Digestive System

Question 1

Digestive tract and GI tract

Answer 1

Digestive tract = alimentary tract/canal
- GI tract = stomach + intestines

Question 2

Digestion Function:

Answer 2

• Ingestion
• Mastication: chewing.
  ○ Chemical digestion
  ○ Mechanical digestion
• Propulsion
  ○ Deglutition: Swallowing
  ○ Peristalsis: moves material
• Secretion: lubricate, liquefy, digest
  ○ Mucus - lubricates, protects from digestion, acid, and digestive enzymes
  ○ Bile - emulsifies fats
  ○ Enzymes - chemical digestion
• Digestion: Mechanical and Chemical
• Absorption: nutrients into circulation or lymph
• Elimination: waste products removed from body

Question 3

Tunic of digestion

Answer 3

• Mucosa: innermost layer
• Submucosa: nerves, blood vessels, small glands, parasympathetic submucosal plexus
• Muscularis:
  ○ Circular and longitudinal
  ○ contains the myenteric plexus. The myenteric and submucosal plexi together are called the enteric or intramural plexus.
  § Controls movement and secretion
• Serosa: visceral peritoneum
• Adventitia: c.t. blends w/ surrounding c.t.

Question 4

Peritoneum of Digestive System

Answer 4

○ Visceral: Covers organs
○ Parietal: Covers interior surface of body wall
○ Retroperitoneal: Certain organs covered by peritoneum on only one surface and are considered behind the peritoneum; e.g., kidneys, pancreas, duodenum

Question 5

Mesenteries of the digestive system

Answer 5

○ Greater omentum: connects greater curvature of the stomach to the transverse colon.
○ Lesser omentum: connects lesser curvature of the stomach and the proximal part of the duodenum to the liver and diaphragm.
○ Transverse mesocolon, sigmoid mesocolon, mesoappendix.

Question 6

Ligaments of the digestive system

Answer 6

○ Coronary: between liver and diaphragm
○ Falciform: between liver and anterior abdominal wall

Question 7

Function of Lips and Cheeks

Answer 7

Mastication

Question 8

Function of Tongue

Answer 8

Moves food in mouth, participates in speech and swallowing

Question 9

Function of Teeth

Answer 9

Two sets
○ Primary = Childhood
○ Permanent = Adult
Mastication and speech

Question 10

Function of Saliva

Answer 10

Alveolar salivary gland produce saliva

Prevents infection, lubrication, amylase for breaking down starch, helps in swallowing, parasympathetic

Question 11

Function of Salivary glands

Answer 11

• Parotid = Largest, Serous, parotid duct
• Submandibular = Mixed (more serous)
• Sublingual = smallest, mixed (more mucous)

Question 12

Esophagus

Answer 12

Esophageal hiatus = opening of diaphragm and ends at stomach

Question 13

Three phases of Swallowing

Answer 13

○ Voluntary = food moved by tongue, oral - pharynx
○ Pharyngeal = reflex lets food pass through larynx
○ Esophageal = reflex, initiate peristalsis in esophagus

Question 14

Stomach Anatomy

Answer 14

• Gastric pits: hold gastric glands
• Cells of gastric pits
  ○ Surface mucus: mucus that protects stomach lining from acid and digestive enzymes
  ○ Mucous neck: mucus
  ○ Parietal: hydrochloric acid and intrinsic factor
  ○ Chief: pepsinogen
  ○ Endocrine: regulatory hormones

Question 15

Secretions of the Stomach

Answer 15

• Chyme
• Mucus
• Intrinsic factor: absorption
• HCl: kills bacteria
• Pepsinogen: break down protein

Question 16

Small intestine

Answer 16

• Primary function: absorb nutrients
• Secondary: absorption of water

Question 17

Duodenum

Answer 17

§ Absorptive cells: cells with microvilli, produce digestive enzymes and absorb digested food
§ Goblet cells: produce protective mucus
§ Endocrine cells: produce regulatory hormones
§ Granular cells (paneth cells): may help protect from bacteria

Question 18

Jejunum and Ileum

Answer 18

Major site of nutrient absorption

Question 19

Liver Function

Answer 19

Bile production, Storage, Nutrient interconversion, Detoxification, Phagocytosis, Synthesis

Question 20

Gallbladder Function

Answer 20

Concentrates and Stores Bile
Bile - emulsifies fats

Question 21

Pancreas Function

Answer 21

Endocrine - produce pancreatic islets (insulin, glucose, somatostatin)
Exocrine - gives out secretions to outside world (pancreatic juice in stomach and large intestine)
- Acini glands are exocrine
- Alpha beta delta are endocrine