Digestive system Flashcards
What type of mucosa does the oral cavity have?
- what type of epithilia is it made up of
- mucosa and submucosa
- non kertainized simple sqamous epithelium
what are the types of papillae on the tongue (4)
- Filaform
- fungiform (mushroom shaped)
- foliate
- Circimvallate (vallate)
Which of these contain taste buds which have the most taste buds
- all except filaform ( mechanical-highly keratinized)
- Vallate has the most ( many sensory nerve)
- what role does saliva have in the papillae
- how does the saliva get to the taste buds? what does it prevent?
- have chemicals that provide taste
- through invaginations that are continuously flushed by new saliva to prevent the proliferation of bacteria
What are the glands are responsible for the continuous flushing of the tastebud invaginations
ebners gland- minor salivary glands that only produce serous fluid
how does ebners gland compare to other salivary glands
- they are serous glands
what are the layers of the digestive tract ( interior to exterior)
- mucosa
- submucosa
- muscularis externa
- adventitia
- mesentary
what are the charecteristics of the mucosa(4)
adjacent to the lumen
- consists of an epithelial lining
- underlying lamina propia
- muscularis mucosae separating mucosa from submucosa
what are the charecteristics of the submucosa (2)
- made of hight distensible CT
- contain meisner plexus»_space; Autonomic nerves» helps with blood flow
what are the characteristics of the muscularis externa (3)
- smooth muscle oriented in different directions
- inner-circular and outer longitudinal layer facilitates the movement of food
- myenteric (Auerbach) plexus»_space; ANS
what are the characteristics of the adventia
what is the funciton
Where is it present ? What does it turn into?
- secures organs to the surrounding tissues
- located where the tract is not covered by a cavity ( mesothelium)
- only loose Ct
- converts to serosa in the abdominal cavity ( mesothelium + loose CT)
what is the serosa how is different than adventita(2)
- lined by mesothelium that is continous along the mesentaries
- mesentaries are continuous with the perotinium
what are the charecteristics of the mesentary (4
What is the function
- not technically a layer of the GI tract
- attaches digestive organs to the posterior wall of the abdomen
- the double layer of the peotineum
- organs with this layer are intraperitoneal (most organs) and those without are retroperitoneal
what is the perotineum
- sac that contains some of the digestive organs
Where is the esophogus located
- what is it not lined by and why
- in the thorasic cavity NOT in the abdominal cavity
- not lined by the perotinium bc not in the abdominal cavity
what is lined by in thorasic vs abdominal cavity
- in the thoracic lined by adventia in the abdominal by serosa
how many sections is the esophogus made up of what is included in these sections? what type of control is it under
Upper ⅓: Skeletal muscle
Middle ⅓: Skeletal and smooth muscle
Lower ⅓: Smooth muscle
- involuntary
what type of epithelial lining makes up the esophogus
- nonkertanized stratified squamous epithelium in the upper and middle third (most of the esophogus)
- simple columnar in the lower third to the anal canal ( where the esophogus connects to the stomach)
what does the mucosa of the digestive system include
-epitheliul lining
- lamina propia
- muscularis mucosa»_space; seperates muscosa from submucosa
what glands does the lamina propia in the mucosa of the esophogus contain
- many different glands - cardiac glands
which layers of the esophogus contain vascularization
- lamina propia ( mucosa)
- submucosa
how do submucosal glands compare to mucosal
theyre larger
what is responsible for the inervation of the esophogus and where is it located?
- what does it regulate
- meisner plexus, submucosa
- blood flow and secretions from the glands
what is the system of the digestive system
enteric system
What are the subsections of the innervation of the digestive tract.
- what are their locations and functions
- Myenteric plexus between inner and outer layers of smooth muscle in the muscularis externa and regulates smooth muscle contraction
- Meissner plexus in the submucosa and regulates glandular secretion and blood flow
how are the parasympathetic and sympathetic NS asscociated with the digestive tract
- Parasympathetic nerve fibers activate physiologic digestive process
- Sympathetic nerve fibers are mainly inhibitory of digestive processes
What is the function of the stomach and what type of epithelium lines it
- primary site of digestion of nutrients
- simple columnar
what are the 4 reigons of the stomach?
- fondus
- cardia
- body
- pylorus
what are the folds in the stomach called and what mucosa do they contain
- what happens to them as the stomach expands
- rugae- mucosa and submucosa
- flatten as stomach expands
what are the shallow invaginations of stomach?
- what type of mucosa is present
- what do they secrete
what is the function of the secretion
- gastric pits with tubular gastric glands
- contain surface mucous cells
- highly alkaline carbonate and mucous
- preotect lining from low ph of stomach / neutralize low ph
what do the glands of the stomach secrete where do these glands pass through?
- mucus , acid , digestive enzymes
- extend into the muscularis mucosa so pass through entire lamina propia
where are cardiac glands located and what is the function
- esophogeal orifice
- mucus secreting
where are the gastric glands what is the functions
- body and fundus
- most developed and most numerous
- mixed secretions of mucus, acid, enzymes
where are the pyloric glands what is the function
- pyloric area close to the duodenum
- mostly mucus secreting
what are the 5 cell types of the gastric glands
- Surface mucosa
- mucosa neck cells
- parietal cells
- chief cells
- G cells
what is the function of the surface mucosa
Secrete alkaline fluid (carbonate) to protect epithelium
what is the function of mucous neck cells
- what is their life span what are they replaced by
- Secretes acid (HCl) to reduce pH of stomach
- Live and die quickly, replaced by stem cells that migrate to the neck of the gland from the base of the pit
what is the function of the parietal cells
- Secretes intrinsic factor and HCl
- Have receptors for gastrin
- Controlled by ANS
what happens if parietal cells are damaged
No secretion of intrinsic factor = no absorption of vitamin B12 = subacute combined degeneration