CH41 Flashcards
(124 cards)
1
Q
What do animals receive by ingesting other organisms?
A
- Chemical energy for synthesizing ATP
- Carbon-containing compounds and minerals for building complex macromolecules
2
Q
Ingestion
A
The act of brining food into the digestive tract
3
Q
Digestive tract
A
In animals, a series of connected chambers & tubes where digestion occurs
- Aka alimentary canal or gastrointestinal (GI) tract
4
Q
Digestion
A
The mechanical & chemical breakdown of food into molecules that can be absorbed into the body of an animal
5
Q
Absorption
A
In animals, the uptake of ions & small molecules, derived from food, across the lining of the digestive tract (epithelium)
6
Q
Elimination
A
The removal of wastes from an animal’s digestive tract
7
Q
Nutrient
A
Any substance that an organism requires for normal growth, maintenance, or reproduction
8
Q
Food
A
Any nutrient-containing material that can be consumed & digested by animals
9
Q
What is the unit of measure for the amount of energy provided by foods?
A
Kilocalories
10
Q
Why do fats provide more energy than other nutrients?
A
They are rich in C-H bonds
11
Q
Essential nutrients
A
Nutrients that cannot be synthesized & must be obtained from the diet
12
Q
Classes of essential nutrients
A
- Essential amino acids
- Essential fatty acids
- Vitamins
- Minerals
13
Q
Essential amino acids
A
Any amino acid that an animal cannot synthesize & must obtain from the diet.
- Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, & valine
14
Q
Essential fatty acids
A
Any fatty acid that an animal cannot synthesize & must obtain from the diet
- linolenic acid & linoleum acid
15
Q
Vitamins
A
Organic, or carbon-containing, micronutrients that are vital for health but are required in only minute amounts & also usually function as coenzymes in critical reactions
16
Q
Minerals
A
Various inorganic substances that are important components of enzyme cofactors or structural materials in an organism
- Includes ions of electrolytes, which influence osmotic balance & are required for normal membrane function
17
Q
What are the major ions of electrolytes in the human body?
A
Sodium, potassium, & chloride
18
Q
Vitamin B1
A
- THIAMINE
- source: legumes, whole grains, potatoes, peanuts
- function: formation of coenzyme in citric acid cycle
- effects if deficient: beriberi (fatigue, nerve disorders, anemia)
19
Q
Vitamin B3
A
- NIACIN
- source: meat, whole grains
- function: component of coenzymes NAD+ & NADP+
- effects if deficient: pellagra (digestive problems, skin lesions, nerve disorders
20
Q
Vitamin B9
A
- FOLATE
- source: green veggies, oranges, nuts, legumes, whole grains; also synthesized by bacteria in intestine
- function: coenzyme in nucleus acid & amino acid metabolism
- effects if deficient: anemia
21
Q
Vitamin B12
A
- COBALAMIN
- source: red meat, eggs, dairy products; also synthesized by bacteria in intestine
- function: coenzyme in synthesis of proteins & nuclei cells acids & in formation of red blood cells
- effects if deficient: anemia (fatigue & weakness due to low hemoglobin content in blood)
22
Q
Vitamin C
A
- ASCORBIC ACID
- source: citrus fruits, tomatoes, broccoli, cabbage, green peppers
- function: used in collagen synthesis, prevents oxidation of cell components, improves absorption of iron
- effects if deficient: scurvy (degeneration of teeth & gums)
23
Q
Vitamin D3
A
- CHOLECALCIFEROL
- source: fortified milk, egg yolk; also synthesized in skin exposed to sunlight
- function: aids absorption of calcium & phosphorus in small intestine
- effects if deficient: rickets (bone deformities) in children; bone softening in adults
24
Q
Calcium
A
- source in diet: dairy products, green veggies, legumes
- function: bone & tooth formation, nerve signaling, muscle response
- effects if deficient: loss of bone mass, slow growth
25
Chlorine
- source in diet: table salt/sea salt, veggies, seafood
- function: fluid balance in cells, protein digestion in stomach (HCL), acid-base balance
- effects if deficient: weakness, loss of muscle function
26
Fluorine
- source in diet: fluoridated water, seafood
- function: maintenance of tooth structure
- effects if deficient: higher frequency of tooth decay
27
Iodine
- source in diet: iodized waltz, algae, seafood
- function: component of the thyroid hormones thyroxine and T3
- effects if deficient: goiter (enlarged thyroid gland)
28
Iron
- source in diet: meat, eggs, whole grains, green leafy veggies, legumes
