human niutrition Flashcards

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1
Q

Autotrophic

A

Autotrophs make their own food e.g.
plants

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2
Q

Heterotrophic

A

Heterotrophs take in food from the
environment. They cannot make their own
food

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3
Q

Heterotrophs can be divided into three main categories;

A

Carnivores

Herbivores

Omnivores

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4
Q

Carnivores

A

Animals that
mainly feed on
other animals

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5
Q

example of carnivore

A

fox

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6
Q

Herbivores

A

Animals that
mainly feed on
plants

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7
Q

example of herbivores

A

rabbits

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8
Q

Omnivores

A

Animals that
mainly feed on
plants and
animals

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9
Q

example of omnivores

A

humans

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10
Q

What is Digestion?

A

The physical and chemical breakdown of food into soluble particles
small enough to pass into body cells

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11
Q

Why do we need a digestive system?

A

To break down large food particles until they are small enough to pass
into body cells

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12
Q

Human Digestive System

A

a long tube, starting
at the mouth and ending at
the anus.

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13
Q

Stages in Human Digestion

A

Ingestion
digestion
absorption
egestion

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14
Q

Ingestion

A

Food is taken into the mouth

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15
Q

Digestion

A

The breakdown of food. Can be either
chemical or physical

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16
Q

Absorption

A

Digested food passes from the digestive
system into the blood

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17
Q

Egestion

A

The removal of the unabsorbed waste from
the digestive system

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18
Q

what does the mouth contain

A

Contains a muscular
tongue and a set of teeth.

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19
Q

what does the mouth secrete and from where

A

a juice called
saliva from the salivary
glands.

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20
Q

what does saliva contain

A

water,
salts, and the enzyme
Salivary amylase.

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21
Q

Humans have four types of teeth;

A

incisors, canines, premolars and molars.

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22
Q

Incisors

A

shaped like chisels and cut and slice food

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23
Q

Canines

A

long, pointed and fang like. They tear food

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24
Q

Premolars

A

large, flat teeth and are used to crush and grind food

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25
Q

Molars

A

large teeth which cut and grind food

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26
Q

Human Dental Formula

A

2 incisors, 1 canine, 2 premolars aand 3 molars

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27
Q

Oesophagus

A

A hollow muscular tube, 25 cm long that connects the pharynx to the stomach.

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28
Q

Oesophagus job

A

The walls of the Oesophagus secrete mucus and the food is moved by Peristalsis

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29
Q

Perestalisis

A

Peristalsis is a wave of muscular action in the walls of the alimentary canal that moves the contents along

30
Q

Describe the shape of the stomach

A

J shaped muscular bag

31
Q

How long does the food store in the stomach

A

About 4 hours

32
Q

What kinds of digestion takes place in the stomach

A

Physical and chemical

33
Q

Explain the mechanical digestion in the stomach

A

Peristalsis physically mixes up the food

with gastric juices, forming chyme.

34
Q

Explain the chemical digestion in the stomach

A

using Gastric Juice containing: a) Mucus

b) HCI

c) Pepsin

35
Q

Mucus in the stomach

A

Lines and protects the stomach wall from HCI & pepsin

36
Q

HCI in the stomach

A

Kills bacteria

b. Activates pepsin, by lowering the pH

37
Q

Pepsine in the stomach

A

Pepsin is an enzyme produced by the cells lining the stomach. Pepsin breaks down protein into peptides

38
Q

Describe the lining in the stomach

A

The lining of the stomach is very muscular and highly folded

39
Q

What happens in the lining of the stomach

A

Millions of gastric glands line the stomach producing gastric juice

40
Q

Functions of hydrochloric acid

A

•This gives stomach a pH of 1 to 2!

•Very acidic

This acidity kills many bacteria, loosens fibrous and cellular foods

•Activates pepsin

•Denatures amylase from saliva

41
Q

What happens if there is too much hydrochloric acid in the stomach

A

Leads to heartburn but can be neutralized with alkalis

42
Q

How can ulcer result

A

If gastric juice does manage to digest the stomach wall, ulcers can result
•If ulcer becomes perforated, bacteria could get into body causing illness

43
Q

What are the two main parts of the small intestine

A

The duodenum
The ileaum

44
Q

What are the gland associated with the small intestines

A

Pancreas and the liver

45
Q

What does the pancreas secreet

A

The hormone insulin and pancreatic juice

46
Q

What does the pancreatic juice consist of

A

sodium hydrogen carbonate (which neutralizes chyme), and also enzymes such as amylase and lipase

