cavity inside the body), connective tissue, nervous tissue, and muscle tissue. Organs
in the body are composed of a layered combination of these basic tissues. As an
example, within the esophagus thefirst layer of the esophageal wall contains
epithelial cells, as Fig.6.10shows. Covering this epithelium layer is connective
tissue and several layers of smooth muscle cells. Glands, nervefibers, and blood
vessels run through the connective and muscle tissues.
Epithelium (cellular
covering of the
inner surface)
Smooth muscle
(2 or 3 layers)
Connective tissue
(contains glands,
blood vessels, nerves)
Connective tissue
(supports and binds the
esophagus to other organs)
Organ
cavity
Fig. 6.10 Layered combination of basic organ tissues
10 μm
1 μm
100 nm
10 nm
Rayleigh
scattering
Eukaryotic cells (10-100 μm)
Size scales Types of scattering
elements and their sizes
Nucleus (5-10 μm)
Mitochondria (prolate spheroid:
1-2 μm length; 0.2-0.8 diameter)
Lysosomes (250-800 nm sphere)
Collagen fibrils (300 nm × 1.5 nm cylinder)
Macromolecules: cellulose, proteins, polypeptides
(2 – 100 nm)
Cell membranes (7 nm)
White blood cells (7-20 μm spheroids)
Red blood cells (biconcave dish: 7.8 μm diameter)
Golgi apparatus 100-400 nm)
Wavelengths used
in biophotonics
Infrared
UV
Fig. 6.11 Sizes of scattering elements in biological tissue
6.3 Scattering 161