Week 2

Question 1

Role of the digestive system (3 parts)

Answer 1

• Digestion: breakdown food, extract nutrients, breakdown macronutrients
• Absorption: transfer nutrients from lumen of small intestine into blood or lymphatic capillaries
• Excretion: eliminating remaining food waste

Question 2

List the whole digestive process and its key parts

Answer 2

• Salivary glands secrete saliva; chewing breaks down food.
• Epiglottis prevents food entering windpipe.
• Bolus moves to oesophagus; sphincter controls passage to stomach.
• Stomach adds juices, grinds bolus into chyme.
• Pyloric sphincter regulates chyme flow to small intestine.
• Small intestine receives bile and juices from gallbladder and pancreas.
• Large intestine starts at ileocaecal valve; undigested residues move to rectum, excreted from anus.

Question 3

What is mastication?

Answer 3

Chewing, saliva release to break down food

Question 4

What is peristalsis?

Answer 4

Muscle contractions that move food through the digestive tract

Question 5

What is segmentation?

Answer 5

Muscle contractions create segments in intestines that mix and break down food

Question 6

List the different sphincters

Answer 6

• oesophageal sphincters
• pyloric sphincter
• ileocaecal valve
• two sphincters of anus

Question 7

What are the three types of macronutrients broken down into?

Answer 7

Carbs –> Glucose + other monosaccharides
Proteins –> Amino acids
Triglycerides –> Glycerol + fatty acids

Question 8

How does stomach create low pH environment and what does this do in the stomach?

Answer 8

• Gastric glands release HCl
  Serves to:
• Denature proteins
• Activate the enzyme
• Kill harmful bacteria

Question 9

What role does each of the three sections of the small intestines play?

Answer 9

• Duodenum: where most digestion occurs
• Jejunum: where most nutrient absorption occurs
• Ileum: absorption of some important nutrients (B12, A, D, E, K)

Question 10

What are the pH levels of the mouth, stomach and small intestine?

Answer 10

Mouth - neutral
Stomach - low
Small intestine - neutral

Question 11

How does small intestine function?

Answer 11

Small nutrients are trapped in microvilli and absorbed into mucosal cells, then pass into blood stream (water-soluble vitamins and small products of fat digestion) or lymphatic vessels (fat-soluble vitamins and larger fat form chylomicrons)

Question 12

Path blood takes when leaving the digestive system

Answer 12

Heart → arteries→ capillaries (intestines)→ portal vein
→ liver → capillaries (liver) → hepatic vein → heart

Question 13

Role of hepatic portal vein and hepatic vein

Answer 13

Hepatic portal vein: collects blood from GI tract and delivers to liver capillaries
Hepatic vein: collects blood from liver and delivers to heart

Question 14

Role of liver

Answer 14

• Removes toxins
• Stores nutrients
• Releases nutrients into the
  blood

Question 15

Explain the lymphatic system process

Answer 15

• Drains excess fluid.
• Transports large fatty acids and fat-soluble vitamins (chylomicrons) to the blood.
• Filters waste and supports immunity.

Question 16

Probiotics vs prebiotics

Answer 16

Probiotics: bacteria found in foods such as yoghurt
Prebiotics: not absorbed but used as food by intestinal bacteria

Question 17

List some healthy GI tract tips

Answer 17

Eat a healthy diet
Get enough sleep
Stay active
Relax during meals