a&p exam 4 digestive system (not finished)

what is the organ system that processes food, extracts nutrients, and eliminates residue?

digestive system

what are the 5 stages of digestion in order?

1. Ingestion

2. Digestion

3. Absorption

4. Compaction

5. Defecation

what is selective intake of food?

ingestion

what is the mechanical and chemical breakdown of food into a form usable by the body?

digestion

what is the uptake of nutrient molecules into the epithelial cells of the digestive tract and then into the blood and lymph?

absorption

what is absorbing water and consolidating the indigestible residue into feces?

compaction

what is the elimination of feces?

defacation

what is the physical breakdown of food into smaller particles?

mechanical digestion

why is mechanical digestion important?

it exposes more food surface to digestive enzymes

what are examples of mechanical digestion?

- cutting and grinding action of teeth

- churning action of stomach and small intestines

what is a series of hydrolysis reactions that breaks down dietary macromolecules into their monomers (residues)

chemical digestion

mechanical digestion is carried out by ___

digestive enzymes

what are digestive enzymes produced by?

salivary glands, stomach, pancreas, and small intestine

polysaccharides are broken down into ___

monosaccharides

proteins are broken down into ___

amino acids

fats are broken down into ___

monoglycerides and fatty acids

nucleic acids are broken down into ___

nucleotides

some nutrients are present in a ___ in ingested food and can be ___

usable form

directly absorbed

what nutrients can be directly absorbed?

vitamins, amino acids, minerals, cholesterol, and water

the digestive system has ___ subdivisions: ___ and ___

2: digestive tract and accessory organs

30 foot long muscular tube extending from mouth to anus

digestive tract (alimentary canal)

this is the stomach and intestines

gastrointestinal (GI) tract

what are the organs in the digestive tract?

mouth, pharynx, esophagus, stomach, small intestine, large intestine

what are the accessory organs?

teeth, tongue, salivary glands, liver, gallbladder, and pancreas

what is the only place in the digestive tract that has 3 layers of muscle instead of 2?

stomach

nervous network in esophagus, stomach, and intestines that regulates digestive tract motility, secretion, and blood flow

enteric nervous sytstem

does the enteric nervous system function independently from the central nervous system?

-yes, it can function independently, but CNS often influences it

-often considered part of autonomic nervous system

connective tissue sheets that suspend stomach and intestines from abdominal wall

mesenteries

mesenteries makeup and function

-looseness allows stomach and intestines to undergo strenuous contractions with freedom of movement in the abdominal cavity

-hold abdominal viscera in proper relationship to each other

-prevent intestines from becoming twisted and tangled by changes in body position and by its own contractions

-provide passage of blood vessels and nerves that supply digestive tract

-contain many lymph nodes and lymphatic vessels

a serous membrane that lines the wall of the abdominal caviy

parietal peritoneum

a translucent two-layered membrane extending to the digestive tract

dorsal mesentary

the two layers of the mesentary separate and pass around opposite sides of the organ forming the ___ and come together on the far side of the organ and continue as another sheet called the ___

serosa, anterior (ventral) mesentary

a ventral mesentary that extends from the lesser curvature of the stomach to the liver

lesser omentum

hangs from the greater curvature of the stomach (its left inferior margin)

greater omentum

attaches stomach to liver

lesser omentum

covers small intestine like an apron

greater omentum

extension of the mesentery that anchors the colon to the abdominal wall

mesocolon

when an organ is enclosed by mesentery on both sides (considered within the peritoneal cavity)

intraperitoneal

when an organ lies against the posterior body wall and is covered by peritoneum on its anterior side only (considered to be outside the peritoneal cavity)

retroperitoneal

mesentery of small intestine holds many ___

blood vessels

the mouth is known as the ___ cavity

oral/ buccal

how many adult teeth do you have?

32

what are the 4 kinds of teeth?

incisors, canines, premolars, molars

what are the functions of the mouth?

-ingestion (food intake)

-taste and other sensory responses to food

-chewing and chemical digestion

-swallowing, speech, respiration

muscular, bulky, but remarkably agile and sensitive organ

tongue

what are the functions of the tongue?

-manipulates food between teeth

-senses taste and texture of food

-can extract food particles from the teeth after a meal

what are the functions of saliva?

