Alimentary System Overview Flashcards
What is the opening to the alimentary canal?
Mouth
What is the function of digestive system?
Digestion: to process food
Absorption: transfer of nutrients to circulation
What are the 2 groups of organs in the digestive system?
- Digestive tract
2. Accessory organs e.g. salivary glands, gallbladder, liver, pancreas
What are the components of the alimentary system?
Oral cavity -> pharynx -> oesophagus -> stomach -> small intestine -> large intestine
What are the 4 layers of the G.I. system?
- Mucosa
- Submucosa
- Muscularis externa/muscularis propria
- Adventitia
What is the mucosa layer of the G.I. system comprised of?
Epithelium, lamina propria and muscularis mucosa
What does the submucosa layer of the G.I. system contain?
Blood vessels and glands
Describe the arrangement of the muscularis externa/muscularis propria layer of the G.I. system
Inner circular layer and outer longitudinal layer
What does the adventitia layer of the G.I. system contain?
Larger/major blood vessels and nerves
What does metaplasia mean?
Going from one structure to another
Describe metaplasia in G.O.R.D (gastro-oesophageal reflex disease)
Stratified squamous epithelium changing to columnar epithelium
What might G.O.R.D lead to?
Dysplasia (pre-cancer) and cancer
The change from stratified squamous epthelium to columnar epithelium in Barret’s oesophagus is referred to as what?
Metaplasia
What do the fundic glands of the stomach do?
Secrete hydrochloric acid (HCl)
What is the purpose of villi in the small intestine?
Increase the surface area by up to 30x for absorption
Describe the features of coeliac disease
- Villous atrophy
- Hyperplastic crypts
- Increase in inflammatory cells (lymphoid cells)
- Autoimmune condition where body attacks villi
- Stop eating gluten - symptoms should be relieved, villi grow back
What is the recommended treatment for coeliac disease?
- Stop eating gluten, villi should grow back, symptoms should be relieved
What is the function of the large intestine?
Absorption and protection
What is the purpose of mucus producing cells (goblet cells) in the large intestine?
- To produce mucus
- Mucus sits on layer of epithelium to protect it from faeces
What are the 2 main types of inflammatory bowel disease?
Crohn’s disease and ulcerative colitis
Crohn’s disease can cause pain the mouth. What effect can this have on patients?
- Patients may not eat or drink properly due to pain, may not brush their teeth. Dental problems may arise.
Where are effects of UC observed?
Only in the colon
How much liquid goes into the alimentary system/how much is absorbed?
~7,600ml absorbed, 7,500ml secreted
What are the functions of the mouth?
Communication, general sensory (noiception, mechanoreception), special sensory (gustation), higher level perceptions (enjoying the taste of something)
