lesson 3 Flashcards
two main groups of the digestive system
those forming the alimentary canal; accessory digestive organs
performs the whole menu of digestive functions as it propels the foodstuffs along its tract.
Alimentary canal
functions of the alimentary canal
ingests
digests
absorbs
defecates
where does the blood group antigens of the alimentary canal found?
found on the membrane of the red blood cell of individuals
assist the process of digestive breakdown in various ways.
Accessory Digestive Organs
Organs included in the Accessory Digestive Organs
teeth
tongue
several large digestive glands
Explanation of the human digestive system
First, the mouth or the oral cavity contains the tongue. Inside, we have the salivary glands, namely the parotid, sublingual, and submandibular gland. Then, the pharynx. Going down, it’s the esophagus. Going down again, it’s the stomach. Beside the stomach [area] you can see the liver, gallbladder, spleen at the back and pancreas. After the stomach it goes down to the small intestine, comprising of the duodenum, jejunum, & ileum. Followed by the large intestine comprising the ascending colon, transverse colon, descending colon, cecum, sigmoid colon, rectum appendix, anal canal, and anus.
Also known as Gastrointestinal Tract or Gut
Alimentary Canal
A continuous, coiled hollow muscular tube that winds throughout the ventral body cavity from stomach to anus.
Alimentary Canal
Organs of the alimentary canal
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
leads to the terminal opening or anus
Large intestine
In a cadaver, the alimentary canal is approximately ________ or about _________.
9 meters or 30 ft long
In a living person, however, it is considered to be ________ because of its muscle tone.
shorter
Food material within this tube is technically _______ the body, because it has contact only with cells lining the tract and the tube is open to the __________ at both ends.
outside; external environment
The relationship becomes ______ if you think of the alimentary canal as an________.
clear; elongated donut
it is the first organ
mouth
it is where the food enters through the digestive tract and has and has a mucous membrane lined cavity
mouth
protects the anterior opening
lips/labia
form its lateral walls
cheeks
forms the anterior roof
hard palate
forms the posterior roof
soft palate
fleshy finger-like projection of the soft palate and Extends inferiorly from the posterior edge of the soft palate
uvula
Space between the lips and cheeks externally at the teeth and gums internally
vestibule
the area contained by the teeth
oral cavity proper
occupies the floor of the mouth.
muscular tongue
has several bony attachments
tongue
what are the two several bone attachments of the tongue
Hyoid bone
Styloid processes of the skull
Fold of mucous membrane that secures the tongue to the floor of the mouth and limits its posterior movements.
Lingual frenulum
From the mouth, the food passes posteriorly into the ___________________________
oropharynx and laryngopharynx
both of which are common passageways for food, fluids, and air.
oropharynx and laryngopharynx
part of the respiratory passageway
Nasopharynx
posterior to the oral cavity
Oropharynx
continuous with the esophagus below
Laryngopharynx
The walls of the pharynx contain two skeletal muscle layers
The cells of the inner layer run longitudinally;
Those of the outer layer (the constrictor muscles) run around the wall in a circular fashion.
Also known as gullet
esophagus
It runs from the pharynx through the diaphragm to the stomach and is essentially a passageway that conducts food by peristalsis to the stomach.
esophagus
measurement of the esophagus
Approximately about 25cm or 10 inches long
It is the innermost layer; moist membrane that lines the cavity or lumen of the organ; consists primarily of a surface epithelium, plus a small amount of connective tissue (lamina propria) and a scanty muscle layer.
Mucosa
beneath the mucosa
Submucosa
The submucosa is a soft connective tissue layer containing?
blood vessels
nerve endings
mucosassociated lymphoid vessels
muscle layer typically made up of an inner circular layer and an outer longitudinal layer of smooth muscle cells
Muscularis Externa
outermost layer of the wall and it consists of a single layer of flat, serous fluid-producing cells, the visceral peritoneum.
Serosa
is continuous with the sleek, slippery parietal peritoneum, which lies the abdomino-pelvic cavity by way of a membrane extension—the mesentery.
Visceral peritoneum
A C-shaped, located on the left side of the abdominal cavity, nearly hidden by the liver and diaphragm.
Stomach
Varies from __________ in length, but its diameter and volume depend on how much food it contains.
