digestion & waste Flashcards
Essential Nutrient
- we make most fatty acids and amino acids
- those we can’t make “essential”, therefore must obtain from the diet
- plants make many essential nutrients
- cultures around the world developed complete diets
ex: beans and rice to obtain all essential amino acids
Vitamins
organic molecule needed for metabolism
- 2 types of vitamins
- water-soluble vitamins
- the B vitamins (B1, B2, B3, B5, B6, B7, B9, B12)
- vitamin C
- fat-soluble vitamins (eggs, carrots, nuts, broccoli)
- A, D, E, and K
- water-soluble vitamins
Minerals
- inorganic molecules
- we need many minerals in trace amounts (ex: Na+, K+, etc)
- these are found in many food (like: vegetables, eggs, milk etc.)
Filter feeding
such as the humpback whale; move water through a filtering structure to obtain food
Substrate feeding
are animals that live in or on their food source
Fluid feeding
suck nutrient-rich fluid from a living host
Ingestion
bringing food into your body, act of eating or feeding
Digestion
the breaking down of food into smaller pieces
Absorption
the animal’s cells take up (absorb) small molecules such as amino acids and simple sugars
Elimination
completes the process as undigested material passes out of the digestive tract
Gastrovascular cavity
a central cavity with a single opening in the body of certain animals; that functions in digestion and the distribution of nutrients throughout the body
- some animals have only one gastrovascular cavity:
- cnidarians & flatworms
Alimentary cavity
a complete digestive tract with 2 openings (consisting of a tube running between a mouth and an anus)
Incisor
“are the front teeth present in most mammals.”
Canine
“a pointed tooth between the incisors and premolars of a mammal, often greatly enlarged in carnivores.
Premolar
” are transitional teeth located between the canine and molar teeth.
- have a flat biting surface. “
Molar
“are large, flat teeth at the back of the mouth.”
Cellulose
“Humans cannot digest cellulose, but it is important in the diet as fibre.”
Cellulase
“an enzyme that convert cellulose into glucose or a disaccharide.”
Ammonia
- is a byproduct of protein metabolism
- animals must remove it from their bodies
- 3 primary ways:
- as AMMONIA (MOST AQUATIC VERTEBRATES)
- as urea (ex: humans)
- as uric acid (most non-mammalian land animals)
Urea
a form of ammonia
ex: humans
Uric acid
a form of ammonia
most non-mammalian land animals
Filtration
(1st step of excretory system)
blood pressure PUSHES water and solutes across filter membrane
Reabsorption
(2nd step of excretory system)
water and important solutes (salts, sugars, amino acids, bicarbonate, etc.) are returned to the blood (either actively or passively)
Secretion
(3rd step of excretory system)
toxins (ex: drugs) are actively secreted out of blood into the excretory tube
Excretion
(4th step of excretory system)
filtrate is excreted as urine
the Protonephridium (an excretory system example)
ex: in flatworms
- remember: NO circulatory system! (so no blood pressure/blood)
- cellular waste dumped out through cell membranes within body INTO INTERSTITIAL FLUID
- cilia PULL interstitial fluid into tubules, where it is filtered
- filtrate travels through tubules and EXITS body wall via small pores
the Metanephridium (an excretory system example)
ex: in earthworms (similar to ours)
- remember: CLOSED circulatory system! (have blood pressure - in order to push things across the membranes)
- cilia PULL IN fluid from coelom (body cavity)
- In that liquid that they PUSH all the filtrate through membranes into tubules
- Things are reabsorbed back into the blood as necessary
- Left over ACCUMATES into bladder as urine
- Eliminated out
the Malpighian tubule (an excretory system example)
ex: in insects
- NO circulatory system!
- NO liquid is pushed through a filtration membrane
- Waste materials are ACTIVELY transported into tubules from hemolymph
(liquid “insect blood” that bathes everything surrounds the malpighian tubules and materials are transported into malpighian tubules and water follows just following the concentration gradient) - Waste is combined with dietary waste/digestive tract
- Water & important solutes (ions, valuable organic molecules) recovered in rectum
- Everything else REMOVED through ANUS
Nephron
the tubular excretory unit of the vertebrate kidney
List the requirements for cellular respiration within animal tissues.
