Histology

1
Histology

• The Cell

2
Cell Organization

• Cytoplasm
• 1) membranes
• 2) organelles
• 3) inclusions
• 4) cytosol
• Nucleus

3
The CytoplasmPlasma Membrane (plasmalemma)
7 10 nm thick limiting membrane
100,000x
4
Plasma Membrane
5
Plasma Membrane

• forms the plasma membrane as well as membrane
  bound organelles typical of eukaryote cells.
• also forms exvaginations as microscopic fingers
  on many cells as microvilli (brush borders)
• semipermeable to intra- and extracellular
  substances.

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Integral Membrane Proteins
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Endocytosis/ Exocytosis
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Organelles (functional internal structures
within the cell)
1. Mitochondrion
9
Organelles

• Ribosomes
• Electron dense
• 20 to 30 nm
• Protein and ribosomal RNA (rRNA)
• Polyribosomes (polysomes) on mRNA
• In cytosol, mitochondrial matrix, ER (rough)

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Organelles

• Endoplasmic Reticulum

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Organelles

• Golgi Complex

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Organelles

• Lysosomes
• Hydrolytic enzymes
• Acidic pH
• 0.05 to 0.5 mm
• Proteosomes
• Proteolytic Enzymes
• Ubiquitin Tagged Prot.
• Peroxisomes
• Catalase
• Oxidation of lipids

13
Cytoskeleton

• Microtubules
• a and b Tubulin (50 kDa)
• 24 nm diameter
• Hollow core
• Flagella, cilia, centrioles, mitotic spindle

14
Cytoskeleton
15
Cytoskeleton

• Actin- 5 to 7 nm in diameter

60,000x
16
Other Cytoplasm

• inclusions - non-functional storage bodies in the
  cell, sugar, lipids, pigments e.g.
  glycogen granules
• cytosol - liquid of cell, mostly water, salts,
  especially K, PO4, and amino acids.

17
Nucleus

• Operational center of the cell.
• Operates by implementing the genetic code
  resulting in protein production
• usually 1 per cell.
• Components
• a) double membrane - many pores
• b) DNA - genetic code of nucleotide units.
• c) nucleolus - RNA
• d) nucleoplasm

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Nucleus
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Nucleus
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Nuclear Envelope
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Mitosis