digestion

Question 1

4 groups of nutrients

Answer 1

carbohydrates,
proteins,
lipids,
vitamins and minerals

Question 2

how many vitamins and minerals are there

Answer 2

13 vitamins and 15 minerals

Question 3

3 animal feeding strategies

Answer 3

filter feeders,
detritivore,
fluid feeders

Question 4

3 different digestive specialisations

Answer 4

carnivore,
herbivore,
omnivore

Question 5

4 stages of a generalised digestive system and what happens in each

Answer 5

1. motility - mixes and propels digestive contents forwards
2. secretion - of digestive enzymes, under neuroendocrine control
3. digestion - sequential hydrolysis of complex molecules
4. absorption - uptake of simple absorbable units, water, vitamins and electrolytes via specialised epithelia transporters

Question 6

what animals have the simplest digestive structure where the mouth and anus are the same

Answer 6

Ctenophora, Cnidaria and Platyhelminthes

Question 7

what animal has a digestive system which is a simple line

Answer 7

hagfish

Question 8

what unique structure is found in a gar’s digestive tract

Answer 8

pyloric cici

Question 9

what unique structure is found in a shark’s digestive tract

Answer 9

spiralised intestine

Question 10

what unique structure is found in a chicken (and other bird’s) digestive tract and what is it for

Answer 10

‘crop’ to store digestive material

Question 11

what do fish have that show the beginning evolution of the pancreas

Answer 11

pancreatic ducts

Question 12

what differences lie among vertebrate digestive systems

Answer 12

all have same organs, but different arrangement
look different anatomically

Question 13

birds have an additional glandular portion of the stomach, what is this called and what is it for

Answer 13

proventriculus which secretes hydrochloric acid

Question 14

what is a bird’s gizzard for

Answer 14

grinding of food

Question 15

what 2 intrinsic nerve plexuses make up the enteric nervous system

Answer 15

myenteric plexus and submucous plexus make up the enteric nervous system

Question 16

what extrinsic nerves are responsible for digestive system regulation

Answer 16

autonomic (parasympathetic) nervous system including vagus nerve

Question 17

what is the role of the mouth and what enzymes are released

Answer 17

grind food and mix with saliva
saliva lubricates bowla (food mass) allowing it to pass smoothly down oesophagus
saliva has amylase to begin digestion

Question 18

how is swallowing achieved

Answer 18

waves of peristatic muscular contraction

Question 19

what is the role of the stomach

Answer 19

stores ingested material,
kill microorganisms

Question 20

what is used in initial digestion occuring in the stomach

Answer 20

chyme

Question 21

3 types of gastric exocrine secretory cell and what do these release

Answer 21

parietal cells - hydrochloric acid and intrinsic factor
chief cells - pepsinogen
mucus cells - mucus is protective layer against HCl

Question 22

how is pepsinogen converted to pepsin

Answer 22

hydrochloric acid

Question 23

how are gastric pits formed and what do they contain

Answer 23

deeply infolded mucosa containing gastric gland cells at base

Question 24

3 types of gastric endocrine / paracrine secretory cells and what do they do

Answer 24

histamine - promote HCl secretion,
gastrin - promote HCl secretion,
somatostatin - decrease HCl secretion

Question 25

2 pancreatic proteolytic enzymes

Answer 25

trypsinogen (trypsin),
chymotrypsinogen (chymotrypsin),
procarboxypeptidase (carboxypeptidase)

Question 26

what is the name for the combine pancreas and liver in invertebrates and fish

Answer 26

hepatopancreas

Question 27

why are pancreatic proteolytic enzymes sencreted as their inactive forms

Answer 27

to prevent self-digestion of cells secreting them

Question 28

what other enzymes does the pancreas release

Answer 28

amylase, chitinase and lipase

Question 29

what type of control are enzymes released in the pancreas under

Answer 29

negative feedback / hormonal

Question 30

what makes up the biliary system

Answer 30

liver, gallbladder and ducts

Question 31

what does bile contain

Answer 31

bile salts, cholesterol and lecithin

Question 32

what is the role of bile salts

Answer 32

aid fat digestion and absorption
fats are hydrophobic so are broken down into smaller droplets by bile salts

Question 33

what adaptations does the mucosal lining of the small intestine have

Answer 33

maximised surface area and specialised transport mechanisms

Question 34

what is the role of the brush border in the small intestine

Answer 34

final carbohydrate and protein digestion

Question 35

how does vitamin absorption occur

Answer 35

via micelles or via specialised transporters

Question 36

what is an indirect benefit of Na+ / K+ active transport

Answer 36

water uptake by diffusion

Question 37

what steps are involved in lipid absorption

Answer 37

1. micelles freely diffuse into cell and become triglycerides
2. coated in lipoprotein and become chylomicrons
3. pass into lymphatic system, not blood

Question 38

what happens to most absorbed nutrients from the small intestine

Answer 38

immediate processing in liver

Question 39

what are the roles of the liver

Answer 39

metabolic processing
detoxification

Question 40

what is the role of the large intestine

Answer 40

storage of excreted material
microbiota

Question 41

what minerals are absorbed in the large intestine

Answer 41

active Na+ absorption and passive uptake of Cl- and water

Question 42

what is rumination

Answer 42

regurgitation followed by further grinding

Question 43

what occurs in the rumen

Answer 43

microbial digestion,
fermentation of carbohydrates,
protein hydrolysis

Question 44

what is the name for the true stomach in ruminants

Answer 44

abomasum - site of acid secretion