Digestive System Flashcards
consists of organs that ingest food, break it down, absorb the small molecules, and eliminate undigested wastes
digestive system
provides a steady supply of carbohydrates, proteins, fats, water, minerals, and vitamins to replace materials that leave the body
digestive system
it is the process by which the body obtains and uses certain components of food
nutrition
the chemicals taken into the body that are used to produce energy, to provide building blocks for new molecules, and to function in other chemical reactions
nutrients
refers to all chemical reactions on how the cells utilize the energy we have absorbed from food during digestion necessary to maintain life
metabolism
energy releasing process by which large molecules are broken down into smaller molecules
catabolism
energy requiring process by which small molecules are joined to form larger molecules
anabolism
it is the intake of solid or liquid food into the stomach
the normal route is through the oral cavity
ingestion
it is the process by which the teeth chew food in the mouth
mastication
it is the movement of food from one end of the digestive tract to the other
each segment of the digestive tract is specialized to assist in moving its contents from the oral end to the anal end
propulsion
moves liquids or a soft mass of food and liquid, called a bolus from the oral cavity into the esophagus
swallowing / deglutition
are muscular contraction consisting of a wave of relaxation of the circular muscles in front of the bolus, followed by a wave of strong contraction of the circular muscles behind the bolus, which force the bolus along the digestive tube
peristalsis
are contractions that move material in the distal parts of the large intestine to the anus
mass movements
some contraction do not propel food from one end of the digestive tract to the other but, rather, move it back and forth within the digestive tract to mix it with digestive secretions and help break it into smaller pieces
mixing
gentle contractions that churn the food with secretions in the stomach
mixing waves
mix food particles with digestive secretion in the small intestine
segmental contractions
as food moves through the digestive tract, secretions are added to lubricate, liquefy, buffer, and digest the food
secretion
secreted ___________ coats and protects the epithelial cells of the digestive tract from mechanical abrasion, stomach acid, and digestive enzymes
mucus
_____________ secreted by the oral cavity, stomach, small intestine, and pancreas break down large food molecules into smaller molecules that can be absorbed by the intestinal wall
enzymes
it is the breakdown of large organic molecules into their component parts
digestion
food is physically broken down into small particles which involves the mastication and chewing of food
mechanical digestion
break food molecules into small subunits accomplished by digestive enzymes secreted along the digestive tract
chemical digestion
it is the movement of molecules out of the digestive tract and into the circulation or into the lymphatic system
absorption
it is the process by which the waste products of digestion are removed from the body
during this process, which occurs primarily in the large intestine, water and salts are absorbed, changing the material in the digestive tract from liquefied to semi-solid
elimination
these semi-solid waste products, called _____________, are then eliminated from the digestive tract by the process of defecation
feces
the digestive system consists of the ___________ __________ and the __________ __________
gastrointestinal tract
accessory organs
serous membrane that lines the walls and organs of the abdominal cavity
these membrane are very smooth and secrete a serous fluid, which provides a lubricating film between the layers of membranes
the membranes and fluid reduce friction as organs move within the abdomen
peritoneum
the serous membrane that covers the organs
visceral peritoneum
the serous membrane that covers the interior surface wall of the abdominal cavity
parietal peritoneum
connective tissue sheets that hold many of the organs in place within the abdominal cavity
mesentery
they consist of two layers of serous membranes with a thin layer of loose connective tissue between them
they provide a route by which vessels and nerves can pass from the abdominal wall to the organs
mesentery
are abdominal organs that lie against the abdominal wall that have no mesenteries
retroperitoneal organs
also known as the alimentary canal, is a continuous, coiled, hollow muscular tube with opening at both ends and performs the breakdown of food
gastrointestinal tract
the innermost layer, a moist mucus membrane that lines the hollow cavity, or lumen, of the organ
