Lower Digestive System

Question 1

What are the 3 sections of the small intestine?

Answer 1

• Duodenum
• Jejunum
• Ileum

Question 2

What is the duodenum and what does it do?

Answer 2

Short tube which exits the stomach on the right side of abdomen and receives ducts from the pancreas and liver

Question 3

What is the jejunum and what does it do?

Answer 3

Longest tube, which digests and absorbs nutrients

Question 4

What is the ileum and what does it do?

Answer 4

Shortest tube lined with lymphocytes for gut immunity which joins the large intestine at the ileoceceal junction

Question 5

What is emulsification?

Answer 5

Physical breakdown of fats into small droplets

Question 6

What is the digestive function of the liver?

Answer 6

• Hepatocytes produce bile which contains bile acids, which emulsify big droplets of fats into small droplets
• Bile is stored in the gall bladder
• Converts fatty acids into phospholipids and cholesterol
• Stores glucose as glycogen
• Use digested amino acids to make new protein or covert it to glucose
• Converts wasted ammonia to urea
• Detoxification
• Stores iron and vitamins
• Excretes bilirubin (breakdown product of haemoglobin)

Question 7

What is the digestive function of the pancreas?

Answer 7

Secrete digestive enzymes and sodium bicarbonate which neutralises stomach acid

Question 8

What are the 3 main digestive enzymes?

Answer 8

• Trypsin and peptidases
• Amylase
• Lipase

Question 9

How are proteins digested?

Answer 9

Typsin digest proteins into peptides and eventually amino acids by peptidases

Question 10

How are carbohydrates digested?

Answer 10

Amylase digest starch into disaccharides and then monosaccharides by lactase or sucrase

Question 11

How are fats/lipids digested?

Answer 11

Fats are emulsified by bile and then lipase digests the fats into fatty acids and glycerol

Question 12

Describe small intestine motility

Answer 12

Segmentation alternates contraction and relaxation to mix chyme and digestive enzymes
- Peristalsis for one-way progression of chyme along the small intestine

Question 13

How are nutrients absorbed in the small intestine?

Answer 13

• Amino acids and sugars absorbed into blood capillaries and carried by hepatic portal vein to liver for further processing
• Fatty acids absorbed into lymphatics

Question 14

What are the 3 sections of the large intestine?

Answer 14

• Caecum
• Colon
• Rectum

Question 15

What is the function of the caecum and colon?

Answer 15

• Absorbs water and electrolytes forming chyme into solid faeces
• Have goblet cells to secrete mucous with lubricates faeces
• Large numbers of bacteria to prevent pathogens colonising
• Storage of faecal matter in colon

Question 16

What does diarrhoea in the small intestine look like?

Answer 16

• Large volumes and very watery liquid

Question 17

What does diarrhoea in the large intestine?

Answer 17

• Small volumes
• Increased frequency
• Variable consistency often containing blood and mucus

Question 18

How do herbivores digest cellulose?

Answer 18

Ferments cellulose in the gut and produces volatile fatty acids, which as used as energy

Question 19

What are foregut fermenters called?

Answer 19

Ruminants

Question 20

What is a diastema and where is it found?

Answer 20

A gap between incisors and cheek teeth in ruminants

Question 21

How many chambers does the ruminant stomach have?

Answer 21

4

Question 22

Why is muscular contractions for forestomach motility beneficial?

Answer 22

• Mix contents of the rumen promoting fermentation
• Allows cud to be regurgitated to be re-chewed and re-swallowed
• Allows eructation (Built up CO2 or methane gas is expelled)

Question 23

What causes bloating in the ruminant and why is it dangerous?

Answer 23

Oesophagus is blocked or ruminant is stuck upside down, which means tehy cannot burp the gas out and therefore will die