A+P II Lab: Ex. 5: Digestive System

Réussis tes devoirs et examens dès maintenant avec Quizwiz!

the digestive system is composted of two separate groups of organs:

1. alimentary canal or gastrointestinal tract - organs that are tubular in shape and connected sequentially together 2. accessory digestive organs - connected through various ducts or are attached to the alimentary canal. these aid in mechanical and chemical digestion through the alimentary canal

enzymes found within the brush border include:

1. alpha dextrinase - carbohydrase 2. maltase - carbohydrase 3. sucrase - carbohydrase 4. lactase - carbohydrase 5. aminopeptidase - protease 6. dipeptidase - protease 7. nucleosidases - nuclease 8. phosphatases - nuclease

major components of saliva include:

1. immunoglobulin A - important in preventing attachment of microbes, preventing penetration into the epithelium 2. bacteriolytic lysozyme - kills bacteria 3. salivary amylase - carbonhydrase 4. lingual lipase - lipase 5. bicarbonate - buffers acidic foods

gastric glands are found at the base of the gastric pits and consist of 4 types of cells:

1. mucous cells 2. parietal cells 3. chief cells 4. G cells

components of gastric juices include:

1. water 2. hydrochloric acid (HCI) - denatures proteins, making it easier for protease enzymes to target peptide bonds. also has an antimicrobial function 3. pepsinogen - activated into pepsin (protease) by HCI within the stomach lumen 4. gastric lipase - lipase 5. intrinsic factor - aids in vitamin B12 absorption within the ileum

pancreatic acini produce...

a mixture of enzymes, water, and bicarbonate, named pancreatic juice

chymotrypsinogen

activated into chymotrypsin (Protease) by trypsin

procarboxypeptidase

activated into chymotrypsin (Protease) by trypsin

Proelastase

activated into elastase (Protease) by trypsin

trypsinogen (pancreatic juice)

activated into trypsin (Protease) by enterokinase within the duodenum

amino acids are absorbed by...

active transport or secondary active transport, using Na+ symporters

bile aids in lipid digestion by serving as...

an emulsifier

salivary secretions serve as an immune function by containing...

bacteriolytic lysozymes

produced by the liver, then concentrated, stored and released by the gall bladder aids lipid digestion by serving as an emulsifier aids in lipid absorption by making fatty acid chains more water soluble contains bicarbonate to aid in the neutralization of the acidic chyme coming from the stomach

bile

fatty acids and lipid-soluble vitamins are absorbed with the assistance of...

bile salts via simple diffusion

once the brush border enzymes have generated monomers, the majority of nutrients with the exception of some lipids will be absorbed into...

blood capillaries

chemical digestion occurs both within the lumen of the small intestine through bile and pancreatic enzymes as well as along the mucosal border in a region referred to as the ________ ___________

brush border

pancreatic amylase

carbohydrase

as ________ sits in the stomach, a small amount of absorption occurs as water, ions, short chain fatty acids, as well as some drugs and alcohol are absorbed. most absorption is prevented as the mucosal cells are relatively impermeable to most materials.

chyme

gastric contortions mix the bolus of food with gastric juices, forming a liquid mixture of enzymes and food called...

chyme

feces are eventually eliminated when the ____________ _________ is initiated when fecal matter enters into the rectum

defecation reflex

as the bolus enters the oropharynx, receptors initiate the...

deglutination reflex (this first involves lifting the uvula to block off the nasopharynx, followed by closing the epiglottis to block the trachea

regulation of digestion is accomplished by interactions of the...

diencephalon, cerebrum, enteric nervous system, autonomic nervous system, and endocrine system

ribonuclease and deoxyribonuclease

digest RNA and DNA respectively

the stomach serves as a site of continued mechanical and chemical digestion, as well as a holding area for food as only small amounts can be moved into the ___________ of the small intestine at one time

duodenum

the small intestine is divided into three regions:

duodenum, jejunum, ileum

the sympathetic nervous system does the opposite of the parasympathetic nervous system. it inhibits the activities of the __________________

enteric nervous system

the stomach receives the semisolid bolus of food from the...

esophagus

which portion of the pancreas produces pancreatic juices containing a mixture of water, bicarbonate, ions and enzymes

exocrine portion of the pancreas

pancreatic lipase breaks down...

fat

absorption in the large intestine is restricted to finishing water and electrolyte absorption along with some vitamins. as chyme moves through the large intestine and more water is absorbed, solid or semi-solid _________ __________ are generated

fecal boli

hepatic portal triads

found among the borders of the lobule contain a hepatic artery, portal vein, and bile duct

once the food has entered the stomach, the lower ________ ______________ contracts, preventing the contents within the stomach from regurgitating back into the esophagus

gastoesophageal sphincter

chemical digestion occurs through secretions of...

gastric glands found within the mucosa of the stomach

the gastric mucosa is lined with an epithelium, which folds, creating...

