HTHS Mod 7

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HTHS Mod 7
2013-11-11 17:06:15
Tissue Level Organization

Tissue level of organization
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  1. Four types of body tissue
    • epithelial
    • connective
    • muscular
    • nervous
  2. Epithelial tissue
    • found wherever borders are needed - where itssue meets the outside world
    • Covers, Lines and forms Glands
    • *has very little intercellular space
    • *is avascular (no blood vessels) ~ gets oxygen by diffusion from blood vessels beneath.
    • *does have nerve supply
    • Ex: Skin (outer layer to outside world)
  3. Intercellular space vs. intracellular space
    • Intercellular space = space btwn cells
    • Intracellular space = space inside the cell itself
  4. lumen
    • opening of a tube
    • open space
  5. connective tissue
    • hooks things together.
    • connects epithelium to rest body
    • To be a connective tissue, must hook things together and have a matrix that holds cells together
  6. muscular tissue
    • moves body parts around
    • 3 types: Cardiac, smooth and skeletal
  7. nervous tissue
    • the central nervous system (brain and spinal cord)
    • plus peripheral nervous system (ganglia and nerves)
    • Responsible for senation, info processing and control of body parts
  8. How many cells in the body
    10 trillion cell in body, but only 200 diff. types
  9. Locations of epithelium
    • Barriers to keep outside out and inside in
    • Barriers that secrete substances
    • Barriers for protection
  10. Two surfaces of epithelial cells
    • apical surface
    • basal surface
  11. apical surface
    • surface of epithelial tissue that faces the outside world
    • Ex: in intestinal tract, the layer in contact with food or in the skin, the part exposed to the outside world
    • the "free" surface
    • Latin for "top, pinnacle"
  12. basal surface
    • surface of epithelial tissue that rests on, and is attached to the basement membrane
    • bottom surface of cells
    • *note "base" and "basement"
  13. basement membrane
    • has two thin layers: basal lamina and reticular lamina 
    • basically "glue" which holds epithelium onto connective tissue
    • basal surface of epithelial tissue connected to it
    • beneath is a layer of connective tissue w/ blood vessels and nerves
  14. basal lamina
    • layer of the basement membrane nearest the epithelial cells
    • formed by epithelial cells & their secretions
  15. reticular lamina
    • layer of basement membrane, deep to the basal lamina
    • formed by underlying connective tissue
  16. Classification of epithelia
    • by two adjectives following the word "epithelium"
    • First word describes the arrangement of the epithelial cells
    • Second word describes the shape of the cells at the apical surface of the epithelium
    • 7 possible combinations (since only columnar are pseudostratified), and 8 with transitional epithelia
    • *Even if the cells beneath the surface have different shape, we still use the name that describes the apical cells
  17. 3 Classifications of arrangement of epithelia
    • simple, pseudostratified and stratified
    • *key feature is whether all cells are in contact w basement membrane
  18. Classification of epithelia by arrangement: Simple
    • the cells are a single layer
    • all are in contact w the basement membrane
  19. Classification of epithelia by arrangement: pseudostratified
    • even though the cells appear to have layers, every one is in contact w the basement
    • only cells in this arrangement are columnar cells
    • *Greek for "false, lying, untrue"
  20. Classification of epithelia by arrangement: stratified
    • the cells have layers, so only the lowest layer is in contact with the basement membrane
    • Latin "layer"
    • two or more layers
  21. 3 classifications of epithelia by shape
    • squamous, cuboidal, and columnar
    • *question to ask is what is the shape of the cells at the apical surface? are they wider than they are tall, or vice versa?
    • *Shape can affect how easy stuff can diffuse across cell membrane.
