Animal Digestion & Nutrition

Nutrition

food is taken in, taken apart, then taken up

Herbivores

plant and algae eaters

carnivores

meat/animal eaters

omnivores

plant and meat eaters

4 essential nutrients

amino acids, fatty acids, vitamins, and minerals

how many amino acids are essential for us

9/20

what does essential mean in this sense

we do not naturally produce enough, we need to consume it in order to synthesize it

where can we get our essential amino acids

meat, eggs, and cheese

plant proteins are incomplete in

amino acid composition

what are the essential fatty acids

omega-3 and omega-6

fatty acid deficiencies are

rare

how many essential vitamins are there

13

essential vitamins are required in what amounts

small amounts

fat soluable

can be dangerous if there are too many

water soluble vitamins

does not pose a threat if there are too many

vitamins are

organic

minerals are

inorganic

undernutrition

diet does not provide enough chemical energy

effects of undernutrition

used up stores fat and carbs, breaks down proteins, lose muscle mass, suffer protein deficiency in the brain, death

Ingestion

eating food

suspension feeders

sift small food particles from water (ex: whales)

substrate feeders

live inside food source (ex. caterpillars)

fluid feeder

drinking fluid like blood (ex. mosquitoes)

bulk feeders

eats whole foods (ex. humans)

Digestion

process of breaking food down

mechanical digestion

chewingto increase surface area

chemical digestion

splits food into smaller molecules with enzymes

enzymatic hydrolysis

splits bonds into molecules with the addition of water

absorption

taking in of nutrients

elimination

getting rid of unabsorbed nutrients

Intracellular digestion

food particles are engulfed by phagocytosis

extracellular digestion

breakdown of food outside cells

Alimentary canal

the tract that food travels through

Sphincters

valves that move materials between digestive organs

First area of digestion

oral cavity and salivary glands

Salivary amylase

enzyme that initially breaks down food into bolus

bolus

food that initially gets broken down by saliva

epiglottis

the flap that separates the esophagus and trachea, it flips back and forth

Pharynx

the junction that opens to both the trachea and the esophagus

second area of digestion

stomach

chyme

the substance that the stomach converts food into

Gastric Juice

hydrochloric acid and pepsin; kills unwanted bacteria and denatures proteins

HCl

hydrochloric acid

pepsin (protease)

breaks proteins into smaller peptides

Parietal cells

H and Cl ions separate in the lumen

Lumen

the lining in the stomach that protects from the gastric juice

Chief cells

inactive pepsinogen, is activated to pepsin when mixed with hydrochloric acid in the stomach

Gastric ulcers

lesions in the stomach lining

Helicobacter pylori

the bacterium that caused gastric ulcers

third area of digestion

small intestine

duodenium

beginning of the small intestine, where chyme from the stomach mixes with digestive juices from the pancreas, liver, gallbladder, and small intestine

jejunum

middle of the small intestine

ileum

end of the small intestine

pancreas

organ that proteases trypsin and chymotrypsin, neutralizes acidic chyme

bile

made in the liver, stored in gallbladder, aids in digestion and absorption of fats. Also destroys non-functional red blood cells

small intestinal enzymatic digestion occurs in

the duodenum

nutrient and water absorption occurs

in the jejunum and ileum

villi and microvilli

intestinal lumen; creates greater surface area of food to increase speed of nutrient absorption

hepatic portal vein

carries nutrient-rich blood from the capillaries of the villi to the liver, then to the heart

hepatic

liver

fourth area of digestion

large intestine

colon

connects the small and large intestine

cecum

aids in the fermentation of plant material and connects where the small and large intestines meet

appendix

in humans, attached to the cecum. very minor role

Dentition

(teeth) structural variation reflecting diets

nonmammalian species have

less specialized teeth

carnivores have

large, expandable stomachs

herbivores and omnivores have

longer alimentary canals; longer time todigest vegetation

herbivores have

fermentation chambers; mutualistic microorganisms digest cellulose

feedback circuits

regulates digestion, energy storage, and appetite

nervous system

enteric division (ENS) regulate digestion

endocrine system

regulates digestion through hormone release/transport

humans store energy rich molecules in

the liver and muscles cells in polymer glycogen

excess energy is stored in

adipose tissue

insulin and glucagon (hormones)

regulate glycogen—>glucose

liver is the site for

glucose homeostasis

carb-rich meals raise

insulin levels

synthesis of glycogen

brings down blood sugar (non-diabet

glucagon

stimulates the breakdown of glycogen to release glucose; elevating blood sugar

overnourishment

obesity; results from excessive intake of food energy with the excess fat stored

obesity can contribute to

type 2 diabetes, cancer of the colon and breasts, heart attacks, and strokes

stores bile, which emulsifies fat

gallbladder

peristalsis

muscular, wave-like motions that pushes food through the digestive system