Chapter 41 Flashcards
1
Q
What is nutrition?
A
food being taken in, taken apart, or taken up
2
Q
All animals are heterotrophs, but…
A
they need to eat enough food and have a balanced diet to survive and reproduce
3
Q
Three nutritional needs
A
- Fuel for cells
- Organic materials for biosynthesis
- Essential nutrients
4
Q
Fuel for cells
A
ATP
5
Q
Organic materials for biosynthesis
A
proteins, carbohydrates, lipids, and nucleic acids
6
Q
carbohydrates
A
sugars
7
Q
lipids
A
fats
8
Q
Essential nutrients
A
cannot by synthesized, must be consumed
9
Q
Examples of essential nutrients
A
some amino acids, fatty acids, and vitamins and minerals
10
Q
Malnutrition
A
occurs when diet lacks one or more essential nutrient or consistently supplies less energy than body needs
11
Q
What can malnutrition cause?
A
deformities, disease, death
12
Q
Undernutrition
A
occurs when diet lacks adequate sources of chemical energy (carbs, protein, lipids)
13
Q
When are humans considered undernourished?
A
If they consume less than the recommended 2,200 kcals/day
14
Q
Kwashiorkor
A
occurs mainly in children whose diet lacks high quality protein
15
Q
Marasmus
A
caused by a diet low in protein and calories
16
Q
Characterized by discolored skin and bloated stomach
A
Kwashiorkor
17
Q
Characterized by being very thin, shriveled with low resistance to infection
A
Marasmus
18
Q
Ingestion
A
the act of eating/feeding
19
Q
Hydrolysis
A
using water to break down food
20
Q
Digestion
A
breakingn down food into absorbable molecules
21
Q
Two types of digestion
A
- Mechanical digestion
2. Chemical digestion
22
Q
Mechanical digestion
A
breaks food into smaller pieces (chewing)
23
Q
Chemical digestion
A
chemical breakdown of food particles into nutrients via enzymes
24
Q
What are nutrients used for?
A
energy and biosynthesis
25
Protiens
amino acids
26
Carbohydrates
sugars
27
Lipids
fatty acids and glycerol
28
Absorption
cells take up (absorb) nutrients through the bloodstream
29
Steps to processing food
1. Ingestion
2. Digestion
3. Absorption
4. Elimination
30
Elimination
undigested material exits through the digestive track
31
How is it that animals do not digest their own cell tissues?
Digestive compartments
32
Digestive compartments
food processing happens in specialized areas of the body to prevent enzymes from breaking down animals' own tissues
33
Digestion can be...
Intracellular or extracellular
34
Intracellular digestion
food particle engulfed by the cell
35
Where does intracellular digestion occur?
within organelles that contain digestive enzymes
36
Extracellular digestion
occurs outside cells in a specialized compartment and is continuous with exterior
37
When is food "inside" the body
nutrients cross a layer of cells (absorption)
38
Two types of extracellular digestion
1. Gastrovascular cavity
| 2. Alimentary canal
39
Step 1 of the Gastrovascular cavity
Digestive enzymes are released from a gland cell
40
Step 2 of the gastrovascular cavity
enzymes break food down into small particles
41
Step 3 of the gastrovascular cavity
food particles are engulfed and digested in food vacuoles
42
Gastrovascular cavity
digestive sac with a single opening that functions as a mouth and anus
43
What does the gastrovascular cavity function in?
digestion and circulation of nutrients
44
Where is gastrovascular cavity observed in?
simple animals
45
Alimentary canal
1. complete digestive tract
2. two openings
3. food moves in one direction
4. specialized regions for different tasks
46
Two openings in alimentary canal
mouth and anus
47
Accessory glands of alimentary canal
secrete digestive juices through ducts into the canal
48
4 types of accessory glands
1. Salivary glands
2. Liver
3. Pancreas
4. Gullbladder
49
Peristaisis
alternate waves of contractions and relaxation in the smooth muscle lining the canal
50
What does the peristaisis do?
propels food
51
Sphincters
muscular valves that regulate passage of material between segmenets
52
What occurs in the oral cavity
mechanical digestion and chemical digestion
53
Mechanical digestion increases...
SA
54
What occurs during chemical digestion?
1. Salivary glands release saliva
| 2. Salivary amylase begins carb digestion
55
What does the tongue do?
shapes the food into a bolus and pushes it to the pharynx
56
Pharynx
"throat," opens to trachea and esophagus
57
Epiglottis
blocks trachea during swallowing
58
Esophagus
moves food from pharynx to stomach
59
What types of muscles near top of esophagus?
Skeletal (swallowing)
60
What type of muscles in the middle to lower esophagus?
Switches to smooth (involuntary contractions (peristalsis))
61
Stomach
food storage
62
the stomach is where the preliminary digestion of ____ occurs
proteins
63
What is the stomach lined with
epithelial tissue
64
Where do stomach pits lead to?
gastric glands that secrete gastric juice
65
Gastric juice mixes with food to form ____
chyme
66
Chief cells
secrete pepsinogen
67
Where are chief cells found?
stomach
68
Pepsinogen
protein digesting enzyme (protease)
69
What does pepsinogen break?
long protein chains into smaller chains
70
Parietal cells
secrete HCI and gives gastric juice low pH (2)
71
Where are parietal cells
stomach
72
What do parietal cells disrupt?
the extracellular matrix that binds cells together in meat and plant mater
73
What does parietal cells kill
bacteria
74
What do parietal cells unfold
protein
75
What does parietal cells convert pesinogen into
active pepsin
76
Mucus cells
secrete mucus
77
What do mucus cells do for the stomach?
lubricates and protects stomach lining from gastric juice
78
What do chief cells release?
pepsinogen
79
What do parietal cells do?
release HCI and convert pepsinogen into pepsin
80
Where are pepsin and HCI formed?
outside of cells (in lumen)
81
What does mucus secreted by mucous cells do?
protects stomach ining from gastric juice
82
Contents of the stomach are mixed by...
smooth muscles
83
The stomach combines...
food and enzymes into acid chyme
84
Chyme then moves to...
the small intestine
85
what is the small intestine controlled by?
