Prac 1: Oral Cavity, Pharynx & Oesophagus Flashcards
(34 cards)
What types of glands are present on the external surface of the LIP? What type of secretions do these glands produce?
Sebaceous Gland
Epithelium: Keratinized stratified squamous epithelium
What types of glands are present on the INTERNAL surface of the LIP? What type of secretions do these glands produce?
Seromucous & salivary glands (moisten mouth, initiate digestion of food and help protect teeth from decay)
Epithelium: non keratinized stratified squamous epithelium
The region that is devoid of hair and glands?
What type of muscle is present at the region of the lip?
Vermillion Border
Simple squamous Epithelium (slightly less keratinised)
Muscle type: Skeletal muscle- orbicularis oris - sphincter of the mouth
How are the skeletal muscle fibres arranged within the tongue?
They are arranged at right angles- they are the intrinsic muscles of the tongue and include the:
- superior longitudinal
- vertical and transverse muscles
- inferior longitudinal muscle
Name the various papillae of the tongue
Which contain taste buds?
Curcumvillate papillae: have Von Ebners glands underneath and secrete lingual lipase. 1/2 taste buds
Folliate papillae: posterolateral margins of the tongue, contain 1/4 taste buds
Fungiform papillae: mushroom like, everywhere. Contain 1/4 of the taste buds
Filliform Papillae- NON gustatory, act to increase friction in the mouth
Lingual Papillae- what type of papillae are these? What type of glands release their secretions into these crypts? What is the name of these specific glands and what do they produce?
Lingual papillae are circumvillate papillae (gustatory). beneath them are Von Ebners glands which release their secretions into the crypts formed on either side of the papillae.
Von Ebners glands are serous secreting glands which produce lingual lipase (breaks down fats)
How can you tell the difference between the anterior 2/3 and posterior 1/3 of the tongue?
Anterior 2/3: lingual papillae and skeletal muscle fibres in 3 directions. stratified squamous non keratinised epithelium.
Posterior 1/3: No papillae, lots of primary and secondary lymphoid follicles present (MALT) as well as salivary glands
What is the primary stage of tooth development? Explain
CAP PHASE:
Mesenchyme adjacent to the enamel organ (formed from the dental lamina) condenses to form the dental papillae
What is the second stage of tooth development?
BELL PHASE:
The enamel organ develops a layer of ameloblasts (produce enamel). The dental papilla develops a layer of odontoblasts (secrete dentine)
The formation of the dentine & enamel has begun between the two epithelial layers!!
What is the third stage of tooth development?
ERRUPTION PHASE
Elongation of the tooth
Which cells are responsible for the production of the enamel? From which of the three embryonic tissues do they arise from?
Ameloblasts produce enamel and they arise from the ectoderm
Which cells are responsible for the production of dentin? which embryonic tissue does this arise from?
Odontoblasts produce dentin!! From embryonic mesenchyme (mesoderm)
What is the dental Lamina?
During the BUD Stage, the dental lamina is the intiial downgrowth of ectoderm that will form the enamel organs. There are 4 of these which appear at about six eeks
What is the Stellate Reticulum?
The stellate reticulum is located within the enamel organ (bell stage, may be present but less developed in the cap stage). The cells of the stellate reticulum are star shaped and have many cellular processes interconnected with one another to form a network within the enamel organ. It plays a role in maintaining tooth shape & protecting underlying dental tissue
Permanent Tooth Bud
Primary/decidious teeth begin to form between the 6th and 8th weeks, and permanent teeth begin to form in the 20th week. Permanent teeth develop when the dental lamina develops posteriorly & gives rise to a bud (side branch) adjacent to the deciduous one.
Name two enzymes found in saliva
Amylase (breaks down starch) & lingual lipase (breaks down fats)
What are the three cell types found in a secretory acinus?
Serous cells
Mucous cells
Myoepithelial cells- basement of the acinus
Describe a SEROUS cell
A serous cell generally has a round nucleus which can be either in the centre of the cell or pushed to the basal region. The cytoplasm stains positively in H&E sections.
Describe a MUCOUS cell. Why dont they stain well with H&E?
Mucous cells have a flattened nucleus that is pushed to the basal region of the cell by an accumulation of mucin which does not stain well with H&E.
Mucin has a large water carrying capacity & also has less RER than serous cells, plus it has lots of GLYCOGEN (carbohydrate that doesn’t stain) and for these reasons it stains much lighter with H&E.
What does the parotid gland secrete?
100% serous
What does submandibular gland secrete?
80% serous 20% mucous
What does the sublingual gland secrete?
80% mucous, 20% serous
In what form are the serous components of the sublingual gland? Can this type of structure be found in any of the other salivary glands?
The sublingual gland is mainly mucous with small amounts of serous components, and these are usually seen as serous demilunes (cap in the shape of a half moon). Small numbers of serous demilunes will also be present in the submandibular gland.
What is the pathway of drainage from the Acini?
Acini drain from their central lumen to intercalated ducts to striated ducts (intralobular ducts) and eventually to interlobular ducts. Striated ducts are more commonly seen in serous glands, but be aware that they are not present in the pancreas.