15-25cm (6-10 inches)
When it is full, it can hold about _________ of food
4 liters (1 gallon)
___________, it collapses inward on itself and its mucosa is thrown into large folds called _______.
When it is empty; rugae
also known as cardia; named for its position because it is near from the heart; surrounds the cardioesophageal sphincter, through which food enters the stomach from the esophagus
cardial region
expanded part of the stomach lateral to the cardial region
Fundus
midportion; as it narrows inferiorly, it becomes the pyloric antrum
body
funnel-shaped; terminal part of the stomach;
continuous with the small intestine through the pyloric sphincter or valve
pylorus
Act as a temporary “storage tank” for food, as well as a site for food breakdown, besides the usual longitudinal circular muscle layer.
stomach
After the food has been processed in the stomach, it resembles heavy cream is called ________.
chyme
enters the small intestine through the pyloric sphinter.
chyme
simple columnar epithelium, composed entirely of mucous cells that produce a protective layer of bicarbonate-rich alkaline mucus that clings to the stomach mucosa and protects the stomach wall from being damaged by acid and digested by enzymes.
mucosa of the stomach
The otherwise smooth lining is dotted with millions of deep gastric pits, which lead into the gastric glands that secrete the solution called _________.
gastric juice
some ________ produce intrinsic factor, a substance needed for absorption of Vitamin B12 in the small intestine.
stomach cells
produce protein digesting enzymes mostly
chief cells
produce a corrosive hydrochloric acid, which make the stomach contents acidic and activates the enzymes, as in the conversion of pepsinogen pepsin by hydrochloric acid.
parietal cells
is quite different from those secreted by the mucous cells in the mucosa
mucus neck cells
produce local hormones such as gastrin, which are important in the digestive activities; entero, meaning gut.
enteroendocrine cells
Most digestive activity occurs in which region of the stomach?
in the pyloric region
The _____________ of the stomach is the greater curvature
convex lateral surface
Its ___________ is the lesser curvature.
concave medial surface
The _________ is a double layer peritoneum that extends from the liver to the lesser curvature
lesser omentum
The ____________, another extension of the peritoneum, drips downward and covers the abdominal organs like before attaching to the posterior body wall.
greater omentum
is riddle-wig fat, which helps insulate cushion and protect the abdominal organs. It has also a large collection of the lymphoid follicles containing macrophages in defensive cells in the immune system—this is for the protection of the gastrointestinal system.
Greater omentum
The body’s major digestive organ
small intestine
within its passageways, usable food is finely prepared to its journey to the cells of the body.
small intestine
It is the longest section of the alimentary tube, with an average length of ________, wrapped around a living person.
2 to 4m
encircles and frames small intestine in the abdominal cavity.
Large intestine
contribute 5% of the length of the small intestine; meaning from the Latin word ‘12 finger-widths long’
duodenum
contribute 40% of the length of the small intestine; from the Latin word ‘MT’
jejunum
contribute 60% of the length of the small intestine; meaning, twisted intestine
Ileum
meets the large intestine at the _________, which joins the large and small intestines
ileocecal valve
Chemical digestion of foods begins in earnest in the __________
small intestine
controls food movement into the small intestine from the stomach and prevents the small intestine from being overwhelmed.
pyloric sphincter
the shortest subdivision of the small intestine.
C-shaped duodenum
formed by the liver, also enters the duodenum or the bile duct in the same area.
bile
join at the duodenum to form the flask-like hepatopancreatic ampulla
main pancreatic and bile ducts
the bile and pancreatic juice travel to the ___________ and enter the duodenum together.
duodenal papilla
Nearly all food absorption occurs in the ______________.
small intestine
tiny projections of the plasma membrane of the mucosa cells that give the cell surface a fuzzy appearance, sometimes referred to as the brush border.
microvilli
fingerlike projections of the mucosa that give it a velvety appearance and feel, much like the soft nap of a towel.
villi
Within each villus is a rich capillary bed and a modified lymphatic capillary called?
lacteal
also called plicae circulares
circular folds
deep folds of both mucosa and submucosa layers
circular folds
all these structural modifications, which increase the surface area, __________ in number toward the end of the small intestine.
decrease
local collections of lymphatic tissue (called Peyer’s patches) found in the submucosa, ________ in number toward the end of the small intestine.
increase
Much larger in diameter than the small intestine (thus, named the large intestine), but shorter in length
Large intestine
About ____________, it extends from the ileocecal valve to the anus.
15 m (5 feet) long
It goes around on the small intestine; From the right goes up, transverses, and goes down the sigmoid.
Large intestine
Major functions of the large intestine
to dry out the indigestible food residue by absorbing water;
to eliminate these residues from the body as feces.
most of the large intestine, one on the bottom-right; sac-like; first part of the large intestine
Cecum
extension; worm-like vermiform; hanging from a cecum
Appendix
inflammation of pancreas
Appendicitis
a common spot (you might be heard of the appendix site or appendicitis) because it is usually twisted since it is an ideal location for bacteria to accumulate and multiply.
Appendix
what goes around
colon
travels up the right side of the abdominal cavity and makes a turn
Ascending colon
Right colic (or hepatic) flexure, to travel across the abdominal cavity as?
transverse colon
It then turns again at the left colic (or splenic) flexure and continues down the left side as the _________, to enter the pelvis, where it becomes the __________ colon.
descending colon
S-shaped sigmoid
The sigmoid colon, rectum, and anal canal lie in?
the pelvis
