Lecture 24 EXAM 4 Flashcards
what are the functions of the digestive system?
- mechanical processing
- chewing (mastication)
- churning by stomach
- segmentation in the SI - chemical breakdown: sugar/lipid/protein
- secretion of acids/enzymes/buffers
- GI tract
- accessory organs: pancreas, liver - absorption across gut epithelium into blood vessels
- nutrients electrolytes, vitamins and water - dehydration, compaction, and excretion
- dehydration/compaction of indigestible gut contents
- elimination of waste from body (defecation)
- waste products to be defecated = feces
what are the 2 groupings of organs?
- Gut = alimentary canal = GI tract
- muscular tube extending from mouth to anus
- extensive series of diverticulae - accessory organs/structures
- tongue, teeth, liver/gallbladder, pancreas
- salivary, gastric, and intestinal glands
what are the diffrent names for the gut?
gastrointestinal tract
alimentary canal
what makes up the foregut?
celiac truck
- mouth and duodenum
what makes up the mid gut?
superior mesenteric
jejunum and ileum
what makes up the hindgut?
inferior mesenteric
- colon and rectum
what epithelium is on the lips and cheek?
stratified squamous epithelium
what keeps food in your mouth while chewing?
CN VII (facial nerve?)
what stabilizes the lips?
labial frenulum
what is Gingiva?
mucosa covering alveolar bone/hard palate
what are the 3 salivary glands?
- parotid : drained by the parotid duct
- submandibular - drained by the submandibular duct
- sublingual - drained by sublingual duct
what are the functions of saliva?
cleanses teeth, moistens food
- contains enzyme amylase: breaks down starch
what are the intrinsic muscles that are very complicated called?
muscular hydrostat
what is the tongue anchored to? stabilized by?
hyoid and jaw
stabilized by lingual frenulum
what is it called when the tongue is too tightly bound to the floor of the mouth?
ankyloglossia
what is the soft palate?
muscular flap (continuation of the hard palate)
What makes up the hard palate?
palatine and maxilla
define them: microglossa - macroglossia - ankyloglossia - Frenulae redux - hairy tongue - **
microglossa - small tongue
macroglossia - large tongue
ankyloglossia - tongue tied (anchored tongue)
Frenulae redux - affects the fenulae (overgrowth)
hairy tongue - hypertrophy of FILIFORM PAPILLAE ** (smoking, dry mouth, poor oral hygiene
what are the 3 types of the teeth?
- enamel
- hardest substance in the body (calcium phosphate) - dentin
- not as hard
- forms roots and encloses pulp cavity - cementum
- cements tooth in socket
what is the pulp cavity? root canal?
hollow area in tooth
- contains blood vessels and nerve
root canal = narrow tunnel through each root
what are the 4 types of teeth and how many of each?
incisors (8) 1 root blade like cusp
Cuspids (canine) (4) 1 root conical pointed cusp
bicuspid (8) 1-2 roots blade like cusps
molars (8-12) 3-4 roots, large flattened crown
what are the 2 generations of teeth?
- deciduous teeth (milk/baby teeth (20 teeth)
- erupt @ 6 months to 2 years (no bicuspids) - adult teeth (non deciduous) (28 -32 teeth)
- erupt @ 6-21 years
the gut has 4 tunics what are they? innermost to superficial?
- mucosa
- submucosa
- muscularis
- serosa
what is the apperance of the mucosa epithelium? and its fuction?
- mucosal epithelium = mucous membrane
- secretes mucus to protect lining of gut
- pleated appearance (plicae circularis or rugae)
lamina propria (CT) supports overlying epithelium
what layer of the gut has exocrine glands?
submucosa
enzyme secretion = digests food
what layer of the gut is the meissners plexus of ANS fibers associated with?
Submucosa
what does the meisser’s plexus do?
controls the secretion of the submucosal gland
what layer of the gut is highly vascularized?
submucosa
= absorption of nutrients from food
what is the muscularis layer of the gut used for?
2 muscle layers = peristalsis
what muscle does the inner layer of the muscular tunic have?
inner layer: circular muscles
= decreases diameter better then increase in length
what muscle does the outer layer of the muscular tunic have?
outside layer: longitude muscles
- decreases tube length better than increases diameter
What layer is the myenteric plexus of ANS fibers associated with? what does it do?
Muscularis layer
- controls the peristalsis/ segmentation of chyme
what serous membrane is associated with the serosa layer of the gut?
outermost layer (serous membrane) - visceral peritoneum
where does the esophagus extend from?
extends from pharynx to the stomach though the diaphragm
describe the structure of the esophagus?
collapsible muscular tube (2 muscle layer)
What are the 4 regions of the stomach?
cardia: entrance to the stomach (cardiac sphincter)
fundus: domed portion
body: greater and lesser curvature
pyloric: pyloric sphincter
How many layers does the stomach have and name them?
- outer layer
- inner layer
- oblique layer
what are variety of cell types that are produced in the stomach?
gastric juices: HCL, pepsinogen/pepsin and rennin (breakdown food)
mucous: protects walls from gastric juices
what are some things that can happen to the stomach if there is something wrong?
gastic ulcers,
GERD - lower esophageal sphincter
diaphragmatic hernia - hole in diaphragm?
is the small intestine mucosa more elaborate then gastric mucosa?