•These enzymes enter the duodenum through the

pancreatic duct

47
Q

Functions of pancreas

A

• Lipase converts lipids into fatty acids

Amylase converts starch into maltose

48
Q

Liver functions

A
  1. Making bile
  2. Detoxifying the body
  3. Converting glucose to glycogen
  4. Converting excess carbohydrate to fat
  5. Storing vitamins and minerals
  6. Breaking down amino acids to form urea
49
Q

Describe bile

A

Bile is a yellow-green liquid that is made in the liver and stored in the gallbladder

Enters the duodenum through the bile duct

50
Q

Function of bile

A

Breaks down fats and oils, neutralizes chyme from the stomach and excretes pigments

51
Q

Describe villi

A

The inner lining of the small intestine contains infoldings called villi which contain many microvilli.

52
Q

Function of villi

A

These infoldings increase the surface area in the duodenum (for digestion) and in the ileum (for absorption)

53
Q

Functions of the duodenum

A

The cells lining the duodenum produce digestive enzymes

•The products of the pancreas and liver also enter the duodenum

•Amylase and Lipase from the pancreas enter the duodenum. Amylase converts starch into maltose

Lipase converts lipids into fatty acids and glycerol

54
Q

Carbohydrates digest into

A

Monosacharides

55
Q

Proteins digest into

A

Amino acids

56
Q

Lipids digest into

A

Fatty acids and glycerol

57
Q

How is the food when it enters the ileum

A

Almost fully digested

58
Q

What happens to the food in the ileum

A

The walls of the ileum contain many villi which are surrounded by many capillaries I

-The capillaries absorb water, glucose, amino acids, vitamins and minerals and carries them to the hepatic portal vein

The hepatic portal vein carries them to the liver where some nutrients are stored and some are released

  • Amino acids cannot be used in the body and are broken down in the liver to form urea. The urea passes to the kidneys via the hepatic vein

• The capillaries in each villus absorb water and nutrients (e.g. glucose, amino acids and vitamins)

•The capillaries carry these to the hepatic portal vein which takes them to the liver

•The liver stores the nutrients

Amino acids are toxic to the body and cannot be stored - they are broken down in the liver to form urea- deamination

59
Q

What is inside each villus

A

A lacteal which contains a liquid card lymph

60
Q

What is transported by the lymph

A

Fats are transported by lymph in the lymph vessels to the bloodstream

61
Q

Adaptations of the Small Intestine for Absorption

A
  1. It is very long
  2. Has villi and microvilli
  3. The walls of villi are very thin
  4. There is a rich blood supply to carry away water soluble products
  5. Each villus has a lymph system to carry away fats
62
Q

Where are the caecum and appendix

A

The Caecum is at the junction of the small intestine, the appendix is at the end of the caecum

63
Q

Function af caecum and apendix

A

In herbivores, the caecum and appendix contain bacteria which help in the digestion of cellulose

Large Intestine

Caecum

Appendix

• In humans, the caecum and appendix are vestigial organs (they no longer have a use)

64
Q

What is the function of the colon

A

The function of the colon is to reabsorb water which converts the liquid waste that enters the large intestine into semi-solid waste called faeces

Faeces are stored in the rectum before being egested from the anus

65
Q

What is Fibre made out of

A

Cellulose

66
Q

Tole of fibre

A

•Humans cannot digest cellulose

• Fibre absorbs and stores water which causes the unabsorbed waste to expand

•This stimulates the muscles of the intestine to work i.e. it stimulates peristalsis

• Prevents constipation

67
Q

What are symbiotic bacterias

A

Beneficial bacteria prevent the growth of disease causing bacteria and fungi

68
Q

Functions of symbiotic bacteria

A

• Bacteria in the colon feed on waste and produce some B and K group vitamins. These vitamins are reabsorbed into the bloodstream in the colon

• Bacteria in the digestive system break down food, especially cellulose

69
Q

Balanced diet

A

A balanced diet contains all the necessary food types in the correct

proportions

70
Q

Components for balanced diet

A
  1. Carbohydrates
  2. Protein
  3. Lipids
  4. Vitamins
  5. Minerals 6. Water
  6. Fibre
71
Q

The amount of food a person needs depends on

A
  1. Age
  2. Activity levels
  3. Gender
  4. Heath