Cells and Tissues

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Cells and Tissues

• Karen Kraus
• BIOL203
• February 8, 2007

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Where the Cell Things Are

• Intracellular vs. Extracellular
• Extracellular Matrix
• Ground substance
• Fibers
• Fluid
• Solids
• Function of extracellular matrix?

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Sticking Together.

• Types of junction
• Cell-cell
• Cell-matrix
• Tight junctions
• Gap junctions
• Desmosomes and hemidesmosomes
• Cadherins and integrins (CAMs)

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Its Tight, aight?

• Fusion of membranes
• Virtually impermeable

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Fall into the Gap

• Cell membranes remain separate
• Connexon tunnel
• Direct passage of small molecules

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Dizzy desmosomes

• Cell membranes remain separate
• Structurally similar to a rivet
• Cadherins link the membranes
• Hemidesmosomes

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Sticking Together

• Cell adhesion molecules (CAMs)
• Cadherins
• Integrins
• Movement, anchoring and SOS signals

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Lets Talk about It

• Cell Signaling
• Membrane receptors
• Contact signaling
• Electrical signaling
• Chemical signaling

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Chemical Signals

• Extracellular ligands
• Paracrine
• Neurotransmitters
• Endocrine
• Nitric oxide (NO)

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Getting the Message Across

• Catalytic receptors
• Gated channels
• G protein linked (secondary messenger)

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Do You Have Potential?

• Membrane potential
• Polarization
• Negative vs. positive polarization
• Resting potential

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Two alkalis, a halogen and a membrane

• Sodium, chlorine and potassium
• Potassium wants out
• Sodium wants in
• Sodium/potassium pump

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Pump those ions!

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Why move sodium?

• Besides the potential?
• Osmotic gradient!

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a.a.achoo!

• Types of tissues
• Epithelial
• Connective
• Muscle
• Nerve

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Background Check!

• Zygote
• Blastula
• Gastrula
• Ectoderm
• Mesoderm
• Endoderm

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Cover it up

• Where?
• What?
• Why?
• Epithelial characteristics
• Epithelial classification

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Short-sheeted

• Single layer
• Squamous cells
• diffusion, filtration, secretion

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Roll the dice

• Single layer
• Cuboidal cells
• Secretion, absorption

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Ionic or doric?

• Single layer
• Columnar cells
• Sometimes ciliated
• Secretion, absorption

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Counterfeit

• Single layer
• Sort of columnar-type cells
• Sometimes ciliated
• Secretion

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Layer it on

• Stratified layer
• Mostly squamous cells basal cells mostly
  cuboidal
• Protection

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Stacking blocks

• Stratified layer
• Cuboidal cells
• protection and some secretion/absorption

• Stratified layer
• Columnar cells
• Protection and secretion

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Segue-way

• Stratified layer
• Basal cuboidal and columnar apical varying
  shapes
• Allows stretching

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To secrete or not to secrete

• Glands can be one or more cells
• exocrine
• secrete to a surface directly or via ducts
• sweat, tears, sebum, etc.
• endocrine
• not connected to surface use blood or lymph to
  send product to destination

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Formation of glands

• Both types begin as in-growing epithelial cells
• endocrine glands lose epithelial connection at
  maturity, but are vascularized
• exocrine maintain contact with epithelium

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Name that gland!

• Structure
• duct and secretory portion
• acinar
• tubular
• tubuloacinar
• coiled

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Name that gland!

• Function
• merocrine
• holocrine
• apocrine