Human Nutrition (Chapter 29)

Question 1

Nutrition

Answer 1

Nutrition is the process by which an organism obtains and uses its food.

Question 2

Autotrophic

Answer 2

Autotropic means an organism can make its own food

Question 3

Heterotrophic

Answer 3

Heterotrophic means that an organism cannot make its own food, but must obtain its food from the environment.

Question 4

Herbivores

Answer 4

Herbivores are animals that feed exclusively on plants eg. Cattle, sheep, deer.

Question 5

Carnivores

Answer 5

Carnivores are animals that feed on other animals. They are often called flesh-eaters. eg. fox

Question 6

Omnivores

Answer 6

Omnivores are animals that feed on animals and plants. eg. humans, bears, badgers.

Question 7

Digestion

Answer 7

Digestion is the physical and chemical breakdown of food into small soluble pieces which are absorbed into the body.

Question 8

Long tube starting at the mouth and ending at the anus

Answer 8

Alimentary Canal.

Question 9

Sequence of events in human nutrition

Answer 9

1. Ingestion
2. Digestion
3. Absorption
4. Egestion

Question 10

Ingestion

Answer 10

This is the taking of food into the alimentary canal. ie. putting food into the mouth.

Question 11

Digestion

Answer 11

This is the mechanical and chemical breakdown of food.

Question 12

Absorption

Answer 12

Food absorbed into the blood and enters the body when it passes across the membranes lining the alimentary canal

Question 13

Egestion

Answer 13

This is the removal of unabsorbed and undigested material from the digestive system.

Question 14

Incisors

Answer 14

Chisel shaped with sharp edges for cutting, slicing or biting.

Question 15

Canines

Answer 15

long, pointed teeth. They are poorly developed in humans but well developed in carnivores. They grip, stab and tear food.

Question 16

Premolars

Answer 16

teeth with projections on the surface called cusps. They crush and chew food.

Question 17

Molars

Answer 17

the large teeth located at the back of the jaws. They also crush and chew food.

Question 18

Human Dental Formula

Answer 18

2(I 2/2, C 1/1, PM 2/2 M 3/3)

Question 19

Chemical Digestion

Answer 19

Takes place due to the action of the enzyme amylase.

Question 20

Peristalsis

Answer 20

Peristalsis moves food through the alimentary canal. It helps break down food mechanically, mixes food with the secretions of the stomach and forces the mixture into the small intestine.

Question 21

Stomach

Answer 21

The stomach is a muscular bag that stores and digests food

Question 22

The lining of the stomach is heavily folded, forming millions of _______

Answer 22

Gastric Glands

Question 23

Gastric glands produce a range of secretions called

Answer 23

gastric juice

Question 24

Gastric juice consists of

Answer 24

Mucous (coats the stomach and prevents self digestion)

Question 25

Pepsinogen

Answer 25

an inactive enzyme- does not digest the cells in the stomach lining that produce it. Converted to the active enzyme pepsin by acid.

Question 26

Hydrochloric acid (HCI)

Answer 26

Gives the stomach a pH of 1-2. Acid kills bacteria, activates pepsinogen and denatures salivary amylase.

Question 27

Chyme

Answer 27

The contraction of the stomach walls helps to churn and digest the food mechanically. This turns it into a thick, soupy mixture called Chyme.

Question 28

Bile

Answer 28

yellow-green viscous liquid. Consists of water, bile salts and bile pigments.

Question 29

Bile functions

Answer 29

1. Emulsifies lipids
2. Contains sodium hydrogen carbonate, which helps to neutralise chyme from the stomach (as chyme is acidic)
3. Excretes the pigments biliverdin and bilirubin which are made from dead red blood cells.

Question 30

Small intestine- first 25 cm?

Answer 30

duodenum

Question 31

5.5 meters in small intestine

Answer 31

ileum.

Question 32

Function of duodenum

Answer 32

digestion

Question 33

rectum function

Answer 33

stores faeces

Question 34

colon function

Answer 34

reabsorbs water from the waste, forming faeces.

Question 35

vestigial organs

Answer 35

lost former use eg. appendix and caecum

Question 36

capillaries carry nutrients to, ____

Answer 36

hepatic portal vein

Question 37

deamination

Answer 37

Amino acids cannot be stored in the body, they become toxic. Deamination is when amino acids not used by the body are broken down in the liver, forming urea.

Question 38

Adaptations of the small intestine for absorption

Answer 38

1. very long
2. numerous villi and microvilli
3. walls of villi are very thin
4. rich blood supply to carry away water-soluble products
5. Each villus has a lymph supply to carry away the fats.