Digestive system Flashcards
Homeostasis
internal stability of the body
How does the digestive system aid in homeostasis
digestive system provides energy
How does the digestive system rely on other systems
needs blood and O2 to function
Autotrophs
make energy by making their own food using sunshine
Heterotrophs
consume other organisms to obtain energy
4 feeding mechanisms
1) filter feeding
2) substrate feeding
3) fluid feeding
4) bulk feeding
filter feeding
use structure similar to a filter basket to gather food suspended in water
ex: sponges, tube worms, clams, barnacles
Substrate feeding
live in their food source and eat through it
ex: caterpillars, earthworms
Fluid feeding
suck or lick nutrient rich fluid from plants or animals
ex: mosquitoes, ticks, spiders, bees
bulk feeding
ingest large pieces of food
ex: humans and all other mammals
what type of organisms have longer digestive tracts
Herbivores and omnivores have longer tracts than carnivores
main function of the digestive system
break down foods into their molecules so they can be used by the body
why is food broken down into soluble units
so they can pass through the plasma membranes of each cell
how are broken down substances transported through the body
circulatory system
4 phases for the digestive system to function
Ingestion → Digestion → absorbtion → Egestion
Ingestion
Bringing Nutrients into the body
usually happens in the mouth
Digestion
Breaks down food into smaller pieces
2 types of digestion
mechanical and chemical
mechanical digestion
physically break down food
decreases surface area
chemical digestion
Enzymes break down food to a molecular level
chemical bonds in food particles are separated
Absorption
nutrients are absorbed mainly in the small intestine
moved to circulatory system to be distributed to the rest of the body
Egestion (elimination)
Food molecules are removed from body
it is usually the food that the body is unable to digest
Alimentary Canal (digestive tract)
long, open tube (usually one-way)
How is the alimentary canal organized
specialized regions, with different organs along the tube processing food in different ways.
what is the alimentary canal lined with
mucus lining to protect canal and move food more easily along
what do parts of the alimentary canal produce
digestive enzymes to help break down food.
mouth
1st point of contact with food
performs chemical and mechanical digestion
what parts is the mouth divided into
roof of the mouth is made up of a hard palate and a soft palate
separates the oral cavity from the nasal cavity
hard palate
anterior (front)
mainly made up of bones
soft palate
posterior (back)
muscular
What does saliva contain
mucus, digestive enzymes (like salivary amylase), and other chemicals`
what does salivary amylase do
begins the chemical digestion of food by breaking down starches
Teeth
Perform mechanical digestion by physically breaking food
bite, tear and grind food into smaller pieces
Tongue
Mixes chewed up food with saliva
what is the tongue made out of
skeletal muscles which help to push food down into the esophagus
taste buds are located here
when do taste buds activate
once food is present, taste buds will be activated
sight or smell of food can trigger the salivary glands to produce saliva
Tonsils
help body fight infections
located at the back of the mouth on both sides of the tongue
what other system are tonsils a part of
lymphatic system
may need to be removed if they become infected
Bolus
name of food once they’ve been digested in the mouth
Uvula
finger like shape at end of soft palate
pharynx
upper portion of the throat
gets air from nasal cavity & food from mouth
Epiglottis
flap of cartilage
when food is present it seals off airway to prevent from entering (usually covers the esophagus)
Swallowing
occurs in the pharynx
can start by choice when it begins it turns involuntary
what happens to bolus during swallowing
gets moved to the back of the mouth by the tongue
once the bolus reaches the pharynx, it triggers the swallowing response
moves down the esophagus by peristalsis