  22. Classification of epithelia by shape: squamous
    • cells are flat and shaped like fish scales or wide "paving stones"
    • are wider than they are tall

    *Latin for "scale", "fish scale"
  23. Classification of epithelia by shape: cuboidal
    cells are as wide as they are tall, like little ice cubes or dice
  24. Classification of epithelia by shape: columnar
    cells, like a column, are taller than they are wide
  25. transitional epithelia
    • special type of epithelia containing cells that change shape, depending on whether the organ is enlarged or shrunken
    • Only examples are found in urinary tract & bladder
    • full bladder: squamous cells
    • empty bladder: cuboidal cells
  26. Why add microvilli?
    adds surface area to cells for absorption
  27. How can you tell the difference between epithelium
    Look at the apical layer to determine it's type
  28. simple squamous epithelium; define, locations and function
    • a single layer of cells which are thin and flat
    • Function: diffusion, filtration, and passage of materials where little protection is needed
    • Locations: Lungs, blood vessels, kidney filtration
  29. simple cuboidal epithelia; define, location & function
    • secretion & absorption, as in glandular tissue
    • Locations: Kidney tubules, ovaries, eye
  30. simple columnar epithelia
    • two subtypes: one has cilia and one doesn't
    • may or may not have microvilli 
    • Function: movement and secretion of mucus
  31. simple columnar epithelium, ciliated
    • has cilia on apical surface
    • moves mucus and substances by the wave-like motion of the cilia
    • may or may not have microvilli and goblet cells
    • Locations: respiratory tract
  32. simple columnar epithelia, nonciliated
    • does not have cilia
    • used for secretion such as the mucus secreting cells of gut and respiratory system
    • also used for absorption, as in intestines
    • may or may not have goblet cells & microvilli 
    • Locations: GI tract, glandular ducts, gallbladder
  33. goblet cells
    cells which produce mucus
  34. pseudostratified columnar epithelia
    • only classification of pseudostratified arrangement
    • May or may not have cilia
    • Location: trachea
    • Function: protection and secretion of mucus
  35. pseudostratified columnar epithelium, ciliated
    • found in upper respiratory tract 
    • goblet cells secrete mucus to trap dust and invaders, move up the throat by the mucociliary escalator
  36. mucociliary escalator
    moves mucus which traps dust and invaders, up and out of the respiratory tract
  37. pseudostratified columnar epithelia, non-ciliated
    • found in some glands
    • in the epidydymis and urethra of the male where it lines the tubes that conduct sperm and urine
  38. Stratified squamous epithelia
    • Apical surface is made up of squamous (flat) cells
    • other layers have different shapes, but name based on apical layer
    • *difference in skin type & mucous type: skin has 1 extra protein (keratin)
    • Location: skin, mouth and throat lining, vaginal lining, anal lining, and cornea
    • Function: Protection (from friction), hard outer layer being continuously removed by friction and replaced from below
  39. Keratin
    • the protein in skin (that mucus membranes do not have)
    • gives skin it's strength
  40. integument
    • another name for skin
    • largest organ of body
    • makes up for 1/6 of body weight
  41. stratified cuboidal epithelium
    • Apical surface is made up of cube-shaped cells
    • two or more layers (stratified)
    • Locations: sweat gland ducts
    • esophageal gland ducts
    • part of male urethra
  42. stratified columnar epithelium
    • apical surface is made of tall cells (taller than they are wide)
    • *remember, although the cells on basal layers may have different shape, we name the shape of cells on the apical surface
    • Locations: mammary ducts, epidydymis
  43. Glandular epithelium
    • "glands"
    • responsible for secretion
    • released by endocrine or exocrine glands
  44. secretion
    the production of substances that are released outside the body(exocrine) or within the body (endocrine)
  45. exocrine glands
    • secrete their products through ducts (tubes) to the lumen (ex: digestive juices) or surface of the body (sweat)
    • secretes outside body
    • generally lined w (simple or cuboidal) epithelium
  46. endocrine glands
    • secrete their products (hormones) into the interstitial fluid (surrounding the cells) and blood stream
    • generally lined w (simple or cuboidal) epithelium
    • Ex: hormones
