digestive system and dissection orientations

dorsal side

back side, dark on earthworm

ventral side

front/chest, light on earthworm

anterior

top/head

posterior

bottom

lateral

on the outside of body: fingers

median

vertical plane through middle of body (heart)

mouth

???????

urogenital opening

external opening of urogenital systems (urethra/vulva)

anus

opening for solid waste

cloaca

opening for urine and feces in birds, amphibians, and reptiles

pharynx

connection between nasal passages and mouth

crop

for earthworms and birds: storage space for food

gizzards

break down food, in worms, birds, reptiles

hard palate

roof of the mouth, helps with initial food breakdown

soft palate

soft tissue under tongue

saliva

fluid composed of water, enzymes, intestinal fluid, begins chemical digestion

amylase

enzyme that chemically breaks down starch in saliva

teeth

mechanical digestion

esophagus

tube to move processed food from mouth to stomach

peristalsis

muscular contractions that move food through the digestive system

cardiac sphincter

connection between the esophagus and stomach, fills with stomach acid and causes heart burn

stomach

muscular sac that stores food and continues digestion, can also absorb drugs into the blood stream

stomach mechanical digestion

muscular contraction turns food like a washing machine

stomach chemical digestion (gastric juices)

acidic liquid made from hydrochloric acid and enzymes

pepsin

enzyme that breaks down proteins in stomach

pyloric sphincter

two way valve that leads from stomach to small intestine

duodenum

first part of small intestine

small intestine

very long tube that causes chemical digestion and nutrient absorption, has a high surface area to volume ratio

microvilli

small projections on surface of the small intestine, contain enzymes that break down food

capillary vessels in microvilli

nutrient absorption into blood stream

liver location

Below the lungs

What does the liver produce for chemical digestion?

Digestive fluids, enzymes, bile that it puts into the small intestine

bile

breaks down fats

gallbladder

stores bile, behind liver, looks green

pancreas

gland behind the stomach that produces insulin and glycogen to regulate blood glucose

beta pancreas cells

insulin, endocrine function

alpha pancreas cells

glycogen, endocrine function

pancreas exocrine function

creates digestive enzymes to put into the small intestine

exocrin glands

makes substances that are released through a duct or opening to body surface (sweat, tears, saliva, digestive juices)

endocrin gland

release substances directly into blood stream

large intestine/colon

shorter than small intestine, large radius, reabsorbs water and bile, bacteria break down fiber and produce vitamins

what color is the large intestine?

green

appendix

vestigial structure, could have previously stored digestive bacteria

rectum

storage muscle for feces, comes after large intestine

order of digestive system

mouth, esophagus, stomach, small intestine, large intestine, rectum

what organs look green?

liver, gallbladder, large instestine