Alimentary Canal

absorption is

the passage of nutrients into the blood

metabolism is

converting nutrients to ATP

what body structures do mechanical digestion?

teeth, tongue, palate, muscles of stomach and small intestine

what is chemical digestion

acids and enzymes break down food molecules into smaller molecules

polymers are broken down into

monomers

carbohydrates are broken down into

simple sugars (glucose)

starches are

complex carbohydrates

proteins are broken down to

amino acids

lipids are broken down to

fatty acids and glycerol (alcohols)

what is the enzyme in the mouth that aides digestion

amylase, it is in the salivary secretions, it breaks down carbohydrates and starches

what is a bolus

food that has been chewed and mixed with saliva (after the mouth)

what is a chyme

a bolus that has mixed with gastric juices (after the stomach)

muscle layers in the esophagus

inner layer is longitudinal, outer layer is circular

what is saliva a mixture of

mucus and serous (lubricating) fluids

where does the esophagus pass through

the middle of the diaphragm

what is peristalsis

wave-like smooth muscle contractions that move food along the digestive tract, occurs in the esophagus, stomach, small intestine, large intestine, rectum

sphincters in the stomach

cardioesophageal sphincter and pyloric sphincter

what is cardioesophageal sphincter function

prevents gastric acid from going backwards into the esophagus (acid reflux)

what are the regions of the stomach

cardia, fundus, body, pylorus

what is the structure and function of the folds in the stomach wall

deep folds in the stomach wall called rugae allow the stomach to expand when filled with food

covering of the abdominal cavity that is closest to the organs and its function

visceral peritoneum, covers the organs

second covering of the abdominal cavity and its function

parietal peritoneum, covers the cavity walls

covering of the abdominal cavity that is furthest from the organs and its function

mesentery, holds the organs in place

what are the acids and enzymes in the stomach

pepsin and hydrochloric acid

pepsin breaks down…

proteins into amino acids

hydrochloric acids function

activates enzymes and kills bacteria

what is the mucosa/mucous

a mucus membrane that lines the stomach and protects it from the acidity of the gastric juices

what happens when the stomach mucosa is broken down

an ulcer forms

what causes a stomach ulcer

bacteria, medications, regular use of OTC meds

what is the ileocecal valve

connection between the small and large intestines

in what organ does the most digestion occur

small intestine

where does the most chemical digestion occcur

duodenum

in what organ does nutrient absorption occur

small intestine

what are the parts of the small intestine

duodenum, jejunum, ileum

where does the small intestine receive its secretions from

liver, pancreas, gallbladder

what helps the small intestine with nutrient absorption

circular folds, villi, microvilli

what do villi do

lubricate chyme and absorb nutrients

at what point is digestion completed

after the small intestine

what are the secretions in the small intestine

bile and pancreatic juices such as sodium bicarbonate

why are pancreatic juices important in the small intestine

chyme is very acidic and would break down the small intestine without the pancreatic juices from the pancreas, such as sodium bicarbonate, which neutralizes the acid. bile breaks down lipids

how are most substances absorbed in the small intestine

active transport through cell membranes (requires ATP)

how are lipids absorbed in the small intestine

diffusion

how are nutrients transported to cells after absorption

the bloodstream

what enters the large intestine

leftovers/waste products

what is the function of the large intestine

break down indigestible materials and absorb water, vitamin K, vitamin B

what are the regions of the large intestine

ascending, transverse, descending, sigmoid

what are the features of the ascending colon

contains the cecum, a sac-like structure, which has a small projection called the appendix

what is the purpose of bacteria in the large intestine

breaks down indigestible materials, source of odor and gas, produces vitamins K and B

after bacteria in the large intestine has broken down the indigestible materials, what are they called

feces

what are the anal sphincters called, and are they voluntary or involuntary

involuntary internal anal sphincter and voluntary external anal sphincter

what triggers the anal sphincters to open

prescence of feces

what is the expulsion of feces called

defecation