15. Nutrient Sensing and Uptake Flashcards
TASTE RECEPTORS in the TONGUE send information via which CRANIAL NERVES
FACIAL (VII)
GLOSSOPHARYNGEAL (IX)
TASTE RECEPTORS send information via FACIAL and CRANIAL NERVES to the … in the BRAIN STEM
SOLITARY TRACT (NTS)
what is the INIATED from the BRAIN STEM NTS from taste receptors activation
VISCERAL REFLEXES TO GUT
- to PREPARE for incoming mean
CEPHALIC RESPONSE
- GASTRIC SECRETIONS
what AFFERENT NEURONS send signals from the TONGUE TO NTS - BRAIN STEM
GUSTATORY
which EFFERENT NERVES come from NTS (BRAIN STEM)
FACIAL (VII) to salivary glands,
GLOSSOPHARYNGEAL (IX) to salivary glands and oesophagus
VAGUS (X) to gut
what does HYPOGLOSSAL NERVE (XII) control
conscious control of TONGUE MUSCLES
what does TRIGEMINAL NERVE (V) control
CHEWING
(& sensory to pain)
the NUCLEUS of the SOLITARY TRACT PROJECTS to what nucleus
specific GUSTATORY NUCLEUS in the THALAMUS
NUCLEUS of the SOLITARY TRACT projects to a specific GUSTATORY NUCLEUS in the THALAMUS and from there to the…
INSULAR CORTEX
a lot of our TASTE is based on … SIGNALS
OLFACTORY
(OLFACTORY NERVE I)
MAIN OLFACTORY PATHWAY runs from … to …
from OLFACTORY BULB
to PRIMARY OLFACTORY CORTEX (PIRIFORM CORTEX) on the Underside of the TEMPORAL LOBE
GUSTATORY PATHEAYS PASS through the…
THALAMUS
VISCEREL RESPONSES to taste
- SALIVARY Secretion
- GASTRIC juice
- PANCREATIC Secretion
- GALLBLADDER CONTRACTION
GUSTOTOPIC MAP:
TASTE RECEPTORS are EVENLY DISTRIBUTED in tongue
LINGUAL EPITHELIAL TASTE RECEPTORS:
TASTE RECEPTOR 1 (T1R) has 3 members.
which are used for UMAMI - taste of L-AMINO ACIDS
T1R1 & T1R3
LINGUAL EPITHELIAL TASTE RECEPTORS:
TASTE RECEPTOR 1 (T1R) has 3 members.
which are used for SWEET TASTE?
T1R2 & T1R3
LINGUAL EPITHELIAL TASTE RECEPTORS:
TASTE RECEPTOR 2 family (T2Rs) are used for what taste?
BITTER TASTE
What type of receptors are TASTE RECEPTORS
G-PROTEIN COUPLED RECEPTORS (GPCR)
which G-PROTEIN is coupled with TASTE RECEPTORS
GUSTDUCIN
(from Transducin family of GPCRs)
which TASTE RECEPTOR is used for perception of SALTINESS
ENaC - SODIUM CHANNEL
what TASTE perception is PKD2LI used for
SOUR TASTE
where are there also TASTE CIRCUITS
GUT (INTESTINE)
BILE DUCT
STOMACH
NASAL EPITHELIUM
Which GUT CELLS act as NUTRIENT SENSORS
ENTEROENDOCRINE CELLS (EECs)
- central to the chemosensing pathway of the intestinal tract
there are AT LEAST … DIFFERENT EEC populations of the GI TRACT PRODUCTING …. HORMONES
at least 12 different EEC
producing >20 HORMONES
what are EXPRESSED on the LUMINAL MEMBRANE of EECs
NUTRIENT SENSING GPCRs
-> nutrient sensing of these receptors leads to SECRETION of key regulatory GUT HORMONES
STOMACH G-CELLS
key TASTE RECEPTORS:
HORMONE released:
receptors for PEPTIDES and AMINO ACIDS
-> GASTRIN release
(regulates acid and pepsinogen secretion)
STOMACH P/D1 CELLS
key TASTE RECEPTORS for:
HORMONE released:
receptors for SUGARS (SWEET) & BITTER
-> GHRELIN release
STOMACH P/D1 CELLS
key TASTE RECEPTORS for:
HORMONE released:
receptors for SUGARS (SWEET) & BITTER
-> GHRELIN release
(hunger)
DUODENUM I CELLS
key TASTE RECEPTORS:
HORMONE released:
for LONG-CHAIN FATTY ACIDS (LCFAs), AMINO ACIDS (UMAMI), BITTER
-> CCK release
(control satiety and motility)
JEJUNUM ENTEROCYTES
key TASTE RECEPTORS:
HORMONE released:
SGLT-1 RECEPTOR for SUGARS (SWEET)
-> GLP-1 RELEASE
(insulin, regulate blood glucose)
ILEUM L CELL
key TASTE RECEPTORS:
HORMONE released:
SUGARS (SWEET), LCFAs, AMINO ACIDS, BITTER
-> GLP-1 RELEASE
COLON L-CELLS
key TASTE RECEPTORS:
HORMONE released:
SHORT CHAIN FATTY ACIDS
-> PYY and GLP-1 RELEASE
(satiety, ion secretion, motility)
CCK secreted from which CELLS
I CELLS in DUODENUM
CCK I CELLS have which TASTE RECEPTORS
(what do they taste)
LCFAs, PROTEIN/AAs (UMAMI)
& BITTER
what does CCK STIMULATE
PANCREATIC SECRETIONS
- protease, amylase, lipase, secretin
GALLBLADDER CONTRACTION
what does CCK INHIBIT
FOOD INTAKE
& reduces GASTRIC EMPTYING (motility)
SGLT-1 is the MAJOR ROUTE for ABSORPTION of SUGARS from INTESTINAL LUMEN into..
ENTEROCYTES -> BLOOD
what is the MAJOR ROUTE for ABSORPTION of SUGARS from INTESTINAL LUMEN
SGLT-1
GLUCOSE also STIMULATES the RELEASE of which GUT HORMONE
GLP-1
(L CELLS)
-> stimulates INSULIN RELEASE from Pancreas
(increase glucose uptake to tissues and enhancing enterocyte glucose uptake via increasing expression of SGLT-1 and GLUT2 in enteroycytes)
which TRANSPORTERS are used to TRANPORT GLUCOSE across ENTEROCYTES
- SGLT-1
glucose transported with Na+ - GLUT2
transports glucose out
also NA+-K+ ATPase for conc. gradient
GLP-1 STIMULATES the EXPRESSION of which TASTE RECEPTOR
SGLT-1
- SWEET TASTE (glucose)
as GLUCOSE is TRANSPORTED through ENTEROCYTE in ABSORPTION, what FOLLOWS (is also absorbed)
Cl- through TIGHT JUNCTIONS
-> H2O also FOLLOWS
(H2O ABSORPTION)
future clinical potentials of TASTE RECEPTOR targetting:
- compounds that Block activation of gut’s taste receptors might serve as appetite suppressants
- selective targeting of taste receptors to release hormones that signal feelings of FULLNESS (ie cck)
- activating taste receptors of gut L-cells to release GLP-1 for Insulin release may treat Diabetes
