Gut Communication With Enviroment

Question 1

Tongue and taste innervation

Answer 1

▪️muscle of the tongue controlled by hypoglossal nerve
▪️chemoreceptors on the tongue-tastebuds send signal by CN7/9/10 to brain when detect different substances of food
-signals sent through CN7-anterior 2/3 of tongue, 9 (glossohphalengeal)- posterior 1/3, CN10-pharynx
-prepares gut for meal-cephalic phase
-gets mouth ready
▪️signals go through nucleus of solitary tract (NTS) and then gustatory complex via thalamus
-CN9 and CN7-salivation-prepare mouth for food
-CN10-acid secretion of stomach and bile and pancreatic juices

Question 2

Gustotopic map

Answer 2

▪️taste buds for different tastes lie within the same region but are different for ethnicity and individuals

Question 3

Types of Taste receptors

Answer 3

- g-protein couple receptor (gustducin)
▪️unami -proteins,L-AA
-T1R1+T1R3
▪️sweet-glucose, artificial sweeteners , D-AA
-T1R2+T1R3
▪️bitter
-T2Rs
▪️saltiness-NaCl
-ENaC
▪️sour-citric acid, HCL
-PKD2L1

Question 4

Taste in GIT

Answer 4

▪️taste receptors expressed in

• stomach
• trachea
• intestine