Chapter 22a

Peritoneal cavity

_____ is a slitlike potential space containing fluid secreted by the serous membranes; the serous fluid lubricates the mobile digestive organs, allowing them to glide easily across one another and along the body wall as they carry out their digestive activities

Absorption

_____ to occur, these substances must first enter the mucosal cells by active or passive transport processes; the small intestine is the major absorptive site

Lamina propria

_____'s isolated lymph nodules, part of MALT, are important in the defenses against bacteria and other pathogens, which have rather free access to our digestive tract; particularly large collections of lymph nodes occurring at strategic locations, such as within the pharynx and in the appendix

Submocusa

_____'s rich supply of elastic fibers enables the stomach to regain its normal shape after temporarily storing a large meal; its luxuriant vascular network supplies surrounding tissues of the GI tract wall

Long reflexes

______ are initiated by stimuli arising within or outside the GI tract and involve CNS centers and extrinsic autotomic nerves

Short reflexes

______ are mediated entirely by thet local plexuses in response to GI tract stimuli

Chemical digestion

______ is a series of catabolic steps in which complex food molecuels are broken down to their chemical building blocks; it is accomplished by enzymes secreted by various glands into the lumen of the alimentary canal; the enzymatic breakdown of foodstuffs begins in the mouth and is essentially complete in the small intestine

Ingestion

______ is simply taking food into the digestive tract, usually via the mouth

Secretion

______ of mucus, digestive enzymes, and hormones

Peritonitis

______ or inflammation of the peritoneum, can arise from a piercing found of the abdomen or from a perforating ulcer that leaks stomach juices into the peritoneal cavity, but most commonly it results from a burst appendix;

Segmentation

______ or rhythmic local constrictions of the intestine;

Mesentery

______ provide routes for blood vessels, lymphatics, and nerves to reach the digestive viscrea;

Digestive activity

______; when appropriately stimulated, these receptors initiate reflexes that (1) activate or inhibit gladns that secrete digestive juices into the lumen or hormones into the blood or (2) mix lumen contnets and move them along the length of the tract by stimulating the smooth muscle of the GI tract walls

Protection

_______ against infectious disease

Serosa

_______ is formed of areolar connective tissue covered with mesothelium, a single layer of squamous epithelial cells

Digestive activity

_______ is provoked by a range of mechanical and chemical stimuli; sensors involved in controls of GI tract activity are located in the walls of the tract organs; these sensors respond to several stimuli, the most important being stretching of the organ wall by food in the lumen, osmolarity and pH of the contents, and the presence of substrates and end products of digestion;

Absorption

_______ is the passage of digested end products from the lumen of the GI tract into the blood or lymph; for

Segmentation

_______ mixes food with digestive juices and increases the efficiency of absorption by repeatedly moving different parts of the food mass over the intestinal wall

Propulsion

_______ moves food through the alimentary canal; it includes swallowing, which is initiated voluntarily, and peristalsis, an involuntary process

Absorption

_______ of the end products of digestion into the blood

Mechanical digestion

_______ processes include chewing, mixing food with saliva by the tongue, churning food in the stomach, and segmentation

Muscularis mucosae

_______, in the small intestine, it throws the mucosa into a series of small folds that immensely increase its surface area

Peristalsis

_______, the major means of propulsion involves alternate waves of contraction and relaxation of muscles in the organ walls; its main effect is to squeeze food from one organ to the next, but some mixing occurs as well;

Controls of digestive activity are both extrinsic and intrinsic

_______, these plexuses extend essentially the entire length of the GI tract and influence each other both in the same and different digestive organs; as a result, two kinds of reflex activity occur, short and long

Defecation

________ elmininates indigestible substances from the body via the anus in the form of feces

Mechanical digestion

________ physically prepares food for chemical digestion by enzymes;

Controls of digestive activity are both extrinsic and intrinsic

__________; another novel trait of the digestive tract is that many of its controlling system are intrinsic—a product of in house nerve plexuses of local hormone producing cells; as described shortly, the wall fo the alimentary canal contains nerve plexuses;

Mesentery

a ________ is a double layer of peritoneum—a sheet of two serous membranes fused back to back—that extends t othe digestive organs from the body wall;

Intraperitoneal/ peritoneal organs

digestive organs that keep their mesentery nad remain in the peritoneal cavity are called ______; it is not known why some digestive organs end up in the retroperitoneal position, while others are suspended freely

Muscularis mucosae

external to the lamina propria is the _______, a scant layer of smooth muscle cells that produces local movements of the mucosa; for example, the twitching of this muscle layer dislodges food particles that have adhered to the mucosa;

