digestive system Flashcards
1
Q
balanced diet
A
consists of all food groups in correct porportions
2
Q
food groups
A
carbohydrates
proteins
lipids
dietary fibre
vitamins
minerals
water
3
Q
what can having an unbalanced diet lead to
A
malnutritions
4
Q
causes of starvation
A
taking in less energy than is used over a long period
5
Q
effect of starvation
A
the body breaks down energy stores
- first fat, then muscle tissue
- severe weight lose and damage to heart and immune system
6
Q
coronary heart diseases cause
A
diet too high in saturated fat and cholesterol
7
Q
constipation cause
A
lack of fibre in diet
8
Q
effect of constipation
A
- food lacks bulk for muscles to push through the alimentary canal
- risk of bowel cancer increases
9
Q
obesity cause
A
taking in more energy than used
10
Q
obesity effect
A
- extra energy stored as fat
- mass increases and contributes to heart diseases and type 2 diabetes.
11
Q
carbohydrate function
A
source of energy
12
Q
protein function
A
growth and repair
13
Q
lipid function
A
insulation and energy storage
14
Q
dietary fibre
A
provides bulk for the intestine to push food through it
15
Q
vitamins
A
needed in small quantities to maintain health
16
Q
minerals
A
needed in small quantities to maintian health
17
Q
water funcation
A
needed for chemical reactions to take place in the cell
18
Q
calcium function
A
needed for strong teeth and bones and involved in the clotting of blood.
19
Q
calcium deficiency
A
osteoporosis
20
Q
vitamin D function
A
helps absorb calcium and is required for strong bones and teeth
21
Q
vitamin D source
A
oily fish, dairy, made naturally by sunlight
22
Q
vitamin C function
A
collagen, protein, gums and bones
23
Q
vitamin C deficiency
A
scurvy
24
Q
vitamin A function
A
needed to make pigment in retina for vision
25
vitamin A sources
meat, liver, dairy, leafy greens
26
iron function
needed to make haemoglobin, which transports oxygen
27
iron sources
red meat, liver, leafy greens
28
age dietary needs
amount of energy that young people need increases towards adulthood for growth.
- energy needs of adults decreases as they age
29
activity dietary needed
more active, more energy as muscles are contracting more and respiring faster
30
pregnancy dietary needs
- more energy required to support the growth of the foetus and the larger mass the woman carries around
- extra calcium and iron needed to help build bones, teeth and blood
31
breastfeeding dietary requirements
energy increases and extra calcium is needed to make high quality breast milk
32
sex dietary needes
male need more energy as they tend to exceed that of females due to larger proportion of muscles
33
digestion
large, insoluble molecules in food are broken down into smaller, soluble molecules which can be absorbed into the blood stream.
34
what are small, soluble molecules used
provide energy via respiration or to build other molecules to grow, repair and function
35
alimentary canal
channel through which food flows through the body starting with the mouth and ending at anus
36
mouth/salivary gland
- teeth chew food to break into smaller pieces
- increases SA:V
- amylase enzyme digests starch into maltose
- food shaped into a bolus by the tongue and lubricated by saliva so it can be swallowed easily.
37
oesophagus
- the tube which connects mouth to stomach
- food bolus swallowed with wave like contractions to push to food bolus down
38
stomach
- food digested by churning actions
- protease starts to chemically digest proteins
- HCL acid present to kill bacteria in food and provide optimum pH for protease enzyme to work.
39
duodenum
- food finishes being digested by enzymes produced and secreted from the pancreas
- pH is alkaline (9)
40
ileum
- absorption of digested food molecules takes place
- long and lined with villi to increase SA over which absorption can take place.
41
large intestine
water is absorbed from the remaining material in the colon to produce faeces
- faeces stored in rectum and removed through anus
42
pancreas
- produced all 3 types of digestive enzymes
- secretes enzyme in an alkaline fluid into duodenum for digestion to raise the pH
43
liver
- produces bile
- amino acids not used to make proteins breakdown here to produce urea
44
bile function
emulsify fats
breakdown of large droplets into small droplets
45
gall bladder
stores the bile to release into duodenum
46
stages of food breakdown
1) ingestion
2) mechanical digestion
3) chemical digestion
4) absorption
5) assimilation
6) egestion
47
ingestion
the taking in of substances
48
mechanical digestion
the breakdown of food into smaller pieces without chemical change to the molecules
49
chemical digestion
breakdown of large insoluble molecules, into small soluble molecules
50
absorption
movement of small food molecules and ions through the walls of the intestine into blood
51
assmilation
movement of digested food molecules into the cells of the body where they are used to becoming part of the cells
52
egestion
passing out of food that has not been digested or absorbed through anus
53
peristalsis
mechanism which helps food move along the alimentary canal
54
what is peristalsis controlled by
circular and longitudinal muscles
55
circular muscles
reduced the diameter of the lumen of the oesophagus
56
longtitudinal muslces
reduced length of that section the oesophagus or the small intestine
57
mucus in oesophagus
produced to lubricate food mass and reduce friction
58
dietary fibre in oesophagus
provides roughage required for the muscles to push against
59
why is mechanical digesition useful
increases surface area for enzymes to work on
60
what is chemical digestion controlled by
enzymes
61
what are enzymes
biological catalysts which speeds up chemical reactions without themselves being used in the reaction
62
3 main types of digestive enzymes
carbohydrases
proteases
lipases
63
amylase
breaking down of starch into maltose
64
maltase
breaking down of maltose into glucose
65
where is amylase produced
salivary glands
pancrease
small intestine
66
where is pepsin made
stomach
67
pepsin
breaks down proteins into smaller polypeptide chains
68
where is protease made
pancrease and small intestine
69
proteases
breaks down peptide into amino acids
70
where is lipase produced
pancrease and secreted into small intestine
71
lipase
breaks down lipids into glycerol and fatty acids
72
role of bile
- neutralizes HCL acid
- breaks apart large drops of fat into smaller ones.
73
what allows lipase to chemically break down the fats molecules into glycerol and fatty acids
- alkaline conditions
- larger SA:v ratio
74
where is small digested food molecules absorbed to
blood (glucose and amino acids)
lymph (fatty acids and glycerol
75
through which process are small molecules absorbed into the blood by
diffusion and active transport
75
by which process is water absorbed and to where
osmosis in the small intestine and colon
76
adaptations of small intestine
- very long
- highly folded surfaces with millions of villi to increase the SA
77
adaptations of villi
- large SA
- short diffusion distance (one cell thick)
- steep concentration gradient
78
what are villi supplied with
network of blood capillaries that transport glucose and amino acids away from the small intestine
79
what runs through the centre of thr villus and why
lacteal
transpot fatty acids and glycerol away from the small intestine in the lymph