- function: enzyme cofactor; synthesis of hemoglobin & electron carriers
- effects if deficient: anemia, weakness
29
Magnesium
- source in diet: whole grains, green leafy veggies
- function: enzyme cofactor
- effects if deficient: nerve disorders
30
Phosphorus
- source in diet: dairy products, meat, grains
- function: bone & tooth formation; synthesis of nucleotides & ATP
- effects if deficient: weakness, loss of bone mass
31
Potassium
- source in diet: dairy productive; meat; nuts; fruits; potatoes, legumes, & other veggies
- function: nerve signaling, muscle response, acid-base balance
- effects if deficient: weakness, muscle cramps, loss of muscle function
32
Sodium
- source in diet: table salt/sea salt, seafood
- function: nerve signaling, muscle response, BP regulation
- effects if deficient: weakness, muscle cramps, loss of muscle function, nausea, confusion
33
Sulfur
- source in diet: any source of protein
- function: amino acid synthesis
- effects if deficient: swollen tissues, degeneration of liver, intellectual disability
34
Suspension feeders
An animal that obtains food by filtering small particles or small organisms out of water by means of cilia, music-lined “nets,” or other structures
- aka filter feeders
- e.g. sponges & tube words
35
Deposit feeders
An animal that eats organic matter such as sediments & other types of deposited material
- e.g. earthworms & sea cucumbers
36
Fluid feeders
An animal that feeds by sucking or mopping up liquids such as nectar, plant sap, or blood
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Mass feeders
An animal that ingests chunks of food
- majority of animasl
38
Adaptive radiation
Rapid evolutionary diversification within one lineage, producing many descendant species that have adapted to a wide variety of habitats
39
What are the types of digestive tracts?
Incomplete & complete
40
Incomplete digestive tracts
Has a single opening, the mouth, through which the animal both ingests food & eliminates wastes
- mouth opens into a chamber, called a gas trove scalar cavity, where digestion takes place
41
Complete digestive tracts
Has 2 openings- they start @ the mouth & end @ the anus
- interior of this tube communicates directly w/external environment via these openings
42
Organs of the digestive tract
1. Mouth
2. Esophagus
3. Stomach
4. Small intestine
5. Large intestine
6. Appendix
7. Anus
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Mouth
Site of mechanical & chemical digestion (tongue manipulates food so that teeth can chew food; saliva digests carbs)
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Esophagus
Transports food, connects mouth & stomach
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Stomach
Site of mechanical & chemical digestion (digests proteins)
- tough, muscular pouch in the digestive tract btwn esophagus & small intestine
- Bracketed on both superior & inferior ends by ring like muscles called sphincters
46
Small intestine
Site of chemical digestion & absorption (digests proteins, fats, carbs; absorbs nutrients & water)
- long tube that is folded into a compact space within abdomen
- partially digested food mixes with secretions form the pancreas, liver, & gallbladder & begins journey of 6 m (20 ft)
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Large intestine
Absorbs water, microbes digest plant material not digested in small intestine, & forms feces; contains symbiotic bacteria
- posterior portion of vertebrate digestive tract consisting of cecum, colon, & rectum
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Appendix
Contains immune tissue; harbors symbiotic bacteria
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Anus
Eliminates feces
50
Accessory organs
1. Salivary glands
2. Liver
3. Gallbladder
4. Pancreas
51
Salivary glands
Secrete enzymes that digest carbs; supply lubricating mucus
52
Liver
Secretes molecules that aid in fat digestion
- synthesized bile salts
- large, complex organ of vertebrates that performs storage of glycogen, processing & conversion of food & wastes, & production of bile
53
Gallbladder
Small pouch that stores secretions from liver & releases it as needed; empties into small intestine
54
Pancreas
Secretes enzymes & other materials into small intestine
- synthesized inactive form of protease (prevents pancreatic cells form digesting themselves
55
What distinct chemical changes occur during chemical digestion as food moves through each compartment in the digestive tract?
