Ch. 21 Nutrition & Digestion Flashcards
What are the 2 major modes of nutrition?
1) Autotrophs “self feeding”
2) Heterotroph “feed on other organisms”
What are the 2 types of autotrophs?
1) Chemoautotrophs - chemosynthesis
2) Photoautotrophs - photosynthesis
What are the 2 types of heterotrophs?
1) Absorptive - digest food outside (via body surface)
2) Ingestive - to eat; internal digestion
- herbivores, carnivores, omnivore
What are the 4 stages of food processing?
1) Ingestion
2) Digestion
3) Absorption
4) Elimination
Ingestion
Act of eating; putting food in body
1) Suspension feeders “filter feeds”
2) Substrate feeders
3) Fluid feeders
4) Bulk feeders
Suspension feeders
“Filter feeders”
- obtain food molecules suspended in water
- ex. whales, clams, oysters, scallops
Substrate feeders
Live/on food source; eat way thru it
- ex. caterpillars, snails, earthworm
Fluid feeders
Suck nutrient rich fluids from plant/animal
- ex. mosquitos, hummingbirds, ticks
Bulk feeders
Ingest large pieces of foods; specialized body parts to ingest large pieces (jaws, pincers, fangs)
- ex. wolf, octopus, people, buffalo, frog
Digestion
Breaking large complex food molecules into smaller, simpler monomers
- 2 phases: Mechanical breakdown (chewing, muscle) & chemical breakdown (enzyme hydrolysis)
Function: Mechanical/chemical breakdown of food
Absorption
When small nutrient molecules are taken in by cells lining the digestive tract and transported via vessels
- used to make ATP and building material
Function: Transfer of nutrients into bloodstream (first to liver)
Elimination
No longer useful so elimination
- indigestible materials passes out of digestive tract
How do single celled organisms digest?
Intracellular digestion
- lysosomes combine with food vacuoles
How do simple multicellular organisms digest?
Gastrovascular cavity (one opening, most of body) - support, facilitate distribution of materials
How do complex multicellular organisms digest?
Complete digestive tract
- alimentary canal
- 2 openings w/ long tube
What does the type of specialized region of digestion depend on?
Type of habitat, types of food digested, and complexity.
Omnivores
An animal that eats both plants/animals
Herbivores
An animal that eats only plants
Carnivores
An animal that eats other animals
Why can’t animals use large polymers in organic matter directly?
1) macromolecules are too large to pass thru plasma membrane and enter cell
2) needs monomers to make polymers of own body
Gastrovascular cavity
A digestive compartment w/ a single opening, the mouth, may function in circulation, body support, waste disposal, and gas exchange, as well as digestion
- simple animals
Alimentary canal
Continuous passage way that extends 30ft from mouth to anus
- 8 specialized regions w/ unique structure/function
- A digestive tract consisting of a tube running b/w a mouth and anus
Accessory Organs
Not apart of the alimentary canal but attached to it and aids
- 4 regions: liver, pancreas, gallbladder, salivary glands
What are the 8 specialized regions of the alimentary canal?
1) Oral Cavity (mouth)
2) Pharynx (throat)
3) Esophagus (gullet)
4) Stomach
5)
6)
7)
8)
Oral Cavity
Structure that receives food (ingestion) and tastes food
- prepares food for swallowing
- carbohydrates digested here
- structures: teeth (32), tongue, salivary glands
What is the function of teeth?
Break down food into smaller pieces
- increases surface area for enzymes
What is the function of the tongue?
Most muscular organ, speech but also aids in chewing/swallowing
- taste buds
What is the function of salivary glands?
Produce saliva
- helps lubricate food for chew/swallow
- contains salivary amylase (begins carbohydrate digestion)
- antimicrobial agents (fight infection)
Pharynx
Digestive & respirator tract (food/liquid and air)
- receives bolus from mouth and passes to next region
- structures: tonsils, uvula, epiglottis
Tonsils
2 lymph glands that attacks foreign substances
Uvula
Deflect food downwards, not upward to nose
Epiglottis
Covers windpipe while swallowing
Esophagus (gullet)
Muscular tube that receives food from pharynx, carries thru neck/chest to stomach
- 2 layers: circular & longitudinal
- peristalsis
Peristalsis
Involuntary rhythmic waves of muscle contraction
- propels food thru a digestive tract and also enables many animals, such as earthworms to crawl
Stomach
Storage pouch, allows for discontinuous eating
- acts as churn b/c mixes/breaks food
- enzymatic digestion
- structure: size of 2 fists but expands and highly folded
- entrance is guarded sphincters (cardiac and pyloric)
- gastric glands and chyme
- digestion of proteins begins
Gastric glands
Tissues lining stomach and activated by smell, sight, taste, release gastric juice
- regulated by brain/hormones
- 3 types: mucus (line stomach), parietal (for HCL acid), chief (for pepsinogen -> HCL)
Crop
A pouchlike organ in a digestive tract where food is softened and may be stored temporarily
Gizzards
A pouchlike organ in digestive tract b/w the gizzard or stomach
Intestine
The region of a digestive tract b/w the gizzard or stomach and the anus, where chemical digestion and nutrients absorption usually occurs
Anus
Opening on the far end of canal thru which undigested materials are expelled
- 12 to 36 hours
What are considered digestive glands?
