Digestive System Flashcards
mucous membrane–lined cavity
Oral cavity
- protect the anterior opening
Lips - Labia
form the lateral walls
Cheeks
forms the anterior roof
Hard palate
- forms the posterior roof
Soft palate
- fleshy projection of the soft palate
Uvula
space between lips externally and teeth and gums internally
Vestibule
area contained by the teeth
Oral Cavity proper
- attached at hyoid bone and styloid processes of the skull, and by the lingual frenulum to the floor of the mouth
Tongue
two parts of the tonsils
Palatine and Lingual
located at posterior end of oral cavity
palatine
located at the base of the tongue
Lingual
Organs of the Alimentary Canal
Mouth, Pharynx, Esophagus, Stomach, Small intestine, Large intestine, Anus
- taking in food
Ingestion
- breaking food into nutrient molecules
Digestion
movement of nutrients into the bloodstream
Absorption
excretes to rid the body of indigestible waste
Defecation
Serves as a passageway for foods, fluids, and air
Pharynx
- posterior to oral cavity
Oropharynx
below the oropharynx and continuous with the esophagus
Laryngopharynx
Anatomy of the esophagus
About 10 inches long
Runs from pharynx to stomach through the diaphragm
Conducts food by peristalsis (slow rhythmic squeezing) to the stomach
Passageway for food only (respiratory system branches off after the pharynx)
Esophagus
Layers of Tissue in the Alimentary Canal Organs
Mucosa
Submucosa
Muscularis externa
Serosa
Innermost, moist membrane consisting of:
Surface epithelium that is mostly simple columnar epithelium (except for esophagus - stratified squamous epithelium)
Small amount of connective tissue (lamina propria)
Scanty smooth muscle layer
Mucosa
Lines the cavity (known as the lumen)
Mucosa
Just beneath the mucosa
Soft connective tissue with blood vessels, nerve endings, mucosa-associated lymphoid tissue, and lymphatic vessels
Submucosa
smooth muscle
Inner circular layer
Outer longitudinal layer
Muscularis externa
- outermost layer of the wall; contains fluid-producing cells
Serosa
- innermost layer that is continuous with the outermost layer of the serosa
Visceral peritoneum
outermost layer that lines the abdominopelvic cavity by way of the mesentery of the serosa
Parietal peritoneum
Alimentary canal wall contains two intrinsic nerve plexuses that are part of the autonomic nervous system. these are….
Submucosal nerve plexus
Myenteric nerve plexus
C-shaped organ located on the left side of the abdominal cavity
Stomach
Food enters at the ________ from the esophagus
cardio esophageal sphincter
Food empties into the small intestine at the ________
pyloric sphincter (valve)
Regions of the stomach
Cardial(cardia)
Fundus
Body
Greater Curvature
Lesser Curvature
Pylorus
near the heart and surrounds the cardioesophageal sphincter
Cardial
- expanded portion lateral to the cardiac region of the stomach
Fundus
midportion of the stomach
Body
is the convex lateral surface
Greater curvature
is the concave medial surface
Lesser curvature
funnel-shaped terminal end
Pylorus
Stomach can stretch and hold_________of food when full
4 L (1 gallon)
internal folds of the mucosa present when the stomach is empty
Rugae
Double layer of the peritoneum
Extends from liver to the lesser curvature of stomach
Lesser omentum
- Another extension of the peritoneum
- Covers the abdominal organs
- Fat insulates, cushions, and protects abdominal organs
Greater omentum
produce protein-digesting enzymes (pepsinogens)
Chief Cells
produce hydrochloric acid that activates enzymes
Parietal cells
produce thin acidic mucus (different from the mucus produced by mucous cells of the mucosa)
Mucos neck cells
produce local hormones such as gastrin
Enteroendocrine cells
Delivers chyme (processed food) to the small intestine
Stomach
The body’s major digestive organ
small intestine
Site of nutrient absorption into the blood
small intestine
Muscular tube extending from the pyloric sphincter to the ileocecal valve
small intestine
Suspended from the posterior abdominal wall by the mesentery
small intestine
Subdivisions of the small intestine
Duodenum
Jejunum
Ileum
Enzymes produced by intestinal cells and pancreas are carried to the _____ by ________
