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35 Cards in this Set

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  • Back
What are nutrients? What 5 categories do they fit into?
Nutrients: substances that must be supplied in the diet.

lipids, carbohydrates, proteins, minerals, vitamins
What are the primary sources of energy?
Carbs and Fats
Describe 3 types of lipids.
1. fat/triglycerides: source of energy
2. phospholipids: make up cell membranes
3. cholesterol: makes up sex hormones and bile.
What are essential fatty acids? What are essential amino acids?
Must acquire lipids/amino acids from the diet because are not synthesized naturally in the body
What is the quickest source of energy? How is this source stored in humans?
Carbohydrates, including sugars and starches!

Stored in form of glycogen: a polysaccharide that is a chain of glucose molecules
define urea
the waste product of protein breakdown, which is filtered from the blood by the kidneys
List some functions of proteins.
- composed of amino acids that help make hormones, other amino acids, and new proteins
- act as enzymes
- antibodies
- muscle proteins
Describe what occurs during a protein deficiency.
protein deficiencies can result in a lot of scary conditions, like kwashiorkor. muscles are wasted due to a lack of protein.
define minerals and describe iron.
include various elements and inorganic molecules that must be obtained through the diet.

Iron: produces hemoglobin... a lack of can lead to anemia
define vitamins.
group of organic compounds that must be obtained through diet
Vitamin C (water soluble vitamins?)
is an antioxidant. It combines with free radicals that would usually damage DNA to limit their effects. (can cause scruvy)

is water soluble, which means..
- dissolves in blood plasma
- not much is stored in body
- works with enzymes
Vitamin D (fat soluble vitamin?)
promotes bone growth and increases calcium absorption. (can cause rickets)

is fat soluble which means...
- can be stored in fat and can accumulate over time
Vitamin K (fat soluble?)
regulates blood clotting.
Digestion systems must accomplish....
ingestion, mechanical breakdown, chemical breakdown, absorption, elimination
Define intracellular digestion (sponges)
: digestion occurs within individual cells
1. once food is englufed, food is enclosed in a food vacuole.
2. food vacuole fuses with digestive enzymes called lysosomes.
3. food is broken down
define extracellular digestion
larger, more complex organisms evolved a chamber where food could be broken down by enzymes OUTSIDE of the cells
Describe the gastovascular cavity in Hydras. Why is this still a very simple digestive system?
: digestive sac with a SINGLE OPENING, therefore both food is ingested and waste is ejected here

Because of the single opening, simple sac digestive systems can only process one meal at a time
describe the tubular digestive system in earthworms.
- mouth
- pharynx (connects mouth to esophagus)
- esophagus
- crop - storage organ tht collects food
- gizzard- where food is ground
- intestine - enzymes break down
- anus
What are ruminant animals?
Have a special digestive system in order to break down the cellulose in the food that they eat
(microorganisms produce cellulase)
- herbivore intest. are longer because need more time for absorption
- mechanical breakdown begins with the teeth
- 3 salivary glands pour out saliva, which contains amylase (breaks down starches into dissaccharides)
-lubricates food, carries bacteria killing enzyme to fight infection
- tongue pushes food into the pharynx, which connects to the esophagus
- larynx: connects nose/mouth to trachea
epiglottis: flap of tissue that blocks of respiratory passages so food is directed into esophagus, not trachea.
The Esophagus
- Swallowing forces food into a muscular tube called the esophagus

- The esophagus forms waves of muscular contraction (peristalsis) that carry food to the stomach
The Stomach and Pyloric Sphincter
stomach: expandable muscular sac
pyloric: ring of muscle that separates the stomach from the small intestine; also regulates the passage of the food into small intest
What are the stomach's 3 major functions?
1. store food; release to small intestine
2. mechanical breakdown: muscular walls contract and churn food
3. chemical breakdown: there are glands in stomach that secrete enzymes and hormones and such
What are the stomach's secretions?
- gastrin: (hormone) stimulates the production of hydrochloric acid
- HCI: makes fluid in stomach acidic, allows pepsin to activate
- pepsin (a type of protease): breaks proteins into shorter chains
- mucus: protects stomach wall from acid
define chyme
: mix partially digested food particles + stomach secretions.
- highly acidic
- goes through the pyloric sphincter and into the small inestine
- stores fats and carbs (in glycogen) for energy, regulates blood glucose levels, stores iron, detoxifies harmful
- produces BILE, stored in gallbladder
define bile
: mixture of bile salts, water, other salts, cholesterol

- bile salts breaks down fat in the chyme by dispersing them into small particles that enzymes (lipases) can act on
The Small Intestine: PANCREAS
- secretes pancreatic juice
- made up of water, sodium bicarbonate (buffer: neutralizes the acidic chyme), and digestive enzymesssss such as *amylase, lipase, protease
The Small Intestine: Absorption
most absorption occurs in the small intestine.
- fingerlike projections, VILLI and stemming from that MICROVILLI, create more surface area
- fats = absorbed by lacteal on each villus
- water, monosaccharides, amino acids, vitamins, minerals.... absorbed by small intestine
define segmentation movements
: contractions in the small intestine that slosh chyme back and forth
- brings nutrients into the surface of the intestine where they can easily be absorbed
The Large Intestine
colon: most of length
rectum: terminal end
A mix of water, undigested nutrients, and fiber enters the large intestine

- contains bacteria that consume the unabsorbed nutrients
The Large Intestine: FECES
: semi solid remnants that consist of indigestible wastes and dead bodies of bacteria
- peristalsis moves the feces out
How does the nervous system impact the digestive system?
1. sceretion of saliva
2. secretion of HCI and gastrin
3. acid secretion is regulated by negative feedback