lecture 6- disorders Flashcards
Disorders affecting the oral cavity and swallowing
Xerostomia and Dysohagia
Two reflexes that lead to an increase of salivation
Conditioned reflex and Simple reflex
Xerostomia (oral- dry mouth) causes-
caused by anxiety, Sjogren’s syndrome, damage to salivary glands, cancer treatment, dehydration, medications (can be treated)
Dysophagia (swallowing)
reduced laryngeal closure> aspiration. disruption in the swallowing process, problem can occur at any 3 stages of swallowing.
Neuorological conditions and dysphagia
stroke (most common) traumatic brain injury, cerebral palsy, Parkinson disease and other degenerative neurological disorders
disorders affecting the oesophagus and stomach
reflux (heartburn), peptic ulcers, gastritis
Upper sphincter
neurally induced tonic contraction= Pharyngo-oesophageal keeps air out
Lower sphincter
myogenic activity= Gastro-esophageal keeps out stomach contents
Primary peristalsis
preceded by pharyngeal phase, controlled by the swallowing centre and vagus
Secondary peristalsis
If food is stuck, pressure receptors trigger intrinsic nerve plexus leading to a stronger force (not sensed)
how does reflux oesophagi tis (heartburn) occur?
inflamed oesophagus, acid reflux, relaxed lower oesophageal sphincter
Exocrine secretions
Parietal cells: HCI, intrinsic factor, Chief cells: pepsinogen, Mucous cells: mucus
Endocrine/paracrine secretions
G cells: gastrin, D cells: somatostatin, ECL cells: histamine
Helicobacter pylori
reside in mucus layer, settle in antrum, produce urease
H. Pylori contribute to peptic ulcer formation by:
secreting toxins that cause persistent inflammation (gastritis) at the site of infection. Disrupting the tight junctions between epithelial cells, allowing acid to penetrate
Disorders affecting the biliary system
Biliary obstruction
biliary system
made up of the liver and gall bladder. liver produces bile which is released into small intestine during meals
Terminal ileum
95% of bile salts are reabsorbed by terminal ileum
Biliary obstruction
blockage of any duct that carries bile from liver or gallbladder to S.I. most common cause is choleliths (gallstones)
Disorders affecting the S.I
Gluten intolerance (Celiac disease)
Celiac disease
T-cell mediated inflammatory response upon ingestion of gluten causing destruction of villi. If villi and microvilli are damaged> decreased surface area of S.I > indiscriminate impairment of nutrient absorption
Disorders affecting the L.I (also known as Colon)
Inflammatory bowel disease
L.I mixing=
haustral contractions, controlled by ICCs and locally mediated reflexes in response to distension
L.I propulsion=
mass movements, controlled by the gastrocolic reflex (food in stomach releases gastrin)
Rectal distension> defecation reflex
internal sphincter relaxes, sensation of urge, voluntary relaxation of external sphincter
Absorption and secretion
Imbalance between secretion and absorption leads to diarrhoea or constipation (because of altered motility, infection, osmotic drag, or L.i inflammation)
Inflammatory bowel disease (IBD)
Ulcerative colitis