  47. (gland) duct
    conducts the secretory product to where it is supposed to be
  48. secretory portion (of gland)
    where the cells that make the glandular secretion are located
  49. Naming for glands
    Based on the branching pattern of the duct and the shape of the secretory portion

  50. Branching pattern of glandular duct
    • unbranched = simple
    • branched = compound
  51. Shapes of secretory portion of glandular duct
    • tube-like = tubular
    • grape - like = acinar
    • both = tubuloacinar
    • *tubular shape easy: it's shaped like a tube
    • *acinar looks like a single grape, or a bunch or grapes
  52. alveolar
    • another name of the acinar shape
    • *notice that it is somewhat dilated on the end, like a grape hanging from a vine
  53. tubuloacinar (shape of duct)
    • combo of tubular and acinar types in secretory portion
    • Only glands that are tubuloacinar are branched in the duct portion, so only one time to remember: 
    • compound tubuloacinar
  54. Eight types of epithelial gland
    • 5 unbranched duct: 
    • simple tubular
    • simple branched tubular
    • simple coiled tubular
    • simple acinar
    • simple branched acinar
    • 3 branched duct:
    • compound tubular
    • compound acinar
    • compound tubuloacinar
  55. Three names in the functional classification of cells in the secretory portion of gland
    • *based on how the cell secretes it's product to the outside environment
    • Merocrine secretion
    • Apocrine secretion
    • Holocrine secretion
  56. Steps in Merocrine secretion
    • Watery sweat to thermoregulate our bodies (keep from getting too hot)
    • 1~ DNA instructions transcribed to mRNA in nucleus
    • 2~ synthesized in rough ER
    • 3~ packaged in Golgi complex
    • 4~ formed into secretory vesicle that can fuse w cell membrane on demand to release cell's secretory product on surface of cell (exocytosis)
    • Ex: Saliva and Pancreatic enzymes are secreted this way
    • **Apocrine sweat glands work by merocrine secretion
  57. Steps in Apocrine secretion
    • begins like merocrine: DNA transcribes mRNA in nucleus, synthesized in rough ER, packed in Golgi complex, formed into vesicle
    • Top of cell pinches off and is dissolved, released product is released portion (cell top)
    • Ex: Milk glands (lactation glands) work by Apocrine secretion
  58. Steps in Holocrine secretion
    • most violent and destructive form of secretion (think "holocaust") cell suicide
    • *cell divides. mature cells die, products of dead cell become secretion
    • Secretory product made in cytoplasm
    • then the cell blows itself to bits, releasing the secretory product
    • lost cell replaced by division of stem cells
    • Ex: Sebaceous glands of hair follicles, glands of eyelids
  59. Connective tissue (in general)
    • one of 4 tissue types
    • to be connective tissue it MUST: 1. hook things together & 2. Have a matrix that holds the cells together
    • 2 main components: cells & matrix
    • connects epithelium to rest of body
    • Job is to form bone, fat, tendons, ligaments, cartilage, blood
    • made up of three parts:
    • Ground substance (extracellular matrix)
    • Fibers
    • Cells
  60. ground substance
    • secreted by cells of connective tissue
    • 2 main components: fibers and background substance
    • substances secreted can vary from liquid, as in blood, all the way to rock-hard, as in bone
    • a number of fibers mixed in the extracellular substance
    • Also composed of several proteins
  61. Proteins of the extracellular matrix
    • fibronectin, laminin, and proteoglycans
    • Functions: hook the cells together with the connective tissues
    • important part of ex. matrix
  62. proteoglycans
    • one of several proteins found in ground substance
    • *not a specific protein but rather a class of proteins which contain proportionately more sugar than protein
  63. Fibers mixed in w extracellular matrix
    • collagen fibers
    • elastic fibers
    • reticular fibers
    • The proteins which make up these fibers are secreted by fibroblasts
  64. Collagen fibers
    • one of 3 fibers in ground substances
    • very strong and resist stretching
    • made up of collagen (naturally)
    • comes in several different types (called type I collagen, type II collagen, etc. up to type XXIX collagen) that vary btwn tissues
    • because it's a triple helix, give strength along fiber
    • Ex: tendons, ligaments, and scar tissue
  65. Elastic fibers
    • one of 3 fibers in ground substances
    • have some strength, but can stretch and have the ability to recoil