it consists primarily of surface epithelium plus a small amount of connective tissue and a scanty smooth muscle layer
beyond the esophagus, which has a friction resisting stratified squamous epithelium is mostly simple columnar
mucosa
found beneath the mucosa
it is soft connective tissue containing blood vessels, nerve endings, mucosa-associated lymphoid tissue, and lymphatic vessels
submucosa
muscle layer typically made up of an inner circular layer and an outer longitudinal layer of smooth muscle cells
muscularis
outermost layer of the wall
it is the visceral peritoneum that covers the organs in the peritoneal cavity
it consists of a single layer of flat, serous fluid-producing cells
the visceral peritoneum is continuous with the slippery parietal peritoneum, which lines the abdominopelvic cavity by way of a membrane extension, the mesentery
serosa or adventitia
a mucous membrane lined cavity where food enters
mouth / oral cavity
muscular structures formed by muscles and connective tissues with its outer surfaces covered by the skin
lips / labia
form the lateral walls of the oral cavity
it includes the buccinators muscle and the buccal fat pad which rounds out the profile on the side of the face
cheeks
separates the oral and nasal cavities and prevents food from passing into the nasal cavity during chewing and swallowing
palate
bony part that forms the mouth’s anterior roof
hard palate
non-bony part the forms the mouth’s posterior roof
soft palate
it is a fleshy fingerlike projection of the soft palate, which extends downward from its posterior edge
uvula
large muscular organ that occupies the floor of the mouth
it moves food in the mouth and, in cooperation with the lips and gums, holds the food in place during mastication
it also plays a major role in swallowing
tongue
secretion of the mouth that is mostly water and bicarbonate ions, moistens food and mucus membrane; neutralizes bacterial acids; flushes bacteria from the oral cavity
serous saliva
secretion of the mouth that digests carbohydrates
salivary amylase
secretion of the mouth that lubricates food and protects digestive tract from digestion
mucus
secretion of the mouth that digests minor amount of lipids
lingual lipase
common passageways for food, fluids and air
it provides a passageway of food to the esophagus
pharynx
portion of the pharynx that transmits air only
nasopharynx
portions of the pharynx that transmit air and food
oropharynx and laryngopharynx
runs from the pharynx through the diaphragm to the stomach and is a passageway that conducts food to the stomach
it is about 25 cm long and lies in the mediastinum, anterior to the vertebrae and posterior to the trachea
esophagus
the esophagus passes through the __________ __________ of the diaphragm and ends in the stomach
esophageal hiatus
secretion of the esophagus that lubricates it; protects its lining from abrasion and allows food to move more smooth through the esophagus
mucus
located at the upper end of the esophagus
upper esophageal sphincter
located at the lower end of the esophagus
lower esophageal sphincter
the movement of food through the pharynx and esophagus is controlled by the __________ __________ of the autonomic nervous system
parasympathetic division
food is moved through the pharynx and then into the esophagus by __________
peristalsis
occurs when the upper part of the stomach pushes through an opening in the diaphragm and into the chest cavity
hiatal hernia
occurs when stomach acid repeatedly flows back into the tube connecting your mouth and stomach (esophagus)
this backwash (acid reflux) can irritate the lining of your esophagus
gastroesophageal reflux disease (GERD) / heart burn
a C-shaped organ on the left side of the abdominal cavity that secretes gastric juice (enzymes, mucus, and hydrochloric acid) for digestion
it primarily functions as a storage and mixing chamber
stomach
a valve that opens to allow the entry of food from the esophagus to the stomach also called the lower esophageal sphincter
cardiac sphincter
a valve that controls the flow of partially digested food from the stomach to the small intestine
pyloric sphincter
the upper portion of the stomach closest to the heart
cardiac region
it is the expanded part of the stomach lateral to the cardiac region
fundus
it is the mid-portion of the stomach and the largest part of the stomach
body
the lower portion of the stomach near the intestine where the food mixes with the gastric juice
antrum
terminal part of the stomach and is continuous with the small intestine
pylorus
stomach secretion when mixes with food forms __________
chyme
it is a semifluid material of processed food that is released from the stomach to the small intestines through the pyloric sphincter
