Chapter 9

Question 1

What is human digestive system made up of?

Answer 1

Alimentary canal

Question 2

What glands secrete digestive juices?

Answer 2

Salivary
Gastric
Intestinal

Question 3

What is digestion?

Answer 3

Process that breaks down large complex pieces of food into simpler pieces to be dissolved for easy absorbtion

Question 4

What types of digestion are there?

Answer 4

Physical and chemical

Question 5

Meaning of physcial and chemical digestion

Answer 5

Mechanical breakdown process of food into small particles
Decomposition process of complex molecules into simple molecules

Question 6

What is pH range of saliva

Answer 6

6.5 - 7.5

Question 7

What stops food from entering trachea when swallowing

Answer 7

Epiglottis

Question 8

What is peristalsis

Answer 8

Rhythmic contraction and relaxation of muscles along alimentary canal

Question 9

What epithelial cells make up for gastric glands and what do they secrete

Answer 9

Chief cells - Pepsinogen
Parietal cells - Hydrochloric acid
Mucous cells - Mucus

Question 10

What is pepsinogen

Answer 10

Inactive enzyme activated by HCL to become pepsin

Question 11

Function of HCL

Answer 11

• Prepare a medium with suitable pH for pepsin to act
• Kill bacteria
• Stop enzymatic action of salivary amylase

Question 12

Function of pancreas

Answer 12

Releases pancreatic amylase, trypsin and lipase into duodenum

Question 13

Function of liver

Answer 13

Produces bile stored in gallbladder
Bile is transported to duodenum through bile duct

Question 14

Function of bile

Answer 14

Neutralise acidic chyme
Prepare alkali condition for enzyme action in duodenum

Question 15

Function of duodenum

Answer 15

Lipase hydrolyses lipids into fatty acid and glycerol
Pancreatic amylase hydrolyses starch into maltose
Trypsin hydrolyses polypeptides into shorter peptides

Question 16

What enzymes are contained in intestinal juice

Answer 16

Maltase
Sucrase
Lactase
Lipase
Erepsin ( Hydrolyes peptides into amino acids )

Question 17

What is the function of the ileum

Answer 17

Absorb nutrients
Folded and covered in villi

Question 18

Adaptations of the villus

Answer 18

• Epithelial layer is 1 cell thick to accelerate nutrient absorbtion
• Goblet cells to secrete mucus
• Network of blood capillaries to transport digestive products
• Lacteal carries fatty acids and glycerol
• Intestinal glands to secrete intestinal juices that have digestive enzymes

Question 19

Function of microvillus on surface of villi

Answer 19

Increase surface area to increase rate of nutrient absorbtion

Question 20

Purpose of hepatic portal vein

Answer 20

Transports blood to the liver

Question 21

Function of liver in assimilation of food

Answer 21

• Glucose for cellular respiration
• Amino acids for synthesising plasma protein and enzymes
• Excess amino acids are turned into urea
• Expel toxic substances from blood
• Glucose converted to glycogen to be stored

Question 22

Explain the assimilation processes in liver

Answer 22

Glucose for cellular respiration
Excess glucose into glycogen when glucose level in blood decreases and body needs energy
Excess glucose is converted fats when glycogen levels are max
Synthesises plasma protein and enzymes from amino acids
Excess converted to urea

Question 23

Explain assimilation processes in cells

Answer 23

Amino acids to synthesise protoplasm and repair damaged tissues
Amino acids to synthesis hormones and enzymes
Glucose for cellular respiration to produce energy, H20 and CO2
Excess glucose converted to glycogen
Energy used for cell processes
LIpids are primary components that build plasma membrane
Fat is oxidised for energy when there is insufficient glucose

Question 24

Function of large intestine

Answer 24

• Absorption of water and vitamins
• Formation of faeces

Question 25

What is absorbed in the large intestine

Answer 25

Water Mineral Salts Metabolic byproducts of bacteria such as vitamin K, B and folic acid

Question 26

Explain the formation of shit (faeces) and defaecation

Answer 26

- Water is absorbed and faeces are produced - Contains dead cells, bacteria and toxic substances - Walls of large intestine secrete mucus to smoothen movement of faeces - Faeces accumulate in rectum - Pressure in rectum increases and triggers the need to expel faeces - Rectum muscles contract to expel faeces this is known as defaecation

Question 27

WHat causes obesity

Answer 27

Storage of excess fats as a result of imbalanced food intake and use of energy

Question 28

Effects of obesity

Answer 28

Diabetus Mellitus Cardiovascular diseases Hypertension Stroke Heart attack

Question 29

Surgery to reduce body weight and explain it and its side effects

Answer 29

Gastric bypass Reduction of stomach size Acid reflux, vomiting, nausea, risk of infection

Question 30

What food class is most important for defaecation?

Answer 30

Fibre and water

Question 31

Function of fibre

Answer 31

- Stimulate peristalsis - Absorb and expel toxic substances - Regulate absorption of glucose - Increase population of beneficial bacteria in large intestine

Question 32

Function of water

Answer 32

Ensure faeces stay soft ad move easily along large intestine to aid defaecation

Question 33

Examples of health issues related to eating habits

Answer 33

Gastritis Anorexia nervosa Bulimia nervosa Muscle dysmorphia

Question 34

What is gastritis?

Answer 34

- Inflammation and corrosion of stomach epithelial layer when there is no food in stomach - Caused by eating irregular amounts of food at irregular hours or excessive intake of alcohol and painkillers

Question 35

What is anorexia nervosa?

Answer 35

- Common among those obsessed with body weight - Avoid food to achieve ideal body weight - Suffer from psychological problems and nutrient deficiencies

Question 36

What is bulimia nervosa

Answer 36

- Eat a lot of food and vomit out food to control body weight - Suffer from dehydration, nutritional problems and cardiovascular diseases

Question 37

What is muscle dysmorphia

Answer 37

- Subject themselves to extreme weightlifting and exercise because they think they're size is small - May consume steroids or muscle building supplements