1. In the mouth, enzymes in the saliva begin the chemical breakdown of carbs & lipids
2. Chemical digestion of protein begins in the acidic environment of the stomach. Meanwhile, lipids continue to be chemically digested in the stomach, but carbs aren’t broken down further
3. Chemical processing of carbs, proteins, & lipids completed in small intestine
4. Small molecules that result from digestion of the macromolecules are absorbed in the small intestine, along w/water, vitamins, & ions
56
What was the first enzyme-catalyzed reaction discovered?
Starch breakdown
57
Salivary amylase
Enzyme produced by the SALIVARY GLANDS that digests starch & glycogen by catalyzing hydrolysis of the glycosidic linkages btwn glucose residues
- responsible for carb digestion in mouth
- Cleaves bonds in starch to release dextrins (small carbs) & disaccharides such as maltose
- released in response to taste & smell stimuli
58
Salivary glands
In vertebrates, 1 of several glands that secrete saliva (a mixture of mater, mucus-forming glycoproteins, & enzyme salivary amylase) into the mouth
- Also produces slimy substance
59
Mucus
Slimy mixture of glycoproteins (mucins) & water that is secrete in many animal organs
- function: provide lubrication & serving as a barrier to protect surfaces from infection
- Lines gastric epithelium & protects stomach from damage by HCl
60
Lingual lipase
Enzyme produced by SALIVARY GLANDS in the tongue that breaks down triglycerides into fatty acids & diglycerides
- released in response to taste & smell stimuli
61
Gastric lipase
Enzyme produced by glands in the STOMACH that breaks down triglycerides into fatty acids & diglycerides
- released in response to gastrin from stomach
62
Peristalsis
Rhythmic waves of muscular contraction. In the digestive tract, pushes food along. In animals with hydrostatic skeletons, enables crawling
63
How long does it take for swallowed food to reach the bottom of the esophagus?
6 seconds
64
Crop
In animal anatomy, a storage organ in the digestive tract of certain vertebrates
- regulates flow into the stomach
65
What species has the crop independently evolved into a digestive organ?
The leaf-eating hoatzin and kakapo
66
Why are leaves difficult to digest?
They contain a large amount of cellulose
67
Sphincters
Muscular valve that can close off a tube, as in a blood vessel or a part of the digestive tract
68
Churning
When muscular contractions mix the stomach contents to a uniform consistency & solute concentration
69
What is the predominant acid in the stomach?
Hydrochloric acid (HCl)
70
Pepsin
Protein-digesting enzyme secreted in inactive form (as pepsinogen) by chief cells in STOMACH lining
- purified in 1836
- Cleaves peptide bonds next to certain amino acids, reducing long polypeptides to small chains of amino acids
- released in inactive form (pepsinogen); activated by low pH in stomach lumen
71
Pepsinogen
Precursor compound of pepsin
- converted to active pepsin by contact w/acidic environment of the stomach
72
What does the acidic environment of the stomach do to proteins?
Disrupts the secondary & tertiary structures
73
Parietal cells
Cell in the stomach lining that secretes hydrochloric acid (HCl) in gastric juice
74
Chief cells
Secrete pepsinogen
75
Mucus cell
Type of cell found in the epithelial layer of the stomach that secretes mucus into the stomach
76
Carbonic anyhdrase
Enzyme that catalyzes the formation of carbonic acid from carbon dioxide & water
- catalyzes the formation of a proton (H+) & a bicarbonate ion (HCO3-) from carbon dioxide & water
- In parietal cells
77
What stimulates parietal cells to secrete HCl?
