Digestive System Flashcards
Water in the human body
Main fluid compartment of:
- intracellular fluid (inside cell)
- extracellular fluid (outside cell)
- intersitial fluid (between cells)
Functions:
1. transport dissolved nutrients
2. remove waste from cells
3. lubricate tissues and joints
4. main component of essential body fluids
5. regulate body temperature (sweat)
6. eliminate waste (urine and sweat)
Minerals
Inorganic substances that enable chemical reactions and aid in tissue development, growth, and immunity
Ex. calcium, iron, magnesium, potassium, sodium
Vitamins
Organic substances that enable chemical reactions and aid in tisse development, growth, and immunity
Ex. A (carotene), B (thiamene), C (ascorbic acid), D, E
What is dissolved in the fluid of a cell?
- Inorganic molecules and ions
- small and simple
- water, phosphate, H, Na - Organic molecules
- macromolecules
- made up of C and H (N, O, etc.)
- called nutrients
Nutrients
Organic molecules used for energy, repair/building, regulating cell activity
The 4 Types of Macromolecules
- Carbohydrates
- Lipids (fats)
- Protein
- Nucleic acids
Essential nutrients
What the body cannot create, and must therefore be consumed in the diet (not nucleic acid)
Provide energy to maintain body’s metabolism (mostly carbohydrates and lipids)
Carbohydrates
Contain elements C, H2, O2
Provide short and long term energy storage
1. Simple sugars (mono- and di- saccharides)
2. Polysaccharides
Simple sugars
- Monosaccharides
- 6 carbons long
- GLUCOSE, FRUCTOSE, GALACTOSE - Disaccharides
- made of two monosaccharides
- SUCROSE, MALTOSE, LACTOSE
Polysaccharides
Complex carbs
- many monosaccharides linked together
- long term energy storage (liver)
- STARCH (plants), CELLULOSE (pants), GLYCOGEN (animals)
Lipids
Fats are a type of lipid
Insoluble in water
Contain, C, H2, O2
BUTTER, LARD, OIL
Proteins
Assembled from small sub-units - amino acids
Amino acids are joined by peptide bonds
20 amino acids (8 essential, 12 non-essential)
Chains of amino acids are called polypeptides
Most enzymes and some hormones (e.g. insulin) are proteins
Build/repair, catalyze reactions (enzymes), fight infection (antibodies), messengers (hormones)
How do animals obtain food?
They are heterotrophs
1. Filter Feeders
2. Substrate feeders
3. Fluid Feeders
4. Bulk (Chunk) Feeders
Filter Feeders
Aquatic animals that filter food into their mouths and then filters it to smaller organisms to digest
Ex. tube worms, clams, whales, tube sponges
Substrate Feeders
Live on or in their food source, eating their way through it
Ex. caterpillars, earthworms
Fluid Feeders
Special mouthparts adapted for piercing and sucking
Some obtain nutrient rich fluids from plants
Ex. mosquitoes, ticks, spiders, hummingbird
Bulk (Chunk) Feeders
Ingest large pieces of food
Ex. animals, most vertibrates
Stages of food processing
- Ingestion
- Digestion
- Absorption
- Elimination (egestion)
Ingestion
The taking in or eating of food
Digestion
Breakdown of food by mechanical and chemical means into small molecules
Absorption
Occurs in the small intestine
Transportation of the products of digestion from the digestive system into the circulatory system, which distributes them to the rest of the body
Elimination (egestion)
The removal of undigested solid waste matter from the body
Types of Digestion
- Mechanical: physical breakdown of the food into smaller bits. Use of teeth
- Chemical: breakdown of nutrient molecules into smaller molecules. Use of enzymes
How long does it take for food to go through the digestive system?
24-36 hours
Mouth (oral cavity)
Opening for food, equipped with teeth and tongue
Food enters in a process called ingestion
Teeth
Arranged in the upper and lower jaws
Initiate the physical breakdown of food
Incisors - cut
Bicuspids and canines - tearing and piercing
Molars - grinding