  and irritating particles)
• line small bronchi, uterine tubes

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Lab 2-Tissues

• Helpful hints
• the shape of the nucleus matches the shape of the
  cell
• remember this when you are trying to identify the
  type of epithelial cell
• cell membranes dont stain well so you may not
  see them.
• Count the number of cells by looking for the cell
  nucleus

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Connective Tissue Lab 2-Tissues

• found everywhere in the body
• Major functions
• 1. Binding and support
• 2. Protection
• 3. Insulation/storage of fat
• 4. Transportation of substances within the body

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Lab 2-Tissues

• Has comparatively few cells and a lot of
  non-living matter (called the matrix)
• Types of Connective tissue
• Fibrous-connects various body parts provides
  strength, support and flexibility
• consists of several types of fibers
• Collagen--provides strength and slight
  flexibility
• Elastic--very flexible can stretch without
  breaking
• Reticular--serves as framework for some organs
  fiber flexibility is between elastic and collagen
  fibers

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Lab 2-Tissues

• Fibrous connective tissues are subclassified
  according to the density and arrangement of their
  fibers
• Areolar or Loose connective tissue
• most common type
• contains collagen fibers and elastic fibers in an
  irregular pattern is very flexible but not
  strong
• usually found below the skin, between muscles,
  and around nerves and organs

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Lab 2-Tissues

• Adipose (Fat) tissue
• specialized for fat storage
• has few connective tissue fibers primarily made
  up of fat cells (large, round cells which look
  empty but really contain an oil droplet which
  takes up most of the cell and pushes the nucleus
  to one side)
• Primary role is energy storage
• also acts as a shock absorber and as an insulator
• forms a protective layer around internal organs
• Found below skin, around various organs, and
  around certain muscles

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Lab 2-Tissues

• Dense White Fibrous Connective Tissue
• fibers are densely packed and run in the same
  direction
• is very strong when stress is in the same
  direction as the fibers run
• has few blood vessels
• functions to bind, protect and connect
• primarily attaches muscles to bones or to other
  muscles, bones to bones
• usually found in tendons, ligaments and joint
  capsules

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Lab 2-Tissues

• Hyaline Cartilage
• Is a specialized connective tissue
• consists primarily of densely packed collagen
  fibers which contain water
• Because of the high water content, cartilage
  provides firm support, cushioning and flexibility
• Found at the connection of the ribs to the
  sternum, covering of bones at moveable joints,
  the tip of the nose

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REMINDER Lab 2-Tissues

• There are 7 slides--3 epithelial, 4 connective
  tissue
• Start with the 4x lens, however you will not see
  actual tissue until you reach the 40x lens
• You will likely need to move the slides around to
  find the tissue you want to draw.
• Slides may contain a variety of tissue types.
• The lung slide has simple, squamous epithelial
  tissue
• the white fibrous tissue slide has dense
  connective tissue
• Use the color photos on the charts in the back of
  the room to help you identify the slides

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INTEGUMENTARY SYSTEM(also known as SKIN)

• Functions --outer covering of the body
• protects from dehydration
• protects from injury
• protects against invasion by bacteria and viruses
• helps regulate body temperature
• synthesizes vitamin D
• Sensory awareness receptors for touch,
  vibration, pain and temperature provide
  information about the environment

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Lab 2-Tissues

• Skin consists of
• epidermis outermost layer of stratified
  squamous epithelial tissue
• made up of 5 sub-layers stratum corneum, stratum
  lucidum, stratum granulosum, stratum spinosum,
  and stratum basale layers
• most epidermal cells are keratinocytes.
• Scattered among these in the deepest layers are
  melanocytes which give the skin its color

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Lab 2-Tissues

• Dermis inner layer of fibrous connective tissue
  and all structures embedded within it
• composed of two sub-layers
• this layer binds the body together
• richly supplied with nerve fibers, blood vessels,
  and lymphatic vessels

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Lab 2-Tissues

• Hypodermis supportive layer consisting of loose
  connective tissue containing fat cells
• also called subcutaneous tissue or superficial
  fascia
• anchors the skin to underlying structures
  (primarily muscles)
• is flexible so the skin can move and bend
• its fat cells insulate against excessive heat
  loss and cushion against injury

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Lab 2-Tissues

• Appendages of the Skin
• Sweat glands
• Ceruminous or wax glands
• Sebaceous or oil glands
• Hairs are flexible strands produced by hair
  follicles that consist largely of dead,
  keratinized cells
• Nails a scale like modification of the epidermis
  that forms a clear protective covering on the
  dorsal surface of the ends of fingers and toes

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REMINDER, page 1 Lab 2-Tissues

• 1. All skin identification questions will be
  based on the model you will not need to identify
  any skin slides for the practical exams.
• There are "answer keys" next to the models
  however they tend to use the Latin names of the
  structure and may be confusing to you.
• The answer keys may have been moved and may no
  longer be next to the correct model.
• It may be easier to use pictures in the text, lab
  manual, or on charts to help you identify
  structures.

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REMINDER, page 2 Lab 2-Tissues

• 2. Do not do any of the activities on page 34.