The Digestive System and Metabolism

Question 1

6 major processes
ingestion

Answer 1

taking food and drink into the digestive tract

Question 2

propulsion

Answer 2

moving food through
the digestive tract,
peristalsis- alternate waves of muscle
contraction and relaxation

Question 3

Mechanical breakdown

Answer 3

physical breakdown of food
into smaller parts

Question 4

Chemical digestion

Answer 4

enzymatic breakdown of food into building blocks

Question 5

Absorption

Answer 5

movement of monomers from the
digestive tract into the blood or lymph

Question 6

Defaecation

Answer 6

removal of indigestible food from the
digestive tract

Question 7

digestive process(es)

Answer 7

Mouth: Ingestion
Propulsion involves swallowing
Mechanical breakdown (chewing and mixing food with saliva to form bolus)
Chemical digestion (carb)
Pharynx oesophagus: Propulsion (by peristalsis)
stomach: Chemical digestion (pepsin initiates breakdown of protein)
Absorption (fat soluble chemical and alcohol)
Propulsion (by peristalsis)
Mechanical breakdown ( mixes food with gastric juice to produce chyme)
Small intestine: Absorption (majority of all building blocks move form lumen of digestive tract into the blood supply of the lymph)
Propulsion (by peristalsis)
Mechanical breakdown (segmentation to increase SA)
Chemical breakdown (of all food class)
Large intestine: Propulsion haustral contractions
Defaecation
Absorption water electrolyte and vitamins

Question 8

functions of the accessory organ

Answer 8

liver produce bile
gall bladder stores bile
pancreas produces amylase, proteases, lipases and nucleases to break down all food class

Question 9

chemical digestion class of enzymes
carb

Answer 9

monosaccharides (glucose, fructose, galactose)
disaccharides (sucrose, lactose, maltose)
polysaccharides, (glycogen, starch, cellulose)
mouth: salivary amylase
Pancreas: pancreatic amylase
Small Intestine: brush border

Question 10

protein

Answer 10

Stomach: pepsin
Pancreas: pancreatic proteases
Small Intestine: brush border

Question 11

fats

Answer 11

fat droplet coated in bile salts which the lipases breakdown into fatty acids and glycerol
pancreas: lipases

Question 12

Nucleic Acid

Answer 12

DNA/ RNA broken down by Pancreatic
nucleases into nucleotide, then broken down by brush border enzymes into base, sugar & phosphate ions

Question 13

nutrient absorption

Answer 13

all nutrients go to the liver to be processed or stored via the hepatic portal vein
lipids taken via the lacteal to the lymph where it enters the general circulation then taken to liver for processing

Question 14

define terms

Answer 14

Metabolism = the sum total of the chemical reactions occurring in an organism
Anabolism = reactions that build larger molecules from smaller ones
Catabolism = reactions that break down larger molecules into smaller ones

Question 15

anabolic state

Answer 15

Cellular respiration produce ATP
glucose converted to glycogen or triglycerides
amino acids converted to triglycerides
glycerol and fatty acids reconverted to
triglycerides

Question 16

Catabolic state

Answer 16

Glycogenolysis = breakdown of glycogen to glucose
Gluconeogenesis = production of new glucose from non carbohydrate sources

Question 17

gastric pits/gastric glands
contain: stomach

Answer 17

Parietal cells: produce HCl
activates pepsin= denatures proteins and
destroys most bacteria
Chief cells: produce pepsinogen, the inactive form of pepsin
Goblet cells: mucus – protect mucosa from HCl

Question 18

small intestine anatomy

Answer 18

circular folds?
slow the movement of chyme, thus increasing time for nutrient absorption
villi?
absorptive epithelial cells for nutrient absorption
microvilli?
increase surface area and have brush border enzymes present on plasma membrane to chemically digest food.