    • made of elastin
    • are abundant in tissues that need to stretch and then snap back into previous shape
    • Ex: blood vessels
  66. Reticular fibers
    • provide soft structural integrity
    • form a network or reticulum
    • made of type III collagen
    • originally named separately cause of silver staining properties, but biologists proved later they are a type of collagen fiber
    • possible product of fibroblasts
  67. argyrophilic
    structures that stain w silver
  68. Cells found in connective tissue
    • Fibroblasts
    • adipocytes
    • mast cells
    • white blood cells
    • macrophages
    • plasma cells
    • "First Add Many White Men Please"
  69. fibroblasts
    • the most numerous connective tissue cells
    • lay down protein fibers
    • secrete fibrous components and ground substance
  70. adipocytes
    • found in connective tissue
    • produces body fat & store
    • used for insulation & energy storage
    • store triglycerides
  71. defensive cells
    • cells that defend the body against invaders
    • patrol the connective tissues and attack any enemies they find
    • mast cells, white blood cells, macrophages, and plasma cells
  72. mast cells
    • big grandular cells sitting in connective tissue
    • near blood vessels
    • help process of inflammation by producing histamine

  73. white blood cells
    • including immune cells
    • found in connective tissue
    • migrate (out of bloodstream) to sites of damage 
    • Ex: Eosinophil
    • Neutrophils ~ come from bloodstream, get out of bloodstream w/ help from histamine
  74. macrophages
    • found in connective tissue
    • Already present in tissue (compared to other defenders who come from bloodstream)
    • "big eaters" : swallow and destroy invaders or debris
    • fixed or wandering
  75. Plasma cells
    • found in connective tissue
    • Antibody producing cells
    • formed from white blood cells (B lymphocytes) 
    • Secrete special proteins called antibodies that help attack invaders
  76. antibody
    protein that helps attack invaders
  77. Connective tissue classification
    • 2 types: 
    • Embryonic connective tissue
    • Mature connective tissue
  78. Embryonic connective tissue
    • Consists of mesenchyme & mucous connective tissue
    • exists to support the movement and formation of tissues and organs
    • once tissues and organs take final form, the embryonic connective tissue type switches over to one of the mature types
  79. mesenchyme
    • is immature connective tissue (not differentiated) which later differentiates into all the other mature connective tissues
    • makes up almost all of embryo 
    • is almost fluid in consistency and cells are widely-spaced
  80. mucous connective tissue
    • previously called Wharton's jelly
    • a jelly-like connective tissue in the umbilical cord of the embryo, connecting mother and child
  81. Mature connective tissue
    • job is to hold things in place, and generally doesn't allow movement of cells (w/ exception of immune cells patrolling tissue to detect & destroy invaders)
    • 5 broad categories:
    • loose connective tissue
    • dense connective tissue
    • cartilage
    • bone 
    • liquid
  82. Loose connective tissue
    • one of 5 categories of mature connective tissue
    • basically the "packing material" inside body
    • 3 categories:
    • areolar connective tissue
    • adipose tissue
    • reticular connective tissue
  83. Areolar connective tissue
    • one of 3 types of loose connective tissue
    • most common connective tissue type
    • Areolar connective tissue used interchangeably with loose connective tissue 
    • found in wide variety of locations, such as in layer supporting the skin & mucous membranes and supporting & surrounding organs
    • consists of a mixture of fiber types (collagen, elastin, and reticular fibers) and cell types (fibroblasts and defense cells)
    • "areolar" means "little space"
  84. Adipose tissue
    • one of 3 types of loose connective tissue
    • fat; found under skin, around heart and kidneys, in yellow bone marrow, and forming cushion in joints and around eye socket
    • energy storage
    • consists of adipocytes (fat cells) that have a huge fat droplet surrounded by rim of cytoplasm and nucleus
  85. reticular connective tissue
    • one of 3 types of loose connective tissue
    • reticular fibers in a loose meshwork with reticular cells
    • soft and gently holds together things like red bone marrow and lymph nodes
    • forms a stroma of the liver, spleen, lymph nodes, and red bone marrow.
