Digestion Flashcards

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1
Q

What is the name of the tube that passes through all humans and mammals for absorbing energy from food?

A

The alimentary canal.

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2
Q

What is ingestion?

A

Taking food in through the mouth and swallowing.

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3
Q

What is digestion?

A

Breaking down large insoluble molecules in food into smaller pieces (physical digestion) and smaller, soluble molecules (chemical digestion).

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4
Q

What is absorption?

A

The movement of small soluble molecules out of the gut and into the blood by diffusion and active transport.

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5
Q

What is egestion?

A

Passing out undigested food through the anus.

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6
Q

What is assimilation?

A

Building larger biological molecules from the small soluble molecules, in all cells.

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7
Q

What is the first structure in the alimentary canal?

A

The mouth.

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8
Q

Where does ingestion take place?

A

The mouth.

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9
Q

What two types of digestion happen in the mouth?

A

Mechanical and chemical.

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10
Q

How is food mechanically digested in the mouth and what 2 things does this help with?

A

Food is broken up into smaller pieces by chewing. This increases the surface area for enzymes and also prevents discomfort when swallowing.

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11
Q

How is food chemically digested in the mouth?

A

Saliva is released into the mouth by the salivary glands. It makes the food easier to swallow and also contains the enzyme amylase. Amylase breaks down the starch to maltose.

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12
Q

What happens to the amylase in the mouth when it reaches the stomach? Why?

A

It denatures and stops working because it works best at neutral pH.

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13
Q

What happens to food before it is swallowed?

A

It is shaped into a ball by the tongue and moved towards the back of the mouth.

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14
Q

What is the ball of food called just before swallowing?

A

A bolus.

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15
Q

What is the epiglottis?

A

A flap which blocks the food from entering the trachea.

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16
Q

What process pushes food down from the mouth to the stomach?

A

Peristalsis.

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17
Q

What 2 sets of muscles work when during peristalsis?

A

Circular and longitudinal muscles.

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18
Q

How do the circular and longitudinal muscles work during peristalsis?

A

The circular muscles contract behind the bolus, pushing it along. When the longitudinal muscles contract they make the oesophagus wider.

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19
Q

What is the end product of the digestion of carbohydrates?

A

Smaller carbohydrate molecules ie glucose.

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20
Q

What is the end product of the digestion of proteins?

A

Amino acids.

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21
Q

What is the end product of the digestion of lipids?

A

Glycerol + 3 fatty acids.

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22
Q

Where is amylase found?

A

The mouth and the duodenum.

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23
Q

Where is pepsin found?

A

The stomach.

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24
Q

Where is lipase found?

A

The duodenum.

25
Q

Where is trypsin found?

A

The duodenum.

26
Q

Where is maltase found?

A

The duodenum.

27
Q

Where is peptidase found?

A

The duodenum.

28
Q

What secretes the enzyme amylase?

A

The salivary glands and pancreas and ileum

29
Q

What secretes the enzyme pepsin?

A

Gastric glands in the stomach wall.

30
Q

What secretes the enzyme lipase?

A

The pancreas.

31
Q

What secretes the enzyme trypsin?

A

The pancreas.

32
Q

What secretes the enzyme maltase?

A

The lining of the duodenum.

33
Q

What secretes the enzyme peptidase?

A

The lining of the duodenum.

34
Q

What does amylase do?

A

Converts starch to maltose.

35
Q

What does pepsin do?

A

Converts proteins to peptides.

36
Q

What does lipase do?

A

Converts lipids to fatty acids + glycerol.

37
Q

What does trypsin do?

A

Converts proteins to peptides.

38
Q

What does maltase do?

A

Converts maltose to glucose.

39
Q

What does peptidase do?

A

Converts peptides to amino acids.

40
Q

Why does the stomach wall contract?

A

To mix the contents of the stomach, maximising contact between enzymes and food.

41
Q

Where is hydrochloric acid released from?

A

Gastric glands.

42
Q

What prevents the hydrochloric acid in our stomachs from burning through?

A

A mucus lining.

43
Q

What are 2 functions of the hydrochloric acid in our stomachs?

A

-Help the enzyme pepsin work at its optimum condition (acidic pH)
-Kills many bacteria and fungi which may be present in the food we eat.

44
Q

What 2 processes take place in the duodenum?

A

Digestion and absorption.

45
Q

Where is the final site of chemical digestion?

A

The duodenum.

46
Q

What organ makes several enzymes and secretes them into the duodenum?

A

The pancreas.

47
Q

What does the large intestine consist of?

A

The colon and rectum.

48
Q

What is the function of the colon?

A

It is the site for all reabsorption of water.

49
Q

What is the function of the rectum?

A

Stores faeces.

50
Q

What are the 3 digestive enzyme groups?

A

1) Carbohydrases - carbohydrates to smaller molecules like glucose
2) Proteases - proteins to amino acids
3) Lipases - lipids to glycerol and 3 fatty acids

51
Q

The duodenum wall contains gland which secretes which enzymes?

A

Maltase and peptidase.

52
Q

Where is bile produced and stored?

A

Produced by the liver and stored in the gall bladder.

53
Q

What are the 2 functions of bile?

A
  • Neutralises stomach acid as enzymes in duodenum work best at pH7-8
  • Emulsifies lipids - breaks large droplets into smaller droplets, increasing surface area for lipase to digest the fats
54
Q

What 2 processes take place in the small intestine?

A

Digestion and absorption.

55
Q

Where is the final site of chemical digestion?

A

The duodenum.

56
Q

Which 3 enzymes are secreted into the duodenum by the pancreas?

A

-Trypsin
-Amylase
-Lipase

57
Q

What is the ileum covered with?

A

Finger like projections called villi.

58
Q

What 2 ways are small soluble molecules absorbed by the vili?

A

By diffusion and active transport.

59
Q

Give 3 ways the rate of diffusion is increased in the villi:

A

1) Large surface area - folding of ileum, villi and microvilli all increase this
2) Short diffusion distance - the villi walls are one cell thick
3) High concentration gradient - provided by capillary network and lacteals removing absorbed molecules