Pyloric sphincter
86
Small intestine
longest compartment of alimentary canal
87
The small intestine is the site of..
most digestion and ALL nutrient absorption
88
The small intestine consists of the...
1. duodenum
2. jejunum
3. lleum
89
Duodenum (first 25 cm)
digestion completes in this section
90
What occurs in the duodenum?
Chyme mixes with digestive juices from pancreas, liver, gallbladder, and small intestine
91
Two portions of the pancreas
1. endocrine
| 2. exocrine
92
Endocrine
directly to bloodstream
| - insulin and glucagon
93
Exocrine
ducts
| - digestive secretions
94
Digestive secretions
bicarbonate-rich alkaline (basic) solution that buffers acidic chyme
95
Hydrolytic enzymes
1. Pancreatic amylases
2. Pancreatic trypsin and chymotryspin
3. Pancreatic nucleases
4. Pancreatic lipases
96
Pancreatic amylases
carbohydrates
97
pancreatic tryspin and chymotryspin
proteins
98
pancreatic nucleases
nucleic acids
99
pancreatic lipases
lipids
100
Liver
produces bile that is stored in the gallbladder
101
Bile
contains bile salts that serve to break down lipids (emulsifiers)
102
Where does absorption take place
jejunum and ileum of small intestine
103
What forms villi
folds in the epithelial tissue lining the intestine
104
microvilli
tiny projections each cell has
105
What do villi and microvilli do together
increase surface area for nutrient absorption
106
What does the core of each vilus contain?
blood vessels andn a lacteal for nutrient distribution
107
Sugars and amino acids
enter blood stream directly
108
What do capillaries and veins converge to form?
Hepatic portal vein
109
Where do hepatic portal veins carry nutrient rich blood?
directly to the liver where detoxification occurs
110
Where do nutrients from from the liver to?
the heart, where they are then pumped to toher tissues in the body
111
what are fats repackaged into and where do they enter?
they are repackaged into chylomicrons and enter lacteals (lmphatic vessels)
112
Where does the lymphatic system eventually carry chylomicrons to?
large veins that return blood to the heart
113
What does teh large intestine consist of?
1. cecum
2. colon
3. rectum
114
cecum
ferments ingested material
115
appendix
a projection of cecum and plays a minor role in immunity
116
colon
leads to rectum and anus
117
what is the colon responsible for?
reabsorption of water to produce feces - fiber hels move food along
118
rectum
stores feces until elimination
119
Three adaptations the text covers
1. dental adaptations
2. stomach and intestinal adaptations
3. mutualistic adaptations
120
Carnivore
kill, rip, tear, shred
121
Herbivore
bite veg. and grind
122
Omnivore
bladelike incisor-bite, pointed canines-tear molars-grind/crush
123
Digestive system of carnivores
relativel short digestive tract for absorbing nutrients from meat
124
Digestive system of herbivore
relatively long (more time and surface area for absorption)
125
Why do carnivores also have large expandable stomachs?
uncertainty of meals so they eat as much as they can
126
Why do herbivores also have long cecum with bacteria
to facilitate digestion of plant material
127
Enteric division of the nervous system
activates parts of the digestive system at the appropriate time
128
What does the enteric division of the nervous system trigger?
secretion of substances that promote next stage of digestion
129
What does enteric division stimulate?
peristalsis
130
Endocrine system
secretes hormones that control digestive secretions
131
What does energy from food replace?
energ lost during metabolism, activity, and storage
132
Excess nutrients are stored...
sugars are stored as glycogen in liver and muscle
133
Once glycogen stores are full...
excess sugar is converted to fat and stored in adipose tissue
134
Glucose
the primar fuel for cells
135
What does regulation of glucose rely on?
opposing effects of insulin and glucagon
136
Where is glucose produced in?
pancreatic islets
137
alpha cells
produce glucagon
138
beta cells
produce insulin
139
Concequence of disrupted glucose homeostasis
1. deficiency of insulin (type 1)
| 2. decreased response to insulin (type 2)
140
Blood glucose levels rise but...
cells cannot take up enough to meet metabolic needs
141
What becomes the main energy source when blood glucose levels rise?
fat
142
Excess glucose in the blood excreted in...
the urine
143
Whater excreted with the glucose, leading to:
1. increased urination
2. increased thirst
3. increased hunger
144
Type 1
1. usually begins in childhood
2. body destroys beta cells, leading to lack of insulin
3. treated with insulin injections
145
Type 2
1. usually begins later in life
2. target cells do not respond to insulin, and therefore do not uptake glucose
3. often can be treated with diet and exercise, some patiente require medication
146
Feedback loops and hormones control appetite, nutrient storage, and me tabolism
1. Grehlin
2. PYY
3. Insulin
4. Leptin
147
Grehlin
secreted by stomach wall when empty
| triggers feelings of hunger
148
PYY
secreted by small intestine after meals
| suppresses appetite
149
Insulin
Secreted by pancrease after meals
| Suppresses appetite
150
Leptin
Produced by adipose tissue
| Suppresses appetite
