Gastric Inhibitory Peptide
________ (GIP)- stimulated by chyme with high fat content.
Leptin
________- thought to be the main signaling molecule in the afferent portion of the control circuit for energy sensing.
Essential nutrients
________ are those that the body can not manufacture (vitamins, essential amino acids, long-chain unsaturated fatty acids, trace elements)
Liver
largest internal organ, main exocrine secretion is bile, modifies chemicals to maintain homeostasis
Chyme
________- the mixture of partially digested food and gastric juice.
Pepsinogen
________- the inactive form of pepsin (which digests proteins)
Mouth
________- a chamber for ingestion and initial processing.
nematodes, vertebrates, and earthworms
have one-way digestive tracts.
Exertion
________ increases metabolic rate.
Peristalsis
________- series of involuntary wave-like muscle contractions which move food along the digestive tract.
Insulin and Glucagon
from the liver, help maintain blood glucose concentration
Gastric Juice
________- an acidic secretion of the tubular gastric glands of the mucosa.
kilocalories
measures intake of food energy (under neuroendocrine)
large intestine
or colon, eliminates waste material, small intestine empties into the cecum, no digestion, only about 4% of absorption, many bacteria (excess is released in feces)
small intestine
aprx 14ft long, duodenum, jejunum, ileum, epithelial wall is covered with villi, epithelial cell lining is covered with microvilli, absorbed nutrients move into the blood or lymph capillaries
Invertebrate digestive systems
________ are bags of tubes.
Secretin
stimulated by increased chyme acidity
CCK
stimulated by high fat content
Gastrin
proteins in the food stimulate its secretion in the stomach
Enterohormones
duodenal hormones secreted into the blood
Hormones
stimulate salivary and gastric responses to sight, smell, and consumption of food
Pancreas
also functions as an endocrine gland, has hormones to digest proteins (trypsin and chimotripsin), starch (pancreatic amylase), and fat (lipase)
Accessory Organs
secrete enzymes into the small intestine
Stomach Acid
sterilizes food, protein digestion, activating pepsin, activating intrinsic factor, stimulating deliver of bile and enzymes, closing the esophageal sphincter, opening the pyloric sphincter
Stomach
acidic breakdown of food, chyme leaves the stomach through the pyloric sphincter and into the small intesine
Intrinsic Factor
popypeptide needed for the intestinal absorption of b12
Tissues of the Digestive Tract
serosa, mucosa, submucosa, muscularis externa
BMR
basal metabolic rate, minimum rate of energy consumption under defined resting conditions