Digestive system

Question 1

digestive system consists of:

Answer 1

• digestive tract
• gastrointestinal tract
• the gut

Question 2

necessity of digestive system

Answer 2

• receive & move food material
• process to reduce size
• absorbs digested components via gut membranes & blood vessels
• remove waste products

Question 3

parasympathetic nervous system

Answer 3

• stimulates DS
• increases salivation, motility

Question 4

sympathetic nervous system

Answer 4

• inhibits DS

Question 5

mouth & oral cavity

Answer 5

• bite, chew, grind, lubricate
• pharynx = food & air passage

Question 6

foregut

Answer 6

• oesophagus = transports
• stomach = degrade & digest

Question 7

mid gut

Answer 7

• last part of duodenum
• small intestine = propels and digests
• appendix & part of caecum-colon

Question 8

hindgut

Answer 8

-colon, rectum, anal canal
- ferments, expels

Question 9

mouth & lip functions

Answer 9

• select, bite, grasp food
• move food to oral cavity
• taste to select/reject food
• salivate = lubricate & neutralise
• prehensile & masticate to form bolus

Question 10

prehension

Answer 10

moving food to oral cavity
e.g. with arms

Question 11

carnivorous teeth & jaws:

Answer 11

-canines for tearing
- pointed molars to crush bone

Question 12

omnivorous teeth & jaws:

Answer 12

• molars to grind
• incisors for ripping
• tongue to move food onto teeth

Question 13

pseudo ruminants teeth and jaws

Answer 13

• incisor for biting
• angled molars
• circular jaw movements to help grind

Question 14

ruminant teeth & jaws

Answer 14

• no upper incisors, strong dental pad instead
• molars w/ tongue & jaw movement = crush & chew

Question 15

where are ruminant salivary glands located?

Answer 15

oral vestibule - via cheek
- parotid
- buccal
oral cavity proper
- mandibular
- sublingual

Question 16

what are ruminant salivary gland functions?

Answer 16

• produces saliva
• moistens, neutralises food
• protects oral cavity
• contains salt, HCO, mucous & lysozymes

Question 17

ruminant tongue

Answer 17

• ingests, chews, rotates & makes boluses
• helps drink water
• rough, hook-like papillae
• taste buds

Question 18

four compartments of ruminant stomach

Answer 18

1- rumen
2- reticulum
3- omasum
4- abomasum

Question 19

ruminant digestion

Answer 19

• rapid swallowing of food, no chewing
• all ingested moves directly to rumen
• stay solid in rumen
• liquids & solubles move from reticulum to abomasum

Question 20

oesophageal groove

Answer 20

• muscular folds
• control passage of food from cardia > omasum
• open = food enter Rumen & Reticulum

Question 21

rumination

Answer 21

chewing cud when rumen full
- regurgitate the food
- mini muscular contraction

Question 22

rumination function:

Answer 22

• moves & processes food
• utilises 50-85% of digestible organic matter
• saliva maintains rumen pH
• papillae inc. surface area
• remove gas by belching, prevents bloating

Question 23

ruminant omasum function

Answer 23

• strong, muscular w/ piles
• grinds & squeezes food
• removes food
• absorbs volatile fatty acids

Question 24

ruminant abomasum function

Answer 24

true stomach
- gastric juices aded to undegraded feed
- low digestion of fat, cellulose, starch
- pH 3
- food turns to slurry before entering SI

Question 25

factors affecting bile

Answer 25

-food as slurry in duodenum - HCl in duodenum - salts in duodenum -fat molecules in duodenum

Question 26

features of ruminant large intestine:

Answer 26

- caecum - colon - rectum

Question 27

ruminant large intestine function

Answer 27

- hind gut fermentation - 17% volatile fatty acid absorption - ammonia N absorption - mineral & water absorption

Question 28

mono-gastric digestive system

Answer 28

- from mouth to anus - single stomach - no pre-gastric fermentation

Question 29

mono-gastric mouth and oral cavity function

Answer 29

- gather, sort, process food - physical rupture - disintegration

Question 30

mono-gastric tongue structure

Answer 30

- 8 muscles (4 extrinsic - attached to bone) (4 intrinsic - not attached to bone) - papillae & taste buds - salivary glands

Question 31

components of mono-gastric stomach

Answer 31

- oesophageal > no glands - cardiac > mucous - fundic > parietal cells > chief cells - pyloric > mucous

Question 32

mono-gastric oesophagus functions

Answer 32

- start of peristalsis = muscular contractions - deglutition = swallowing

Question 33

Gastrointestinal tube layers

Answer 33

outermost = serosa - muscularis - submucosa innermost = mucosa

Question 34

gastric pits & motility

Answer 34

- many folds in epithelium - glands release secretions in pits - motility (independent movement) helps mix & hydrolyse chyme

Question 35

gastric secretions

Answer 35

- acid = HCl - mucous - rennin = clots milk, in newborns - lipase

Question 36

gastric function

Answer 36

first major digestive process - mix, churn, moisten - acid, enzyme & hormone secretion -mucous formation - proteolysis (break down of proteins)

Question 37

mono-gastric small intestine components

Answer 37

-duodenum -jejunum -ileum

Question 38

mono-gastric duodenum function

Answer 38

-bile & pancreatic fluids - active digestion

Question 39

jejunum function

Answer 39

- nutrient absorption - otherwise excreted = waste of food & energy

Question 40

ilium function

Answer 40

- absorption of water, vitamins & minerals

Question 41

bile

Answer 41

green viscous liquid - salts, pigments - alkaline - emulsifies fats - 95% returns to liver

Question 42

mono-gastric pancreas exocrine tissue

Answer 42

-neutralise acidic chyme - salts - many enzymes

Question 43

mono-gastric pancreas endocrine tissue

Answer 43

produces: -insulin -glucagon

Question 44

hepatic portal system

Answer 44

delivers blood to liver form: - hepatic artery - hepatic vein - hepatic portal vein venous blod contains absorbed nutrients