Digestion

Smooth:unstriated, slow acting, autonomic control

Move towards the center of sarcomere

no, they just slide past each other

1) Suspension feeders- sessile animals that filter suspended particulates 2)deposit feeders-consume substrate and extract whatever nutrients they can 3) filter feeders, actively acquire and filter smaller organisms( from water)

animals that eat other animals (one on one interactions)

gut microbes are required to digest cellulose adaptations for crushing plant material Large amounts needed to meet energy demands

unspecialised feeders, adapted for consuming a range of food types, including plant and animal

liquid diet

sponges digest theri food intracellulary -the alimentary canal of most eumetazoans allows for extracellular digestion -cnidarians and flatworms have a cavity with single opening (bind digestive) -specialization occurs went here is one way transport of food form mouth to anus. ex) annelids

-tubular gastrointestinal tract plus accessory digestive organs

1)Physical fragmentation-chewing grinding, increased exposure to enzymes 2)chemical digestion-break down carbohydrates, lipids, and proteins into smaller units 3) absorption and waste excretion

-) devices for feeding and limited digestion -patterns of dentition reflect diets in mammals -human saliva contains the enzyme amylase, which initiates the breakdown of starch

-human saliva contains the enzyme amylase, which initiates the breakdown of starch

1)The esophagus transfers food to the digestive region -rhythmic waves of contraction(peristalsis) move food to the stomach Birds and many invertebrates have a crop for storing food. -The gizzard of birds and gastric mill of crustaceans assist in grinding food.

-Collapsible muscular bag -mucus, HCL, and pepsinogen are secreted. HCL kills most bacteria. mucus protects the lining of the stomach HCL causes (inactive) pepsinogen to transform into (active) pepsin, a protease. some protein digested. Goes to small intestine

Food enters the small intestine(duodenum, jejunum, and ileum) from the stomach duodenum, and receives pancreatic juice (first part of the small intestine) -neutralize gastric acids -enzymes critical for digestion,(eg.proteases,lipases,amylases) Bile is produced by the liver, stored in the gallbladder, and transported to the duodenum (produces bile pigments, and bile salts) The internal surface area of S.I. is increased by coiling and by villi and microvilli(on top of villi)

Bile is produced by the liver, stored in the gallbladder, and transported to the duodenum Produces bile pigments; worn-out blood cells Bile salts: help emulsify fat

Coiling and by villi and microvilli

Small intestine to Large, Large intestine(colon) begins at the point where the appendix and cecum meet small intestine. -Colon is shoter than the S.I and lacks villi -no digestion occurs in the colon -consolidation of waste via water absorption, absorption of products of bacterial metabolism. -colon empties in to dectum: fecex excreted

Carnivores have a more convoluted stomach -eat large items infrequently; need for expansion Herbivores have larger stomach-plants are difficult to guess and are low in nutritional value. must consume large quantities

Cellulose can only be digested with the aid of microorganisms(that produce cellulase) Mammals ave three places to ferment cellulose 1)foregut:stomach 2)hindgut:cecum bigger than stomach 3)hindgut: colon eg) elephanr

The rumen is a larger chamber housing bacteria, fermented food is regurgitated, re-chewed, and then swallowed again. eg) cows

-many non-ruminant herbivores (eg, horses, rodents, rabbits) have a large cecum that contains bacteria needed to break down cellulose -Long intestines increase the opportunity for absorption -rodents and lagomorphs also engage in coprophagy(eat their own poop to digest again)

No cecum