    • also forms the reticular lamina of the basement membrane
  86. stroma
    • supporting framework
    • Greek: "bed" or "couch"
  87. dense connective tissue
    • one of 5 categories of mature connective tissue
    • has tighter and more dense fibers
    • three categories:
    • dense regular
    • dense irregular
    • elastic
  88. dense regular connective tissue
    • One of 3 types of dense connective tissue
    • has dense fibers all going in the same direction 
    • appears grossly as a white, shiny sheet
    • made up of collagen fibers in regular bundles w a few fibroblasts
    • Found in tendons, ligaments, and aponeuroses
    • extremely slow to heal after an injury because of the combination of a dense structure and lack of blood supply
  89. Why are tendons and ligaments dense regular connective tissue
    • they are only pulled on in one direction, so they need most of their strength in only one direction 
    • Therefore fibers need to be really strong and run all together
  90. tendons
    connect muscle to bone
  91. When skeletal muscles shorten, what happens to tendons?
    tendons are pulled on to move the bone, creating quite a bit of strain on the tendon, in one direction
  92. ligaments
    connect bone to bone
  93. aponeuroses
    sheetlike tendons
  94. dense irregular connective tissue
    • one of 3 types of dense connective tissue
    • has dense fibers, but they are going in many different directions
    • has fibroblasts and collagen fibers
    • but as name suggests, collagen fibers run in many different directions
    • this gives strength in all directions
    • Found in fasciae which form sheets btwn muscles; in deeper part of skin & in "peri-" tissues
  95. "peri-" tissues
    • "Periosteum, Perichondrium, Pericardium"
    • surround bone, cartilage and heart, respectively
    • heart valves
    • and capsules surrounding organs
  96. Why is the "peri-" muscles (ex: pericardium) and skin dense irregular connective tissue?
    because it's stretching in multiple directions, so it needs to have strength in all directions
  97. laceration
    • occurs when the skin is unable to withstand the forces against it and pulls apart
    • More force on an given area than what your skin can withstand
  98. elastic connective tissue
    • one of 3 types of dense connective tissue
    • needs to have the ability to stretch and recoil back to it's original shape
    • made up of many oriented elastic fibers (like little bungee cords) & a few scattered fibroblasts
    • Found in: aorta; lungs, trachea, bronchial tubes and vocal cords;
    • in walls of arteries
    • in ligaments btwn vertebrae
    • in the suspensory ligaments of penis
  99. cartilage
    • one of 5 categories of mature connective tissue
    • Again... since it's a connective tissue... it must have cells and a matrix
    • harder and less flexible than dense connective tissue
    • 3 types:
    • hyaline
    • fibrocartilage
    • elastic cartilage
    • *living part of each is the chondrocyte
  100. chondrocyte
    • living part of all 3 cartilage types
    • cartilage forming cells
    • a cell that looks like a fried egg through the microscope
    • "chondro" is Greek for "grainy"
  101. Hyaline
    • most abundant type of cartilage
    • all bones start out as hyaline cartilage
    • *growth plates are cartilage until you reach your full height
    • *articular cartilage (made of hyaline cartilage) is on the ends of bones to help them slide past each other w/o pain as they move
    • a shiny, bluish-white substance that consists of fine (thin) loosely organized collagen fibers and many chondrocytes, which are enclosed in lacunae
    • "hyaline" means transparent or glasslike
  102. lacunae
    encloses chondrocytes
  103. fibrocartilage
    • this type of cartilage has a more fibrous appearance
