Digestive System Flashcards
(122 cards)
1
Q
2 types of digestive system invertebrates have
A
- simple
- Alimentary
2
Q
4 types of vertbrate digestive systems
A
- Monograstic
- Avian
- Ruminant
- Pseudo-ruminant
3
Q
Simple digestive system
A
1 opening - gastrovascular cavity where the mouth is the anus.
4
Q
How do simple digestive systems work
A
Cells within the vacity secrete digestive enzymes that breakdown the food. The food particles are engulfed by the cells lining the gastrovascular cavity
5
Q
Alimentary Canal
A
2 openings
Mouth for ingestion
Anus for elimination
6
Q
Digestive system of Jellyfish
A
Simple
7
Q
Digestive system of Earthworm
A
Alimentary canal
8
Q
how do alimentary canals works
A
- Food passes through the esophagus
- its stored in the crop
- then passes through gizzard where it is churned and digested
- then passes through the intestine where nutrients are absorbed
- waste is eliminated as castings through the anus
9
Q
What digestive system do rabbits have
A
Monograstic single-chambered stomach
10
Q
How and why are rabits digestive system dif to humans
A
Rabbits are herbivorous (consume more cellulose) therefore have a much longer GI tract and double cycle.
Large cecum which contains lots of microbes to break down tough fibre
11
Q
What kind of digestive system do birds have
A
Avian
12
Q
How is birds mechanical digestion different
A
Birds do not have teeth as an adaptation for flight, and therefore have a different system of manipulation of food
13
Q
Function of gizzard in birds
A
Crush food into smaller pieces instead of teeth
14
Q
What digestive system do cows have
A
Ruminant
15
Q
How do cows diet differ from humans
A
Quality and quantity - huge amounts of plant material
16
Q
How do cows digestive system differ from humans
A
No upper incisor teeth as only chew plant material. The stomach is four-chambered to breakdown large amounts of cellulose and ferment ingested.
17
Q
Alpaca digestive system
A
Pseudo ruminants
18
Q
What are pseudo ruminants
A
3 chambered stomach - lacks a rumen
19
Q
Cecum
A
The pouched organ at beginning of large intestine; contains microorganisms necessary for the digestion of plant materials; is large & is where roughage is fermented and digested
20
Q
Function of saliva
A
- contains mucus that moistens food and buffers pH of food
- Containts immunoglobins and lysozomes which have antibacterial action to reduce tooth decay
- contains enzymes amalyse and lipase
21
Q
Function of salivary amalyse
A
Convert starches into disaccharide
22
Q
Function of lipase
A
Produced in the tongue and breaks down triglyceride
23
Q
Function of tongue
A
Assist in swallowing and food manipulation, moves bolus from mouth into pharynx
24
Q
What does the pharynx open into
A
2 passageways
- oesophagus leading to stomach
- trachea leading to lungs
25
Epiglottis function
When swallowing, epiglottis closes the glottis and food passes into the esophagus and not the trachea
26
Function of esophagus
Softened food passes through the esophagus after being swallowed
27
Structure of esophagus
Tubular organ connecting mouth to stomach
28
How does the esophagus work
Smooth muscles of esophagus undergo peristalsis (unidirectional, involuntary reflex)
29
What is the gastro-esophageal sphincter
Located stomach end o esophagus in most mammals but not humans
- prevents contents of stomach from travelling up the esophagus as it remains closed when there is no swallowing actions.
