Chapter 22 Flashcards
digestive system
organ system responsible for digestion and the processing of food, extracting nutrients, and eliminating residue
five stages of digestion
ingestion, digestion, absorption, compaction, defecation
ingestion
selective process of food intake
digestion
breakdown of food into a form that is useable by the body
absorption
uptake of nutrients from food by absorption into the epithelial cells of the digestive tract, then into blood and lymph
compaction
absorbing water and consolidating indigestible residue to form feces
defecation
elimination of feces
mechanical digestion
physical breakdown of food into smaller particles through chewing and churning
chemical digestion
hydrolysis reactions that break down macromolecules into monomers by digestive enzymes
chemical digestion is required in absorption of all nutrients except for
vitamins, amino acids, minerals, cholesterol, and water`
alimentary canal
muscular tube from the mouth to anus
alimentary canal is also called
the digestive or gastrointestinal tract
organs in the alimentary canal
mouths, pharynx, esophagus, stomach, small intestines, large intestines
accessory organs of the digestive tract
teeth, tongue, salivary glands, liver, gallbladder, pancreas
walls of the alimentary canal
mucosa, submucosa, muscularis externa, serosa or adventitia
layers of the mucosa
epithelium, lamina propia, mucosae
submucosa
thin layer of loose connective tissue that allows passage of blood vessels
the submucosa contains what
submucosal nerve plexus
muscularis externa
two muscular layers responsible for movement of stuff through the alimentary canal
arrangement of the layers of the muscularis externa
inner circular layer and outer longitudinal layer
serosa are found
in alimentary canal organs within the abdominal cavity
the serosa is composed of
areolar connective tissue and a simple squamous outer layer
the serosa attaches to
the mesentery of the periosteum
Adventa is found
in the alimentary canal outside of the abdominal cavity
the adventitia is composed of
fibrous connective tissue
peritoneum
lining of the abdominal cavity
the peritoneum is composed of
connective tissue lined with simple squamous epithelium
the peritoneum contains
vessels and nerves to supply the abdomen
layers of the peritoneum
parietal and visceral
parietal peritoneum
outer layer lining the abdominal wall
visceral peritoneum
inner layer lining the abdominal organs
mesentary
visceral peritoneum lining the alimentary canal that attaches to the serosa
enteric nervous system
regulates motility, secretion, and blood flow from the esophagus through the intestines
is the enteric nervous system dependent or independent
independent of the CNS but influenced by the ANS
submucosal plexus controls
secretion from mucosa glands and movement of mucularis mucosae
where is the submucosal plexus located
submucosa
myenteric plexus controls
contractions of muscularis externa and contains parasympathetic ganglia
where is the myenteric plexus located
between layers of muscularis externa
myenteric reflexes are known as
short reflexes
myenteric reflexes
stretch or chemically stimulate myenteric plexus to trigger peristalsis
vasovagal reflexes are known as
long reflexes
vasovagal reflexes
parasympathetic stimulation of the digestive tract to target myenteric nerve plexus and other organs
stomach acid secretes
HCl
stomach acid secretion process
histamine made by enterochromaffin cells in the stomach help stimulate HCl secretion
G-cells function
make gastrin when the stomach is distended by food to stimulate HCl production
oral cavity is also called
buccal cavity or mouth
functions of the oral cavity
ingestion, taste, mechanical digestion, chemical digestion
mechanical digestion of the oral cavity
chewing
chemical digestion of the oral cavity
saliva
bolus
chewed, saliva-mixed food that is swallowed
epithelium of the oral cavity
stratified squamous
epithelium of the hard palate and gums
keratinized stratified squamous
functions of saliva
moisten mouth, prevent cavities, dissolve food molecules to stimulate taste buds, begin chemical digestion
cavities are caused by
acid made by bacteria
how does saliva prevent cavities
saliva lysosomes kill bacteria that produce acid, IgA antibodies inhibit bacterial growth, saliva buffers acid and remineralizes enamel
salivary gland
secrete saliva
parotid is located
pair of glands inferior and anterior to ears
what saliva gland makes the most saliva
parotid gland
submandibular gland is located
inferior to mandibular angular
location of sublingual glands
inferior to the tongue
saliva chemical digestion enzymes
salivary amylase, lingual lipase
salivary amylase digests
starch
lingual lipase digests
fats
what activates lingual lipase
stomach acid
how much saliva is produced per day
1-1.5 Liters
salivation is regulated by
the salivatory nuclei
where is the salivatory nuclei located
in the oblongata and pons
what stimulates the salivation
odor, sight of food, thought of food, flavor,chewing
the salivatory nuclei sends signals through
the facial and glossopharyngeal nerves
parasympathetic signals from the salivatory nuclei stimulates
secretion
sympathetic signals from the salivatory nuclei stimulates
less secretion, more nucleus
pharynx
muscular funnel connecting the oral cavity to esophagus