    • collagen fibers here are big, coarser and gathered together into thick bundles
    • found in:pubic symphysis (where bones of pelvis are joined) 
    • in discs btwn vertebrae
    • in padding of knee (menisci)
    • where tendon inserts into cartilage
    • *the fibrous yet strong nature of pubic symphysis makes childbirth possible
  104. elastic cartilage
    • has elastic fiber in matrix 
    • Found in the epiglottis, the external ear, and the auditory tubes (tubes that connect the ear to mouth that "pop" when pressure changes)
    • made up of meshwork of elastic fibers surrounding the chondrocytes
  105. Bone (as mature connective tissue classification)
    • *to be connective tissue, have cells and matrix :)
    • two types: compact and spongy
  106. osteocytes
    • bone cells in the Lacuna (little chambers in the calcified, compact bone matrix)
    • *canaliculi are the tunnels between the osteocytes
  107. compact bone
    • outside surface of bone, matrix is solid
    • gives bones their strength
    • has complex and regular structure consisting of osteons as basic function and anatomical unit
    • Bulk of bone is nature's first composite material: a mixture of inorganic (hydroxyapatite, a mineral) and organic (collagen) components
  108. spongy bone
    • inside of bone; makes skeleton lighter and houses bone marrow (either yellow or red)
    • has much more irregular structure
    • spikes of mineralized tissue have ample space btwn for red bone marrow
  109. Why would bone be a dynamic tissue (constantly changing)?
    • It's built up & broken down, constantly,
    • depending on needs of the body at the time
  110. hydroxyapatite
    an inorganic mineral which is one ingredient which makes up the bulk of bone
  111. liquid connective tissue
    • blood & lymph
    • *remember, to be a connective tissue, must have cells and a matrix w/ fibers & background substance
  112. blood
    • one form of liquid connective tissue
    • 3 components: erythrocytes, leukocytes, and thrombocytes
  113. erythrocytes
    red blood cells
  114. leukocytes
    white blood cells
  115. thrombocytes
    • platelets ~
    • not true cells.....are cell fragments
  116. formed elements
    • the collective term for the components of blood
    • (erythrocytes, leukocytes, and thrombocytes)
  117. plasma
    • is the background substance in blood
    • a thick liquid connective tissue matrix which surrounds the formed elements (of blood)
    • primarily salt water plus proteins
  118. the fibers in blood
    • Remember we have "potential" clotting proteins (which form fibrin) that have to be activated to become fibers
    • only when clots are formed
  119. lymph
    • a filtrate of blood w most of the cells and some of the protein removed
    • very similar to extracellular fluid
    • white blood cells move around in lymph to guard against invaders
  120. cytoskeleton
    the microfilaments, intermediate filaments, and microtubules that five each cell it's structure
  121. cell junctions
    • the way each cell's cytoskeleton can link to another cell or to the connective tissue supporting the cell
    • Solves the problem: need to link cytoskeleton of adjacent cells to each other & need to link cytoskeleton to extracellular matrix
  122. Five main types of cell junctions
    • Tight junctions
    • adherens junction
    • desmosomes
    • hemidesmosome
    • gap junctions
  123. Tight Junctions
    • one of the 5 main types of cell junctions
    • are the Ziploc bags of the tissue world
    • form a tight, waterproof seal btwn two or more cells where substances cannot be allowed to percolate btwn cells
    • *The cells of the digestive system are held together with tight junctions to keep digestive enzymes from leaking out of the digestive tract and start digesting you!