Salivary glands, pancreas, liver
pyloric sphincter
In the vertebrate digestive tract, a muscular ring that regulates the passage of food out of the stomach into small intestine
Trachea
The windpipe; the portion of the respiratory tube b/w the larynx and the bronchi; one of many tiny tubes that branch thru out an insect’s body, enabling gas exchange b/w outside air and body cells
Gastrin
A digestive hormone that stimulates the secretion of gastric juice
- acts like a negative feedback mechanism
Gastric ulcers
An open sore in the lining of the stomach, resulting when pepsin and hydrochloric acid destroy the lining tissues faster than they can regenerate
- caused by spiral prokaryote, Helicobacter Pylori
Small Intestine
“MVP” greatest amount of digestion, all of the absorption
- longest region of canal (23 ft)
- duodenum, jejunum, and ileum
Pancreas
A gland w/ dual functions
- the digestive portion secretes pancreatic juice
- the endocrine portion secretes the hormones insulin and glycogen into the blood
- neutralizes acid chyme
Liver
Largest internal organ, most versatile
- gatekeeper of blood
1) Produce bile
2) Detoxifying
3) Stores glycogen
4) Forms antibodies
5) Stores vitamins
6) Makes heparin (thins blood)
7) Produce blood plasmid proteins (thicken)
8) Urea can be removed
Bile
A solution of bile salts secreted by the liver, which emulsifies fats and aids in their digestion
- fat emulsifier
Gallbladder
An organ that stores bile and releases it as needed into small intestine
- small cone shaped organ bellow liver
Duodenum
The 10 - 12 inches of the vertebrate small intestine after the stomach, where acid chyme from the stomach is mixed with bile and digestive enzymes
- 2 ducts empty contents here (pancreatic and bile)
- digestion of fats begins
Villi
A fingerlike projection of the inner surfaces of the small intestine; a fingerlike protection of the chorion of the mammalian placenta; large #s increase surface area of organs
Microvilli
A microscopic projection on the surface of a cell; increases surface area
Colon
Large intestine; the tubular portion of the vertebrate alimentary tract b/w the small intestine and anus; functions mainly in water absorption and the formation of feces
- organ of reabsorption of water (90% of 7L)
- contains E. coli
Cecum
A blind out pocket of a hollo organ such as an intestine
Appendix
A small, fingerlike extension of the vertebrate cecum; contains a mass of white blood cells that contribute to immunity
Feces
Waste products of digestion, mainly indigestible plant fibers
Rectum
Temporary storage tube for fecal matter until defamation
- 6 to 8 inches
- 2 sphincters (voluntary, involuntary)
Why do herbivores (omnivores) have longer alimentary canals than carnivores?
Provides extra time to extract nutrients b/c plants are harder to digest due to cell walls and also have more surface area to absorb
Ruminant mammals
A mammal w/ 4 chambered stomach housing microorganisms that can digest cellulose
- ex. cattle, deer, sheep
Rumen -> Reticulum -> Omasum -> Abomasum
What are the 3 requirements of a healthy diet?
Animals must obtain…
1) Fuel to power all body activities
2) Organic raw material needed to make animal’s own molecules
3) Essential nutrients (substances the animal cannot make for itself from any raw material but must obtain in prefabricated for from food)
Kilocalories
A quantity of heat equal to 1000 calories; used to measure the energy content of food, it is usually called a “calorie”
Basal Metabolic Rate
The # of kilocalories a resting animal requires to fuel its sensual body processes for a given time
- 1300 to 1800 kcal/day
Why are fats and lipids essential?
Insulate against cold. Can relate w/ healthy immune system.
Too much leads to disease and decreased lifespan.
Recommended Dietary Allowance
A recommendation for daily nutrient intake established by nutritionalists
What are the 9 essential amino acids?
1) Tryptophan
2) Methionine
3) Valine
4) Histidine
5) Threonine
6) Phenylalanine
7) Leucine
8) Isoleucine
9) Lysine
Where do you get essential amino acids and what is the consequences of their absence?
Eat meat and animal-by-products.
Consequences are limit use of other amino acids, impair protein synthesis, and protein deficiency.
Vitamin
An organic nutrient that an organism requires in very small quantities. Generally function as coenzymes.
- water soluble or fat soluble
Minerals
In nutrition, a chemical element other than carbon, hydrogen, oxygen, nitrogen that an organism requires for proper body functioning
Low Density Lipoproteins
A cholesterol-carrying particle in the blood, made up of cholesterol and other lipids surrounded by a single layer of phospholipids in which proteins are embedded; carries more cholesterol than a related lipoprotein (HDL) and high LDL levels in the blood correlate w/ a tendency to develop blocked blood vessels and heart disease
High Density Lipoprotein
A cholesterol-carrying particle in the blood, made up of cholesterol and other lipids surrounded by a single layer of phospholipids in which proteins are embedded; an HDL particle carries less cholesterol than LDL and may correlate w/ decreased risk of blood vessel blockage
What are the 3 regions of the small intestine?
1) Duodenum
2) Jejunum
3) Ileum
Jejunum
Longest section at 22 ft
- major site of absorption, transfer of nutrients to bloodstream
- lots of folds, villi that enable absorb nutrients
Ileum
Last few inches
- contain ileocecal sphincter
What is the ileocecal sphincter for?
Ring like muscle at exit of small intestine, determine how long food will be in small intestine
What are the 4 regions of the large intestine?
1) Ascending
2) Transverse
3) Descending
4) Sigmoid Colon
What is inside pancreatic juice?
Pancreatic amylase to complete carbohydrate digestion in small intestine. Trypsin + Chymotrypsin completes protein digestion into smaller intestine. Lipase is enzyme that breaks down fat. Sodium bicarbonate (NaHCO3-) neutralizes the chyme acid, deactivates protein enzymes of stomach, and activates small intestine enzymes.
Gallstones
Collection of cholesterol + substances that interfere with passing of bile
