Human Nutrition (chpt. 28)

Question 1

Nutrition

Answer 1

The way an organism obtains and uses its food

Question 2

Functions of nutrition

Answer 2

Energy source
Growth
Repair
Reproduction
Formation of new substances
Defence

Question 3

Autotrophs

Answer 3

An organism that makes its own food e.g. green plants

Question 4

Heterotrophs

Answer 4

An organism that cannot make its own food and must take in ready-made food e.g. humans

Question 5

Herbivore

Answer 5

Eats plants only e.g. rabbits

Question 6

Carnivore

Answer 6

Eats animals only e.g. fox

Question 7

Omnivore

Answer 7

Eats plants & animals e.g, hedgehogs, humans

Question 8

Parasite

Answer 8

An organism that gets its food from a live source e.g. disease-causing bacteria

Question 9

Saprophyte

Answer 9

An organism that gets its food from a dead source e.g. bread mould fungus

Question 10

Stages of human nutrition

Answer 10

1. Ingestion (taking in food)
2. Digestion (breaking up food)
3. Absorption (transfer of digested food into bloodstream & lymphatic system)
4. Assimilation (use of digested food in body)
5. Egestion (getting rid of undigested food)

Question 11

Chemical digestion

Answer 11

The breaking up of food into smaller parts through the use of enzymes

Question 12

Mechanical digestion

Answer 12

The physical breakdown of food into smaller parts e.g. using teeth

Question 13

Name the 4 teeth and functions

Answer 13

Incisor - cutting and biting
Canine - tearing
Premolar - crushing and grinding
Molar - crushing and grinding

Question 14

Human dental formula

Answer 14

2(I 2/2 C1/1 P2/2 M3/3)

Question 15

Chemical digestion in the mouth

Answer 15

Salivary amylase
Produced by salivary glands
Saliva - water, salts, mucin, amylase, lysozyme
Soften and dissolve food
pH 7-9

Question 16

Peristalsis

Answer 16

The rhythmic contraction and relaxation of the muscles in the gut wall to push food down to the stomach

Question 17

What is the stomach?

Answer 17

A muscular, expandable, bag

Question 18

Physical digestion in stomach

Answer 18

By peristalsis
Physically churns the food turning it into chyme

Question 19

Role of HCl in stomach

Answer 19

pH of 1-2
Converts pepsinogen to pepsin
Sterilises food (by killing microorganisms)
Denatures salivary amylase

Question 20

Role of pepsin / protease in stomach

Answer 20

pH 1-2
Some absorption occurs in stomach
Breaks down proteins into amino acids (smallest unit of a protein)

Question 21

Name a substance stored in the liver

Answer 21

Vitamins A D E K
Glycogen
Iron
Copper

Question 22

Pancreas

Answer 22

Produces insulin and digestive enzymes
Pancreatic juices: sodium hydrogencarbonate , amylase , lipase

Question 23

Functions of the liver

Answer 23

Produces bile
Detoxification of poisonous substances e.g. drugs
Produces heat to warm blood & body
Deamination (removal of amino acids)
Storing vitamins e.g. vitamin D
Storing minerals e.g. iron, copper, zinc

Question 24

What is bile

Answer 24

Formed from dead and broken down red blood cells
Green / yellow alkaline liquid
Produced in liver
Stored in gall bladder
Acts in liver and dudodenum
Made up of water, bile salts and bile pigments
Emulsifies fats

Question 25

Function of duodenum

Answer 25

Digestion

Question 26

Function of ileum

Answer 26

Absorption

Question 27

Function of villi

Answer 27

Increase surface area for absorption

Question 28

What is absorbed in the ileum

Answer 28

Glucose
Amino acids
Water-soluble vitamins and minerals

Question 29

How has the small intestine adapted for increased absorption

Answer 29

Villi and microvilli
Walls are one cell thick which allows rapid movement (by diffusion)
Rich blood capillary network to carry soluble nutrients to the liver

Question 30

Functions of large intestine

Answer 30

Water reabsorption
Elimination of faeces

Question 31

Vestigial organ

Answer 31

No longer needed / used
E.g. caecum , appendix

Question 32

Colon

Answer 32

Reabsorbs water and mineral salts to prevent dehydration
Diarrhoea occurs when material moves too quickly through colon
Constipation occurs from a lack of water or fibre

Question 33

Rectum

Answer 33

Stores semi-solid waste

Question 34

Anus

Answer 34

Waste removed as faeces (EGESTION)

Question 35

What does the hepatic portal vein connect

Answer 35

Liver to the ileum

Question 36

Benefits of symbiotic intestinal bacteria

Answer 36

Make vitamins B K
Protect us against pathogenic bacteria

Question 37

Symbiotic

Answer 37

2 organisms living together (beneficial to both)

Question 38

Sources of fibre

Answer 38

Cereal grains
Vegetables
Fruit

Question 39

Role of fibre

Answer 39

Stimulates peristalsis
Prevents constipation
Soaks up cholesterol and toxic chemicals
Encourages the growth of symbiotic intestinal bacteria

Question 40

Role of hepatic portal vein in digestive system

Answer 40

Brings nutrients and amino acids from intestine to the liver

Question 41

Hepatic artery

Answer 41

Brings oxygen and lipids from the heart to the liver

Question 42

Adaptations of the small intestine for absorption

Answer 42

Villi and microvilli increase surface area for absorption
Walls are one cell thick which allows for rapid movement of substances through them by diffusion
Rich blood capillary network

Question 43

What type of waste is removed by egestion

Answer 43

Un absorbed food

Question 44

Functions of HCl in stomach

Answer 44

• Activate pepsin
• Denature amylase
• Destroy microorganisms

Question 45

Which stage of nutrition takes place predominantly in the duodenum

Answer 45

Digestion

Question 46

Waste product of deamination

Answer 46

Urea

Question 47

Which part of the alimentary canal has an endocrine function

Answer 47

Pancreas

Question 48

DRAW the digestive system

Answer 48

Question 49

DRAW the relationship between the alimentary canal and the liver and pancreas

Answer 49

Question 50

DRAW longitudinal section of a villi

Answer 50