- the activities of cells, tissues, organs, & whole animals depend on sources of chemical energy in the diet
- this energy is used to produce ATP, which powers processes ranging from DNA replication & cell division to vision & flight
- to meet the continuous requirement for ATP, animals ingest & digest nutrients, including:
- carbohydrates
- proteins, and
- lipids
…for use in cellular respiration & energy storage**
Outline the basic nutritional requirements animals obtain from their diets.
each animal has a suite of essential nutrients - molecules that the animal cannot produce & therefore must obtain from the diet
- essential amino acids
- essential fatty acids
- vitamins
- minerals
Define essential nutrient.
- we make most fatty acids and amino acids
- those we can’t make are “essential” (have to eat something that will provide them for us, can’t build them ourselves)
- plants make many essential nutrients
EX: beans and rice to obtain all essential amino acids
Explain the four stages of food processing by animals.
ingestion: bringing food into your body, act of eating or feeding
digestion: the breaking down of food into smaller pieces
absorption: the animal’s cells take up (absorb) small molecules such as amino acids and simple sugars
elimination: completes the process as undigested material passes out of the digestive tract
Identify examples of the four animal feeding mechanisms.
suspension feeders: EX: CLAMS & OYSTERS feed on tiny morsels of food in the water that passes over their gills; cilia sweep the food particles to the animal’s mouth in a film of mucus
- many aquatic animals; which eat small organisms or food particles suspended in the water
filter feeders: EX: the HUMPBACK WHALE; move water through a filtering structure to obtain food
substrate feeders: EX: LEAF MINER CATERPILLAR, the larva of a moth, is eating through the soft tissue of an oak leaf, leaving a dark trail of feces in its wake OR MAGGOTS (fly larvae), which burrow into animal carcasses
- are animals that live in or on their food source
fluid feeders: EX: MOSQUITO has pierced the skin of its human host with hollow, needle-like mouth parts and is consuming a blood meal OR APHIDS tap the phloem sap of plants OR in contrast to such parasites, some actually benefit their host AKA hummingbirds and birds move pollen b/t flowers as they fluid-feed on necter
- suck nutrient-rich fluid from a living host
bulk feeders: most animals, including HUMANS, which eat relatively large pieces of food
Describe the benefits of eating a prey item in pieces rather than whole.
need to get it across the membranes, if you swallow a piece of pie you won’t be able to shove pie through intestinal lining into the blood stream and you’re body cells won’t be able to do anything with a piece of pie, so you need to break it down to be able to do anything with it *
Summarize the function of each of the four mammalian tooth types.
incisor: “to cut”
canine: “for tearing apart food” *sharpest teeth
premolar: “tearing and crushing food”
molar: “grind food during chewing”
Predict a mammal’s diet based on its dental formula.
carnivore: EX: dog or cat families
- generally have large, pointed INCISORS & CANINES that can be used to kill prey & rip or cut away pieces of flesh
- the jagged premolars & molars crush & shred food
herbivore: EX: horses & deer
- usually have PREMOLARS & MOLARS with broad ridged surfaces that grind tough plant material
- the incisors & canine are generally modified for biting off pieces of vegetation
- sometimes, canines are absent
omnivore: EX: humans
- are adapted to eating both plants & meat
- adults have 32 teeth
- from front to back along either side of the mouth are 4 bladelike INCISORS of biting, a pair of pointed CANINES for tearing, 4 PREMOLARS for grinding, & 6 MOLARS for crushing
Compare internal and external digestion.
intracellular digestion: EX: sponges
- the hydrolysis of food INSIDE food vacuoles (cellular organelles in which hydrolytic enzymes break down food - simplest digestive compartments), begins after a cell engulfs solid food by phagocytosis or liquid food by pinocytosis
extracellular digestion: EX: in most animal species
- hydrolysis of food begins with extracellular digestion, the breakdown of food in compartments that are continuous OUTSIDE of the animal’s body
Identify which animals employ intracellular digestion, extracellular digestion, or both.
intracellular digestion:
- sponges!
- also, Platyhelminthes (flatworms), Ctenophora (comb jellies), and Cnidaria (coral, jelly fish, and sea anemones)
extracellular digestion:
- this more advanced type of digestion occurs in chordates, annelids, and crustaceans.
Discuss the advantages of an alimentary canal over a gastrovascular cavity.
alimentary canal aka COMPLETE digestive tract is better because food moves along the alimentary canal in a single direction, the tube can be organized into specialized compartments that carry out digestion & nutrient absorption in a stepwise fashion
- an animal with an alimentary canal can ingest food while earlier meals are still being digested, a feat that is likely to be difficult or inefficient for animals with gastrovascular cavities