BIO 163 Exam 4

What are the three main functions of the digestive system?

Processes food, extracts, nutrients, and eliminates wastes

What is the function of the "disassembly line"?

Breaks down complex molecules to simple forms we can absorb and use

What is ingestion?

Intake of food

What is digestion?

Break down of food

What is absorption?

Uptake of nutrients into bloodstream

What is excretion?

Elimination of undigested food

What are the main themes of the digestive system?

Motility, secretion, absorption

What is motility?

getting food where it should be

What is secretion?

digestive enzymes and hormones

What is the gastrointestinal tract (GI tract)?

Tube extending from mouth to anus

What is another name for the GI tract?

Alimentary canal

About how long is the GI tract?

About 9 meters

What is the function of accessory organs?

Aid in digestion by secreting various substances into the GI tract

What are examples of accessory organs?

Salivary glands., pancreas, liver, and gallbladder

Where are the majority of digestive structures located?

Abdominal cavity within the peritoneal cavity

What are the two kinda of layer of tissues that make up the membranes of the digestive system?

Epithelial and areolar layers

What is the peritoneal cavity?

The space between the parietal and visceral serous a membrane

What are mesenteries of the digestive tract?

Double layers of serous tissue found in the peritoneal cavity

What are are the main functions of mesenteries?

Connect visceral and parietal peritoneal, hold organs in place, prevent friction, cushion organs with fat deposits, allows nerve and blood to reach intraperitoneal organs

What are the four layers of the GI tract?

mucosa, submucosa, muscularis, serosa

What are the functions of the mucosa layer of the GI tract?

Secretion and absorption

What is the function of the submucosa layer of the GI tract?

Secretion

What is the function of the muscularis layer of the GI tract?

Motility

where is stratifies squamous epithelial cells located in the GI tract?

Mouth, anus, and esophagus

What does simple columnar epithelium do?

Secretes enzymes and absorbs nutrients

What specialized simple columnar epithelial cells secrete mucus?

Goblet

What specialized simple columnar epithelial cells secrete hormones?

Enteroendocrine

Where are specialized simple columnar epithelial cells grouped together?

Glands

What are lamina propria?

Thin layer of loose connective tissue

What does the lamina propria contain?

Capillaries

What is the muscularis mucosae?

Very thin layer of smooth muscle

What is the function of the muscularis mucosae?

Increases movement for digestion

Where is the submucosal (meissner's) plexus?

Submucosa layer

What are the functions of the submuscoal plexus?

Involuntary nerves cause contraction of muscle layers, stimulates secretion of hormones

Through what mechanism does the muscularis layer help with motility?

Peristalsis

Are the two smooth muscle layers of the muscularis layer voluntary or involuntary?

Involuntary

What performs peristalsis and mixing movements?

Smooth muscle layers of the muscularis layer

Is the specialized skeletal muscle of the muscularis muscle involuntary or voluntary?

Voluntary

What does the skeletal muscle of the muscularis layer control?

Swallowing and defecation

Where is the skeletal muscle of the muscularis layer located?

Mouth, pharynx, upper esophagus, and anus

What does the skeletal muscle of the muscularis layer contain?

Myenteric plexus

What are the four I important functions for digestion?

Food intake, mechanical digestion, chemical digestion, special sense - taste

What is the hard palate?

Palatine bone and maxilla

What is the soft palate?

Muscles covered in muscles membrane - stratified epithelial tissue

What produces saliva that helps with processes related to digestion?

Salivary glands

What makes up saliva?

Water, muscles, and enzymes

What are 3 functions of saliva?

Helps with lubrication, chemical digestion, special sense

What os chemical digestion?

Salivary amylase starts carbohydrate digestion

What is degultition?

Swallowing

What is peristalsis?

Muscle contraction to move food

What are the three functions of the stomach?

Food storage, mechanical digestion, and initial chemical digestion

How much ingested material and the stomach hold?

4 liters

What is mechanical digestion?

Grinding and pulverizing action

What performs initial chemical digestion?

Proteins

What controls movement of food into and out of the stomach?

Sphincters

What regulates movement of chyme?

Sphincters

What forms rugae?

Mucosa

What is the function rugae?

Allow stomach to expand

What are gastric pits?

depressions in gastric mucosa

Where are gastric glands located?

base of gastric pits

What makes up chyme?

Gastric secretion mixed with food and saliva

What kind of gastri cells secrete mucus?

Mucous neck cells

What kind of cells secrete pepsinogen?

Chief cells

What converts pepsinogen to pepsin?

HCl

What kind of cells secrete hydrochloride acid (HCl)?

Parietal cells

What does hydrochloric acid do?

Denatures (unfolds) proteins, activated pepsinogen, and kills pathogens

What are the two hormones that enteroendocrine (EE) cells secrete?

Gastric and histamine

What is the function of gastrin?

Stimulates parietal cells to release HCl and chief cells to release pepsinogen

What does histamine stimulate?

Release of acid

What is the overall result of EE cells releasing hormones?

Decreased pH that promotes protein digestion

In what kind of manner does chyme enter the small intestine? And how is it regulated?

Slow and controlled manner; related by hormones and nervous system

Where do pancreatic juices/bile enter?

Duodenum

What are the parts of the small intestine?

duodenum, jejunum, ileum

What two parts of the small intestine has a high surface area for absorption of nutrients?

Jejunum and ileum

What two structures help improve the surface area for absorption of nutrients?

Villi and microvilli

What does the mucosa layer of the intestine have instead of gastric pits?

Crypts

What do crypts contain?

Absorptive cells, mucus producing cells, intestinal enteroendocrine cells

What do intestinal enteroendocrine cells secrete?

gastric inhibiting peptide, secretin, cholecystokinin

What is the function of gastric inhibiting peptide (GIP)?

Inhibit stomach function and promote insulin release

What is the function of secretin?

Stimulate pancreas and liver, inhibit parietal cells

What is the function of cholecystokinin (CCK)?

Stimulate pancreas, liver, gallbladder, inhibits stomach function

Where is the pancreas located?

By the duodenum

What accessory Ryan does the pancreas share a common duct with?

Gallbladder

What kind of pancreatic cells secrete digestive juices?

Acinar cells

what kind of pancreatic cells secrete insulin/glucagon?

Cells of islets of langerhans

What three things stimulate the release of pancreatic juices?

Parasympathetic system, CCK, and secretin

What are pancreatic juices made up of?

Water, sodium bicarbonate, and enzymes

What is the function of sodium bicarbonate?

neutralizes stomach acid

What are the four digestive enzymes?

Pancreatic amylase, pancreatic lipase, proteases, nuclease

What is the function of pancreatic amylase?

Digest starch

What is the function of pancreatic lipase?

Digest fat

What is the function of proteases?

Digest proteins

What is the function of nuclease?

Digest nucleic acids

What are three functions of the liver?

Metabolism of digested nutrients, detoxifies alcohol/drugs, produces bile

What is bile secreted by?

Liver cells

Where is bile stored?

Gallbladder

Where does bile get released to by the gallbladder?

Duodenum

What will stimulate the muscularis layer to contract and release bile into the duodenum?

Neurons and hormones

What is the gallbladder stimulates by to release bile?

Parasympathetic system, CCK, and Secretin

What is the function of bile salts?

Digestion, helps with fat emulsification