Human Nutrition - Digestion Flashcards
(122 cards)
1
Q
nutrition
A
the way in which an organism obtains and uses food
2
Q
autotrops
A
organisms that can make their own food ie. green plants, but photosynthesis
3
Q
heterotrops
A
organisms that canot make their own food and must get it from environment
4
Q
herbivores
A
feed only on plants
5
Q
carnivores
A
eat other animals
6
Q
omnivores
A
eat both plants and animals
7
Q
example of herbivore
A
cow
8
Q
example of carnivore
A
dogs
9
Q
example of omnivore
A
human
10
Q
stages of human nutrition
A
- Ingestion
- Digestion
- Absorption
- Egestion
(assimilation)
11
Q
ingestion
A
the taking of food into the alimentary canal i.e putting it into the mouth
12
Q
digestion
A
the mechanical or chemical breakdown of food into smaller molecules so that it can be absorbsed
13
Q
absorption
A
soluble products of digestion can now pass through the cells lining the small intestine into the blood and lymph systems
14
Q
egestion
A
the removal of unabsorbed and undigested material from the digestive system (through the anus)
15
Q
assimilation
A
the absorbed food is used to make new molecules of for release of energy
16
Q
7 components of a balanced diet
A
carbohydrates, protein, lipids, vitamins, minerals, fibre, water
17
Q
what is a balanced diet
A
the 7 components must be present in the right amounts
18
Q
factors affecting amount of food required in a person
A
age- growing teenagers need more food than elders
activity levels- more if you exercise a lot
19
Q
frequency of sugar and alcohol
A
restricted intake
20
Q
frequency of dairy
A
2-3 a day
21
Q
frequency of meat/fish/protein
A
2-3 a day
22
Q
frequency of fruit and veg
A
3-5 a day
23
Q
frequency of starchy carbs
A
6-11 a day
24
Q
pH of mouth
A
7-8
25
type of digestion in mouth
chemical and physical
26
mechanical digestion
breakdown of large pieces of food by physical or mechanical ways
27
mechanical digestion in the mouth
chewing action of the teeth
28
chemical digestion
chemical breakdown of food by enzymes
29
chemical digestion in mouth
amylase converts starch to maltose
30
human teeth types
incisors canines premolars and molars
31
incisor function
cutting
32
canine function
stabbing and tearing
33
premolar and molar function
chewing and grinding
34
dental formula for half mouth
I 22 C 11 P22 M33
35
how many teeth in adult whole mouth
32
36
herbivore teeth
broad, rigid premolars and molars
37
carnivore teeth
long sharp canines
38
salivary glands arranged in mouth
3 pairs of them
39
4 components of saliva
water and mucous (mucin)
salts
salivary amylase
lysozome
40
function of mucin in saliva
moisten and lubricate the food and make it easier to swallow
41
function of salts in saliva
provide neutral to slightly alkaline pH, optimum for amylase
42
function of salivary amylase in saliva
enzyme that converts starch to maltose
43
function of lysozome in saliva
helps kill microorganisms eg.bacteria
44
name for ball of food made in the mouth
bolus
45
flap of skin and cartilage in throat
epiglottis
46
peristalsis
involuntary muscle contractions of the gut wall which moves food
47
what is the stomach
a muscular bag that receives food from the oesophagus
48
pH of stomach
2
49
for how long is food stored
2-4 hours
50
semi-solid liquid stomach churns food into
chyme
51
sphincter
a ring of muscle that opens and closes
52
top stomach sphincter
cardiac sphincter
53
bottom stomach sphincter
pyloric sphincter
54
3 components of gastric juice
```
mucous (mucin)
hydrochloric acid (HCl)
enzyme pepsin(ogen)
```
55
function of mucous in gastric juice
protects lining of stomach from digesting itself
56
function of HCl in gastric juice
provides acidic environment of pH 2, optimum for pepsin enzyme and activates pepsinogen
57
type of pepsin in gastric juice and why
pepsinogen, inactive form so as not to digest the lining of the stomach
58
how is pepsinogen activated
by HCl
59
what type of enzyme is pepsin?
