Gut Function (I) Flashcards
What does motility mean
Mechanical breakdown of food
What is peristalsis
Controlled movement after motility
If motility is mechanical breakdown, what is digestion
Chemical breakdown eg via enzymes
Which area does no absorption take place
Oral cavity
What secretions are there by oral cavity
Saliva and lipase
What gets digested in oral cavity
Carbs and fats
What motility properties does stomach have
Propulsion and then peristalsis
What gets digested in stomach
Proteins and fats
What are the only things which get absorbed in stomach
Lipid soluble eg alcohol
How is gut regulated (3 ways)
Neural (ANS via vagus and enteric nervous system)
Hormonal
Local eg histamine paracrine
Name the 3 stages of regulation
Cephalic - sense, taste and sight of food
Gastric - stomach
Intestinal - intestines
Which digestive enzymes/proteins are there in saliva
Amylase for starch
R proteins (bind vitamin B12)
Which 2 things are in saliva for anti bacterial protection
Lysozymes and IG
What are the 3 salivary glands releasing saliva with secretions
Parotid
Sublingual and submandibular
Minor glands
What do parotid glands secrete
Amylase and serous in saliva
What do sublingual and submandibular secrete
Serous and mucous
Which 2 antibacterial GP do minor glands secrete
Mucins 5B and 7
Which cells secrete the primary secretion from salivary glands containing NA,K,CL,HCO
Epithelial acinar cells (from acinus)
What tonic position does primary secretion from acinar cells have
Isotonic
Which cells allow for secretion to become hypotonic (impermeable to water) and how
Duct cells
They reabsorb Cl and Na
More HCO and K is secreted in
Which 2 CN in the PNS system cause increase saliva release
VII (facial) and IX (glosso)
What is SNS saliva containing even if small saliva vol
Enzymes and mucous
What is gastric emptying called
Chyme
Which part of stomach is bacteriocidal
Pepsin
What are the 2 sphincter muscles on stomach
Cardiac sphincter (top)
Pyloric sphincter (bottom)
What is the middle part of stomach called compared to bottom of it
Body
Bottom part is antrum
What increases sa of stomach
Rugae : Folding in epithelium
Which 2 parts of stomach attach to enteric nervous system for control
Myenteric and submucosal plexus
What covers the epithelium for protection from acid
Mucus and HCO
What are folds in epithelium called
Gastric pits
Which cells in the epithelium mucosa / gastric pits causes protection from acid and how
Mucous neck cells and surface cells
They release HCO and mucous layer for protection
What is mucous release by mucous neck cells and surface upregulated by
Irritants
Which cells release HCL gastric acid and intrinsic factor
Parietal cells
When do parietal cells release gastric acid and intrinsic factor
Gastrin released from G cells
Histamine from ECL cells (up regulates H/K pump)
Ach release via vagus and enteric neurones
What does gastric acid secrete
Pepsin which is bacteriocidal and breaks down proteins
What is intrinsic factor for
Complexes with B12 for absorption
Where in the stomach are ECL cells which release histamine for gastric acid secretion
Body
Which cells produce pepsin directly from pepsinogen and secrete gastric lipase for protein and fat digestion
Chief cells/ peptic cells
Which 2 things stimulates chief cells
Ach
Secretin
Gastric acid from parietal cells
Which substance from D cells inhibits gastric acid secretion NF via inhibiting ECL cells
Somatostatin
Other than ECL and Ach from vagus what allows gastric acid secretion from parietal cells
G cells release of gastrin
How does gastrin effect ECL cells
Stimulated them to release histamine which then allows HCL release
When is gastrin secreted
Presence of AA and peptides and ach
Where in the stomach do parietal cells secrete HCL
Body
Which substance from breakdown of carbonic acid allows Cl to pass through parietal cells to apical side to be secreted
HCO
HCO / Cl exchanger on baso lateral side
What system allows H to be pumped out alongside a Cl channel on apical side (from the HCO/Cl exchanger)
H/K ATPase
Stimulated via histamine ECL release
Which cells do ach down vagus stimulate
G cells, ECL cells, parietal cells (all for gastric acid release)
Which cells are inhibited via ach down vagus
D cells which secrete somatostatin to reduce acid via inhibiting ECL
