Chapter 2 - human diet and digestion Flashcards

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1
Q
  • What is an example of carbohydrates
  • What is a carbohydrate’s function
A
  • Example - potatoes, pasta, rice
  • Function - to release energy in respiration
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2
Q
  • What is an example of a fat source
  • What is its function
  • What can high levels of saturated fat cause
A
  • Sources - Plant oils, fatty meat
  • Function - energy storage; making cell membranes
  • High levels of saturated fat increase risk of coronary heart disease
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3
Q
  • What is a souce of protein
  • What is protein’s function
A
  • Source - meat, fish, pulses, dairy
  • Function - building cells, making enzymes, making haemoglobin
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4
Q
  • What is a source of vitamin C
  • What is its function
  • What does a lack of vitamin C cause
A
  • Source - citrus fruits
  • Function - making collagen (an elastic protein found in skin and bones)
  • A lack of vitamin C causes scurvy
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5
Q
  • What is a source of vitamin D
  • What is the function of vitamin D
  • What can a lack of vitamin D cause
A
  • Source - dairy products; formed in skin when sunlight falls
  • Function - helps calcium to be absorbed, important for strong bones
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6
Q

What is a source of calcium

What is the function of calcium

A
  • Source - dairy products
  • Function - strong bones and teeth
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7
Q
  • What is a source of iron
  • What is the function of iron
  • What does a lack of iron cause
A
  • Source - red meat, dark green vegetables
  • Function - making haemoglobin
  • Lack of iron causes anaemia
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8
Q

What is a source of fibre

What is fibre’s function

What does a lack of fibre cause

A
  • Source - fruit, vegetables, brown rice
  • Function - helps muscles in the alimentry canal to work
  • lack of fibre causes constipation
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9
Q
  • What is a source of water
  • What is the function of water
    *
A
  • Source - drinks, most foods
  • Function - acts as a solvent
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10
Q

What are the dietary needs of a person affected by

A
  • Age - younger people need more protein for growth; older people need less energy as they’re inactive
  • Gender - men need more energy intake than women
  • Pregnancy and breast feeding - a woman needs plenty of protein, vitamins and minerals to upply her fetus or young baby
  • Activity - a more active lifestyle requires more energy intake
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11
Q
  • What does low protein intake result in
  • What does the conditions entail
A
  • A low protein intake results in kwashikor
  • The person will have a very low body weight but may have a swollen abdomen
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12
Q
  • What can a low energy intake result in
  • What does this condition entail
A
  • A low energy intake results in marasmus
  • The person has a very low body weight and looks emaciated
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13
Q

What happens in the mouth in the alimentry canal

A
  • Mechanical digestion by teeth takes place - chews up food in smaller bits for larger surface area
  • Salivary glands contain the enzyme maltose to digest starch into glucose
  • Ball of food is lubricated by the saliva
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14
Q

What occurs in the oesophagus during digestion

A
  • The tube that connects the mouth to the stomach
  • Contractions take place to push the food down relying on gravity
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15
Q

What happens in the stomach during the alimentry canal

A
  • Food is mechanically ingested due to the churning actions
  • Protease enzymes start to digest proteins
  • Hydrochloric acid is produced to kill bacteria in the stomach and to provide the optimum Ph for protease enzymes to work
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16
Q

What occurs in the two sections of the small intestine

A

Section 1 - duodenum

  • Food coming out of the stomach is finsihed being digested here; site of amylase, protease, lipase,

Section 2 - ileum

  • Absorbtion of food molecules takes place here
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17
Q

What occurs at the large intenstine during the alimentry canal

A
  • Water is absorbed in the colon to produce faeces
  • Faeces is stored in the rectum
  • Faeces is egested from the anus
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18
Q

What is the function of the pancreas

A

Produces enzymes: Amylase, protease and lipase

  • Secretes enzymes into the duodenum in an alkaline solution
    *
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19
Q