Peritonitis

if ______ becomes generalized, it is dangerous and often lethal; treatment includes removing as much infectious debris as possible from the peritoneal cavity and administering megadoses of antibiotics

Splanchic circulation

in _____, the arterial supply—the hepatic, splenic, and left gastric branches of the celiac trunk that serve the spleen, liver, nad stomach, and the mesenteric arteries that serve the small and large intestines—normally receives one-quearter of the cardiac output; this percentage increases after a meal has been eaten

Peritonitis

in ______ the peritoneal coverings tend to stick together around the infection site; this localizes the infection and provides time for macrophages to mount the attack to prevent the inflammation from spreading;

Alimentary canal/ gastrointestinal tract

in a cadaver, the _____ is approximately 9m long, but in a living person, it is considerably shorter because of its muscle tone; food material within this tube is technically outside the body because the canal is open to the external environment at both ends

Peristalsis

in fact, ______ waves are so powerful that once swallowed, food and fluid will reach your stomach even if you stand on your head

Adventitia

in the esophagus, which is located in the thoracic instead of the abdominopelvic cavity, the serosa is replaced by an _______;

Muscularis externa

just deep to the submucosa is the ______, also called the muscularis; this layer is responsible for segmentation and peristalsis;

Retroperitoneal organs

not all alimentary canal organs are suspended by a mesentery; if the organs lose their mesentery and come to the lie posterior to the peritoneum, which include most of the pancreas and parts of the large intestine, are called _______

Muscularis externa

that is, ______ mixes and propels foodstuffs along the digestive tract; this tunic typically has an inner cellular layer and an outer longitudinal layer of smooth muscle cells; in several places along the GI tract, the circular layer thickens to form sphincters that act as valves to prevent backflow and control food passage from one organ to the next

Absorbs

the GI tract ______ food; the digested fragments are moved though its lining in to the blood

Digest

the GI tract ______ food—breaks it down into smaller fragments

Teeth and tongue

the _____ are in the mouth, or oral cavity; _____ are accessory digestive organs

Serosa

the _____, the protective outermost layer of the intraperitoneal organs, is the visceral peritoneum;

Visceral peritoneum

the ______ covers the external surfaces of most digestive organs and is continuous with the parietal peritoneum that lines the body wall

Accessory digestive

the ______ glands produce a variety of secretions that contribute to the breakdown of foodstuffs

Splanchic circulation

the ______ includes those arteries that branch off the abdominal aorta to serve digestive organs and the hepatic portal circulation;

Adventitia

the ______ is ordaniarly fibrous connective tissue that binds the esophagus to surrounding structures; retroperitoneal organs have both a serosa and an ______

Peritoneum

the ______ of the abdominopelvic cavity is the most extensive of these serous membranes

Submocusa

the ______, just external to the mucosa, is a moderately dense connective tissue containing blood and lymphatic vessels, lymph nodules, and nerve fibers;

Lamina propria

the ______, which underlies the epithelium, is loose areolar connective tissue; its capillaries nourish the epithelium and absorb digested nutrients;

Hepatic portal circulation

the _______ collects nutrient-rich venous blood draining from the digestive viscera and delivers it to the liver; the liver collects the absorbed nutrients for metabolic processing or for storage before releasing them back to the bloodstream for general cellular use

Gallbladder

the _______ lies outside the GI tract and connects to it by ducts

Alimentary canal/ gastrointestinal tract

the ________ is the continuous muscular digestive tube that winds through the body. It digests food and absorbs digested fragments;

Mucosa/ mucous membrane

the ________ the innermost layer, is a moist epithelial membrane that lines the lumen of the alimentary canal from the mouth to the anus; its major functions are secretion, absorption, and protection

Accessory digestive

the _________ organs are the teeth, tongue, gallbladder, and a number of the large digestive glands—the salivarly glands, liver, and pancreas

Alimentary canal/ gastrointestinal tract

the organs of the _______ are the mouth, pharynx, esophagus, stomach, small intestine, and large intestine;

Parietal peritoneum

the visceral peritoneum covers the external surfaces of most digestive organs and is continuous with the ________ that lines the body wall

Mesentery

they also hold organs in place and store fat; in most places the _____ is dorsal and attaches to the posterior abdominal wall, but there are examples of ventral _____ as well

Epithelium

typically the _______ of the mucosa is a simple columnar epithelium that is rich in mucus secreting goblet cells; the slippery mucus it produces protects certain digestive enzymes working within their cavities and eases food passage along the tract; in the stomach and small intestine, the mucosa contains both enzyme and hormone secreting cells

Generalized

widespread within the peritoneal cavity