protease
60
3 roles of HCl in the stomach
- activates pepsinogen to pepsin
- sterilises food, kills microorganisms
- chops up starch into short sections (mechanical di)
61
small intestine pH
7-9
62
sections of small intestine
duodenum
| ileum
63
how long is the duodenum
25cm
64
how long is the ileum
5.5m
65
function of duodenum
where digestion occurs
66
function of the ileum
where absorption of digested foods into blood and lymph
67
3 places from which the small intestine receives secretions
the liver
the pancreas
the lining of the intestine itself
68
where is the liver located
above the stomach
69
function of the liver
produces bile
70
what is bile
a green fluid that breaks down lipids
71
where is bile stored
in the gall bladder
72
how does the bile get from the liver to the duodenum?
through the bile duct
73
3 components of bile
bile salts
bile pigments
sodium hydrogen carbonate
74
function of bile salts in bile
emulsify fat, mechanical process, break down fat droplets to increase their surface area
75
what are bile pigments?
no digestive function
| an excretory product of the breakdown of old blood cells
76
does bile contain digestive enzymes?
no
77
does bile contain water?
yes
78
where is the pancreas located?
below the stomach
79
what does the pancreas secrete?
pancreatic juice (and insulin)
80
3 things pancreatic juice consists of
sodium hydrogen carbonate
enzymes
water
81
function of sodium hydrogen carbonate in the pancreas
An alkaline salt that neutralises the stomach acid, allows enzymes in small intestine to work best
82
enzymes of pancreatic juice
pancreatic amylase
| lipase
83
how is food absorbed
passes through the cells lining the small intestine by diffusion and active transport and into the blood and lymph systems
84
path glucose and amino acids take when absorbed
pass by diffusion into blood capillaries ad go into hepatic portal vein
85
what does hepatic portal vein
brings blood from the gut to the liver
86
path fatty acids and glycerol take when absorbed
absorbed into lymph lacteals, these joinand eventually empty lymph into the blood system
87
which nutrients go into the blood capillaries in villus
```
glucose
amino acids
vitamins
minerals
water
salts
```
88
which nutrients go into the lymph lacteals
fatty acids
glycerol
fat soluble vitamins
89
why is the intestine folded into villi?
to increase the surface area of the wall
90
where are microvilli?
on the cells lining the villi
91
5 ways in which the ileum is adapted for absorption
1. it's very long (about 5.5m)
2. many villi increase surface area
3. wall is only 1 cell thick, products pass through quickly
4. large blood supply in the villus to absorb and carry away products
5. each villus has a lacteal with lymph to carry digested fats
92
how long is the large intestine
approx. 1.5m
93
diameter of small intestine
3cm
94
diameter of large intestine
6cm
95
4 parts of large intestine
caecum, appendix, colon, rectum and anus
96
where is the caecum in the large intestine
below the junction with the small intestine
97
where is the appendix found
at the end of the caecum
98
function of caecum and appendix
no function, vestigial organs
99
vestigial organs
no longer have a function
100
whats different about the caecum and appendix
they contain enzymes to digest cellulose
101
main function of colon
reabsorb water by osmosis
102
faeces
liquid waste turned semi-solid
103
colour of faeces
due to bile
104
diarrhoea
waste moves to fast through colon, not enough water reabsorbed
105
constipation
waste moves too slow through colon, too much water reabsorbed
106
2 functions of symbiotic bacteria in the colon
a) produce vit B & K
| b) prevents growth of pathogenic bacteria
107
symbiosis
relationship between two different species where one or both benefit from the relationship
108
function of rectum
stores faeces before removal through the anus
109
egestion
the removal of undigested or unabsorbed materials
110
is faeces excreted and why
no, excretion is the removal of waste products of metabolism
111
6 components of faeces
```
undigested food
bile pigments
salts
bacteria
dead cells
water
```
112
other name for fibre
roughage
113
how does fibre stimulate peristalsis
it bulks up the food and stimulates the contractions
114
how does fibre prevent obesity?
gives a feeling of fullness
115
what is the largest internal organ/gland in the body?
the liver
116
6 functions of the liver
```
stores energy
deamination
stores fat soluble vitamins
makes bile
stores minerals
detoxifies chemicals and alcohol
```
117
how does the liver store energy
stores glucose as glycogen and breaks it back down when its needed
118
which fat soluble vitamin does the liver not store?
E
119
an example of a mineral stored in the liver
iron
120
Hepatic artery
carries blood from aorta to liver
121
Hepatic vein
carries blood to inferior vena cava
122
hepatic portal vein
bring blood and digested food from the gut to the liver
