A&P II digestive system ch23

What is the primary function of the digestive system?

Break food into absorbable molecules

What transports absorbed nutrients throughout the body?

Cardiovascular system

What is ingestion?

Taking food into the mouth

What is mechanical digestion?

Physical breakdown of food

What is chemical digestion?

Enzymatic breakdown of food

What is absorption?

Movement of digested substances into blood or lymph

What is defecation?

Elimination of feces

What is the innermost GI tract layer?

Mucosa

What is the connective tissue layer of the mucosa?

Lamina propria

What does the muscularis mucosae do?

Creates folds in the mucosa

Which GI layer contains the submucosal plexus?

Submucosa

What is the usual inner muscularis layer?

Circular smooth muscle

What is the usual outer muscularis layer?

Longitudinal smooth muscle

What extra muscle layer does the stomach have?

Oblique muscle

What is the outer serous covering of abdominal GI organs?

Visceral peritoneum

What lines the abdominopelvic cavity?

Parietal peritoneum

What covers the surfaces of abdominal organs?

Visceral peritoneum

What fluid lubricates the peritoneal cavity?

Serous fluid

What does retroperitoneal mean?

Behind the peritoneum

Which peritoneal fold hangs over the intestines?

Greater omentum

Which peritoneal fold attaches the liver to the anterior abdominal wall?

Falciform ligament

Which nerve plexus controls GI motility?

Myenteric plexus

Which nerve plexus controls GI secretions?

Submucosal plexus

How does parasympathetic stimulation affect GI activity?

Increases secretion and motility

How does sympathetic stimulation affect GI activity?

Decreases secretion and motility

What is the oral vestibule?

Space between lips or cheeks and teeth or gums

What are the fauces?

Opening from oral cavity into throat

What forms the anterior roof of the mouth?

Hard palate

What forms the posterior roof of the mouth?

Soft palate

What closes off the nasopharynx during swallowing?

Uvula and soft palate

What do extrinsic tongue muscles control?

Tongue position and movement

What do intrinsic tongue muscles control?

Tongue shape and size

What anchors the underside of the tongue?

Lingual frenulum

What tongue projections contain taste buds?

Papillae

What anchors teeth in their sockets?

Periodontal ligament

What is the visible portion of a tooth called?

Crown

What is the junction between tooth crown and root?

Neck

What tissue covers the tooth crown?

Enamel

What tissue lies beneath tooth enamel?

Dentin

What contains the tooth's nerves and blood vessels?

Pulp

What are the gums called?

Gingivae

What are primary teeth called?

Deciduous teeth

What are cuspids also called?

Canines

What are bicuspids also called?

Premolars

Which salivary gland lies near the ear?

Parotid gland

Which salivary gland lies beneath the mandible?

Submandibular gland

Which salivary gland lies beneath the tongue?

Sublingual gland

What enzyme begins starch digestion in the mouth?

Salivary amylase

What does saliva do to food before swallowing?

Moistens it into a bolus

What salivary enzyme has an antimicrobial function?

Lysozyme

What is mastication?

Chewing

Where does lingual lipase become active?

Acidic stomach

Which pharyngeal region functions only in respiration?

Nasopharynx

Which pharyngeal region lies behind the oral cavity?

Oropharynx

Which pharyngeal region connects toward the esophagus?

Laryngopharynx

What is deglutition?

Swallowing

What does the upper esophageal sphincter regulate?

Entry of food into the esophagus

What does the lower esophageal sphincter prevent?

Reflux of acidic stomach contents

Through what diaphragm opening does the esophagus pass?

Esophageal hiatus

What secretion lubricates the esophagus?

Mucus

What moves the bolus during voluntary swallowing?

Tongue

Which brain region controls the pharyngeal swallowing reflex?

Brain stem

What covers the larynx during swallowing?

Epiglottis

What propels food through the esophagus?

Peristalsis

Which stomach region receives food from the esophagus?

Cardia

What is the dome-shaped superior stomach region?

Fundus

What is the main central stomach region?

Body

What is the distal stomach region?

Pylorus

What are the folds of stomach mucosa called?

Rugae

Which sphincter controls stomach emptying?

Pyloric sphincter

What is chyme?

Food mixed with gastric juice

Which stomach cells secrete hydrochloric acid?

Parietal cells

Which stomach cells secrete intrinsic factor?

Parietal cells

Which stomach cells secrete pepsinogen?

Chief cells

Which stomach cells secrete gastric lipase?

Chief cells

Which stomach cells secrete gastrin?

Enteroendocrine cells

Which cells secrete protective gastric mucus?

Surface mucous cells

What hormone increases stomach motility?

Gastrin

What does hydrochloric acid do to proteins?

Partially denatures them

What is the inactive precursor of pepsin?

Pepsinogen

What activates pepsinogen?

Hydrochloric acid

What type of nutrient does pepsin digest?

Proteins

What protects the stomach lining from acid?

Thick alkaline mucus

Which pancreatic cells produce digestive juice?

Acinar cells

Which pancreatic cells secrete insulin and glucagon?

Pancreatic islet cells

What pancreatic enzyme digests starch?

Pancreatic amylase

What pancreatic enzyme digests triglycerides?

Pancreatic lipase

What activates trypsinogen in the small intestine?

Enterokinase

What neutralizes acidic chyme in pancreatic juice?

Sodium bicarbonate

What does bicarbonate do to pepsin activity?

Stops its action

Where does pancreatic juice enter the GI tract?

Duodenum

Which sphincter regulates the hepatopancreatic ampulla?

Sphincter of hepatopancreatic ampulla

What cells produce bile?

Hepatocytes

What organ stores and concentrates bile?

Gallbladder

Which duct drains the gallbladder?

Cystic duct

Which duct delivers bile to the duodenum?

Common bile duct

What is the digestive function of bile salts?

Emulsify fats

What bile pigment comes from hemoglobin breakdown?

Bilirubin

What blood vessel brings oxygen-rich blood to the liver?

Hepatic artery

What blood vessel carries absorbed nutrients to the liver?

Hepatic portal vein