The Digestive System

Question 1

What are the 6 processes of the digestive system?

Answer 1

1. Ingestion
2. Secretion
3. Mixing and propulsion
4. Digestion
5. Absorption
6. Defecation

Question 2

What is ingestion

Answer 2

Taking food and liquids in through the mouth

Question 3

What is secretion

Answer 3

the release of water, enzymes and acids into the lumen of the digestive tract

Question 4

What is mixing and propulsion

Answer 4

the churning of food and its propulsion through the GI tract

Question 5

what is digestion

Answer 5

the chemical and mechanical breakdown of food

Question 6

what is absorption

Answer 6

products of digestion (vitamins, minerals, and water) cross the mucosa and enter the lymph or the blood

Question 7

What is defecation

Answer 7

where undigested material is eliminated

Question 8

What are the 4 layers of the GI tract:

Answer 8

1. muscosa
2. submucosa
3. muscularis
4. serosa

Question 9

Describe the mucosa

Answer 9

inner lining of GI tract, mucous membrane

Question 10

Describe the submucosa

Answer 10

Connective tissue binding the mucosa and muscularis (2nd innermost layer)

Question 11

Describe the muscularis

Answer 11

smooth muscle layer, both circular and longitudinal (2nd outermost layer)

Question 12

Describe the serosa

Answer 12

serous membrane, outermost layer

Question 13

What is the peritoneum

Answer 13

The serous membrane that lines the abdominal cavity

Question 14

What are the layers of the peritoneum

Answer 14

Parietal (superficial) layer
Visceral (deep) layer

Question 15

What is the difference between the parietal and visceral peritoneum?

Answer 15

Parietal lines abdominal cavity
Visceral lines some organs within the cavity

Question 16

What are 4 names for the folds of the peritoneum?

Answer 16

Greater + lesser omentum
mesentry
colon

Question 16

What is the greater omentum?

Answer 16

A fatty apron which hangs over the transverse colon and small intestine

Question 17

What does retroperitoneal mean?

Answer 17

The space behind the peritoneal cavity

Question 18

Which organs are retroperitoneal? (3)

Answer 18

Kidneys
Pancreas
Ascending/descending colon

Question 19

Composition of saliva? (4)

Answer 19

Mucin
salivary amylase
bicarbonate
lysozyme

Question 20

What are the 6 organs on the digestive system?

Answer 20

1. Mouth
2. Pharynx
3. Oesophagus
4. Stomach
5. Small intestine
6. Large intestine

Question 21

What is the function of the pharynx?

Answer 21

• moves bolus from oropharynx to laropharynx
• closes air passageways

Question 22

How does food path through the oesophagus?

Answer 22

1. upper oesophageal sphincter relaxed - food enters
2. peristalsis pushes bolus through oesophagus
3. lower oesophageal sphincter relaxes and bolus enters stomach

Question 23

What are the 4 regions of the stomach?

Answer 23

1. Fundus
2. Cardiac region
3. Body
4. Pyloric regions

Question 24

What are the functions of the stomach (3)?

Answer 24

1. food storage 2. digestion 3. regulation of delivery

Question 25

Where are parietal cells found?

Answer 25

In fundus and body of stomach

Question 26

What do parietal cells secrete?

Answer 26

Hydrochloric acid (break down food) Intrinsic factors (needed to absorb B12)

Question 27

Which cells secrete pepsinogen?

Answer 27

Gastric chief cells

Question 28

What is the function of pepsinogen?

Answer 28

Breaks down proteins into peptides

Question 29

What is chyme?

Answer 29

Acidic fluid which passes from stomach to small intestine

Question 30

Functions of the small intestine

Answer 30

- Neutralises stomach acid - Adds enzymes and bile - Breaks molecules into absorbable materials

Question 31

What does peristalsis in the small intestine do?

Answer 31

Mixes chyme and brings it into contact with mucosa Moves it along intestinal tract

Question 32

Regions of the small intestine (3)

Answer 32

Duodenum, jejunum, ileum

Question 33

Adaptations of mucosa in the small intestine (2)

Answer 33

Villi containing blood Lacteal capillaries

Question 34

What are the movements of the large intestine? (3)

Answer 34

- haustral churning - peristalsis - mass peristalsis

Question 35

What are the functions of the large intestine? (3)

Answer 35

- Bacteria breaking down proteins and amino acid - Final absorption of water, vitamins and ions - Forming faeces

Question 36

What are the accessory organs to digestion? (3)

Answer 36

- Pancreas - Liver - Gallbladder

Question 37

What is innervation?

Answer 37

the process of supplying nerves to an organ or part of the body

Question 38

What is the enteric nervous system?

Answer 38

Neurons and supporting cells throughout the digestive tract

Question 39

The ENS is the largest part of the ___

Answer 39

Autonomic nervous system

Question 40

The enteric nervous system consists of which plexuses (2)

Answer 40

- Myenteric plexus - Submucosal plexus

Question 41

Function and structure of the myenteric plexus

Answer 41

Motor neurons located between longitudinal and circular muscle Controls GI tract motility

Question 42

Structure and function of submucosal plexus

Answer 42

Motor nerves control secretory cells Contains sensory nerves (chemoreceptors and stretch receptors)

Question 43

What is peristalsis?

Answer 43

- involuntary constriction and relaxation of intestinal muscles - creating wave-like movements that push the contents of the canal forward

Question 44

Early stages of gut microbiomes colonisation coincides with ____ development

Answer 44

Immune

Question 45

What are the 3 phases of digestion?

Answer 45

1. Cephalic phase 2. Gastric phase 3. intestinal phase

Question 46

What is the cephalic phase of digestion?

Answer 46

- seeing, thinking about or tasting food - stimulates salivary and gastric glands to secrete saliva and gastric juice - prepares digestive system for influx of food

Question 47

What is the gastric phase of digestion?

Answer 47

- regulated by neural (chemo and stretch receptors) and hormonal (gastrin) mechanisms - promotes gastric secretion and motility

Question 48

What is the intestinal phase of digestion?

Answer 48

- when food enters the small intestine - regulated by neural (stretch) and hormonal (secretin and cholecystokinin) regulation

Question 49

What are the 3 main hormones involved in the digestive process?

Answer 49

- gastrin - secretin - cholecystokinin