Digestive System 1

Question 1

8 key functions of the digestive system

Answer 1

Ingestion
Mastication
Propulsion
Mixing
Secretion
Digestion
Absorption
Elimination

Question 2

Role of ingestion

Answer 2

Bringing food to the stomach

Question 3

Role of mastication

Answer 3

Chewing

Question 4

Role of secretion

Answer 4

For lubrication, liquification, digestion

Question 5

Role of absorption

Answer 5

Movement of molecules into cells and circulation

Question 6

Role of elimination

Answer 6

Removal of waste products

Question 7

Role of digestion

Answer 7

breakdown of molecules into their constituent parts

Question 8

What are the 2 forms of digestion

Answer 8

Mechanical and Chemical

Question 9

What is mechanical digestion?

Answer 9

Physical disruption of food into smaller parts - chewing food

Question 10

What is chemical digestion?

Answer 10

• Breaks down food into small soluble constituents
• Reliant on enzymes
• Some enzymes produced by the body some are produced by commensal bacteria

Question 11

What are the 4 segments of the gastrointestinal tract

Answer 11

• Mucosa
• Submucosa
• Muscular layers (Tunica muscularis)
• Serosa / adventitia (smooth tissue membrane)

Question 12

Function of the mucosa

Answer 12

absorption

Question 13

Function of the submucosa

Answer 13

support

Question 14

Function of the tunica muscularis

Answer 14

Propels and moves substances along the tract

Question 15

Function of the serosa / adventitia

Answer 15

movement of the tract

Question 16

What is peristalsis

Answer 16

The method that allows the movement of substances along the tract, by contraction of muscles

Question 17

What mechanical digestion takes place in the mouth / oral cavity?

Answer 17

• Chewing / mastication
• Physical break up of food

Question 18

What chemical digestion takes place in the mouth / oral cavity?

Answer 18

• Saliva from salivary glands contains salivary amylase for carbohydrate digestion

Question 19

What is starch broken down into

Answer 19

Starch —-> maltose + isomaltose

Question 20

What are the 3 sets of salivary glands called?

Answer 20

1) Parotid
2) Sublingual
3) Submandibular

Question 21

Location of parotid gland

Answer 21

Beside the ear

Question 22

Location of sublingual gland

Answer 22

below the tongue on the floor of the mouth

Question 23

Location of submandibular gland

Answer 23

Below the jaw

Question 24

Oesophagus function

Answer 24

Transports food from pharynx to stomach

Question 25

Oesophagus structure

Answer 25

Outer longitudinal muscle and inner circular muscle

Question 26

Mechanical digestion functions of the stomach

Answer 26

- Churning and mixing of food - Increases contact between enzymes and digesta

Question 27

3 Chemical digestion functions of the stomach

Answer 27

- Pepsinogen - breaks down protein - Hydrochloric acid - break down protein and absorb essential nutrients - Rennin / Chymosin - helps control blood pressure and maintain healthy level of sodium and potassium in the body.

Question 28

Fermentation function in the stomach

Answer 28

Rely on bacteria, fungi and protists to break down food

Question 29

What are the 3 muscle layers of the stomach?

Answer 29

Outer - longitudinal Middle - circular Inner - oblique

Question 30

What are rugae?

Answer 30

Wrinkles in the stomach. Present in an empty stomach, disappear when bloated.

Question 31

What are ruminants stomach?

Answer 31

The stomach of cows, sheep, goats. Have 4 chambers for specialised cellulose digestion, to break down cellulose. Cellulose is broken down by the enzyme cellulase. Fungi, bacteria and protozoans produce cellulase.

Question 32

Functions of chief cells.

Answer 32

1) Produce pepsinogen 2) produce rennin/ chymosin

Question 33

What are mucosa?

Answer 33

Mucus secreting cells Simple columnar epithelium with gastric pits

Question 34

Functions of parietal cells

Answer 34

1) produce Hydrochloric acid 2) Intrinsic factor

Question 35

Function of pepsinogen

Answer 35

- Break down protein into smaller peptides

Question 36

Function of rennin/ chymoin

Answer 36

- coagulate milk - important in very young babies

Question 37

Function of Hydrochloric acid

Answer 37

- minor digestive effect - maintains acidity - kills ingested bacteria

Question 38

What molecule is Intrinsic factor and what is its function?

Answer 38

- glycoprotein - binds to vitamin B12

Question 39

Function of the rumen

Answer 39

- Receives swallowed food - holding and fermentation vat - Food can be regurgitated, remasticated, reswallowed

Question 40

Structure of the rumen

Answer 40

fluffy fibrous fibers Distinctive papillated mucosa

Question 41

Reticulum function

Answer 41

- Small accessory chamber - Contracts to slosh chyme between itself and rumen

Question 42

Reticulum structure

Answer 42

'Honeycomb' structure mucosa

Question 43

Omasum structure

Answer 43

Epithelium folded into laminae

Question 44

Omasum function

Answer 44

Pumps food into abomasum

Question 45

Abomasum function

Answer 45

Enzymatic digestion, highly acidic

Question 46

Abomasum structure

Answer 46

Distinctive simple columnar, glandular epithelium

Question 47

Ruminoreticula groove

Answer 47

Mill bypasses rumen via ruminoreticula groove Closes into tube connecting oesophagus to omasum

Question 48

Liver function

Answer 48

produces and secretes bile

Question 49

Gall bladder function

Answer 49

Stores bile and secretes it to the digestive tract - releases it into the duodenum during meals

Question 50

What are the 4 anatomical lobes of the liver

Answer 50

Right lobe, left lobe, quadrate lobe, caudate lobe

Question 51

Structure and location of the gallbladder

Answer 51

Pear shaped sac under right lobe of liver

Question 52

What is the function of the pancreas

Answer 52

Produces most of the digestive enzymes in the small intestine - Proteolytic enzymes e.g. trypsin, carboxypeptidase - Nucleic acid enzymes - Pancreatic amylase - for polysaccharide digestion

Question 53

Name the 3 parts of the small intestine

Answer 53

Duodenum, Jejunum, Ileum

Question 54

How is the small intestine involved in chemical digestion?

Answer 54

Secretes pancreatic juice Secretes bile Secretes intestinal juice

Question 55

What does the small intestine absorb?

Answer 55

- Proteins - Carbohydrates - Fats

Question 56

What is the structure of the duodenum?

Answer 56

C - shaped and encircles pancreas

Question 57

Function of the jejunum and ileum

Answer 57

enzymes --> Disaccharidases = disaccharides--> monosaccharides Peptidases = peptide chains --> amino acids Nucleases = DNA --> bases

Question 58

Function of microvilli in the jejunoileum

Answer 58

Increase surface area allowing more nutrients to be absorbed

Question 59

Structure and function of the mucosa of the small intestine

Answer 59

The mucosa is lined with villi and highly folded The cells lining the villi contain microvilli Allow an increased surface area for absorption of protein, carbohydrate and fat

Question 60

Does the amount of nutrient absorption increase or decrease as you approach the large intestine.

Answer 60

Decreases

Question 61

What is midgut fermentation

Answer 61

Cellulose digestion by commensal bacteria in the ascending colon

Question 62

What is the function of smooth mucosa in the intestinal glands - (no villi)

Answer 62

Allows: - Absorption of salts - Absorption of water - Fermentation of complex carbohydrates - Excretion of faeces

Question 63

Functions of the rectum

Answer 63

Pelvic part of GI tract Supports and stores faecal mass before defecation

Question 64

Function of the anus

Answer 64

Build up of pressure against walls causes internal sphincter to relax, open and allow faeces into canal Relaxation of external sphincter allows defecation