Digestion Flashcards
Carbohydrates main function
Provide energy for the body
The Big Four
Carbohydrates
Lipids
Proteins
+ 1 MORE
Sources of carbohydrates
Bread, pasta, fruits, veggies
General formula of carbohydrates
CH2O
Example of carbohydrate
Glucose
Chemical formula of glucose
C6H12O6
How many types of carbohydrates are there?
3
What are the types of carbohydrates
Monosaccharides
Disaccharides
Polysaccharides
Monosaccharides
Single or simple sugars
Simplest type of carbs
Building blocks of more
Examples of monosaccharides
Glucose
Fructose
Mannose
Galactose
Where is fructose found
Fruits, honey
What is galactose
Milk
Disaccharides
Two monosaccharides bonded together
Examples of disaccharides
Lactose
Sucrose
What is sucrose? How is it made?
Table sugar
What are polysaccharide?
Complex carbohydrates
Many (hundred or thousands) of monosaccharides linked together
Examples of polysaccharides
Glycogen
Starch
Cellulose
Glycogen
Made and stored by liver cells in animals and can be broke down when needed in emergencies
Starch
Made and stored in plants during photosynthesis
Cellulose
Material that plant cell walls are made of
Animals cannot break this down
Lipids
Fats
Functions of lipids
Stored energy-provide long term fuel
Used in membrane structure (phospholipids)
Used to help insulate the body
Acts as a cushion or shock absorber
Regulate some body functions (ex hormones)
Structure of lipids
Alcohol call a glycerol (E shaped) and fatty acid (long hydrocarbon chain) that can be saturated or unsaturated and number bathes between 1,2 or 3
What are the three types of fat?
Saturated
Unsaturated
Trans
What fat is solid at room temp?
Saturated
What fat comes from animals?
Saturated
What fat has lots of double bonds?
Unsaturated
What fat is liquid at room temp?
Unsaturated
What type of fat are often called oils?
Unsaturated
What fat generally comes from plants?
Unsaturated
What fat has no double bonds?
Saturated
What fat has a larger number of H atoms?
Saturated
What fat can be turned into cholesterol and be deposited on the walls of arteries?
Saturated
What fat is easier for humans to digest?
Unsaturated
What type of fat tends to not be changed into cholesterol?
Unsaturated
Examples of saturated fats
Butter, lard
Examples of unsaturated fats
Corn oil, peanut oil, canola oil
Structure of saturated fats
H H H H H
| | | | |
HO - C - C - C - C - C - H
| | | | |
H H H H HStructure of unsaturated fats
H H H H H
| | | | |
HO - C - C = C - C = C - H
|
HWhat are trans fats
Saturated fats formed from hydrogenation
Hydrogenation
When double bonds are removed from unsaturated fats and H atoms are added
What are enzymes?
Biologic Catalysts
What is the most complete nutrient?
Protein
3 functions of proteins
Build cellular structures (bone, hair, muscles) Used to control body actions (hemoglobin, hormones, antibodies) Provide energy (as good as sugar)
Are proteins as good as sugar for providing energy?
Yes
Protein-rich foods
Meat, eggs, nuts, fish
Composition of Proteins
C,H,O,N, and some S atoms
10aa to several thousand aa long, composed of the 20aa there are
How many amino acids are there?
20
How many amino acids does the body make?
12
Essential amino acids
The 8 amino acids that must be obtained from the diet.
What determines the protein type?
Type, order, and number of amino acids.
How many proteins does the body make?
5000
Macromolecule
A very large molecule made up of smaller molecules that are linked together
Metabolism
The sum total of all of the chemical reactions that occur in an organism
Essential nutrient
A nutrient that cannot be made by the body and must therefore be obtained from food
Role of minerals
Enable chemical reactions, aid in tissue development, growth, immunity
Examples of minerals
Calcium
Iron
What does calcium do
Conduct nerve signals, contract muscle, clot blood, form bone
Function of iron
Produce hemoglobin
Vitamins and minerals are _________ and we need in ________ _________
Micronutrients
Smaller quantities
Vitamins
Organic substances that enable chemical reactions and aid in tissue development, growth, immunity
Types of vitamins
Water soluble vitamins
Fat soluble vitamins
Water soluble vitamins
Absorbed readily by body. Any extras that are consumed will be excreted by the body (ex in urine). It js difficult to overdose on.
Examples of water soluble vitamins
C, B1, B2
Fat soluble vitamins
Must be absorbed with fat. If consumed in excess, will build up in fat tissue or liver and cause health problems.
Examples of fat soluble vitamins
A,D,E,K
What does vitamin A do?
