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[19-1]:Lip, H&E; This is a low magnification view of the lip. 
While the outside of the lip is characterized by fully keratinized 
stratified squamous epithelium (i.e. the epidermis) with hair 
follicles (large arrow) and sebaceous glands embedded in the 
dermis, the inside of the lip is lined by a non-keratinized 
stratified epithelium supported by a lamina propria.

[19-2]:Inner lining of the lip, H&E; Higher magnification of the 
inner lip showing the lining epithelium.

[19-3]:Tongue, H&E. Note the skeletal muscle running in three 
different planes in this cross-section of the tongue.

[19-4]:Filiform papillae (arrows), H&E.

[19-5]:Fungiform papilla (arrow) H&E.

[19-6]:Circumvallate papilla, H&E; Note the many taste buds (small 
arrows) along the sides of this papilla. A duct (larger arrow) can 
be seen arising from the serous glands of von Ebner.

[19-7]:Circumvallate papilla, H&E; Higher magnification of the 
moat region around a circumvallate papilla showing taste buds 
(arrows) and serous glands of van Ebner (S).

[19-8]:Taste bud, Iron hematoxylin & aniline blue; Taste bud 
showing the darker nuclei of the supporting cells, the lighter 
staining nuclei of the sensory cells (small arrows). The 
microvilli of these cells project out the taste pore as a taste 
hairs (large arrow). 

[19-9]:Parotid gland, H&E; Parts of three lobules can be seen in 
this low magnification view of the parotid gland. Note the 
interlobular duct (arrow) seen in the connective tissue septae 
between the lobules. Can you distinguish this duct from arteries 
and veins also seen in the connective tissue septae?

[19-10]:Parotid Gland, H&E; In the center of the field are 
sections through pink staining striated ducts. Can you see the 
striations in the cells lining these ducts? The secretory units 
stain darker purple due to the RER in their cytoplasm. A small 
intercalated duct can also be seen (arrow).

[19-11]:Parotid Gland, H&E; This is a parotid gland from an older 
individual which has accumulated numerous fat cells. Do not 
confuse the leached out fat droplets for the more tubular mucin 
producing glandular units seen in the  submandibular and lingual 
glands.

[19-12]:Submandibular Gland, H&E; Most of the secretory units are 
serous mixed in with a small number of mucous secretory 
units(these appear more leached out).

[19-13]:Submandibular Gland, H&E; Note the serous demilunes 
(arrows) capping the mucous secretory units.

[19-14]:Sublingual Gland, H&E; Most of the secretory units are 
mucous mixed in with a small number of serous secretory units. 

[19-15]:Schematic diagram of a tooth.

[19-16]:X-ray of teeth. In this x-ray try to distinguish the thin 
layer of enamel from the grayer dentin. Also distinguish the pulp 
cavity and elements of the alveolar bone.

[19-17]:Tooth Crown, Fuchsin; The brown lines seen in the enamel 
(e) represents the lines of Retzius. d; dentin. p; region of the 
pulp cavity.

[19-18]:Tooth, H&E; In this histological section of the tooth, the 
enamal has been lost due to decalcification. Note the clear pulp 
cavity in the dentin (d). Note also the periodontal ligament 
(arrows) situated between the alveolar bone (a) and the dark, thin 
layer of cementum surrounding the dentin. 

[19-19]:Tooth, H&E;Vicinity of the gingival sulcus (arrow) Note 
the sulcus is lined by a non-keratinized stratified squamous 
epithelium while the outside of the gingiva is lined by a fully 
keratinized stratified squamous epithelium. 

[19-20]:Tooth, H&E; Vicinity of the root of the tooth showing 
elements of the periodontal ligament (p) running between the 
alveolar bone (a) and the cementum (c). d; dentin.  

[19-21]:Tooth, Trichrome stain; Elements of the periodontal 
ligament (p) can be seen embedding in the cementum (c) as 
Sharpey’s fibers (arrows). Can you make out section through 
dentinal tubules in the dentin (d)?

[19-22]:Developing tooth, H&E; Low magnification view of the 
developing tooth. The developing pulp cavity (p) is lined by an 
odontoblastic layer of cells (small arrows) which is actively 
making dentin (d). The region of the large arrow is where enamel 
has been leached out as a result of decalcifying the tooth. 

[19-23]:Developing tooth, H&E; Higher magnification of the 
developing tooth seen in the previous slide. Odontoblasts (o) can 
be seen giving rise to predentin (small arrow) which will  become 
more calcified to form the mature dentin (d). Some of the enamal 
which was produced by the ameloblasts (a) remains and can be 
detected despite decalcification of the tooth (large arrow).