30
Structure of stomach
Sack-like organ that secretes gastric digestive juices and can expand ~20x when filled with food
31
Where is the primary site of protein digestion
stomach
32
2 processes occurring in the stomach
Chemical Digestion and Muscular activity
33
Chemical digestion in the stomach (2 things)
Pepsin is secreted by chief cells in the inactive form of pepsinogen. Pepsin can break up proteins into smaller polypeptides
Parietal cells sercete hydrogen and chloride ions, which combine in lumen to form HCL (primary acidic component)
34
Two functions of HCL in the stomach
Convert inactive pepsinogen to pepsin (for protein digestion)
Highly acidic enviornment kills many microbes and aids in hydrolysis of protein
35
Muscular activity in the stomach
Churning action of stomach muscles by contraction and relaxation mixes contents ~every 20 min
36
Chyme
Partially digested food and gastric juice mixed
37
When does gastric emptying occur
2-6 hours after a meal
38
Function of pyloric sphincter
Regulate small amounts of chyme at a time into the small intestine
39
Why doesn't the stomach digest itself
- thick mucus lining to protect underlying tissue
- saliva contains mucus which buffers mouth pH, and immunoglobins and lysosomes which reduce tooth decay
40
How is chyme neutralised in the lower intestive
Rich alkaline solution (bicarbonate) in pancreatic juices neutralises the acidity
41
Function of small intestine
Main site of protein, fat, and carbohydrate digestion
42
Adaptation of small intestine
Enormous surface area because its a
- highly folded surface containing villi
- each villi contains many microvilli
All these folds increase surface area THEREFORE increase absorption efficiency of nutrients
43
How is nutrients absorbed from the small intestine
Bloodstream are right in the villi for efficient nutrient absorbtion
44
Function of bile
Our body is primarily water therefore we need bile to specifically attack fat components so they can diffuse into the blood
FAT DIGESTION
45
Structure of duodenum
C-shaped fixed part of the small intestine - beginning of the small intestine
45
What is bile and where is it produced
Bile contains lipid emulsifying bile salts and is stored and concentrated in the gallbladder
46
What occurs in the duodenum
The bulk of chemical digestion where digestive juices from the pancreas, liver, and gallbladder enter.
Absorbtion of fatty acids therefore occur here as bile is introduced
47
Jejunum
2nd part of small intestine where nutrient hydrolysis continues and by this time most of the carbohydrates and amino acids are absorbed.
48
Ileum
3rd part of the small intestine
- bile salts and vitamins absorbed into bloodstream
- undigested food is sent to colon via peristalsis
49
Function of gallbladder
Store and concentrate bile for fat digestion
50
Structure of large intestine
Wider and shorter than small intestine, however length and proportion varies greatly according to diet of different mammalls
51
Colon
The main part of the large intestine
Home to many bacteria to aid digestive processes
Site of water, salt, and mineral extraction
52
What mainly occurs in large intestine
Water comes out of stool so that we don't lose water
53
What is the rectum
Terminal end of large intestine
54
Function of rectum
Store feces until defecation
55
How is waste eliminated
Feces are propelled out the anus using peristaltic movement of smooth muscle.
56
3 things we need from food
1. organic building blocks
2. chemical energy
3. essential nutrients
57
What are organic building blocks from food
Material to build DNA for reproduction, growth, and maintenance of our body
58
What is chemical energy from food
Source of material for ATP production in cells
59
What are essential nutrients
Minerals and vitamins required for cellular functions that we cant synthesise ourselves
60
4 essential nutrients
Amino acids
Fatty acids
Vitamins
Minerals
61
How do we obtain essential nutrients
Feeding on plants or other animals - some animals can get vitamin C rom dies, whereas most have the ability to synthesise it from other nutrients
62
What are amino acids and how many are there
There are 20 amino acids which are the building blocks of protein
63
Why do we need amino acids/proteins
Structure, function, and regulation of tissues and organs
64
Can animals synthesize amino acids
Most animals have the enzymes to synthesize half the amino acids (as long as the diet includes sulfur and nitrogen)
65
What are essential amino acids
Amino acids we don't make and therefore need to consume
66
How many amino acids do adult humans require from their diet
8 amino acids
67
Why do human infants need histidine but not adults
Histidine is important for growth, repair of damaged tissue, and making blood cells but human infants are unable to synthesize.
