alimentary overview and mouth Flashcards
what are the four components of teeth?
- enamel
- dentin
- cementum
- dental pulp
what are the interchangeable names for the digestive tract?
- gastrointestinal tract
- alimentary system
what is the function of the gastrointestinal tract?
digestion (process food) and absorption (transfer nutrients into the circulation)
what are the two groups of organs in the gastrointestinal tract?
- digestive organs
- accessory organs
what are the accessory organs in the gastrointestinal tract?
salivary glands, gallbladder, liver and pancreas
what is the function of the gallbladder?
helps store and concentrate bile , produced by the liver, and helps fat digestion
what is the pharynx?
muscular tube which food and water (12-15cm)
what is the oesophagus?
muscular tube extending from the pharynx to the stomach (passes behind the heart)
where does the major portion of digestion occur?
the stomach
where is the stomach loacted?
the upper left section of the abdomen
what is the function of the stomach?
secretes acid and enzymes that start digestion
how in saliva involved in digestion?
the enzyme amylase from saliva digests in the oral cavity
what is the name of churned food and drink?
chyme
where does chyme go after the stomach?
through a sphincter or tight circular muscular structure, into the small intestine
what are the three parts of the small intestine?
duodenum, jenjunum and ileum
becomes less digestion and more absorption as you move along
what is in the duodenum?
secretions of pancreas and bile- help with fat digestion- pancreas secretions also help digestion of proteins, starch and other carbs
what does the pancreas secrete which helps maintain an alkaline pH?
bicarbonate rich fluids
what does the pancreas secrete which helps maintain an alkaline pH?
bicarbonate rich fluids
what colour does H&E stain nuclei?
blue
what colour does H&E stain cytoplasm and ECM?
pink
what is the structure of the GIT?
- mucosa
- submucosa
- muscularis propria
- adventitia/serosa
what is the function of the mucosa?
lines all the cavities of the body and surface of internal organs
what makes up the mucosa?
- epithelium
- lamina propria muscalaris mucosa
what is the muscularis mucosae made of?
smooth muscle
what does the submucosa contain?
dense irregular connective tissue and blood vessels, nerves & lymphatics
what is the muscularis propria composed of?
inner circular smooth muscle and outer longitudinal smooth muscle
what is peristalsis?
the movement of food by contraction and relaxation
what is the type of epithelium in the oral cavity, pharynx and oesophagus?
non-keratinised (prevents oesophagus from drying out) stratified squamous- protective
what is barrett’s oesophagus?
If there is continual reflux of acid from the stomach into the oesophagus, this can potentially damage the lining epithelium of the oesophagus.
This is because acid, normally located in the stomach, and controlled there, passes into the oesophagus, and should not be there. This condition of reflux is called gastro-oesophageal reflux disease and is associated with heartburn, regurgitation or indigestion. If this continues, it can cause the cells of the lower oesophagus to change to columnar.
what is metaplasia?
the change in one differentiated cell type to another
what is the change in epithelium at the gastro-oesophageal junction?
stratified squamous to simple columnar
what are the secretions of the stomach?
acid, mucous and enzymes (aid digestion)
what type of epithelium is in the small intestine?
villi simple columnar
what is the function of villi in the small intestine?
increase surface area for absorption
what is coeliac disease?
- a condition where the immune system attacks your own body tissue when you eat gluten, damaging the gut so you are unable to absorb nutrients
- it results in villous atrophy- reduce in villi, reducing the surface area available for absorption
- hyperplastic crypts (crypts are grooves between villi) is when the grooves become elongated affecting absorption
- increase in inflammatory cells
what is the purpose of the epithelium in the large intestine?
absorb water and secrete mucous
what is the function of mucous in the large intestine?
ensures that as the indigestible material passes towards the rectum and anal canal for expulsion as faeces, that the epithelium does not get damaged
what is the function of mucous in the large intestine?
ensures that as the indigestible material passes towards the rectum and anal canal for expulsion as faeces, that the epithelium does not get damaged
what is the function of vitamin K?
blood clotting
what is Crohn’s disease?
a life-long condition that results in inflammation of the lining of the digestive or alimentary system. It can occur anywhere along the gastrointestinal tract and results in inflammation and collections of granulomas or lymphoid infiltrates that are transmural or across the wall of the bowel and alimentary system
what is ulcerative colitis?
inflammation in the colon and rectum only and ulcers can develop, or break down of the epithelium. This can in turn lead to recurrent bouts of diarrhoea, abdominal pain and needing to go to the toilet frequently
what are the alimentary system activities?
secretion
digestion
motility
absorption
excretion
what does the alimentary system secrete?
- saliva
- bile
- gastric juice
- pancreatic juice
- intestinal juice
- faeces
what are the categories within digestion?
- mechanical (breakdown of particles and mixing)
- chemical (enzymes eg HCL break molecules down from complex to simple)
what are the different motility processes in the alimentary system?
- chewing
- swallowing
- churning
- peristalsis
- defaecation
what are the sensory functions of the mouth?
general
- nociception
- mechanoreception
- thermoreception
special
- gustation
what are the motor functions of the mouth?
feeding and communication
what are the jaw muscles of the mouth?
- temporalis
- masseter
what is the facial muscle of the mouth?
- orbicularis oris
- buccinator
what are the salivary glands?
- paratoid (serous)
- submandibular (seromucinous)
- sublingual (mucinous)
what are the exocrine secretions of the mouth?
salt and water
mucous
amylase
what are the exocrine secretions of the mouth?
salt and water
mucous
amylase
what are clinical problems surrounding the salivary glands?
- mumps (enlarged parotid gland0
- sialolithiases (salivary gland stones)
- sialodenitis (inflammation of salivary glands)
- tumours eg parotid (facial nerve)
