digestive system

module 4 anatomy test

functions of digestive system

take in food, break it down into nutrient molecules, absorb molecules into the bloodstream, rid body of any indigestible remains

alimentary canal

continuous muscular tube that runs from the mouth to the anus, digests food, absorbs fragments through lining into blood, includes: mouth , pharynx, esophagus, stomach, small intestine, large intestine

accessory digestive organs

teeth, tongue, gallbladder, digestive glands

digestive glands

salivary glands, liver, and pancreas are examples of __________ __________

bolus

food "ball"

digestive glands

produce secretions that help break down foodstuffs

ingestion

eating

propulsion

movement of food through the alimentary canal which includes swallowing and peristalisis

peristalsis

major means of propulsion of food that involves alternating waves of contraction and relaxation

segmentation

nonadjacent segments of the alimentary canal organs contract and relax

mechanical breakdown

includes chewing, mixing food with saliva, churning food in stomach and segmentation

digestion

series of catabolic steps that involves enzymes that break down complex food molecules into chemical building blocks

absorption

passage of digested fragments from lumen of GI tract into blood or lymph

defecation

elimination of indigestible substances via anus in form of feces

peritoneum

serous membranes of abdominal cavity that consists of visceral peritoneum and parietal peritoneum

peritoneal cavity

fluid filled space between two peritoneums

mesentary

a double layer of peritoneum
-holds organs in place
-sites of fat storage
-provides a route for circulatory vessels and nerves

retroperitoneal organs

pancreas, duodenum, parts of small intestine, kidneys

greater omentum

a "fatty apron" of peritoneum

lesser omentum

attaches to lesser curvature of stomach

mucosa, submucosa, muscularis externa, serosa

layers of the alimentary canal

mucosa

tunic layer that lines lumen, secretes mucus, digestive enzymes, and hormones, absorbs end products of digestion, protects against infectious disease

mucosa

epithelium, lamina, propria, muscularis mucosae, are all parts of the _________

epithelium

secretes mucus, protects digestive organs from enzymes, eases food passage

stratified squamous

what epithelial tissue are the mouth, esophagus, and anus?

lamina propria

made up of loose areolar tissue, rich supply of capillaries (needed for nourishment and absorption), contains lymphoid follicles that help defend against microorganisms

muscularis mucosae

smooth muscle that produces local movements of mucosa

submucosa

consists of areolar connective tissue contain blood and lymphatic vessels, lymphoid follicles, and submucosal nerve plexus that supply surrounding GI tract tissues
-has abundant amount of elastic tissues that help organs to regain shape after storing large meal

muscularis externa

-muscle layer responsible for segmentation and
peristalsis
-contains inner circular muscle layer and outer longitudinal layers

serosa

outermost layer, which is made up of the visceral peritoneum
-formed from areolar connective tissue covered with mesothelium (single layer of squamous epithelium) in most organs

adventitia

the esophagus has ______ instead of serosa

adventitia, serosa

retroperitoneal organs have both an ________ and a ________

oral orifice

anterior opening to the mouth

stratified squamous epithelium

keratinized

cells of gums, hard palate, and part of tongue are _________ for exta protection

lips

composed of fleshy orbicularis oris muscle

cheeks

composed of buccinator muscles

oral vestibule

recess internal to lips and cheeks, external to teeth and gums

oral cavity proper

lies within teeth and gums

labial frenulum

median attachment of each lip to gum

hard palate

formed by palatine bones and palatine processes of maxillae with a midline ridge called raphe
-mucosa is slightly corrugated to help create friction against tongue

soft palate

fold formed mostly of skeletal muscle

soft palate functions

closes off nasopharynx during swallowing, laterally, anchored to tongue by palatoglossal arches, also anchored to wall to oropharynx by palatopharyngeal arches

fauces

area in between two arches is called ________

fauces

palatine tonsils are located in _______

uvula

fingerlike projection that faces downward from free edge of soft palate

skeletal

the tongue is composed of interlacing bundles of _________ muscle

tongue functions

gripping, repositioning, mixing food during chewing
-formation of the bolus, mixture of food and saliva
-initiation of swallowing, speech, and test