Good vision, healthy skin, bones
Actual name of vitamin A
Carotene
Role of vitamin B1
Metabolizing carbohydrates, growth and muscle tone
Actual name for vitamin B1
Thiamine
What percent of the body is water
At least 62%
Role of water in the body
Transporting dissolved nutrients into cells that line the small intestines
Flush toxins from cells
Lubricating tissues and joints
Forming essential body fluids (blood, mucus)
Regulating body temp (by sweating)
Eliminating waste materials (through urine or sweat)
Number of steps in nutrition
4
Steps of nutrition in order
Ingestion, Digestion, Distribution, Egestion
Ingestion
Feeding
Digestion
Chemical and physical breakdown of food
Egestion
Elimination of non-digested waste
Number of feeding methods
6
Types of feeding methods
Engulfment, Diffusion, Filter Feeding, Fluid Feeders, Substrate Feeders, Bulk Feeders
Engulfment
Includes phagocytosis and pinocytosis. Requires energy.
Example of engulfment
amoeba
Pinocytosis
Phagocytosis for a liquid droplet
Diffusion
Nutrients move from an area of high concentration to low concentration.
Example of diffusion
tape worms and unicellular organisms
Filter Feeding
Food particles strained out of water by aquatic creatures
Examples of filter feeding
sponge, whale
Fluid feeders
Use piercing and sucking mouth parts
Example of fluid feeders
Leeches, butterfly
Substrate filters
Live in or on their food source and eat their way through it
Example of substrate filters
Caterpillars,earthworms
Bulk Feeders
Ingest fairly large pieces of food and swallow it whole. Some use tentacles, pincers, claws, fangs, jaws or teeth to kill prey, tear off pieces of meat or vegetation, or take in mouthfuls of food
Example of bulk feeders
Humans, most vertebrae
Number of types of digestive systems
3
Types of digestive systems
Food vacuole, digestive sac, digestive tube/alimentary canal
Food vacuole
Enzymes digest food in a vacuole
Example of food vacuole
paramecium, amoeba
Digestive sac
Ingestion and egestion occurs through a single mouth. Undigested food mixes with digested food. No circulatory system.
Example of digestive sac
Hydra, planaria (flat worms)
Digestive tube/alimentary canal
Most efficient system. 2 openings - mouth, anus. Nutrients and food never mix. Food moves through canal in one direction.
What types of digestive systems are intracellular?
Food vacuole
What types of digestive systems are extracellular?
Digestive sac, digestive tube.
Number of types of digestive methods
2
Physical/Mechanical digestion
Breaks large pieces of food into smaller pieces and increases surface area for chemical breakdown
Example of mechanical digestion
Chewing, biting, grinding
Chemical digestion
Breakdown of nutrient molecules into their simpler units. Uses enzymes and acids
example of Chemical Digestion
Lipids to glycerol and fatty acids
Oral Cavity
The mouth
Functions of the mouth
Site of chemical and physical digestion
Parts of the mouth
Tongue, Palate, Teeth, Salivarry glands
Tongue
Manipulates food between teeth, assists in digestion, tastes food,
What type of digestion does a tongue help with?
Physical
How many taste receptor cells does a tongue have?
2000-6000
How many tastes does a tongue have?
5
What are the tastes a tongue has?
Sweet, sour, salty, bitter, umani
Where are sweet taste receptor cells located?
Tip of the tongue
Where are salty taste receptor cells located?
Front of the tongue, along sides, behind sweet.
Where are sour tast receptor cells located?
Sides of tongue, behind salty.
Where are bitter taste receptor cells located?
Back of the tongue
Where are umani taste receptor cells located?
All over the tongue
What does umani mean?
Savoury. Japanese word.
Function of the palate
Separates the oral and nasal cavities to allow breathing while chewing.
Two types of palates
Hard palate, Soft palate
Where is the hard palate located?
Anterior portion
Attribute of hard palate that assists digestion
Friction ridges assist the tongue in holding food in position.
Where is the soft palate located?
Posterior portion
Soft palate
Spongy tissue with no bone. Includes the uvula.
How many teeth are there in a human mouth?
Typically 16 in each mandible and maxilla.
Maxilla
Upper part of jaw
Mandible
Lower part of jaw
Different types of teeth
Incisors, canines, premolars, molars
Function of incisors
Cutting, biting
Function of canines
tearing
Function of premolars
grinding
Function of molars
crushing
How is food broken down in the mouth?
Through mastication, food is broken down into smaller pieces to increase surface area. Food is then mixed with saliva to a bolus.
Mastication
Chewing
Bolus
Moist, soft, mass of food formed in the mouth
Crown of tooth
Area above gum
Neck of Tooth
Area just below surface of gum
Root of tooth
Lowest part
Number of salivary glands
3
Names of the salivary glands
Parotid glands, submandibular glands, subligual glands
Location of parotid glands
Anterior to earlobe
Location of submandibular glands
Along the lower jaw bone
Location of sublingual glands
Floor of mouth
Function of salivary glands
Produce saliva
Function of saliva
Moisten mouth and food, stimulate taste buds, aid in swallowing, begin chemical digestion
pH of saliva
6.8-7 (neutral)
% of saliva that is water
97-99.5
What enzymes does saliva contain?