After being stimulated by nerves or the arrival of food, certain stomach cells produce gastrin & parietal cells begin secreting HCl in response
78
Gastrin
A hormone produced by cells in the stomach lining in responses to the arrival of food or to a neural signal from the brain. Stimulates other stomach cells to release hydrochloric acid
79
Ruminants
Member of a group of mammals (cattle, sheep, goats, deer, antelope, giraffe, & pronghorn) that have four-chambered stomach specialized for digestion of plant CELLULOSE.
- regurgitate cud, a mixture of partially digested food & cellulose-digesting bacteria & protists, form the largest chamber (rumen) for further chewing
80
Symbiosis relationship
Relationship in which members of different species live in close contact with each other
81
Digestion organs in order in ruminants
1. Rumen
2. Reticulum
3. Omasum
4. Abomasum
82
Rumen
For ruminants, where food initially enters the largest chamber which serves as a fermentation vat
- packed w/symbiotic bacteria & protists that produce cellulase
- oxygen-free environment
- symbiotic organisms produce ATP from glucose via fermentation, releasing fatty acids as a by-product that is absorbed by the ruminant & used as energy
83
Cellulase
An enzyme that digest cellulose by catalyzing hydrolysis of the glycosidic linkages btwn glucose residues
84
Reticulum
In ruminants, has a similar function to rumen. Food is regurgitated & chewed again to enhance mechanical breakdown
85
Omasum
In ruminants, processed cud enters & water & minerals are absorbed
86
Abomasum
In ruminants, contains pepsin & other digestive enzymes & functions like stomachs of other mammals
87
Villi
- Fingerlike projects that cover organ’s folded epithelial tissue
- singular; villus
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Microvilli
Tiny projections on apical surfaces of villi
- project into the lumen of the digestive tract
89
Lacteal
Small lymphatic vessel extending into the center of a villus in the small intestine
- receives chylomicrons containing fat absorbed from food
90
Proteases
Enzyme that can break up proteins by cleaving the peptide bonds btwn amino acid residues
- in small intestine
- specific to certain types of configurations of amino acids in a polypeptide chain
- inactive form synthesized in pancreas
91
Enteropeptidase
Intestinal enzyme that converts pancreatic trypsinogen into its active form, trypsin, thereby triggering activation of a cascade of enzymes important in digesting nutrients int he small intestine
92
Trypsin
Protein-digesting enzyme that is secreted in inactive form (trypsinogen) by the PANCREAS & activates several other protein-digesting enzymes (chymotrypsin, elastase, carboxypeptidase)
- actived by enteropeptidase from small intestine
- breaks specific peptide bonds in polypeptides, releasing amino acids
93
Who discovered the first hormone , secretin?
Baylis & Starling
94
Hormone
Chemical messenger that influences physiological processes at a very low concentration
95
Secretin
Peptide hormone secreted by cells in the small intestine in response to the arrival of food form the stomach. Stimulates secretion of bicarbonate ions (HCO3-) by the pancreas
96
Why are bicarbonate ions important?
