Cells and Tissues Review

• Epithelial tissue (cells)


  Squamous cells

  Columnar cells

  Cuboid cells

  (what type of tissue?)
• epithelial tissue (def)


  lines the cavities and surfaces of structures throughout the body, and also form many glands.

  
  

  Functions: protection, secretion, absorption

  
• simple squamous cells


  one cell thick, very thin, permeable

  found in protected regions where absorption takes place, such as: alveoli (lungs-air sacs), wall of capillary, lining of kidney

  
• Stratified squamous cells


  in layers, flat, scale-like, surface cells are shed and replaced

  keratinized-packed with keratin, makes cells tough and water resistant

  
  

  found in epidermis (surface layer of skin), mucous membranes (line body openings-mouth, throat, esophagus, rectum, vagina, anus)

  
  

  (deeper cells are cuboid or columnar)

  
• Simple Columnar cells


  single layer of column shaped cells.

  Nucleaus is near base

  some have cilia

  
  

  lines the GI tract, resp. tubes, ovarian tubes

  
  

  function: provide protection, secrete and absorb products

  
• simple cuboidal cells


  square (cube) shape

  
  

  make up the lining of the urinary tubules and some glands, kidney tubules, thyroid gland

  
  

  function: secret and absorb products

  
• Muscular Tissue cells (types)

  smooth muscle cells

  skeletal muscle cells

  cardiac muscle cells

  
• Smooth muscle cells


  elongated cells, tapered at both ends (spindle shaped)

  No striations

  more responsive to chemical stimuli than nerve

  myogenic-can initiate own contraction

  slowest response

  
  

  ofund in: GI tract, resp tract, urinary tract, capillary sphincters (regulate blood pressure) and also the myometrium of the uterus

  
  

  function: provide involuntary contraction

  
• Skeletal muscle cells


  cylindrical, elongated cells, multinucleated and striated (caused by filaments actin and myocin)

  called muscle "fiber"

  neurogenic-normally stimulated by nerve impulse

  fastest response of musle types

  
  

  make up skeletal muscles such as biceps brachii

  
  

  function: provide voluntary contraction

  
• Cardiac muscle cells


  striated, branched fibers

  intercalated discs

  myogenic-can initiate own contraction

  
  

  found only in the heart

  
  

  function: provide rhythmic contractions

  
• Neural Tissue cell types


  Neuron cells

  Glial cells

  
• Neuron cells


  soma-body

  axon-larger branch-transmits impulse from soma

  myelin sheath-surrounds some axons-protective coating made of cholesterol

  dendrites-carry impulse to soma

  synapse-gap between neurons

  
  

  found in all nerve tissue, such as brain and spinal cord

  
  

  function: conduct an impulse

  
• Glial cells (nurse cells)


  supportive cells to neural cells

  many appear as small cells located near neurons

  
  

  several types:

  oliglodendrocyts-produce myelin

  microaglia-phagocytic-found in nervous tissue

  astrocytes (most numerous)-growth & repair of neurons

  
  

  some cells surround the axon of a neuron

  some cells attach parallel nerves together

  some cells are located between different nerves

  
  

  function: provide protection for the neuron and or nervous system

  
• Connective Tissue cells


  mucous

  Adipose

  Areloar

  Blood

  Bone

  Cartilage

  Dense

  Reticular
• Adipose cells


  round cells, give the appearance of being empty, nucleus is pushed off to one side

  
  

  found surrounding body organs

  
  

  provide insulation (fat)

  
• Areolar cells


  small, have numerous fibers (elastic & collagenous) coursing between cells

  
  

  found between the skin and muscle

  
  

  function: attach skin to muscle

  
• Blood cells


  has watery matrix - plasma

  cells form concentric rings around central canal.

  
  

  found in circulatory system

  
  

  function: transports cells, dissolved nutrients, dissolved waste material, come CO2, chemicals (hormones, enzymes, etc.)

  
• Blood cells (types)


  Erythrocytes (red blood cells)

  Leukocytes (white blood cells)

  platelets

  
• erythrocytes


  red blood cells

  biconcave discs, no nucleus when mature

  
  

  transport oxygen and carbon dioxide

  
• leukocytes


  white blood cells

  
  

  provide our second line of defense (phagocytic-eats bacteria, pathogens, abnormal cells, cell fragments, cancer cells, etc.)

  provide our third line of defense (anti-bodies--immune system)
• platelets


  blood cell involved in blood clotting
• Cartilage cells


  cells sit in a lacuna.

  
  

  found within joints

  
  

  function: reduce friction that might occur within a joint

  
• Dense regular cells


  mostly collagenous fibers are parallel and packed tightly together

  contains fibrocytes

  
  

  found making up our tendons, ligaments and aponeurosis

  
• Reticular cells


  small cells that have fibers passing between them. Fibers are short and thick

  
  

  found making up the main portions of the liver, spleen, appendix, tonsils and lymph nodes

  
  

  function: involved in making up the "framework" of the liver, spleen, appendix, tonsils and lymph nodes

  
• Bone cells


  cells found in our skeleton

  
  

  provide support

  
• Osteocytes


  individual bone cells that form concentric rings around the central canal (major component of an Osteon)

  
• Central canal


  consists of blood vessels, which supply nutrients to osteocytes (major component of an osteon)

  
• Canaliculi


  Transports nutrients from the blood vessels to the stationary osteocytes (major component of an osteon)

  
• Lacuna


  the depression in the bone in which osteocytes sit

  (major component of an osteon)

  
• Lamella


  the matrix of the bone through which the canaliculi pass

  
• Dense cells (types)


  tendons

  ligaments

  aponeurosis
• Tendons


  connect muscle to bone

  
• ligaments


  connect bone to bone

  
• aponeurosis


  connect muscle to muscle

  
• Cell germ layers


  Ectoderm

  Endoderm

  Mesoderm

  
• Epithelial tissue


  -Tissue covers surfaces (outside [skin] and inside [organs])

  -Cellularity-cells bound closely together, little to no space between

  -Attached to basal lamina

  -Arranged in sheets or layers

  -Avascularity-does not contain blood vessels-must obtain nutrients by diffusion or absorption

  -Regeneration-damaged/lost cells are replaced through division of stem cells

  
  

  function: protection, secretion, absorption

  
• Connective tissue


  tissue with greatest variety of cells

  
  

  function:

  protection & support (cart. & bone)

  transport (fluids/chemicals)

  store energy (fat)

  cellular & chemical defense
• Types of fibers


  Collagenous fibers (white fibers)

  Reticular fibers

  Elastic fibers (yellow fibers)

  
• 3 Germ Layers (in gastrula stage of embryo)

  Ectoderm

  Endoderm

  Mesoderm

  
• Ectoderm


  Cell "germ layer"

  epidermis

  mucous membranes (lining body openings)

  salivary glands

  nervous system