Chapter 24 Digestion

Question 1

Gastrointestinal tract organs

Answer 1

Mouth
Pharynx
Esophagus
Stomach 
Sm. Intestine
Lg. Intestine

Question 2

Accessory organs

Answer 2

Teeth
Tongue
Salivary Glands
Liver
Gallbladder
Pancreas

Question 3

Functions of Digestive System

Answer 3

Ingestion: eating
Secretions: acids, buffers (7L/day)
Motility: mixing, propulsion
Digestion: mechanical and chemical
Absorption: nutrients, fluids
Defecation: removal of metabolic waste

Question 4

Mucosa

Answer 4

Inner lining of Gi tract
Contains:
Epithelial cells: absorbs nutrients and contains enteroendocrine cells
Lamin propria: areolar connective tissues, blood vessels and lymphatic vessels. Contains MALT
Muscularis mucosa: smooth muscle fibers increases surface are

Question 5

Submucosa

Answer 5

Contains collagenous fibers, nerves and blood vessels.
Areolar connective tissue binds the mucosa to the muscularis.
Vascular and contains the submucosal plexus, or the plexus of meissner

Question 6

Muscularis

Answer 6

2 types of smooth muscle: inner circular and outer longitudinal fibers.
Contains the myenteric plexus/ plexus of Auerbach
- mostly controls GI motility

Question 7

Serosa

Answer 7

Superficial layer of the GI tract, suspended in the abdominopelvic cavity
Has a serous membrane that’s composed of areolar connective tissue and simple squamous epithelium (mesothelium)
Epithelial portion is also called visceral peritoneum

Question 8

Peritoneal Folds

Answer 8

Largest serous membrane in the body

Divided into Parietal peritoneum and visceral peritoneum/serosa

Question 9

Mesentery

Answer 9

binds the jejunum and ileum (sm. intestine) to the posterior abdominal wall

Question 10

Mesocolon

Answer 10

binds the transverse and sigmoid colon (lg. intestine) to the posterior abdominal wall

Question 11

Salivary Glands

Answer 11

3 major pairs
1. Parotid glands (Stensen's duct)
2. Submandibular glands (Wharton's duct)
3. Sublingual glands (Rivinus' ducts)
Both sympathetic and parasympathetic innervation

Question 12

Saliva

Answer 12

Salivary amylase begins to breakdown starch in the mouth

Question 13

Teeth

Answer 13

Also called dentes. Composed of:

• crown
• neck
• dentin
• enamel
• pulp cavity

Question 14

Pharynx

Answer 14

Nasopharynx: respiration
Oropharynx: digestive and respiratory functions
Laryngopharynx: digestive and respiratory functions

Question 15

Esophagus

Answer 15

Secretes mucus and transports food into the stomach
- Elevation of larynx causes the upper esophageal sphincter to relax, allowing the bolus to enter the esophagus
Peristalsis control movement of the esophagus (swallowing).
Lower esophageal sphincter is also called gastroesophageal or cardiac sphincter

Question 16

Stomach

Answer 16

J shaped. Connects the esophagus to the duodenum
Functions as a mixing area and holding reservoir.
Digestion of proteins and triglycerides begins in stomach, breakdown of starch continues in stomach.
Up to 6.4 L of liquid food

Question 17

Enzymes in the stomach

Answer 17

Pepsin: protein digesting enzyme
Gastric lipase: triglycerdie digesting enzyme
Pancreatic lipase: fat digesting enzyme.

Question 18

4 Regions of Stomach

Answer 18

1. Carida
2. Fundus: storage of food
3. Body: mixing
4. Pyloric Part
   4a. Pyloric antrum: connects to body of stomach (food mixing)
   4b. Pyloric canal (leads to pylorus)
   4c. Pylorus: connects to duodenum

Question 19

Gastric Gland

Answer 19

3 types of exocrine gland cells
Mucous neck cells, chief cells, parietal cells.
Secretion from all 3 = 2-3L/day.

Question 20

Functions of the Pancreas

Answer 20

Can produce 1200-1500 ml of pancreatic juice/day.
Pancreatic amylase: a starch digesting enzyme.
Enzymes that digest protein:
- trypsin
- chymotrypsin
- carboxypeptidase
- elastase
Principle trigylceride:
- pancreatic lipase
- RNA and DNA digesting enzymes called ribonuclease and deoxyribonuclease

Question 21

Anatomy of the Pancreas

Answer 21

Head
Body
Tail
Pancreatic duct (wirsung)
Hepatopancreatic ampulla (ampulla of vater)
Major duodenal papilla
Accessory duct (duct of Santorini)

Question 22

Gallbladder

Answer 22

Anatomy
- fundus
- body
- neck
Function
- storage of bile

Question 23

Functions of the Liver

Answer 23

Emulsification: breakdown of large lipid globules into small droplets
Absorption
Bile Storage (sphincter of the hepatopancreatic ampulla)
Carb/lipid/protein metabolsim
Vitamin storage
Phagocytosis by Kuffer cells and immune cells
Anatomy:
Divided into two lobes by the falciform ligament (l and r)

Question 24

Hepatic Blood Flow

Answer 24

Oxygenated blood from hepatic artery and nutrient-rich, deoxygented blood from the hepati portal vein 
Hepatic sinusoids
Central vein
Hepatic vein
Inferior Vena Cava
Right Atrium

Question 25

Functions of the Large Intsetine

Answer 25

Haustral churning: contraction and squeezing the contents into the next houstrum.
Peristalsis: slower wave of contraction
Mass peristalsis: occurs in the transverse colon and has stronger waves.

Question 26

Anatomy of the Large Intestine

Answer 26

Extens from the ileum to the anus. 
4 Principal regions
1. Cecum
2. Colon
3. Rectum
4. Canal
Ileocecal sphincter, cecum, appendix and mesoappendix (mesentery of the appendix).