A+P module 3

alimentary canal

the GI tract, a continuous muscular digestive tube

accessory digestive organs

teeth, tongue, gall bladder, salivary glands, liver, and pancreas

The tongue’s attachments

hyoid bone, the mandible, and the lingual frenulum

mastication

food being chewed by the teeth in the mouth

root of the tooth

largest portion, in the jaw bone

neck of the tooth

in the gums

crown of the tooth

visible portion above the gums

tooth pulp cavity

center, contains nerves and blood vessels

dentin

bone-like substance composing most of each tooth

enamel

surface of the tooth, hard connective tissue that protects the rest of the tooth

bolus

a compact mass of food

papillae

bumps on the tongue, circumvallate, fungiform, and filiform

circumvallate and fungiform

contain taste buds

mucosa

secretes mucus into the interior the gastrointestinal tract

submucosa

contains blood and lymph vessels, lymph nodes, nerves, and mucous glands

muscularis externa

two layers of muscle: the outer longitudinal fibers and inner circumferential fibers

serosa

cells that make serous fluid

Cardiac Sphincter

where food enters the stomach from the esophagus. (also called lower esophageal or gastrointestinal)

pyloric sphincter

where food exits the stomach to the small intestines

lesser omentum

attaches the lesser curvature of the stomach to the liver

greater omentum

attaches the greater curvature of the stomach to the posterior wall of the abdomen, covering the transverse colon and anterior surface of the small intestines

cardia

part of the stomach where the food enters from the esophagus

fungus

dome-shaped top of the stomach just under the diaphragm

body

wider midportion of the stomach

pyloric region

funnel-shaped end of the stomach

rugae

folds within the stomach wall, which allows the stomach to expand when it is full

purposes of the stomach

1) temporary food storage

2) mechanical food breakdown

oblique layer

third layer in the muscularis externa to allow mixing of food and juices easier

ulcer

an open sore in the wall caused by the gradual disintegration of tissues

chyme

stomach contents, thick soupy substance

ileocecal valve

controls the entrance to the large intestine

duodenum

first and shortest section of the small intestine, where enzymes from the pancreas and bile from the liver enter the small intestine

jejunum

second section of the small intestine

ileum

final section of the small intestine, slightly longest

circular folds

increase surface area of the wall's mucous membrane

villi

small finger-like projection, absorb a huge number of molecules.

microvilli

smaller projections off of the villi

lacteal

lymphatic vessels, transports molecules that are too large after reassembling

capillary beds

where sugars and amino acids are absorbed

intestinal enzymes

remain attached to the plasma membrane of microvilli, complete the digestion of peptides and sugars.

parts of the large intestine

cecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal

cecum

entrance to the large intestine through the ileocecal valve

appendix

hangs from the cecum and is usually twisted

ascending colon

runs along the right side of the abdomen superiorly

transverse colon

runs across the abdomen, connected with the hepatic flexure

descending colon

runs along the left side of the abdomen superiorly, connected with the splenic flexure

sigmoid colon

travels through the pelvis connecting with the rectum

internal sphincter

involuntary smooth muscle

exernal sphincter

voluntary skeletal muscle

intestinal bacteria

produces vitamin K and certain B vitamins

feces

75% water, intestinal bacteria, undigested plant material, fats, waste products (such as bile pigments), inorganic material, mucus, and dead cells from the intestinal lining.

pancreas

lies deep in the abdominal wall, sends pancreatic juice into the duodenum by the pancreatic duct

pancreatic juice

contains sodium bicarbonate to neutralize chyme and make the pH of the small intestine slightly basic, travel to the duodenum

