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Flashcards in tissues Deck (12)
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1
Q

what is extracellular matrix

A
  • flexible, loose lattice matrix, structure, support, regulation
  • network of protein fibres embedded in polysaccharide gel (polysaccharide, collagen, glycoproteins)
  • varies from tissue to tissue (bone / cartilage has lots, muscle have little)
  • interstitial matrix = connective tissue
  • basal lamina = underlines epithelial tissue, connect to tissue beneath
2
Q

what are examples of intercellular connections

A
  • tissues, tight, anchoring and gap / communicating
3
Q

what are the types of tissue in the body

A
  • epithelial, connective, muscle and nerve (form follows function)
4
Q

what is epithelial tissue

A
  • diverse, covers every major surface in body

- simple, stratified / pseudo stratified (layers), squamous (scaly / thin), columnar or cuboidal

5
Q

what is connective tissue

A
  • ECM more abundant than cells
  • reinforced by protein fibres
  • collagen: 3 polypeptides, triple helix, fibrous
  • reticulin: mesh linke, binding of layers of tissues
  • elastin: cross links between, manipulation, breaks down over time
  • structural support (bones / cartilage), metabolism, storing and cushioning / protection (fats / adipose - peripheral nuclei for fat storage, smaller organelles), defence and transport (blood)
6
Q

what is muscle tissue

A
  • specialised cells with highly organised fibre network (contractile proteins, actin / myosin)
  • motors of body, contractions (voluntary / involuntary)
  • skeletal: stripes, striations, multi-nucleated, voluntary
  • smooth: tapered at ends, multi-nucleated, involuntary
  • cardiac: striated, branched, involuntary
7
Q

what is nervous tissue

A
  • neurons produce and conduct electrochemical impulses throughout body
  • glia: support and insults neurons from foreign materials
  • myelin sheath: insultes glial cells / axons
8
Q

what is a communicating / gap cell junction

A
  • chemical signalling directly between cells
  • allow small molecules or ions to pass for intercellular communication, membranes held apart (contrast tight junctions)
  • can open / close gates which are important for containing damage
9
Q

what is osteogenesis imperfecta

A
  • genetic disorder, inherited as a dominant trait, children suffer from frequent spontaneous fractures
  • lack of production of type 1 collagen, used to make bones
  • brittle bones, easily broken
10
Q

what is a tissue cell junction

A
  • interdependent, bound by ECM, cell to cell physical connection and chemical communication
11
Q

what is a tight / occluding cell junction

A
  • connect membranes of adjacent epithelial cells in a sheet
  • cell membranes ‘fused’ by protein bands
  • form impermeable membrane
  • barrier preventing leakage of extracellular contents between a layer of cells (digestive system)
12
Q

what is a anchoring / desmosome cell junction

A
  • physical connection, bind adjacent cells together (molecular velcro)
  • form an internal tension reducing network or fibres
  • common where mechanical stress occurs
  • desmosomes, hemidesmosomes and adherens