    • Other locations: bladder
  124. Adherens Junctions
    • one of the 5 main types of cell junctions
    • uses the protein cadherin
    • works like a belt (adhesion belt), keeps tissues from separating as they stretch and contract
  125. Cadherin
    the glycoprotein that holds Adherens junctions together
  126. Desmosomes
    • one of 5 main types of cell junctions
    • are used as "spot welds" to hold tissue together against mechanical disruption
    • Uses cadherin plus intermediate filaments hooking it to cytoskeleton
    • Think of the "button on loose sweater" analogy.. where there is filament on one side and filament on the other. So it is a strong attachment in an non-structurally strong place
  127. Hemi-
    means "half"
  128. Hemidesmosome
    • half a desmosome
    • spot welds join cell to basement membrane
    • Uses integrin to link the hemidesmosome to basement membrane; on cell side intermediate filaments anchor the cytoskeleton to integrins, which are in turn connected to basement membrane
  129. gap junction
    • one of 5 main types of cell junctions
    • basically small tunnels of communication betwn cells; one cell builds half the tunnel (connexon) and the other cell builds the other half
    • cells are electrically coupled
    • Calcium and other small, hydrophilic ions can pass through the channel formed by connexons
    • Connexons allow substances less than 1000 Da to pass btwn cells
    • If one of the cells gets sick or dies, than Ca++ increases and these seal like a hatch
  130. What happens when a cell gets sick?
    • *Normally there really isn't any calcium in our cells. 
    • However, when a cell gets sick extra calcium builds up in the cell and seals off the gap junctions leading to other cells
    • "closes the hatch"
  131. connexin
    a protein, forms pore-like structures called connexons
  132. connexons
    • pore-like structure formed from connexin
    • allows small ions to pass from cell to cell
    • Monomers and small polymers can pass as well
    • If one cell gets sick, connexons can seal off like a ships hatch, isolating the damaged cell to die alone w/o making others sick
  133. what will connexons allow to pass
    • substances < 1000 Da to pass btwn cells
    • Passes: Ca++, Na+, Cl-, other ions, amino acids, messengers
    • DOES NOT PASS: proteins, DNA or RNA
  134. membranes
    • flat and flexible sheets which form a lining where parts of the body come together
    • consist of an epithelium plus underlying areolar connective tissue
    • Two types: epithelial and synovial
  135. epithelial membranes
    • epithelium + connective tissue 
    • 3 types (part of distinguishment btwn them is the fluid they produce): 
    • Mucous membranes  (produce mucus)
    • Serous membranes
    • Cutaneous membranes
  136. mucous membranes
    • the interface btwn the body cavities and the outside world
    • lined with epithelium, has goblet cells for protection
    • Ex: digestive tract, respiratory tract, and reproductive tract
  137. Is stomach considered an outside surface?
    • Yes! It is exposed to outside, there are openings exposing it to outside world.
    • Ex: What we just ate, we brought in from the outside world, into our digestive tract.
  138. Mucous
    • a sticky substance that catches harmful substances and keeps them from getting further into the body
    • also keeps some substances in only that area of the body
  139. lamina propria
    the connective tissue layer of mucous membranes
  140. serous membranes
    • form a lining btwn the body wall and internal organs
    • *basically has two main layers, so you end up with a sandwhich (or sorts) w serous fluid in the middle
    • produce serous fluid that allows organs to move over each other and not have friction with each other
