Digestive Tract Flashcards
what is the first sphincter in the digestive tract?
the mouth (orbicularis oris)
how does the mouth contribute to the process of digestion?
- mechanical digestion (mastication)
- chemical digestion (saliva)
where is salvia secreted from?
salivary glands
name the salivary glands
- submandibular
- sublingual
- parotid
name the innervations for the salivary glands
- submandibular and sublingual = CN7
- parotid = CN 9
muscles of mastication are innervated by what?
CN 5
what nerves are responsible for taste?
CN 7, 9, and 10
what nerves are responsible for the somatosensory function of the tongue?
CN 5
what does the somatosensory function of the tongue include?
- touch
- tactile sensation
- pain
what is the upper esophageal sphincter?
a thickening of the proximal esophageal wall
what is the lower esophageal sphincter?
thickening of distal esophagel wall + respiratroy diaphragm crura
what is the role of the lower esophagel sphincter?
prevent backflow of stomach acid to the esophagus
name the sections of the stomach
- cardiac
- fundus
- body
- pyloric regions
muscular wall of the stomach is made up of ___ layers
- circular muscle
- longitudinal muscle
- transverse muscle
what are the ridges in the stomach muscle wall called?
rugae
what does the stomach secrete and why?
gastric juice = chemical digestion of proteins
what is the role of the pyloric sphincter?
regulate flow of chyme into small intestine
the pyloric sphincter regulates flow from the stomach into which portion of the SI?
duodenum
name the parts of the SI
- duodenum
- jejunum
- ileum
what is the role of the SI?
primary site of absorption for water and nutrients (~90% of all absorption)
what is the sphincter of Oddi?
a sphincter that controls the digestive juices from the liver and pancreas into the duodenum
role of pancreatic juice in the duodenum
- digests large molecules
- buffer the stomach acid that has entered the SI
what does the liver secrete into the duodenum?
Bile
what is the role of Bile?
digests fat globs into lipid droplets
what is the duodenal flexure?
a sudden right angle at the end of the duodenum
what is the role of the duodenal flexure?
it is associated with a suspensory muscle which allows it to change the flow from the duodenum to the jejunum
how would you describe the lumen of the SI?
modified for increased SA
- circular fold (plicae)
- projections/villi
- brush border/microvilli
what connects the SI to the LI?
ileocecal sphincter
name the sections of the LI
- cecum/appendix
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
what is the role of LI?
- last 10% of absorption of water
- bacterial digestion = absorption of vitamins and minerals
last stop of the GI after the LI?
rectum/anus
role of the rectum/anus
feces accumulation and defecation
name the sphincters at the anus/rectum
- internal anal sphincter
- external anal sphincter
differentiate between the internal/external anal sphincter
- internal = smooth muscle and involuntary
- external = pelvic diaphragm (puborectalis) - skeletal muscle so it is voluntary
the blood flow in the digestive tract can be broken down into what 2 planes?
- Anterior midline plane = 3 unpaired arteries to viscera
- lateral plane = 4 paired arteries to viscera
Name the 3 unpaired arteries that make up the anterior midline plane
- Celiac Trunk
- Superior mesenteric artery
- Inferior mesenteric artery
what does the Celiac Trunk supply blood to?
- stomach
- spleen
- pancreas
- liver
- proximal duodenum
what does the Superior Mesenteric Artery supply blood to?
- distal duodenum
- jejunum
- ileum
- cecum
- ascending colon
- 1/2 of transverse colon
what does the Inferior Mesenteric Artery supply blood to?
- 1/2 transverse colon (distal)
- descending colon
- sigmoid colon
- rectum
- proximal anus (above pectinate line)
what do all the structures supplied by the celiac, and S/I mesenteric arteries drain into?
Hepatic portal vein
What arteries are in the lateral plane?
- inferior phrenic
- suprarenal
- renal
- gonadal
what does the inferior phrenic artery supply?
inferior diaphragm
what do the suprarenal arteries supply?
adrenal glands
what do the renal arteries supply?
Kindeys
what is the hepatic portal vein?
a large venous system that drains directly into the liver
what does the liver do to blood in the hepatic portal vein?
- takes glucose out of the blood and stores it
- detoxifies the blood
T/F: the sugar removed from the blood at the liver is stored to sustain us between meals?
TRUE
how would liver disease affect venous blood flow in the hepatic portal vein?
liver BP would increase = backflow into portal system
=portal system shunts to azygous and inferior mesenteric veins
=high volumes of blood in those veins can result in hemmorrhoids
the lateral plane (paired arteries) will not drain to the hepatic portal vein. Instead they drain _______
into veins with corresponding names
these eventually drain into the inferior vena cava
describe lymph flow in the digestive tract
- lymph capillaries in cavity and organ
- lymp vessels
- lymph nodes
- cisterna chyli
- thoracic duct
- left angle between jugular and subclavian veins
what is the enteric nervous system?
the gut tube’s own endogenous nervous system
what does the enteric nervous system allow the gut tube to do?
continue to contract and secrete even after being removed from the body
what are the components of the enteric nervous system?
