anatomy

digestive system

maltose

sugar

digestion

group of processes that break complex nutrients into simpler ones

absorption

movement of digested nutrients through GI mucosa and into the internal environment

metabolism

process of which food turns into energy

alimentary canal

winding tube

gastrointestinal (GI) tract

refers to the portion that includes the stomach and intestines

ingestion

process of taking food into mouth

digestion

group of processes that break complex nutrients into simpler ones

motility

movement by the muscular components of digestive tube

secretion

release digestive juices

feces

waste material resulting from digestive process

lumen

inside space within the tube

mucosa

composed of tough and abrasion-resistant stratified epithelium

submucosa

connective tissue layer that lies below the mucosa

muscularis

the two or three layers of muscle tissue

peristalsis

wavelike contraction of the gut wall

segmentation

type of intestinal motility

serosa

outermost covering of digestive tube

mouth

hollow chamber

hard palate

bony structure in anterior or front portion of the mouth formed by parts of the palatine and maxillary bones

soft palate

located above the posterior or rear portion of the mouth.

uvula

hangs down from center of soft palate

frenulum

thin membrane attaches the tongue to floor of the mouth

incisors

front teeth

mastication

chewing of food

canine teeth

elongated and pointed in appearance. pierce the food that is being eaten into smaller shreds

bicuspids

premolars

molars

behind premolars

bolus

small rounded mass of chewed food

deciduous teeth

primary teeth

permanent teeth

full set of 32 teeth

crown

the portion that is exposed and visible in mouth

dentin

bonelike material

enamel

hardest tissue in the body

cementum

root and neck of each tooth are covered by this

neck

narrow portion that joins the crown of the tooth to the root

gingiva

gum

gingivitis

inflammation of the gums

root

fits into the bony socket that surrounds it in either upper/lower jaw bone

periodontal membrane

lines each tooth socket and anchors the tooth to the bone

periodontitis

serious type of inflammation and infection

dental caries

tooth decay

parotid glands

largest of the salivary glands

submandibular glands

open into the mouth on either side of the lingual frenulum

sublingual glands

open into the floor of the mouth

amylase

digestive enzyme

pharynx

tubelike structure made of muscle and line with mucous membrane

nasopharynx

part of pharynx

oropharynx

part of pharynx

laryngopharynx

part of pharynx

deglutition

swallowing

bolus

formation of a ball of food and saliva in the mouth

regulation

voluntary swallowing movements is dependent on nervous impulses orgininating in motor cortex of cerebrum

esophagus

muscular, mucus-lined tube that connects the pharynx with the stomach

sphincter

guards ends of esophagus

upper esophageal sphincter

helps prevent air from entering the tube during respiration

lower esophageal sphincter

normally prevents backflow of acidic stomach contents

stomach

lies in the upper part of the abdominal cavity. serve as large, expandable pouch that ingested material enters after it has been chewed

fundus

enlarged, curving base to the left of and above the opening of the esophagus into the stomach

body

central part of the stomach

pylorus

lower narrow apex section

chyme

semisolid mixture

gastric glands

secrete gastric juice into stomach

rugae

when stomach is empty mucous lining lies in folds

hiatal hernia

bulging of the end of the esophagus and part or all of the stomach upward through the diaphragm and into the chest

gastroesophageal reflux disease

condition where backward movement or reflux of stomach contents into the lower portion of the esophagus

pyloric sphincter

chyme is held in stomach by this muscle

small intestine

part of the GI tract

duodenum

chyme passes through this

jejunum

chyme passes through this

ileum

chyme passes through this

minor duodenal papilla

opening

major duodenal papilla

a small opening in the wall of the duodenum, the first part of the small intestine.

intestinal glands

small tubular structures located in the lining of the small intestine. They secrete digestive enzymes and mucus that aid in the breakdown and absorption of nutrients from food. The two main types of intestinal glands are the crypts of Lieberkuhn and Brunner's glands. The crypts of Lieberkuhn are found throughout the small intestine and secrete enzymes and mucus, while Brunner's glands are found only in the duodenum (the first part of the small intestine) and secrete an alkaline solution that neutralizes stomach acid.

plicae

the folds found in the lining of certain organs, such as the small intestine.

cillia

microscopic, hair-like structures that extend from the surface of many types of cells.

lacteals

lymph capillaries that absorb lipids

microvilli

tiny, finger-like projections that extend from the surface of some cells. They are found in the small intestine, kidney, and other organs where absorption or secretion takes place. Microvilli increase the surface area of the cell, allowing for more efficient absorption or secretion of substances.

bile

a greenish-yellow fluid produced by the liver and stored in the gallbladder. It helps in the digestion and absorption of fats in the small intestine.

heptic ducts

are a system of ducts that transport bile from the liver to the gallbladder and small intestine.

common bile duct

a tube-like structure that carries bile from the liver and gallbladder to the small intestine.

cystic duct

a small tube that connects the gallbladder to the common bile duct.

gallbladder

a small organ located beneath the liver that stores and releases bile, a digestive fluid produced by the liver.

emulsify

process of mixing two immiscible liquids, such as oil and water, to form a stable emulsion.

cholecystokinin

a peptide hormone that is released by cells in the small intestine and stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder.

jaundice

a medical condition characterized by yellowing of the skin and whites of the eyes, caused by an excess of bilirubin in the blood.

pancreatic islets

clusters of cells in the pancreas that produce and secrete hormones such as insulin and glucagon, which regulate blood sugar levels in the body.

large intestine

absorb water and electrolytes from indigestible food matter, and to store and eliminate waste material from the body in the form of feces.

ileocecal valve

sphincter muscle that separates the small intestine (ileum) from the large intestine (cecum). prevents the backflow of fecal matter from the large intestine into the small intestine.

cecum

blind pouch; pouch at proximal end of large intestine

ascending colon

portion of the colon extending from the cecum to the hepatic flexure

heptic flexure

the bend b/w the ascending colon and the transverse colon

transverse colon

division of the colon that passes horizontally across the abdomen

splenic flexure

point at which the descending colon turns downward on the left side of the abdomen

descending colon

portion of the colon that lies in the vertical position, on the left side of the abdomen; it extends from the splenic flexure to the sigmoid colon

sigmoid colon

S-shaped segment of the large intestine that terminates in the rectum

rectum

distal portion of the large intestine

anal canal

terminal portion of the rectum

anus

distal end or outlet of the rectum

microbiome

all the interacting ecosystems of microbes that live on or in the human body