histology of the tongue and salivary glands

Question 1

the tongue

Answer 1

dorsal surface has 2 components

1. oral part
2. pharyngeal part

Question 2

oral part

Answer 2

anterior 2/3
taste fibres from chorda tympani of facial nerve CNVII
large number of small projections called lingual papillae

Question 3

chord tympani

Answer 3

part of the facial nerve CNVII

Question 4

lingual papillae

Answer 4

CT core covered with stratified squamous epithelium

4 types based on shape

Question 5

4 types of lingual papillae

Answer 5

filiform - thread (most abundant)
fungiform - mushroom
circumvallate - surrounded by a rampart
foliate - leaf shaped, poorly formed in humans, often absent in ages people

Question 6

posterior part

Answer 6

posterior 1/3
taste fibres from glossopharyngeal nerve
posterior to terminal sulcus
contains foramen caecum in the midline
covered in the lingual tonsils - lymph nodules

Question 7

what divides anterior 2/3 to posterior 1/3

Answer 7

terminal sulcus
papillae line the sulcus
foramen caecum posteriorly

Question 8

lingual tonsils

Answer 8

small lymph nodules

Question 9

foramen caecum

Answer 9

midline of the pharyngeal part

posterior to the terminal sulcus

Question 10

oral part uses taste fibres from the

Answer 10

chorda tympani - part of the facial nerve

Question 11

pharyngeal part uses taste fibres from the

Answer 11

glossopharyngeal nerve

Question 12

characteristics of the tongue

Answer 12

CT underlying the epithelium is fairly dense
strands of perpendicularly oriented SK.M
small lingual salivary glands within the CT
MALT - mucosa associated lymphoid tissue

Question 13

filiform papillae

Answer 13

smallest and most abundant
epithelium is keratinised around filiform papillae
creates a rough surface to aid in manipulating food in the oral cavity

Question 14

fungiform papillae

Answer 14

occur singularly, but evenly dispersed between filiform
epithelium is non-keratinised
CT core is well vascularised
do have some taste buds `

Question 15

circumvallate papillae

Answer 15

largest and least abundant
8-12 along the terminal sulcus
created by invaginating trench of epithelium
taste buds cover the lateral surfaces of papilla
excretory ducts of serous glands open into trenches

Question 16

foliate papillae

Answer 16

appear as folds along the dorsolateral tongue, closer to terminal sulcus
deep lateral portions contain many taste buds
also have opening for serous excretory glands

Question 17

purpose of excretory ducts in circumvallate papillae

Answer 17

to flush out trenches

Question 18

taste buds

Answer 18

ovoid, lightly stained bodies
taste pore - basement membrane extends to opening in epithelium
4 types
have microvilli extensions
fluid enters the taste pore
contains receptors for 6 taste modalities - sweet, salty, bitter, sour, fat, umami (savoury)

Question 19

6 taste modalities

Answer 19

sweet, salty, bitter, sour, fat, umami (savoury)

Question 20

taste pore

Answer 20

basement membrane extends to opening in the epithelium

Question 21

evolution of taste buds

Answer 21

amount of each modality is linked to age and metabolic hormones
4 cell types are sensitive to different metabolic hormones

Question 22

saliva

Answer 22

mixed secretion from many glands that open into the oral cavity

Question 23

3 large paired tubuloacinar glands

Answer 23

1. parotid
2. sublingual
3. submandibular

Question 24

tubuloacinar glands

Answer 24

have two components - tubule and acing
have secretory acini
divided by CT to have lobules and lobes

Question 25

parotid glands

Answer 25

next to the ear, outside of the oral cavity | duct enters through the cheek around the 2nd molar

Question 26

sublingual gland

Answer 26

beneath the tongue, within the CT septa of the oral cavity

Question 27

submandibular gland

Answer 27

beneath the mylohoid muscle | part of gland reaches around the muscle, so its duct connects to the lingual duct

Question 28

ducts

Answer 28

human of secretory acinus is continuous with the duct system

Question 29

intercalated duct

Answer 29

leads from acinus to larger duct

Question 30

striated duct

Answer 30

striations within columnar cells forming the duct elongated mitochondria on basal side, pushes nuclei towards apical side prominent in serous, absent in mucus, sparse in mixed

Question 31

interlobular vs interlobular ducts

Answer 31

interlobular are larger excretory ducts with more surrounding CT have stratified cuboidal/columnar epithelium

Question 32

secretory acini

Answer 32

making serous - watery product round/ovoid nuclei on cell basal surface cytoplasm appears pink/red with granules - contain amylase enzyme mainly in glands located further away from oral cavity eg. parotid

Question 33

myoepithelium

Answer 33

cell sitting on the outside of a gland | rhythmically contract and squeeze the gland

Question 34

glands secreting mucus

Answer 34

viscious product flattened nuclei, appear pressed against the basal surface mainly in glands located closer to the oral cavity eg. sublingual gland appears pale on staining

Question 35

serous demilunes

Answer 35

half moon shaped serous secreting cells attached to mucus secreting glands secrete product between mucous producing cells sublingual and submandibular glands