Salivary amylase, mucus, lysozyme
Function of salivary amylase
initiate starch digestion
Function of mucus in saliva
lubricates, aids in swallowing
Function of lysozyme in saliva
kills bacteria
Physical characteristics of the esophagus
Long, flexible, muscular tube about 25cm long, that remains flat until swallowing occurs. Is lined with mucus on the inside
Why is the esophagus lined with mucus?
For protection.
Function of the esophagus
Transports food to the stomach
Muscles that the esophagus has
Circular muscles that wrap around the tube, and longitudinal muscles that run up and down the tube.
Peristalsis
Wave like muscular contractions that move bolus to the stomach
Do all muscles contract simultaneously in peristalsis?
No. They alternate contraction and relaxation between different groups - as circular contract, longitudinal relax.
Where does peristalsis occur?
Several areas of the digestive tract - esophagus, intestines, stomach
Pharynx
Back of mouth area
Uvula
End of soft palate
Function of the uvula
Rises to block off the nasal passage as the bolus is pushed towards the pharynx.
Epiglottis
Blocks off the trachea.
When food moves past entrance to the trachea …..
The upper esophageal sphincter relaxes
Where is the upper esophageal sphincter located
End of pharynx, beginning of esophagus
Function of Cardiac sphincter
Constricted to prevent reflux, relaxes to let the bolus enter the stomach.
Cardiac sphincter
Smooth muscle ring located at the end of the esophagus
Parts of the stomach
Fundus, Body, Pylorus, Pyloric sphincter
Functions of the stomach
Chemically and physically breaks down food, reservoir for food.
How does the stomach breakdown food?
Churns the food and mixes it with gastric juices.
How much food can the stomach store?
1 - 2 L
What is absorbed directly from the stomach into the blood?
Aspirin, alcohol, some water
Layers of stomach muscle
Longitudinal, circular, oblique
Is the stomach stretchable or rigid?
Stretchable. More food intake it can expand.
Ruggae
Folds that line the stomach and can be seen when the stomach is empty.
Gastric glands
Secrete gastric juices into the stomach
What does gastric juice contain
Hydrochloric acid and mucus
Function of hydrochloric acid in gastric juice
Kills bacteria and activate enzymes such as pepsinogen and forms active pepsin and starts chemical breakdown of protein
Chyme
The liquefied paste formed in the stomach, consisting of gastric juice and remains of bolus
pH of chyme
1 - 2 (highly acidic)
Where does chyme move after the stomach?
Passes through the pyloric sphincter into the small intestine.
Where does 90% of digestion occur?
Small intestine
Where does 99% of absorption of nutrients occur?
Small intestine
Measurements of the small intestine
2.5 cm diameter, 6-7m length
Sections of the small intestin
Duodenum (25cm), jejunum (2.5m), Ileum (3,)
Dudenum
Most chemical digestion of carbs, fats, proteins, occurs here. 8-9pH
Jejunum
Digestion and absorption
Ileum
Absorption. Ileocaecal valve controls movement of food from SI to LI.
Accessory Organs of the Small intestine
Pancreas, Liver, Gall bladder
Pancreas secretes
Sodium bicarbonate, Amylase, Lipases, Pephideses, Maltose, Insulin, Some other enzymes
Sodium bicarbonate
A base, neutralizes stomach acid, increases pH from a 2 to a 7
Amylase breaks down
starch to dissacharides
Lipases breaks down
fats to glycerol + fatty acids
Pephideses breaks down
Proteins to amino acids
Maltose, sucrose breaks down
Dissacharides to monosaccharides
Insulin
A hormone which regulates blood sugar levels
Liver
Produces bile, storage area for nutrients (ex vitamins minerals, glycogen), removes toxins (ex alcohol), makes cholesterol
Bile
Mixture of bile salts and cholesterol that helps to physically digest fats and provides more surface area for enzymes to chemically digest fats.
Emulsify
Physically digest foods
Gall bladder
Stores bile
Villi
Tiny finger-like projections in the SI which increase surface area for nutrient absorption and have microvillus on them
Where do glycerol and fatty acids go?
Into the lymphatic system to bypass the liver, although some go into the circulatory system and are used by cells.
Measurements of LI
7.6cm diameter, 1.5m long
Another name of LI
colon
Function of LI
Home to good bacteria (ex those that make vitamin K), removal of waste, reabsorbs water, salt, minerals, back into body
How much water does it take to digest food each day? How much is reabsorbed?
5.6L, ).2L
Rectum
End of LI, stores feces
Feces
undigested food, water, dead cells that lined the intestines, bacteria
How is feces finally removed from body?
Squeezed through the anus, and out of the body by peristalsis.
Anal sphincter
Ring of muscle that allows waste to exit the body.
