Digestive system Flashcards

1
Q

Define system

A

a group of organs working together to perform a function

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2
Q

Define nutrition

A

process by which an organism obtains the energy and materials it needs from its environment,
in order to live, grow and reproduce.

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3
Q

What are Autotrophic organisms

A

organisms that make their own food from inorganic materials

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4
Q

And explain the two types of autotrophic organisms

A
  1. Photosynthetic: use light energy to make the food e.g. green plants
  2. Chemosynthetic: use chemical energy to make food e.g. bacteria around undersea volcanic vents
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5
Q

What are heterotrophic organisms

A

can’t make their own food - need to obtain it from other organisms

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6
Q

Types of heterotrophic organisms

A
  1. omnivores: eat both plants and animals e.g. humans
  2. herbivore: eat only plants e.g. cows
  3. Carnivore; eat only meat e.g. Wolf
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7
Q

define digestions

A

The breaking down of food into smaller pieces to enable them to be taken into the body and used

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8
Q

What is mechanical digestion

A

Physical breakdown of food by cutting and grinding of teeth and churning of stomach

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9
Q

Define peristalsis

A

wave of muscular contraction that drives food along alimentary canal

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10
Q

What is chemical digestion

A

Using digestive enzymes and acid to break food into small soluble molecules that can be absorbed by the body.

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11
Q

Name the four stages of nutrition

A
  1. Ingestion taking food into the alimentary canal
  2. Digestion breaking down complex organic molecules into smaller molecules which are easier to absorb
  3. Absorption taking materials through the intestine wall into the body by Diffusion and Active Transport
  4. Egestion getting rid of undigested material from the body.
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12
Q

Labels of the digestive system

A
  1. Mouth
  2. Oesophagus
  3. Liver
  4. Gall bladder
  5. Stomach
  6. Pancreas
  7. Duodenum
  8. Ileum
  9. Colon
  10. Appendix
  11. Rectum
  12. Anus
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13
Q

What is the function of the mouth

A
  1. It’s where ingestion takes place.
  2. Both chemical and mechanical digestion occur there
  3. The tongue tastes food, and forms bolus
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14
Q

What is the function of the Teeth

A

Mechanical breakdown of food

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15
Q

What is the function of the salivary glands

A

Produce saliva, lubricates food, amylase breaks down starch. They are exocrine glands (have ducts)

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16
Q

What is the function of the Epiglottis

A

Prevents food entering lungs

17
Q

What is the function of the Oesophagus

A

Peristalsis moves food to stomach

18
Q

What is the function of the Stomach

A
  1. Produces Bile – which is stored in gall bladder
  2. Bile salts neutralise chyme (acid stomach contents) in duodenum
  3. Emulsifies fats to increase surface area for lipase
19
Q

What is the function of the Liver

A
  1. Produces Bile – which is stored in gall bladder. It contains the pigment bilirubin
  2. Bile salts neutralise chyme (acid stomach contents) in duodenum
  3. Emulsifies fats to increase surface area for lipase
  4. It’s an exocrine gland
20
Q

What is the function of the Pancreas

A

It’s both an endocrine and exocrine gland
Exocrine produces:
1. Pancreatic juice is alkaline to neutralise acid stomach contents
2. Lipase to digest fats
3. Amylase to digest carbohydrates
4. Protease to break down polypeptides to amino acids

Endocrine produces:
1. insulin (islets of langerhans)

21
Q

What is the function of the Duodenum

A

Bile and pancreatic juice added here

22
Q

What is the function of the Ileum

A

Completes digestion

Absorption of products of digestion through villi

23
Q

What is the function of the Appendix

A
  1. Immunity role

2. Vestigial organ

24
Q

What is the function of the Colon

A

Absorbs water.

Symbiotic bacteria produce vitamins B and K and prevent pathogenic bacteria establishing by outcompeting them.

25
Q

What is the function of the Rectum

A

Stores and expels faeces

26
Q

What is the function of the Anus

A

Site of egestion when its sphincter muscle relaxes

27
Q

What are the four types of teeth and their function

A
  1. Incisors: Flat and sharp for cutting food
  2. Canines: Pointed for tearing and gripping food
  3. Pre-Molars: Flat and ridged for crushing and
    grinding food
  4. Molars: Flat and ridged for crushing and
    grinding food
28
Q

Is the dental formula of an adult human

A

I 4/4 C 2/2 P 4/4 M6/6

29
Q

Name the digestive enzymes, their pH, their action site and their role

A
  1. Amylase: pH 7 - 8 in the Mouth. pH 8-10 in the small intestines. Breaks Starch to maltose
  2. Pepsin: pH 1 – 2 in the Stomach. Breaks Protein to polypeptide
  3. Lipase: pH 8-10 in the small intestines. Breaks Fats to glycerol and fatty acids
  4. Protease: pH8-10 in the small intestines. Breaks Proteins to Amino Acids
30
Q

What Are the benefits of fibre in the diet

A

Stimulates peristalsis and prevents constipation by absorbing water i.e. eases digestive transit

31
Q

Villi diagram labels

A
  1. Microvilli
  2. Villi
  3. Lacteal
  4. Epithelium
  5. Capillary network
  6. Arteriole
  7. Venule
  8. Lymph vessel
32
Q

What are villi

A

Villi are finger like projections or folds of the small intestine wall which greatly increase the surface area for absorption

33
Q

What is lacteal

A

Lacteal absorbs fatty acids and glycerol which recombine to form fats. These are carried to the thoracic duct and then into the blood in the subclavian vein.

34
Q

What is the function of the hepatic portal vein

A
  • Capillaries absorb all other products of digestion e.g. amino acids, glucose, minerals, vitamins and
    substances such as alcohol
  • These pass directly to the liver via the hepatic portal vein
  • From there they are transported to all cells of the body in the blood through the Hepatic Vein
35
Q

give the different functions of the liver

A
  1. Produces bile which neutralises acid chyme, and emulsifies fats
  2. Breaks down red blood cells to bilirubin and
    breaks down excess amino acids to urea
  3. Stores glycogen, fat soluble vitamins A and K as well as iron
  4. Detoxifies e.g. breaks down alcohol, antibiotics etc.
  5. Produces heat: all the numerous chemical reactions produce heat which aids homeostasis
36
Q

What is a balanced diet

A

contains all the required nutrients in the correct proportions

37
Q

What is undernourished

A

means not having enough nutrients

38
Q

What is malnourished

A

not having the correct balance of nutrients i.e. too much or too little of certain nutrient

39
Q

What is a food pyramid

A

Gives an indication of the proportions of the various food groups that should be taken.
This varies with factors like age, sex and activity.