Week 10 Flashcards
what is ingestion?
ingestion is the entry of food into the alimentary canal/gastrointestinal tract through the mouth.
what is movement?
the muscular contractions that push food and liquid through the gi tract from the mouth to the anus.
what is secretion?
secretion is the process by which cells release substances that aid in digestion into the lumen of the gastrointestinal tract.
what is digestion?
digestion is the process by which food is broken down into smaller molecules that can be absorbed and used by the body
what is absorption?
the process by which nutrients, water, and other substances that have been broken down during digestion are taken up from the gi tract into the bloodstream or lymphatic system
what is defecation?
the final step in digestion, indigested materials are removed from the body as feces
what are the 4 layers of the gastrointestinal tract?
mucosa, submucosa, muscularis, and serosa/adventitia
describe the mucosa…
structure:
- epithelium
- lamina propria
- muscularis mucosae
function:
absorption of nutrients and secretion of mucus, enzymes, and hormones
describe the submucosa…
structure:
connective tissue that contains large blood vessels, lymphatic vessels, and nerves: the submucosal plexus
function: supples the mucosa with nutrients through blood vessels
describe the muscularis…
structure:
inner circular layer and outer longitudinal layer
also has the myenteric plexus located between the layers.
function: responsible for peristalsis/moving food through the gi tract
describe the serosa/adventitia…
structure:
the serosa consists of a thin layer of connective tissue covered by simple squamous epithelium.
function: reduces friction between gi tract and surrounding organs by secreting serous fluid and anchors the gi tract to surrounding structures.
distinguish between serosa and adventitia layers of the gastrointestinal wall…
serosa is found in parts of the gi tract that are within the peritoneal cavity: stomach, small and parts of large intestine.
adventitia is found in parts of the gi tract that are outside of the peritoneal cavity such as esophagus and some parts of the large intestine.
what is the greater omentum?
the greater omentum is at the bottom part of the stomach it is a large fatty fold of peritoneum that covers the abdominal organs
what is the lesser omentum?
the lesser omentum is a smaller fold of peritoneum compared to the greater omentum. it is on the top part of the stomach.
what is the falciform ligament?
divides the liver into left and right lobes
what is the mesentery?
attaches the intestine to the posterior wall of the abdomen
what is the mesocolon?
attaches the colon to the posterior abdominal wall
what are the structures that form the roof, floor, and sides of the buccal cavity?
roof: hard palate and soft palate.
floor: mandible, tongue, muscles that move it
sides of cavity: cheeks which are formed by muscles
what is the location of the uvula in the buccal cavity?
the small fleshy projection hanging down from the soft palate at the back of the mouth.
what is the division of pharynx into which the buccal cavity opens?
the oropharynx
what are divisions of the two body cavities that the esophagus lies in?
thoracic cavity and the abdominal cavity
what is the esophagus location in relation to the trachea and the heart?
esophagus is located posterior to the trachea and lies posterior to the heart.
what is the function of the pharynx in the digestive process?
provides pathway for food and liquids from the mouth to the esophagus.
what is the function of the epiglottis in the digestive process?
prevents food and liquid from entering the airway during swallowing
what are the details of the stomach
lesser curvature, greater curvature: the top and bottom curve of the stomach.
cardia: located near the gastroesophageal junction.
fundus: the upper region of the stomach
body:the largest and central part of the organ responsible for mixing food with gastric secretions
pylorus: distal portion of the stomach
cardiac sphincter/lower esophageal sphincter: prevents reflux of stomach contents into the esophagus
pyloric sphincter: controls flow of chyme from the stomach into the small intestine.
what is rugae?
folds of the mucosa and submucosa that increase the surface area for more efficient digestion.
what are sphincters?
regulate flow of substances within the body.
what are omentum?
fold of peritoneum: greater omentum and lesser omentum.
whats the duodenum?
the first part of the small intestine after the stomach
whats the jejunum?
the middle segment of the small intestine located between the duodenum and ileum
whats the ileum?
final segment of the small intestine following the jejunum.
whats the ileocecal valve?
sphincter like structure located at the junction between the ileum and the cecum
what is the function of the villi and microvilli?
structure usually found in the mucosa that greatly increase the surface area for absorption of nutrients
what is plicae circularis?
found in mucosa and submucosa of the small intestine
where are the mucosa associated lymphatic tissue and peyers patches found?
found in mucosal membranes throughout the body
what is the cecum?
pouch like structure that marks the beginning of the large intestine/colon
what is the appendix?
small organ attached to cecum which is the beginning of the large intestine
what is the ascending colon?
segmentt of the large intestine that begins at the cecum
transverse colon?
major segment of the large intestine after the ascending colon
what is the descending colon?
segment of the large intestine that follows the transverse colon
what is the sigmoid colon?
s shaped segment of the large intestine that connects the descending colon to the rectum
what is the diverticula?
small bulging pouches that can develop in the lining of the digestive system particularly in the large intestine
what are tenae coli and epiploic appendages?
tenae coli: 3 bands of smooth muscle that run along the length of the colon.
epiploic appendages: small fat filled pouches of visceral peritoneum.
what is the rectum?
final segment of the large intestine located above the anal canal
what is the anus?
the terminal part of the digestive tract and serves as the opening through which feces are expelled from the body during defecation.
internal anal sphincter?
smooth muscle: located in the anal canal and it keeps it closed to prevent the involuntary release of feces and gases.
external anal sphincter?
skeletal muscle: surrounding the anal canal that provides voluntary control over defecation and supports fecal continence by allowing or preventing the release of feces.
whats the definition and purpose for the hepatic portal circulation?
the hepatic portal circulation is a blood flow system that directs nutrient rich and potentially toxic blood from the digestive organs to the liver for processing and detox before returning to the heart.
what is the gastric vein responsible for?
responsible for draining deoxygenated blood from the stomach and delivering it to the hepatic portal vein which then goes to the liver.
what is the pancreatic vein responsible for?
responsible for draining blood from the pancreas and delivering it to the hepatic portal vein then goes to liver.
what is the inferior mesenteric vein responsible for?
collects deoxygenated blood from the lower parts of the gi tract and combines with splenic vein to form the hepatic portal vein
what is the superior mesenteric vein responsible for?
collects deoxygenated blood from the small intestine. it combines with the splenic vein to form the hepatic portal vein
portal vein vs hepatic vein
portal vein carries deoxygenated blood from the gi tract and spleen to the liver. the hepatic vein drain deoxygenated blood from the liver into the inferior vena cava.
what abdominopelvic region and quadrant is the liver in?
it lies in the right hypochondriac region/right upper quadrant
what is the location of the liver?
it sits directly beneath the diaphragm and superior to the stomach
how many lobes of the liver are there?
4 lobes
what are the names and source of the two main blood vessels entering the liver?
hepatic artery: delivers oxygen rich blood to the liver and hepatic portal vein brings deoxygenated blood from the digestive organs to the liver
what are bile salts?
produced by liver and they help break down large amounts of fat.
where do bile pigments originate from
breakdown of heme
where does cholesterol originate from?
originates in the liver
Identify, in order, the components that bile passes through from its source in the liver to
its exit from the body according to the following guidelines
right hepatic duct, left hepatic duct, common hepatic duct, cystic duct, gallbladder, common bile duct, dueodenum, hepatopancreatic ampulla, hepatopancreatic sphincter, small intestine.