    • *Ex: prevents friction as the heart beats (Parietal layer) next to body wall
    • *Serous fluid btwn
    • *Visceral layer next to organ
  141. How are serous membranes like a peanut butter sandwich?
    • Bread = Connective tissue (parietal layer outside)
    • Peanut butter = epithelial tissue (parietal layer outside)
    • Honey in middle = serous fluid
    • peanut butter = epithelial tissue (visceral layer, inside)
    • bread = connective tissue (visceral layer inside)
  142. Parietal layer vs. visceral layer
    • Parietal layer adhere's to the chest wall
    • visceral layer adhere's to the organ itself
    • Ex: heart, lungs, digestive systems
  143. serous fluid
    • the same clear, watery fluid that is found in blisters
    • keeps things from rubbing together and causing pain and inflammation
    • Ex: prevents friction as the heart beats (Parietal layer) next to body wall
    • *As the lungs expand, visceral layer next to organs; as the intestines are continuously moving, also prevents friction here
    • Ex: liquid in sunburn blisters
  144. cutaneous membrane
    skin; covers the outside of the body away from cavities
  145. synovial membranes
    • line the space btwn two bones forming a joint
    • therefore, are only found at joints where two bones come together
    • lack an epithelial layer
    • has a connective tissue capsule that contain the synoviocytes 
    • are only made of connective tissue (areolar)
    • connective tissue secretes synovial fluid
  146. synovial capsule
    • made of connective tissue that surrounds the joint
    • inner cells of capsule are synoviocytes
  147. synoviocytes
    cells that produce the synovial fluid that serve as cushion in joints
  148. synovial fluid
    is thick and keeps the hyaline cartilage on the ends of articulating bones from rubbing and wearing down
  149. What do mucous, serous, and cutaneous membranes have in common?
    They all have a layer of epithelium w an underlying areolar connective tissue
  150. epithelial membranes
    • what mucous, serous, and cutaneous membranes are called because of the overlying layer of epithelium
    • Recall mucous, serous, and cutaneous membranes all have a layer of epithelium w an underlying areolar connective tissue
  151. What do joints allow?
    movement while preventing the bones from rubbing against one another and causing damage to bone
  152. muscle tissue
    • present wherever the body needs to generate force
    • moves the body, maintains posture, and generates heat
    • 3 main kinds: skeletal muscle, cardiac muscle, and smooth muscle
    • Each use myosin and actin
  153. Skeletal muscle
    • Also called voluntary muscle (so it's under our control)
    • A type of striated muscle ~ meaning it appears to be striped or striated under a microscope
    • made up of muscle cells
    • Shortens in one direction
    • Nuclei are eccentric
    • Fibers run parallel to each other
    • Cells are large, long and cylindrical with several nuclei
  154. eccentric
    referring to nuclei in skeletal muscle, nuclei are on the edges of cells; not center
  155. myofiber
    the long, thin tube formed when muscle cells fuse together
  156. What does "striated" refer to
    • how the muscle cells are arranged
    • When they have a regular arrangement, they have striated appearence
  157. syncytium
    • "joined cells"
    • referring to the fusing of skeletal muscle cells to form a myofiber
  158. Cardiac muscle
    • has striated appearance like skeletal muscle
    • not voluntary
    • Fibers are joined in branches; so has branched structure
    • cells shorten in several directions
    • Nucleus in center, one nuclei per cell
    • have intercalated discs

  159. smooth muscle
    • Single cells, central nucleus
    • not under voluntary control
    • contracts all together
    • Nucleus in center; one nuclei per cell
    • smooth, Not striated
    • Ex: the gut tube is lined w smooth muscle that keeps digestion proceeding from mouth to anus
  160. intercalated discs
    • in cardiac muscle cells
    • formed by desomes and gap junctions
  161. Functions of nervous system
    • 1. receive info
    • 2. process info
    • 3. transmit (or respond to) info
  162. nervous tissue
    • only tissue in body that can manipulate electrical charges to receive, process and transmit info
    • Two main cell types: neurons & glial cells
  163. neurons
    • Nerve cells - the functional cells which receive, process or transmit information
    • *recall that each neuron only sends info one way. So it either sends info from body up to spine and brain, or it sends info from brain and spine down to body
  164. effector tissues
    the tissues in the body that produce some sort of output, either the movement of muscle or the secretion of a gland
  165. glial cells
    • support cells that nourish and maintain the neurons
    • Are all the other cells in nervous tissue that are not neurons. 
    • They glue the nervous tissue together
    • Some make myelin to cover axon, other create blood/brain barrier, other protect from bacteria and viruses
  166. excitable tissues
    • term for both muscle and nerve tissue together
    • this is because by manipulating the flow of electrical charge, they can produce action potentials and other unique electrical events inside the cell