Yes
what is the rugae in the small intestine called?
plicae circularis = increase surface area
the pliquae are ormented where?
within the villi = increase surface area
what is the epithelium in the SI?
columnar epithelium
microvilli = increase surface area
how long is the SI?
15 - 25’ long
what are the 3 segments of the SI?
duodenum (8-12’)
- submucosal glands produce mucus and buffers
- heptopancreatic sphincter and absorption
jejunum (7-9’) (majority of digestion and absorption
Ileum (8-14’) final digestion and absorption, GALT
what are the 5 sections of LI?
cecum - chyme enters cecum @ ileocecal valve ascending right colon (10-16') transverse middle colon (10-16') descending left colon (10-16') sigmoid (8-16")
what is the purpose of the Large intestine?
dehydration/compaction of chyme > feces
what are the 3 flexures of the LI?
hepatic flexure (right ) - under liver splenic flexure (left) - under spleen sigmoid flexure: s shaped bent to pass down into pelvis
what are the pouches formed by the colon muscle?
haustra
what are the 3 longitudinal ribbons of muscle?
taenia coli
what are the differences between the diverticulosis, diverticula, diverticulitis?
diverticulosis - are the presence of fluid inside
diverticula - out pocketing of colon wall (has blood vessels)
diverticulitis - are when diverticulosis becomes infected
what does the appendix do?
blind pocket - minor lymphoid function
- helps form Ileocecal valve
what are the fatty associated stuff on outside of colon?
epiplotic appendages
what is considered highly muscular termination of the spinal cord?
rectum
- (6-8’)
the rectum is what resistant?
abrasion resistant
- epithelium keratinized
what is the muscular valve at the terminus of rectum?
anus
internal - ANS involuntary
external - voluntary
- the external wraps around the internal
what is a ileostomy/colostomy?
resection of a portion of the gut
proximal end attaches to a surgical stoma (mouth) in the body wall
who is at risk for hemrroids?
- women @ the end of pregnacy
- body builders
what is the largest organ in the body/ large blood reservoir?
Liver
- right left lobes
quadrate and caudate lobes
what are the functions of the liver?
- metabolize carbs, lipids and AA
- stores vitamins and minerals
- detoxify/remove wastes products (ammonia and urea)
- inactive/removes various drugs and hormones
- produce bile = emulsifies lipids
where is the hepatic artery, hepatic vein and hepatic portal system going?
- hepatic artery - (from celiac trunk)
- hepatic vein - (return to IVC)
- hepatic portal vein
what does the gall bladder do?
stores excess bile
- hollow thin muscular sac (Cyst)
- simple structure: fundus, body, neck
what is cholecystitis? Cholelithiasis?
cholecystitis - inflammation of the gallbladder
Cholelithiasis - presence of gallstones in the gallbladder
what is Cirrhosis?
or hepatitis? destruction of hepatocytes due to: - drugs - viral infection - blockage of hepatic ducts
what is the hepatic portal hypertension?
blood cannot drain via the HPV so it finds alternate routes
- protocaval anastomses**
what is the structure of the pancreas?
elongated organ with lumpy and granular texture
- located between the duodenum and stomach
what are some endocrine secretions of the pancreas?
1%
glucagon: raises glucose levels in the blood
insulin: lowers blood glucose levels
what are some of the exocrine secretions of the pancreas?
(enzymes) : 99%
proteinases : degrade proteins
Lipases: degrade protein
nucleases : degrade DNA and RNA
where does the endocrine secretions go after the pancreas?
hepatic portal system
where does the exocrine secretions go after the pancreas?
pancreatic duct and the duodenum
what does mesenteries do?
- suspends Gi tract from the walls of the cavity
- supports/protect NAVL associated with the gut
- regional/segmental terminology
(durable DOUBLE LAYER of serous membrane)
what are some of the developments associated with the gut?
- mesentery sheets are found anterior and posterior
- entire gut suspended freely within cavity
- organization complicated by elongation of GI tract
what does the mesentary proper do?
encloses the jejunum and ileum
- duodenum : secondary retroperitioneal
what does the mesocolon do?
suspends transverse and sigmoid colon
what does the lesser omentum do?
between stomach and liver
what does the greater omentum do?
(mesogaster)
extends from greater curvature of stomach
- fat storage and locatlization of infection
What does the coronary ligament do?
suspends liver from diaphram
what does the falciform ligament do?
between liver and abdominal wall
- contains ligamentum venosum
what are the retroperitoneal organs
not enclosed within the peritoneal cavity, pushed up against back body wall
- urogenital organs, aorta, vena cava (organs you don’t want moving)
what are the 2nd retroperitoneal organs?
was once enclosed in peritoneal cavity, pushed posterior during development
- duodendum, pancreas, ascending colon, descending colon
what are the peritoneal organs?
enclosed within peritoneal cavity
- stomach, liver, ileum jejunum, transverse colon
