GI Tract I & II Flashcards
what is the digestive system made of?
alimentary canal and associated organs (tongue.. teeth etc.)
what does the sulcus terminalis do?
divides the tongue into anterior 2/3 and posterior 1/3
what do extrinsic tongue muscles do?
attach tongue to other structures
move the entire tongue
what do the intrinsic tongue muscles do?
alters the shape of the tongue
good for speech and swallowing
what are the 4 types of lingual papillae?
filliform, fungiform, circumvallate, foliate
what are the 3 types of cells found in taste buds?
neuroepithelial cells, supporting cells, basal cells
which stimuli use G protein coupled chemosensory receptors with IP3?
bitter, sweet and umami
which stimuli use H+ protons as receptors?
sour
which stimuli use Na+ ions as receptors?
salt
what makes up the mucosa?
epithelium, lamina propria, muscularis mucosae
what does the lamina propria usually contain?
loose CT
blood and lymph vessels
mucosal glands
GALT
what does the muscularis mucosae usually have?
2 layers
inner = circular
outer = longitudinal
what is found usually in the submucosa?
dense irregular CT
large blood and lymphatic vessels
sometimes glands
submucosal plexus = Meissner’s plexus
what does Meissner’s plexus innervate? where is it found?
muscularis mucosae = innervation
submucosa = location
what are the 4 layers that make up the alimentary canal?
mucosa, submucosa, muscularis externa, serosa/adventitia
whats usually in the muscularis externa layer?
inner layer = circular = forms sphincters
outer layer = longitudinal
myenteric plexus = Auerbach’s plexus
where is Auerbach’s plexus found? What does it innervate?
found in between circular and longitudinal layer of muscularis externa and it innervated the muscularis externa for peristalsis
Where is serosa commonly found?
mesothelium
what parts of the GI tract do NOT have a serosa but DO have adventitia?
esophagus (thoracic)
2nd, 3rd, 4th part of duodenum
asending and descending colon
rectum and anal canal
what is special about the submucosa of the esophagus?
esophageal glands proper is there = slightly acidic mucous to lub. lumen - can ID huge duct
whats special about the esophagus mucosa?
it has esophageal cardiac glands that produce neutral mucous to protect regurg of gastric juices
what is special about the musclaris externa of the esophagus?
upper 1/3 is straited
middle 1/3 is both smootha nd striated
lower 1/3 is smooth
what is a distinguishing feature of the duodenum?
submucosal gland = Brunner’s glands - secrete a highly alkaline msolution to neutralize acidic chyme coming from stomach
whats a distinguishing feature of the jejunum?
many plicae circulars
long prominent villi
increase in amount of goblet cells
NO submucosal GLANDS
What is a distinguishing feature of the ileum?
aggregated nodules of lymphatic tissue in lamina propria of mucosa
peyer’s patches- very many in ileum
what are the distinctive features of the Large intestine?
TC, HC, OM
what is different about the mucosa of the large intestine?
its smooth - no villi, no plicae circularis
what is a distinguishing feature of the appendix?
numerous lymphatic nodules that extend into submucosa
does the rectum have serosa or adventitia?
adventitia
what are the 3 zones of the anal canal?
colorectal zone (CRZ) - simple columbar epi anal transition zone (ATZ) - transition epi squamous zone (SQZ) - stratified squamous epi
How are amino acids absorbed?
Secondary active transport
Majority are Na+ dependent
How are carbohydrates absorbed?
SGLT -1 transporter - secondary active transport , Na dependent
GLUT transporter - facilitated transport
How are lipids absorbed?
Diffusion
what lingual papillae has highly keratinized stratified squamous epithelium, has no taste buds and works to grip food?
filliform - looks like a flame
where are fungiform found and where are their taste buds located?
tip of the tongue taste buds (if any) on dorsal surface
which lingual papillae has von ebners glands?
circumvallate - has moat like invaginations, largest
where are circumvallates located?
just anterior to sulcus terminalis
what are the characteristics of cardiac glands? - pits, glands, cells
short pits short glands
enteroendocrine and mucous secreting cells
what are the characteristics of pyloric glands? - pits, glands, cells
long pits, short glands
enteroendocrine, mucous secreting and parietal
what are the characteristics of the fundic glands - pits, glands, cells
short pit, long gland mucous neck cells enteroendocrine cells parietal chief stem
what is an intestinal gland?
crypts of leiberkauhn
what do enterocytes do?
absorption
simple columnar - Mv, tight junctions, lateral plications
secretory - dig enzymes, water, electrolytes
what do paneth cells do?
antimicrobial secretions
what do M cells do?
cover large lymph nodules, antigen transporting cells
what are the components of gastric juice?
HCL, pepsin, mucous and intrinsic factor