Pancreatic amylase

digests starch to maltose

trypsin and other enzymes

digest protein to peptides

lipase

digests fat droplets to glycerol and fatty acids

function of the liver

produce bile, stores glucose as glycogen, produces urea

bile

stored in the gallbladder, sent to small intestine to emulsify fats, looks green, contains bile salts, breaks down fat into smaller pieces and is needed for the absorption of fats

roles of the digestive system

ingestion, digestion, absorption, and defacation

mechanical digestion

occurs when food is physically broken down into smaller pieces. teeth chewing food, stomach mixing food, and food moving along the gastrointestinal tract

chemical digestion

chemical breakdown of food by enzymes into smaller nutrients

salivary amylase

in the saliva, begins the chemical breakdown of starches

peristalsis

rhythmic muscular contractions, to move food through the esophagus and to the small intestine

salivary glands

parotid, sublingual, and submandibular glands, release saliva

gastrin

stimulates the stomach to secrete gastric juices, which contain: pepsinogens, mucus, and hydrochloric acid

parietal cells

secrete hydrochloric acid to kill bacteria with high acidity.

pepsinogen

pro-enzyme, secreted by the chief cells, converted to pepsin by the HCl to breakdown proteins.

mucus

protects the stomach lining from the HCl and pepsinogens

peptides

result from the first step in protein digestion, are digested by peptidases to amino acids

maltose

results from the first step in starch digestion, is digested by maltase to glucose

cholecystokinin

causes the gallbladder to secrete bile, cause the pancreas to secrete juices

secretin

causes the liver to secrete bile, cause the pancreas to secrete juices

hypothalamus

region of the brain that plays a role in hunger, satiety, and the feeling of “being full”

feeding center

nutrients in the blood decline, which stimulates the hypothalamus and makes the body feel hungry

satiety center

when the nutrient level rises, the hypothalamus is activated, and the desire to eat declines

as the stomach expands and nutrients are absorbed…

…the stomach sends sends signals to the brain and the desire to eat declines

hunger increasing hormones

Ghrelin, Endorphins, Neuropeptide-Y

hunger decreasing hormones

Leptin, Serotonin, Cholecystokinin (CCK)

leptin

produced by fat cells, alerts the brain to turn off the hunger center in the brain and activate the satiety center

ghrelin

produced by the stomach, travels to the brain and stimulates the hunger center as it deactivates the satiety center

carbohydrates

starches and sugars including milk, fruits, and grains, main source of energy for most cells

lipids

contain saturated fat, unsaturated fat, and cholesterol,

incomplete proteins

food such as grains, legumes, seeds, and nuts

complete proteins

meat, poultry, eggs, milk, dairy products, and soybeans

essential amino acids

nine amino acids that the body is unable to make, complete proteins contain them all

vitamins

organic compounds that are not consumed in metabolic reaction but help enzymes carry out the metabolic reactions

water soluble vitamins

are not able to be stored in the body and are excreted in urine

fat soluble vitamins

are stored in body fat, excessive amounts can be problematic

minerals

inorganic compounds that are not used as fuel in metabolic reactions but are combined with other nutrients to form necessary body substances

minerals include

calcium, chloride, magnesium, phosphorus, potassium, sodium, and sulfur

anabolism

the set of reactions in which smaller molecules are combined to make larger, more complex molecules

catabolism

the set of reactions in which larger molecules are broken down to be used as energy sources for the body

cellular respiration

the process by which cells generate ATP

aerobic respiration

requires oxygen and a fuel and releases carbon dioxide, water, and ATP.

glucose metabolism

used primarily during high energy demands, used in ATP production, results in 38 ATP per molecule of glucose

glycolysis

first step in glucose metabolism, yields 2 atp, breaks down one glucose molecule into two pyruvate molecules

fermentation or respiration

2nd step in glucose metabolism, yields 2 ATP,

electron transport chain

final step in glucose metabolism, yields 34 ATP, can be aerobic or anaerobic (aerobic in humans) electrons transfers out of NADH/FADH2 to electron acceptors and energy is released

cellular respiration

aerobic process, inside and around the mitochondria, krebs cycle

fermentation

anaerobic process