Ch 18: Dig System

Question 1

What are the main components of the digestive system?

Answer 1

Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine

Question 2

What are the accessory organs of the digestive system?

Answer 2

Salivary glands (parotid, sublingual, submandibular), liver and pancreas

Question 3

What are the functions of saliva?

Answer 3

Bind food particles, food lubrication, breakdown of carbs

Question 4

What are the stages of swallowing, explain them.

Answer 4

1. Voluntary control: bolus formed from chewing + saliva, pushed down through pharynx by tongue.
2. Involuntary: peristalsis of pharyngeal muscles controlled by autonomic nervous system.
3. Food reaches upper part of stomach when bolus reaches circular muscle called lower esophageal sphincter (cardiac sphincter)

Question 5

What are the 4 areas of the stomach?

Answer 5

Cardia, fornix, body of stomach and pyloric antrum(distal)

Question 6

What are the 3 smooth muscle layers of the stomach? What are their roles?

Answer 6

Longitudinal, circular, oblique, role is to mix and break food bolus to make soup like chyme.

Question 7

What are the 3 gastric glands what are their functions?

Answer 7

1. Parietal cells: secrete things that make up gastric juice, contains hcl, activates proteolitice enzymes, secrete also intrinsic factor necessary for vitamin b12 absorption in small intestine.
   2.Mucous cells: secretes mucous gastric juice component , protects gastric cell walls from self digesting
2. Main cells: secrete proteolitice enzymes in its inactive form eg pepsinogen from pepsin

Question 8

From what nervous system is secretion of gastric juice controlled? And what cells is it controlled by?

Answer 8

Parasympathetic nervous system, endocrine cells, gastrin.

Question 9

What does gastrin control the secretion of?

Answer 9

Pepsin, HCl, mucus

Question 10

What does stomach mucosa allow absorption of?

Answer 10

Small amounts h2o, glucose, ions, alcohol, others go into chyme.

Question 11

Is defacation the same as excretion

Answer 11

No they’re diff defecation = pooping excretion isn’t

Question 12

What are the functions of the large intestine?

Answer 12

Absorbs h20 300-400ml a day, absorbs ions, forms, faeces, absorbs vitamins.

Question 13

Does chemical digestion take place in large intestine

Answer 13

No

Question 14

What are the characteristics of bile?

Answer 14

Color, yellow brown/ olive-green liquid ph 7,8-8.6 composition, h20, salts, cholesterol, lecithin (phospholipid), bile pigments (bilirubin), ions