68
What source gives u all 8 of the amino acids you need
Animals/meat
69
What does it mean that proteins from plants are incomplete
Every plant is deficient in one or more amino acids
70
How do vegetarians obtain all the essential amino acids if plants are incomplete
Eating a varied diet of plant proteins
71
Anabolic amino acids meaning
Can build them yourself
72
Why do we need essential fatty acids
Variety of cellular processes - in membrane linings, signalling molecules, and also stored for when we need to deploy energy
73
Can humans produce linoleic acid
No, humans lack the enzyme to form the fatty acid so it must be consumed
74
How do we get essential fatty acids
Must be obtained by diet
75
What are vitamins
Organic molecules required in the diet in small smounts
76
How many vitamins do humans require
13
77
Vitamin C
A water soluble vitamin required for production of connective tissue
78
Vitamin D
Fat-soluble vitamin that aids in calcium absorbtion and bone formation
79
Scurvy
Serious vitamin C deficiency
80
How might a vitamin d deficiency occur
Lactose intolerance, vegan diet, lack of sun exposure
81
Overdose of water soluble vitamins
Harmless because excesses are excreted in urine
82
Overdose of at soluble vitamins
Fat-soluble vitamins are deposited in body fat, so overconsumption can cause them to accumulate to a toxic level
83
Vitamin K
Important for blood clotting, produced by microbiome or can be available from diet
84
Why are babies given a vitamin K shot at birth
Less bacteria in the gut where vitamin K is made and they do not recieve enough from mothers
85
Why is it important for people of blood thinners to maintain a constant level of vitamin K in diet
blood thinning medication reduces risk of blood clots which is the opposite action of vitamin K. Must maintain balance of medication otherwise blood will become too thin
86
Minerals
Inorganic nutrients (iron and sulfur) are required in small amounts.
87
Why do we need iron
Incorporated into the oxygen carrier of blood (haemoglobin)
88
Iodine function
regulate metabolic rate
89
Calcium function
Build and maintain bone
90
What mineral do humans often consume in excess and why
Sodium - flavours food and is used as a preservative. Over indulgence generally means we exceed daily dose
91
What does overconsumption of sodium cause
High blood pressure, health disease, stroke, and calcium loss
92
Why do humans need sodium (3 reasons)
- Conduct nerve impulses
- Contract and relax muscles
- maintain the proper balance of water and minerals
93
How does the type and quantity of 4 essentials of food vary between species
Every animal needs Minerals, vitamins, amino acids, and fatty acids to survive, but how they do it and what they need specifically varies between animals
94
What are carbohydrates
Long chains of sugar molecules that are mainly used for energy
95
what are the three types of carbohydrate
Monosaccharide, disaccharide, polysaccharide
96
Monosaccharide
Single sugar - fructose, glucose, galactose
97
Disaccharide
(simple sugars, 2 sugars linked together) - sucrose, lactose, maltose
98
Polysaccharides
Complex carbohydrate - many sugars linked together including starch, glycogen, fibre
99
What carbohydrate does salivary amylase break down and where
Salivary amylase breaksdown food starches, Polysaccharides, into maltose, a disaccharide
100
Where does carbohydrate digestion mainly take place
Duodenum
101
What enzymes break down disaccharides into monosaccarides
Maltase, sucrase, lactase, which are in the intestinal wall
102
Why are complex carbohydrates better
Take longer to digest and therefore have a more even dispersion of energy
103
Function of Sucrase
Break down sucrose into glucose and fructose
104
Function of lactase
break down lactose into glucose and galactose
105
Function of glucose
Used in metabolic pathways to harness energy
106
Where is glucose stored and in what form
Store in liver and muscles in the form of glycogen
107
Where is excess glucose store
As fat - good for hibernating animals so they can break down fat stores instead of protein (muscle loss)
108
Function of insulin
Essential hormone that helps bodyturn food into energy and control blood sugar levels
109
Diabetes
Body cant produce enough insulin or its defective
110
Pepsin breaks ___ into ____
Pepsin breaks proteins into peptides
111
What is a peptide
Short chain of 4-9 amino acids
112
Function of peptidase
Breakdown peptides into single amino acids so they can be absorbed into the bloodstream
113
Where does the bulk of lipid digestion occur
Small intestine
114
How does bile aid in digestion of lipids
Emulsification
115
Emulsification
Large lipid globules broked down into smaller lipid globules reducing aggregations and increasing surface area
116
Function of lipases
Breakdown lipids into fatty acids and glycerides
117
Adipose tissue
Connective tissue consisting mainly of fat cells
118
Function of adipose tissue
Specialised to synthesize fat and contain large globules of fat, within a structural network of fibres under the skin, in between muscles, and around the heart
119
How do fat stores benefit ectotherms
If ectotherms are not active/eating, they use fat stores to maintain energy
120
4 types of feeders
Filter feeders, substrate feeders, fluid feeders, bulk feeders
121
Dentition
Different diets (carnivores vs herbivores) have different adaptations for obtaining and manipulating food
