Week 3: Digestion and absborption

Question 1

What is ingestion?

Answer 1

Taking in food

Question 2

What does the gastronintestinal system secrete?

Answer 2

Water, acids, enzymes, buffers

Question 3

How does the gastrointestinal system involve mobility?

Answer 3

Contraction and relaxation of smooth muscle

Question 4

What processes occur during digestion?

Answer 4

Mechanical and chemical

Question 5

What % of absorption occurs in the small intestine?

Answer 5

95%

Question 6

What material do we defecate?

Answer 6

Indigestible substances, cells, digested materials not absorbed

Question 7

What does the oral cavity consist of?

Answer 7

Mouth and pharynx

Question 8

What are the first steps of the digestion process?

Answer 8

Mastication (chewing)

Question 9

When does the first step of digestion occur?

Answer 9

Oral cavity

Question 10

Is mastication voluntary?

Answer 10

It is both voluntary and involuntary

Question 11

How is swallowing initiated?

Answer 11

Food bolus is forced by the tongue to the rear of the mount to the pharynx

Question 12

What does saliva consist of?

Answer 12

Serous solution containing electrolytes, mucous, proteins and enzymes

Question 13

How much saliva is produce each day?

Answer 13

1 L

Question 14

What are the three glands that produce 95% of our saliva?

Answer 14

Parotid
Submandibular
Sublingual

Question 15

Where is 5% of our saliva produced?

Answer 15

Simple buccal glands

Question 16

What is the function of the oesophagus?

Answer 16

Moves food from mouth to stomach

Question 17

How many layers of muscle does the oesophagus contain?

Answer 17

Two

Question 18

What are the muscle layers of the oesophagus?

Answer 18

Circular

Longitudinal

Question 19

How does the oesphagus move food?

Answer 19

Wave of contraction sweeps

Question 20

What is the function of the stomach?

Answer 20

Stores food

Delivers food to the gut

Question 21

How much gastric juice is produces per day?

Answer 21

2 L

Question 22

What is in the stomach for protection?

Answer 22

Ions

Mucus

Question 23

What will stimulate gastric secretion during the cephalic phase?

Answer 23

Arrival of food in stomach
Vision
Smell
Chewing
Taste

Question 24

What percent of gastric secretion is down to cephalic phase?

Answer 24

30%

Question 25

What does the parasympathetic nervous system stimulate during the cephalic phase?

Answer 25

The release of gastrin (hormone that stimulates gastric secretion)

Question 26

What percent of gastric secretion is due to the gastric phase?

Answer 26

60%

Question 27

During the gastric phase what does the stretch and products of protein digestion stimulate?

Answer 27

Gastric secretion | Gastrin

Question 28

What type of contractions occur in the small intestine?

Answer 28

Peristaltic, longitudinal | Segmentation contractions

Question 29

What is the purpose of segmentation contractions withing the small intestine?

Answer 29

To mix chyme with pancreatic secretions and bile, to increase exposure to mucosal surface

Question 30

What does motility mean?

Answer 30

Contraction of the muscles that mix and propel contents in the gastrointestinal (GI) tract

Question 31

What does motility mean?

Answer 31

Contraction of the muscles that mix and propel contents in the gastrointestinal (GI) tract

Question 32

What controls the small intestine motility?

Answer 32

Intrinsic enteric nervous system Transmitters and hormones Extrinsic nerves

Question 33

How does the intrinsic enteric nervous system control small intestine motility?

Answer 33

Myogenic mechanisms responsive to stretch pH Products of digestion Osmolality

Question 34

How do transmitters and hormones control the small intestine motility?

Answer 34

ACh, gastrin, CCK increase motility | NO inhibits motility

Question 35

How do the extrinsic nerves control the small intestine motility?

Answer 35

Parasympathetic (ACh) increases motility | Sympathetic (NA) inhibits motility

Question 36

How long does it take for the chyme to reach the terminal ileum?

Answer 36

Around 12 hours

Question 37

What prevents retrograde movement of chyme and bacteria from colon?

Answer 37

Ileal-caecal sphincter

Question 38

What are the principal functions of the large intestine?

Answer 38

Reabsorption of water | Storage of feaces, some bacterial metabolism of carbohydrate to produce short chain fatty acids

Question 39

How often do mass movements in the large intestine occur?

Answer 39

2-3 times per day

Question 40

What is the function of the gastrointestinal system?

Answer 40

Digest and absorb nutrients

Question 41

What is the gastrointestinal system lined with?

Answer 41

Mucosa (thick in mouth, thin in intestine)

Question 42

What is the function of smooth muscle in the gastrointestinal system?

Answer 42

Gastric and intestinal motility

Question 43

How much fluids containing enzymes are secreted into the lumen of the gut?

Answer 43

6 litres per day