They neutralize the acid arriving from the stomach
97
Cholecystokinin
A peptide hormone secreted by cells in the lining of the small intestine. Stimulates the secretion of digestive enzymes form the pancreas & the release of bile by the gallbladder that aid in processing lipids
98
Nucleases
Enzymes that digest RNA & DNA in food into nucleotides
- produced by pancreas
- released in repsonse to cholecystokinin from small intestine
99
Pancreatic amylase
An enzyme produced by the PANCREAS that digests carbs by catalyzing hydrolysis of the glycosidic linkages btwn glucose residues
- releases monosaccharides, disaccharides, trisaccharides
- released in response to cholecystokinin from small intestine
100
Brush border enzymes
Series of enzymes embedded in the epithelial cells of the small intestine that completely break down carbs into monosaccharides
101
2 principles that apply to monosaccharide & amino acid absorption
1. It’s highly selective, in that proteins int eh plasma membranes of microvilli are responsible for bringing specific nutrients into epithelial cells
2. It is usually active, meaning ATP is expended to transport nutrients into the cells against their concentration gradients
102
Steps of glucose absorption
1. Na+/K+-ATPase (sodium-potassium pump) in the base lateral membrane of the epithelial cells creates an electrochemical gradient that favors the entry of Na+
2. Glucose form digested food enters the cell along w/sodium ions via the Na+-glucose cotransporter in the apical membrane
3. Glucose diffuses into nearby blood vessels through a glucose carrier in the basolateral membrane
103
Pancreatic lipase
An enzyme produced by the PANCREAS that digests fats, releasing monoglycerides & fatty acids
- released in response to cholecystokinin from small intestine
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Emulsification
The dispersion of fat into an aqueous solution. Usually requires the aid of an amphipathic substance such as detergent or bile salts, which can break large fat globules into microscopic fat droplets
105
Bile salts
Emulsify fats.
- mechanically digest fats by breaking up large fat golubles into smaller ones
- synthesized in liver
106
Bile
Complex solution produced by liver, stored in gallbladder, & secreted into small intestine.
- Contains steroid derivatives called bile salts
107
What happens to the pH when bile enters the small intestine?
Increases
108
Carboxypeptidase
- synthesized in: pancreas
- regulation: Released in inactive form in response to cholecystokinin from small intestine; activated by trypsin
- function: In small intestine, breaks peptide bonds in polypeptides, releasing amino acids
109
Chymotrypsin
- synthesized in: pancreas
- regulation: released in inactive form in response to cholecystokinin from small intestine; activated by trypsin
- function: In small intestine, breaks peptide bonds in polypeptides, releasing amino acids
110
Elastase
- synthesized in: pancreas
- regulation: released in inactive form in response to cholecystokinin from small intestine; activated by trypsin
- function: in small intestine, breaks peptide bonds in polypeptides, releasing amino acids
111
Colon
Main section of large intestine where fevers are formed by compaction of wastes & reabsorption of water
112
Rectum
The most posterior portion of the digestive tract, where feces are held until expelled
113
Kidney
Maintain water balance
114
Hindgut
In insects, posteriormost portion of digestive tract that reabsorbs water & ions from “pre-urine” & excretes Uris acid & feces
115
Cecum
A blind sac btwn small intestine & colon
- enlarge in some species that use it as a fermentation chamber for digestion of cellulose
116
Coprophagy
Feces eating; allows the animal to absorb more nutrients form food
117
Appendix
A narrow pouch that extends form the cecum in some mammals
- vestigial function
- can be surgically removed from patient with no ill effects
- contains immune system cells & appears to act as a haven for symbiotic microorganisms that inhabit the colon
118
Diabetes Mellitus
A disease caused by defect in insulin production (type 1) or in the response of cells to insulin (type 2). Characterized by abnormally high blood glucose levels & large volumes of glucose-containing urine
119
Insulin
A peptide hormone produced by the pancreas in response to high levels of glucose (or amino acids) in the blood. Enables cells to absorb glucose & coordinates synthesis of fats, proteins, & glycogen
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Glucagon
A peptide hormone produced by the pancreas in response to low blood glucose levels. Raises blood glucose level by triggering breakdown of glycogen & stimulating gluconeogenesis
121
Gluconeogenesis
Synthesis of glucose, often from non-carbohydrate sources. In plants, used to produce glucose form products of the Calvin cycle. In animals, occurs in the liver in response to low insulin level & high glucagon levels
122
Type 1 diabetes mellitus
- autoimmune disease
- insulin-producing cells of the pancreas are destroyed
123
Type 2 diabetes mellitus
- Occurs when receptors for insulin now longer function correctly or are reduced in #
- risk factors; obesity, high-sugar diet, lack of exercise, genetic predisposition
124
Body mass index (BMI)
Mathematical relationship used to assess obesity in humans. Calculated as body mass (in kg) divided by the square of height (in m2)