- submucosal plexus
- myenteric plexus
what is the role of submucosal plexus?
controls secretion from the glands in the mucosa
what is the role of myenteric plexus?
controls contraction of the circular and longitudinal muscles
What regulates the activity of the enteric nervous system?
the automonic nervous system (ANS)
how does PNS input impact the digestive tract?
increases secretion and contraction
what is the main PNS input to the digestive tract from?
CN 10
how does SNS input impact the digestive tract?
decreases contraction and secretion
describe the layers of the gut tube
- lumen surface
- muscular wall
- adventitia
- visceral peritoneum
sympathetic input to the abdominal organs come from what sources?
- chain (paravertebral) ganglia
- prevertebral ganglia (unpaired sympathetic ganglia)
what are the chain (paravertebral) ganglia?
come from lateral horns of T1-L2
extend from cervical to sacral vertebral cord bilaterally
what are the prevertebral ganglia (unpaired sympathetic ganglia)?
associated ganglia with the aorta
names fro blood vessels comming off the aorta they are close too
Name the prevertebral ganglia
- celiac
- aorticorenal
- superior mesenteric
- inferior mesenteric
what are plexi in the abdominal region?
both sympathetic and parasympathetic nerves
name the plexi in the abdominal region
- celiac plexus
- superior mesenteric plexus
- inferior mesenteric plexus
- superior hypogastric plexus
- inferior hypogastric plexus
what are splanchnic nerves?
sympathetic nerves that connect:
- spinal cord to chain ganglia
- sympathetic chain ganglia to prevertebral ganglia and plexi
name the serous membranes in the abdominal cavity
- parietal pertioneum
- viseral peritoneum
- peritoneal cavity
- retroperitoneal
how is visceral peritoneum formed?
lining of the peritoneum is folded around abdominal organs.
the base of fold binds the organ to the posterior abdominal wall and contains nerves, blood, and lymph vessels
What are the prominent peritoneal folds we need to know?
- mesentery
- mesocolon
- falciform ligament
- lesser omentum
- greater omentum
what is the mesentery?
peritonel fold that attaches small intestine to the posterior abdominal wall
what is the mesocolon?
peritoneal fold that attaches large intestine to the posterior abdominal wall
what is the falciform ligament?
peritoneal fold that attaches liver to anterior abdominal wall and diaphragm
what is the lesser omentum?
peritoneal fold that attaches stomach and duodenum to liver
what is found in the lesser omentum?
portal triad/liver hylus
what is the greater omentum?
peritoneal fold that attaches stomach, duodenum, and colon
where is there a pectinate line in the GI tract?
at the anal canal
describe sensory/innervation and blood supply superior to the pectinate line
- visceral innervations (involuntary motor, unconscious sensory)
- inferior mesenteric artery/portal venous drainage
describe sensory/innervation and blood supply inferior to the pectinate line
- somatic (voluntary motor, conscious sensory = pain) innervations
- internal illiac artery and caval venous drainage
- bypasses the portal system
Name the accessory organs in the digestive tract
- Spleen
- Pancreas
- Liver
- Gallbladder, and Bile ducts
where is the spleen located?
superior left quadrant
within the rib cage
posterior to stomach
anterior to diaphram
What is the function of the spleen?
lymphatic organ
remove/recycle old RBCs
act as blood reservoir
where is the pancreas located?
retroperitoneal
superior right and left quadrants
what is the function of the pancreas?
- endocrine organ
- exocrine organ
what is the exocrine function of the pancreas?
secretes pancreatic jucie (which contains buffer and digestive enzymes) into duodenum
how does pancreatic juice enter the duodenum?
hepatopancreatic ampulla duct
what is the endocrine function of the pancreas?
secretes insulin and glucagon into the blood
which pancreatic hormone is anabolic?
insulin
glucoagon is catabolic
how is the pancreas connected to the duodenum?
- pancreatic duct and sphincter
- accessory pancreatic duct
the main pancreatic duct is also called what?
- hepatopancreatic ampulla (of Vater)
- hepatopancreatic sphincter (of Oddi)
where is the liver located?
largest gland
second largest organ
located inthe superior R/L quadrants
what are the functions of the liver?
- Digestion
- Excretion
- glucose storage
- blood detoxification
- production/secretion of plasma proteins
- calcium homeostasis
what does the liver excrete?
- bile acid and salts
- cholesterole
- bilirubin
where is the gallbladder located?
upper R quadrant, visceral surface of liver right lobe in right sagittal fissure
gallbladder and bile duct function
store, concentrate, and convey bile from liver to duodenum
where is the anal canal located?
perineum in an triangle of the pevic diaphragm
what are the attachments of the anal canal?
- anococcygeal ligament
- central point of the perineum = peroneal body
- external sphincter is blended into the levator ani, puborectalis, of the pelvic diaphragm