duodenum, pancreatic ducts
____, formed by the liver, enters the duodenum via the _____.
Bile, bile duct
____________ is the location where the main pancreatic duct and bile ducts join
Hepatopancreatic ampulla
fingerlike projections formed by the mucosa
VIlli
deep folds of mucosa and submucosa
Circular folds (plicae circulares)
tiny projections of the plasma membrane (brush border enzymes)
Microvilli
- Collections of lymphatic tissue
- Located in submucosa
- Increase in number toward the end of the small intestine
- More are needed there because remaining food residue contains much bacteria
`Peyer’s patches
Larger in diameter, but shorter in length at 1.5 m, than the small intestine
Large intestine
Extends from the ileocecal valve to the anus
Large intestine
Subdivisions of the large intestine
-Cecum
-Appendix
-Colon
-Rectum
-Anal canal
saclike first part of the large intestine
Cecum
Hangs from the cecum
Accumulation of lymphoid tissue that sometimes becomes inflamed (appendicitis)
Cecum
travels up right side of abdomen and makes a turn at the right colic (hepatic) flexure
Ascending colon
travels across the abdominal cavity and turns at the left colic (splenic) flexure
Transvers colon
travels down the left side
descending colon
S-shaped region; enters the pelvis
sigmoid colon
______, _____, and _____ are located in the pelvis
Sigmoid colon, rectum, and anal canal
opening of the large intestine
Anus
formed by skeletal muscle and is voluntary
External anal sphincter
formed by smooth muscle and is involuntary
Internal anal sphincter
________ produce alkaline mucus to lubricate the passage of feces
Goblet cells
________ is reduced to three bands of muscle, called teniae coli
Muscularis externa layer
Accessory Digestive Organs
Teeth
Salivary glands
Pancreas
Liver
Gallbladder
Humans have two sets of teeth during a lifetime, these are ____ and ____ teeth
Deciduous and permanent teeth
Teeth are classified according to shape and function
Incisors
Canines
Premolars
Molars
Give their Functions:
Incisors
Canines
Premolars
Molars
Incisors - cutting
Canines (eyeteeth) - tearing or piercing
Premolars (bicuspids) - grinding
Molars - grinding
Two major regions of a tooth
Crown and root
exposed part of tooth above the gingiva (gum)
Crown
covers the crown
Enamel
found deep to the enamel and forms the bulk of the tooth, surrounds the pulp cavity
Dentin
contains connective tissue, blood vessels, and nerve fibers (pulp)
Pulp cavity
where the pulp cavity extends into the root
Root canal
covers outer surface and attaches the tooth to the periodontal membrane (ligament)
Cement of the root
Periodontal membrane holds tooth in place in the bony jaw
Root
Three pairs of salivary glands
- Parotid glands
- Submandibular glands
- Sublingual glands
Found anterior to the ears
Mumps affect these salivary glands
Parotid glands
Both submandibular and sublingual glands empty saliva into the floor of the mouth through small ducts
Sublingual glands
Mixture of mucus and serous fluids
Helps to moisten and bind food together into a mass called a bolus
Saliva
Saliva contains___
Salivary amylase - begins starch digestion
Lysozymes and antibodies - inhibit bacteria
Soft, pink triangular gland
Found posterior to the parietal peritoneum
- Mostly retroperitoneal
Extends across the abdomen from spleen to duodenum
Produces a wide spectrum of digestive enzymes that break down all categories of food
Secretes enzymes into the duodenum
Alkaline fluid introduced with enzymes neutralizes acidic chyme coming from stomach
Pancreas
Hormones produced by the pancreas
Insulin and Glucagon
Largest gland in the body
Located on the right side of the body under the diaphragm
Consists of four lobes suspended from the diaphragm and abdominal wall by the falciform ligament
Liver
is yellow-green, watery solution
Bile
Green sac found in a shallow fossa in the inferior surface of the liver
Gall bladder
movement of materials back and forth to foster mixing in the small intestine
Segmentation
movement of foods from one region of the digestive system to another
propulsion
alternating waves of contraction and relaxation that squeeze food along the GI tract
Peristalsis
Essential processes of the GI tract
Ingestion, Propulsion, Food breakdown(mechanical), Food breakdown(digestion), Absorption, Defecation.