Ageing Gastrointestinal System Flashcards
What are the functions of the gastrointestinal tract (GI)?
Ingestion Secretion Mixing and Propulsion Digestion Absorption Defecation
What age related decines occur within the GI tract?
Slightly reduced smooth muscle tone and motility
Reduced neuroendocrine control and secretary activity
In regards to general ageing and digestion, what are most age related changes associated with?
diseases such as cancer or diabetes
atrophic gastritis and helicobacter pylori infections
poor nutrition (vitamin D deficiency affecting Ca absorption)
What GI tract problems are more common in the elderly?
Dysphagia (difficulty swallowing), diarrhoea, constipation
Gum disease, reduced immunity
Altered drug metabolism in the GI tract and liver
What is Dysphagia?
Swallowing difficulty
What regulates mouth, tongue and throat movements?
Peripheral motor neurons
What is peristalsis?
The spontaneous pacemaker activity and autonomic nervous
system reflexes regulate GI tract motility
What is the role of parasympathetic nerves in digestion?
Promote motility via Acetylcholine
What is the role of sympathetic nerves in digestion?
Inhibit motility via adrenaline and noradrenaline
What is the location of enteric neurons and how many are there approximately?
100 million neurons and runs the entire length of the gut
What are the sub sytems of the enteric nervous system?
Sub-mucosal plexuse
Myenteric plexuse
What is another name for the sub-mucosal
Meissners plexus
What is the role of the sub mucosal sub system in the enteric nervous system?
Sensory neurons respond to distension / stretch, pain,
acidity and nutrients
Motor neurons regulate muscularis mucosa contraction, vasoconstriction and secretions
What is an alternate name for the myenteric plexus?
Auerbach’s plexus
What is the main roll of the myenteric plexus?
regulates the frequency and strength of gastrointestinal contractions via several methods
What neurons and NTs are involved in myenteric plexus activities
(+) and (-) refer to increased of decreased action
Enteric neurons: 5HT +,
histamine +, opiates -
parasympathetic postganglion neurons: Musc ACh +
sympathetic postganglionic neurons: Adrenergic -
What ganglia acts on the enteric system and what NT is used?
parasympathetic ganglia: nicotinic ACh +
What is the average volume of secretions that are added to the GI tract daily?
7000ml
150ml excreted
What glands secrete saliva?
Parotid
Submandibular
Sublingual
Buccal
What molecules are found in saliva?
alkaline bicarbonate
mucous
amyalse
lysozyme
What are related changes occur in relation to saliva excretion?
Volume saliva decreases but concentrations remain the same
What neurological conditions are associated with decreased saliva volume?
Stroke
Myasthenia gravis, Parkinsons disease
Alzheimer’s disease
What are phases of swallowing?
Buccal phase
Pharyngeal phase
Esophageal phase
What are the two types of contractions in the intestines?
Peristaltic (directional)
Segmental (localised)
What is one age related change that occurs during ageing?
constipation, mainly effects older women
What hormones cause gastric contraction?
Gastrin
Histamine
What regulates motility and acid secretion?
Pavlov reaction
Neural reflexes and gastrin / histamine release
Hormone feedback
How do gastrosecretions and general changes occur during ageing?
Significantly less HCO3 is secreted
Peptic ulcer disease
is increased
How are gastric pit secretions changed during ageing
Normal ageing shoud not effect acid secretions
What is the purpose of intrinsic factor and how is it effected by age?
Assists in vitamin B12 absorption abd should not be effected by age
What stomach disease is more common in the elderly and what is the the mechanism?
Atrophic gastritis
Reduces HCl, pepsin and intrinsic factor secretion due cell loss
How does ageing effect pancreas secretions?
Ageing has minor effects on secretions but type 2 diabetes is more prevalent
What is the purpose of gastric inhibitory peptide?
inhibits gastrin release when chyme has left the stomach
How does ageing effect nutrient absorption?
May slow down but does not change effectiveness
What is the cause of Megaloblastic anemia?
Vitamin B12 deficiency
What is the cause of a peptic ulcer?
Helicobactor pylori infection of gastric mucosae
Non-steroidal anti-inflammatory drugs (aspirin)
Hypersecretion of HCL
Questions
Provide examples to support the following statement: most age-related
changes the gastrointestinal tract are associated with disease, infections
and poor nutrition
Describe ageing related changes that affect the gastrointestinal tract