chyme
antibacterial secretion and decreases stomach pH to activate pepsinogen to pepsin
hydrochloric acid
protects stomach lining from acid and digestion
mucus
secretion of the stomach that binds to vitamin B12 and aids in the absorption of this vitamin in the small intestine
intrinsic factor
two digestive enzymes
pepsin
gastric lipase
digests protein into smaller peptide chains and activates pepsinogen
pepsin
digests a minor amount of lipids
gastric lipase
a hormone secreted by the gastric cells in the presence of food and decreasing stomach pH to produce more pepsin, mucus and HCl
gastrin
involve in making changes to your digestive system weight-loss to help you lose weight
it is done when diet and exercise haven’t worked or when you have serious health problems because of your weight
gastric bypass surgery / bariatric surgery
it is a type of weight-loss surgery that involves creating a small pouch from the stomach and connecting the newly created pouch directly to the small intestine
gastric bypass surgery
a muscular tube extending from the pyloric sphincter to the Ileocecal valve for absorption of food
It is where the greatest amount of digestion and absorption of nutrients and water occurs
small intestine
these are fingerlike projections of the intestinal mucosa
villi
these are tiny projection of the plasma membrane of the intestinal mucosa cells
microvilli
it is the first and shortest part where absorption begins
it also receives pancreatic juice and bile from the liver
duodenum
midsection of the small intestine
jejunum
the terminal part and joins the large intestine
ileum
it is the joining point of the small and large intestines
it controls the flow between the small and large intestines and serves a barrier to prevent bacteria laden contents of the large intestine from contaminating the small intestine
ileocecal valve
protects the duodenum from stomach acid and intestinal wall from digestive enzymes
mucus
helps keep the chyme in a liquid form to facilitate the digestive process by pancreatic enzymes
electrolytes and water
a hormone that decreases gastric secretions in response to acidic solutions in the duodenum
it stimulates pancreatic and liver bile secretions
secretin
a hormone produced in response to lipid and protein digestion products in the duodenum
it slightly decreases gastric secretions, stimulates pancreatic secretions high in digestive enzymes, and causes contraction of the gallbladder to release bile
cholecystokinin
movement in the small intestine involves mixing of the chyme and slow propulsion down the tract
__________ __________ mix the intestinal contents, and __________ __________ primarily propel the intestinal contents along the digestive tract
segmental contractions
peristaltic contractions
the chemical digestion of food is accelerated and would take a __________ hour journey in the small intestines
by the time the food reaches the end of the small intestine, digestion is complete and nearly all food absorption has occurred
3 to 6 hour
larger in diameter than the small intestine and function in drying out indigestible food residue by absorbing water
large intestine
the formation of feces involves the absorption of water and salts, secretion of mucus, and extensive action of microorganisms
the __________ stores the feces until they are eliminated by defecation
colon
the first part of the large intestine where it meets the small intestine at the ileocecal junction
cecum
narrow pouch of tissue extending from the cecum
its walls contain many lymphatic nodules, which contribute to immune functions
vermiform appendix
travels up the right side of the abdomen
ascending colon
travels across the abdomen from right to left
transverse colon
travels down the left abdomen
descending colon
short curving of the colon just before the rectum
sigmoid colon
connects the sigmoid colon to the anus where feces are stored before the release via the anal canal
rectum
the last part of the digestive tract
anal canal
it begins at the inferior end of the rectum and ends at the anus which is the opening at the end of the gastrointestinal tract through which fecal matter leaves the body
anal canal
controls the opening and closing of the anus
anal sphincter
anal sphincter with voluntary skeletal muscle
external anal sphincter
anal sphincter with involuntary smooth muscle
internal anal sphincter
secretion of the large intestine that provides adhesion for fecal matter;
protects intestinal wall from bacterial acids and actions
mucus
Resident bacteria metabolize the remaining nutrients in the colon and release gases (methane and hydrogen sulfide) that contribute to the odor of the feces.