intrinsic

______ muscles change shape of tongue

extrinsic

______ muscles alter tongue's position

lingual frenulum

attachment to floor of mouth

filiform papillae

gives tongue roughness to provide friction; only one that does not contain taste buds; gives tongue a whitish appearance

fungiform papillae

mushroom shaped, scattered widely over tongue; vascular core causes reddish appearance of tongue

vallate (circumvallate) papillae

8-12 form V-shaped row in back of tongue

foliate papillae

located on lateral aspects of posterior tongue

terminal sulcus

groove located posterior to vallate papillae
-marks division between body and root
-does not contain papillae, but still bumpy because of lingual tonsil, which lies deep to its mucosa

body

portion of tongue that resides in oral cavity

root

posterior third residing in oropharynx

functions of saliva

cleasnes mouth, dissolved food chemicals for taste, moistens food, begins breakdown of starch with amylase

gustation

dissolved food chemicals for taste

major extrinsic salivary glands

most saliva produced by _______ _______ ______ ______ located outside oral cavity

minor salivary glands

_______ ______ _____ are scattered throughout oral cavity; augment slightly

parotid

anterior to ear and external to masseter muscle
-parotid duct opens into oral vestibule next to second upper molar

submandibular

medial to body of mandible
-duct opens at base of lingual frenulum

sublingual

anterior to submandibular gland under tongue
-opens via 10-12 ducts into floor of mouth

serous cells

produce watery secretion, enzymes, ions, bit of mucin

mucous cells

produce mucus

mucous

sublingual salivary gland consists mostly of _________ cells

serous

parotid and submandibular glands contain mostly _______ cells

mastication

process of chewing that tears and grinds food into smaller fragments

20

primary dentition consists of __ deciduous teeth or baby teeth that reupt between 6 and 24 months of age

32

__ deep-lying permanent teeth enlarge and develop while roots of milk teeth are resorbed from below, causing them to loosen and fall out

incisors

chisel shaped for cutting

canines

fanglike teeth that tear or pierce

premolars

broad crowns with rounded cusps used to grind or crush

molars

best grinders
-during chewing, upper and lower molars lock together creating tremendous crushing force

crown

covered by enamel, the hardest substance in body
-heavily mineralized with calcium salts
-enamel producing cells degenerate when tooth erupts, so no healing if tooth decays or crtacks; needs artificial repair

root

portion of tooth embedded in jawbone
-connected to crown by neck

cement

calcified connective tissue
-covers root; attaches it to periodontal ligament

periodontal ligament

forms fibrous joint called gomphosis
-anchors tooth in bony socket

gingival sulcus

groove where gingiva borders tooth

dentin

bonelike bonelike material under enamel
-maintained by odontoblasts of pulp cavity

pulp cavity

surrounded by dentin

pulp

connective tissue, blood vessels, and nerves

root canal

as pulp cavity extends to root

space

extends from cranial base to inferior border of cricoid cartilage anteriorly and inferior border of C6 vertebra posteriorly

oropharynx

food passes from mouth into ________ and the laryngopharynx

pharynx

allows passge of foods, fluids, and air
-external muscle layers consists of two skeletal muscle layers

stratified squamous

What type of epithelium is the pharynx?

esophagus

flat muscular tube that runs from laryngopharynx to stomach
-is collapsed when not involved in food propulsion
-pierces diaphragm at esophageal hiatus
-joins stomach at cardial orifice
-cardiac sphincter surrounds cardial orifice

esophagus function

keeps orifice closed when food is not being swallowed
-mucus cells on both side of sphincter help protect esophagus from acid reflux

true

T/F: the esophagus has all four alimentary canal layers

stratified squamous

what type of epithelium does the esophageal mucosa contain?

simple columnar

what type of epithelium does the esophagus have when it meets the stomach?

submucosa

esophageal glands in this layer secrete mucus to aid in bolus movement

muscularis externa of esophagus

skeletal muscle superiorly; mixed in middle; smooth muscle inferiorly

adventitia

the esophagus has _______ instead of serosa

rugae

when empty, stomach mucosa forms many folds called _______

major regions of the stomach

cardial part, fundus, body, pyloric part

cardial part

surrounds cardial orifice