chapter 34: animal nutrition and digestive system

only eat meat

can eat non-animal food but is best to eat mostly meat

one opening in body cavity (gastrovascular cavity)

food and waste both go thru mouth

two openings (alimentary canal)

food enters through mouth, waste exits through anus

only one stomach

more than one stomach

stores food in chicken

like human stomach, chemical digestion

pebbles grind food

excretes urine and feces in chickens

have four stomachs

grass taken to rumen → reticulum → omasum → food regurgitated to abomasum → intestine and out

contain prokaryotes and protists to digest cellulose fiber

cud is regurgitated, chewed, and swallowed

removes water

“true stomach”

equivalent of mono gastric stomach chamber where gastric juices are secreted

incisors for clipping

premolars and molars for grinding

pointed incisors and enlarged canines

variety of specializations to accommodate both vegetation and meat

two layers of muscle allow for squeeze movement of esophagus

extracellular

in salivary juice, digests starch

where digestive and respiratory tract come together

closes nasopharynx in presence of food

in larynx, produces voice

opens and closes air passage depending on presence of food

separates esophagus and mouth

separates esophagus and stomach

separates duodenum and stomach

extra layer of muscle in stomach that helps with churning

deep folds in stomach

lined with columnar epithelial cells + muscle/goblet cells

produces HCl in stomach

produce mucus, prevents HCl form making holes in stomach lining (ulcer)

stratified squamous cells in esophagus die and are replaced with acidic columnar cells

precursor to cancer

protease, digests proteins into peptides

mixture of digested food in stomach, small quantity passed into duodenum

neutralized by bicarbonates from pancreas

has pancreatic juices and liver/gallbladder juice

lined w absorption epithelial cells

increases surface for better absorption

creates 4,000 square feet of small intestine

emulsify fats (break into fat droplets)

expands into 4,000 square feet of small intestine

go into lymphatic vessel

chews proteins one amino acid at a time from carboxyl end of amino acid

chews protein one amino acid at a time from amino terminal

has regenerative ability

produces bile

millions of hexagonal tubules

behind the bile

concentrates bile

underneath stomach

produces trypsin: protein → peptides

lipase: fat droplets → glycerol and fatty acids

converts starch → maltose

produces insulin and glucagon

trypsin and chymotrypsin digest food further into smaller peptides and bicarbonate

gets water back from chyme in small intestine

used for fermentation

vestigial organ

used in bacterial storage

large intestine takes too much water away

large intestine doesn’t take enough water away

lipids emulsified by bile, form micelles

amylase in mouth

glucose, fructose

lactose, sucrose

not made in body, must be acquired through food

8 in adults, 9 in children

… proteins are truncated

A, D, E, K

B vitamins and vitamin C

antioxidants

neutralize free radicals, which wear out body

muscle contraction

cofactor for DNA

signaling molecule

present in DNA

used for HCl, which is needed to convert pepsinogen to pepsin

maintains water balance, heartbeat

used for thyroid activity

hemoglobin formation

can be toxic to the body

produce pepsin, secreted as pepsinogen

in the stomach, pepsin breaks protein into peptides

in duodenum, trypsin, elastase, and chymotrypsin break peptides down smaller

carboxypeptidase, dipeptidase, and aminopeptidase reduce peptides to free amino acids, which are absorbed into the bloodstream through small intestines

lipases break triglycerides → monoglycerides + fatty acids

packaged into micelles, absorbed by microvilli

converted back into triglycerides, which aggregate w cholesterol, proteins, and phospholipids to form chylomicrons

chylomicrons move into a lymph capillary, which transports to rest of body

salivary amylase

pancreatic amylase: starch → maltose

maltase: glycogen, starch → glucose

sucrase, lactase