About __________ of flatus (gas) is produced each day
500 mL
a spinal (sacral region) reflex that causes the walls of the sigmoid colon and the rectum to contract and the anal sphincters to relax
defecation reflex
an operation to divert 1 end of the colon (part of the bowel) through an opening in the tummy
it can be permanent or temporary
colostomy
the opening in a colostomy is called a __________
a pouch can be placed over this to collect your poo (stools)
stoma
aid the processes of ingestion, digestion, and absorption
These organs either secrete or store substances that pass through ducts into the alimentary canal
accessory organs
secretes saliva which is mixture of mucus and serous fluids that assist in digestion
salivary glands
a combination of serous and mucus secretions
The mucus moistens and helps to bind food together which makes tasting, chewing and swallowing easier
It is also needed for normal speech
The clear serous fluids contains enzymes and antibodies as digestive and protective function
saliva
digestive enzyme found in saliva which breaks down bonds between glucose molecules in starch and other polysaccharides
salivary amylase
3 paired large salivary glands
parotid glands
submandibular glands
sublingual glands
largest salivary glands, located beside the ear
parotid glands
salivary glands located below the mandible
submandibular glands
salivary glands located below the tongue
sublingual glands
4 numerous small salivary glands
lingual glands
palatine glands
buccal glands
labial glands
salivary glands located deep to the epithelium of the tongue
lingual glands
salivary glands located in the palate
palatine glands
salivary glands located in the cheeks
buccal glands
salivary glands located in the lips
labial glands
function in mechanical digestion by tearing and grinding food, breaking it down into smaller fragments
It also assists in speech
teeth
milk teeth or primary teeth
deciduous teeth
secondary teeth
permanent teeth
teeth for cutting
incisors
teeth for tearing and piercing
canines
teeth for grinding
molars and premolars
is a soft triangular exocrine and endocrine gland behind the stomach that produces enzymes breaking down all categories of digestible foods
pancreas
The __________ are secreted into the duodenum by the pancreas in an alkaline fluid, which neutralizes the acidic chyme coming from the stomach
pancreatic enzymes
are the exocrine cells of the pancreas that produce and transport enzymes that are passed into the duodenum where they assist in the digestion of food
acinar cells
the exocrine secretions of the pancreas are called
pancreatic juice
secretions of the pancreas that neutralize acid from stomach and provide appropriate pH for pancreatic enzymes
bicarbonate ions
secretions of the pancreas that digests proteins, activates trypsinogen and other digestive enzymes
trypsin
secretions of the pancreas that digests carbohydrates
pancreatic amylase
secretion of the pancreas that digests lipids
pancreatic lipase
secretions of the pancreas that digests ribonucleic acid
ribonuclease
secretion of the pancreas that digests deoxyribonucleic acid
deoxyribonuclease
Endocrine hormones of the pancreatic islets (3)
insulin
glucagon
somatostatin
is the largest gland in the body
It is located under the diaphragm more to the right side of the body
liver
The liver has many metabolic and regulatory roles, but its digestive function is to produce __________
bile
the functional cells of the liver and produces bile, these cells take up nutrients from the portal blood
hepatocytes
located at the inferior surface of the liver, where blood vessels and nerves enter and bile ducts and lymphatic vessels leave the liver
porta
is a yellow to green, watery solution that emulsify fats by physically breaking large fat globules into smaller one
bile
Bile produced each day is at __________ mL
It contains bile salts, bile pigments – bilirubin, cholesterol, lipids, and lipid-soluble hormones
600 to 1000 mL
component of bile that emulsify lipids, which is necessary for subsequent digestion by lipase
bile salts
component of bile which are pigments produced by the breakdown of hemoglobin and have greenish-yellow to brown colors and give feces their characteristic color
bile pigments (bilirubin)
can remove sugar from the blood and store it in the form of glycogen
These cells can also store lipids, vitamins and minerals
hepatocytes
The liver makes many harmful substances less toxic or makes their elimination easier
Hepatocytes remove toxic __________ (a byproduct of amino acid metabolism not readily removed by the kidneys) from the blood and convert it to the less toxic urea
Urea is then secreted into the blood and eliminated by the kidneys in the urine
ammonia
is a small thin-walled green sac found below the liver
It functions as a storage area of bile from the liver
It also functions for the concentration of bile
gall bladder
The liver continually secretes bile, which flows to the gallbladder, where __________ mL of bile is stored. While the bile is in the gallbladder, water and electrolytes are absorbed
Bile salts and pigments become as much as 5 – 10 times more concentrated than when secreted by the liver
40 – 70 mL
the duct system that conveys bile from the liver, also receives ducts from the gallbladder and pancreas before connecting to the small intestine
biliary system
formed by the union of the right and left hepatic ducts from the liver
common hepatic duct
duct from the gallbladder that joins the common hepatic duct
cystic duct
formed by the union of the cystic duct and the common hepatic duct
common bile duct
is a duct joining the pancreas to the common bile duct to supply pancreatic juice for digestion
pancreatic duct
an enlargement formed by the union of common bile duct and the pancreatic duct
hepatopancreatic ampulla / hepatopancreatic duct / ampulla of Vater
controls the flow of bile and pancreatic enzymes into the ampulla of Vater
sphincter of Oddi
