Gut L3 Flashcards
how much water is taken into the body per day
2L
HOW MUCH SALIVA IS FORMED IN A DAY
1.5L
HOW MUCH GASTRIC ACID IS FORMED PER DAY
1.5L
how much pancreatic juices are formed per day
1.5L
how much bile is formed per day
0.5L
how much intestinal secretions is formed per day
1.5L
how much water is absorbed by the colon per day
0.4L
how much water is absorbed by the s.int per day
8.5L
how much water is excreted per day
0.1L
what happens in the cephalic phase
when is it initiated
what is the purpose
give an example
- initiated when receptors in the head (cephalic) are stimulated by though, sight, smell and taste of food
- involves PARASYMPATHETIC NS (preganglionic fibres in vagus nerve)
- prepares body for the influx of food
- stimulates SALIVA, GASTRIC ACID production
- causes GALLBLADDER contraction
- secretion of INSULIN
- eg Pavlovs dogs
what is the importance of the cephalic phase
feed forward mechanism
saliva contains what?
saliva production is triggered by what
what are the 2 phases of
- mucus, enzymes, lipase and amylase
- CONDITIONED reflex, triggered by the PARASYMPATHETIC NS
- BUCCAL/oesophagal phase: food in mouth and swallowing
- GASTRIC phase: irritating food in stomach causing excess salivation and nausea and vomiting
what are the 3 glands that produce saliva and what % of saliva do they produce
SUBMANDIBULAR gland-70%
PARTOID gland- 20%
SUBLINGUAL gland- 5%
acid is released from what
- from PARIETAL cells
- stim by :
- Ach
- local HISTAMINE production
- circulating GASTRIN (hormone) from G cells
amount of acid produced is proportional to what
the amount of ligands that bind
what is the mechanism for HCl secretion
H+ and Cl- separately secreted
- H+ secreted by proton pump
how can gastric acid secretion be dec
1) proton pump inhibitor (O protons can’t enter lumen)
2) histamine receptor drug (removes Histamine as a stimulus for producing HCl, less effective)
para NS connects with whar
submucosal plexus
what is phase 2
gastric phase
once food is eaten
what happens in the gastric phase
- long (3-4 hours)
- stim by: distension in somach, chemoreceptors detect pH changes
- secretion of HCl, pepsinogen, intrinsic factor
- production of MUCUS-BICARBONATE layer (protect stomach from acid)
gastritis is what?
what is it a risk factor for
- inflammation of the lining of the stomach
- inc risk of cancer
what is the role of the bicarbonate in the stomach
- acts as a buffer, titrate protons that get too close to the mucus layer H+ + HCO3—> H2CO3–> CO2 + H2O
- H2O produced O makes the mucus more fluid
how thick is the mucus layer
what is it composed of
what is release stimulated by
- 2mm thick
- 80% CHO, 20% protein
- release stim by ACh from nerve endings
- rich in bicarbonate
what is the purpose of HCO3- in the mucus layer
what is HCO3- inhibited by
- creates micro env around surface cells to prevent damage
- inhibited ADRRENERGIC INPUT (stress)