-moistens mouth

-begins starch (and fat) digestion

-cleanses teeth

-inhibits bacterial growth

-dissolves molecules so they can stimulate the taste buds

-moistens food and binds it together into bolus to aid in swallowing

saliva is a ___ solution that consists of:

hypotonic solution

-water

-salivary amylase

-lingual lipase

-mucus

-lysozome

-immunoglobin A (IgA)

-electrolytes

enzyme that begins starch digestion in the mouth

salivary amalyse

enzyme that is activated by stomach acid and digests fat after food is swallowed

lingual lipase

binds and lubricates a mass of food and aids in swallowing

mucus

enzyme that kills bacteria

lysozyme

an antibody that inhibits bacterial growth

Immunoglobulin A (IgA)

the mouth has a ___ pH than the stomach

higher

small glands dispersed amid other oral tissues (located in the mouth)

intrinsic salivary glands

three pairs of glands connected to oral cavity by ducts

extrinsic salivary glands

pair of salivary glands located beneath the skin anterior to earlobe (on cheek)

parotid glands

pair of salivary glands located halfway along the body of the mandible (most superior)

submandibular glands

pair of salivary glands located in the floor of the mouth (under the tongue)

sublingual glands

___ produce most of the saliva that aid with digestion

extrinsic salivary glands

mumps is an inflammation and swelling of the ___ caused by a virsus

parotid

extrinsic salivary glands secrete about ___ L of saliva a day

1-1.5

mass swallowed as a result if saliva binding food particles into a soft, slippery, easily swallowed mass

bolus

where's the first place food goes once swallowed?

pharynx

where does starch digestion start?

the mouth

muscular funnel connecting oral cavity to esophagus and nasal cavity to larynx

pharynx

the pharynx has a superficial layer of circular skeletal muscles that form ___ that force food downward during swallowing

pharyngeal constrictors (superior, middle, inferior)

when not swallowing, the ___ remains contracted to exclude air from the esophagus and prevents anything from entering thr pharynx from the esophagus

inferior constrictor (upper esophageal sphincter)

referred to as physiological because they disappear at the time of death when the muscles relax

sphincters

straight muscular tube that extends from pharynx to cardiac oriface of stomach

esophagus

where does the esophagus pass through the diaphragm at?

esophageal hiatus

food pauses here because of constriction, prevents stomach contents from regurgitating into the esophagus, and prevents esophageal mucosa from erosive stomach acid

lower esophageal sphincter

burning sensation produced by acid reflux into the esophagus?

heartburn

what prevents heartburn?

lower esophageal sphincter

a muscular sac in upper left abdominal cavity immediately inferior to the diaphragm

stomach

what is the primary function of the stomach?

functions as a food storage organ

what's the only thing the stomach is really needed for?

intrinsic factor

the stomach turns the bolus of food to ___

chyme

soupy or pasty mixture of semi-digested food in the stomach

chyme

how does food move down the esophagus?

peristalsis

what is the least important digestive organ?

the stomach

where does ALL absorption occur?

the small intestine

what digestion occurs in the stomach?

-mechanical digestion for everything

-begins chemical digestion of protein and fat (not carb)

what are the four regions of the stomach?

cardiac region, fundic region, body, pyloric region

the stomach is ___ in tall people and ___ in short people

vertical, horizontal

small area of the stomach within about 3 cm of the cardiac orifice

cardiac region (cardia)

dome-shaped portion superior to esophageal attachment

fundic region (fundus)

makes up the greatest part of the stomach

body (corpus)

narrower pouch of the stomach at the inferior end

pyloric region

the pyloric region has a narrower ___ that terminates at ___

pyloric canal that terminates at pylorus

regulates the passage of chyme into the duodenum

pyloris (gastrodeuodenal) sphincter

what is the first part of the stomach that food passes through?

cardia

what is the last region of the stomach that food passes through?

pylorus

the stomach has ___ and ___ curvatures

greater and lesser

the stomach receives both ___and ____ stimuli

parasympathetic and sympathetic fibers

longitudal wrinkles in the stomach

rugae

what supplies the stomach with blood?

branches of the celiac trunk (gastric)

blood drained from the stomach and intestines enters ___ and is filtered though the ___ before returning to the heart

hepatic portal system

liver

depressions in gastric mucosa

gastric pits

stomach lining is ___ cells

simple columnar epithelium