What is the function of the liver

A
  • Produces bile to emulsify fats - mechanical digestion
  • Amino acids here are used to produce urea
20
Q

What is the function of the gall bladder

A
  • To secrete bile into the duodenum
21
Q

What are the four types of human teeth

A
  • Incisors
  • Canines
  • Premolars and molars
22
Q

What are incisors

A
  • Teeth at the front of the mouth
  • Chisel-shaped and bite off food
23
Q

What are canines

A
  • Just behind the incisors
  • They are more pointed and are used to bite and hold food
24
Q

What are premolars and molars

A
  • At the sides and back of the mouth
  • They have broad, ridged surfaces that grind food into smaller pieces
25
Q

What is dental decay

A
  • Where acid dissolves the enamel and dentine
  • Caused by leaving sugary layers on or between teeth
  • Bacteria on the teeth break down by respiration to form acid
26
Q

How can dental decay be avoided

A

By eating too many sugary foods

Brushing teeth regularily to remove food remains

27
Q

What is the definition of ingestion

A

Taking substances into the body through the mouth

28
Q

What is the definition of mechanical digestion

A

Breakdown of food into smaller pieces without chemical changes to the food molecules

29
Q

What is the definition of chemical digestion

A

Breakdown of large, insoluble molecules into small, soluble molecules

30
Q

What is the definition of absorbtion

A

Movement of digested food molecules into the cells of the body where they are used, becoming part of the cells

31
Q

What is the definition of assimilation

A

Movement of digested food molecules into the cells of the body where they are used, becoming part of the cells

32
Q

What is the definition of egestion

A

Passing out of food has not been digested or absorbed, as faeces, through the anus

33
Q

What does amylase do

A

Breaks down starch to simple sugars

34
Q

What does protease do

A

Breaks down proteins into amino acids

35
Q

What does lipase do

A

It breaks down fats into fatty acids and glycerol

36
Q

In carbohydrate digestion, what do amylase and maltase break down starch and maltose into

A
  • Starch—amylase—> disaccharide maltose
  • Maltose—maltase—> monosaccharide glucose
    *
37
Q

What are the two cases where amylase is secreted

A
  • From the salivary glands -
  • From the pancreas in pancreatic juice
38
Q

Where is maltase secreted from

A

Epithelial cells covering the villi in the small intestine

39
Q

What are the two protease molecules secreted in protein digestion

A
  • Pepsin - secreted in the stomach, has a low optimum Ph provided by the secretion of HCL
  • Trypsin - secreted by the pancreas into the pancreatic juice; works in the small intestine
40
Q

What does bile contain, what do these things do?

A
  • Sodium hydrogencarbonate - a base which neutralises acidic mixture of food and gastric juice entering the duodenum from the stomach
  • Bile salts - break large globules of water-insoluble fats into smaller droplets; these mix with watery fluids in the small intestine to produce an emulsion. This increases the surface area of fat droplets. which aloows lipase to work quicker
41
Q

Why does the small intestine have villi

A

To increase the rate at which absorbtion can take place

42
Q

What is a villi in the small intestine made up of

A
  • Epithelium - a layer of cells that covers the villus, secretes enzymes, including maltase, which completes the chemical digestion of nutrient molecules
  • Blood capillary - absorbs amino acids, glucose, vitamins and minerals ; transports these along the liver by the heptic portal vein
  • Lacteal - absorbs digested fats
43
Q

What is cholera

A
  • A disease caused by bacterium which causes the loss of watery faeces
  • It produces a toxin that causes the cells covering the villi to secrete chloride ions into the small intestine
44
Q
A
45
Q

In cholera, what do the chloride ions secreted into the small intestine do

A
  • It decreases the water potential inside the small intestine; so water moves out of the cells by osmosis, down a water potential gradient
  • This causes the patient to suffer from diarrhoea
46
Q

Why is cholera dangerous

A
  • The patient loses salts from the blood
  • The patient loses a lot of water and becomes severely dehydrated