gastric pits

mechanical digestion in the large intestine is responsible for the formation of feces through ___________ ____________

haustral churning

bile coats lipid aggregates in a way that produces a _____________ core and a _______________ cover

hydrophobic core and hydrophilic cover

The majority of absorption occurs in the _______

ileum

components of the liver and pancreatic juices include:

in liver - 1. bile pancreatic juices - 1. bicarbonate 2. trypsinogen 3. chymotrypsinogen 4. procarboxypeptidase 5. proelastase 6. pancreatic amylase 7. pancreatic lipase 8. ribonuclease 9. deoxyribonuclease

where are gastric juices found

in the mucosa of the stomach

as the stomach transitions to the duodenum, the gastric pits transition to the long and slender ____________ _______

intestinal villi seen in the duodenum

no human produced enzymes are found in the...

large intestine

pancreatic lipase

lipase

lipids are absorbed by the lymphatic system where they are transported to the ________ and metabolized

liver

materials from the blood are processed in the _______, where they can be stored or converted into other organic compounds

liver

which accessory digestive organs secrete digestive aids into the duodenum?

liver and pancreas

peristalsis serves to mix chyme with secretions from the ________________ ___________ and __________

liver, pancreas, and small intestines

the liver is organized into several ______________, each with a central vein surrounded by rows of ______________

lobules hepatocytes

the mucous that is generated from mucin works as a __________, and makes swallowing the ball of food (bolus) easier

lubricant

the process of breaking down food is accomplished by two digestive mechanisms:

mechanical digestion and chemical digestion

chyme

mixture of enzymes and partially-digested food

lacteals

modified lymphatic capillaries found in intestinal villi

general functions of saliva include:

moistening food to make it easier to swallow, dissolving food for tasting, buffering acidic foods with the help of bicarbonate ions, and protecting the mouth from infection with its rinsing action

when the bolus reaches the esophagus, stretch receptors in the myentric plexus trigger the muscularis to commence peristalisis...

moving the bolus into the stomach

secretions from the liver and pancreas enter the duodenum through ducts piercing the _________

mucosa

mechanical digestion occurs as gastric contortions initiated by the ________________________ mix the bolus of food with secretions from gastric glands

muscularis of the stomach

bicarbonate (pancreatic juice)

neutralizes acidic chyme from the stomach

deoxyribonuclease

nuclease

ribonuclease

nuclease

Three main salivary glands

parotid, submandibular, sublingual

mechanical digestion within the small intestine occurs through _______________

peristalsis

ions found in saliva that serve as a buffer for acidic food entering the mouth

phosphate & bicarbonate

deglutination

process of swallowing

mucous acini

produce mucin, a glycoprotein

the parasympathetic nervous system stimulates the enteric system as well as...

promotes salivation, secretion of gastric fluids, and defecation

within pyloric region of the mucosal, gastric glands are now referred to as __________ ___________, but secrete the same substances

pyloric glands

the duodenum receives chyme from the stomach through the ________________

pyloric sphincter

the large intestine consists of several regions ending in the _________ and __________

rectum and anus

serous acini

release a water and electrolyte solution laced with salivary amylase of lingual lipase.

hormones regulating digestion: secretin

released by enteroendocrine cells of the duodenum in response to a drop in duodenal pH. responsible for stimulating the secretion of bile and pancreatic juices rich in bicarbonate. INHIBITS secretion of gastric juices

hormones regulating digestion: cholecystokinin (CKK)

released by enteroendocrine cells of the duodenum in response to chyme rich in proteins and lipids. responsible for increasing the secretion of pancreatic juices rich in digestive enzymes and the ejection of bile from the gall bladder. INHIBITS gastric emptying

hormones regulating digestion: gastrin

released by the stomach in response to stomach distension and an increase in gastric pH. stimulates digestion by secreting additional gastric juices and increasing gastric motility

glucose is absorbed by...

secondary active transport employing Na+ symporters

parietal cells

secret hydrochloric acid, which denatures proteins and intrisic factor, which is needed for vitamin B12 absorption within the ilieum

Brunner's glands

secrete alkaline mucus (to help neutralize the acidic chyme coming from the stomach)

G cells

secrete gastrin

chief cells

secrete pepsinogen, which is activated by HCI into pepsin in the stomach lumen and targets peptide bonds and gastric lipase, which targets triglycerides

primary function of the liver

secretion of bile

the endocrine system regulates...

secretion of gastric fluids, intestinal, pancreatic, and hepatic fluids, as well as the motility of several digestive organs

bolus

semisolid mass of chewed food mixed with saliva

the rows of hepatocytes in the liver are separated by ___________ ___________ that connect to the central vein

sinusoid capillaries

mechanical and chemical digestion occur throughout the ______________ ______________

small intestines

pancreatic amylase furthers the digestion of...

starch

gastric emptying and intestinal motility are controlled by both the...

sympathetic and parasympathetic nervous systems

mechanical digestion within the oral cavity primarily occurs through the actions of...

teeth

chemical digestion

the breakdown of the larger food materials at the chemical level, separating individual organic monomers from their larger polymers. ____________ targets chemical bonds with the assistance of enzymes and other chemical agents. the process begins with the dissolution of food materials in saliva and continues with various digestive secretions, enzymatic activity, and the action of pH shifts in the stomach and small intestines

mechanical digestion

the physical degradation of larger food materials into smaller pieces. this process increases the surface area of the food, which will increase the efficiency of the enzymatic chemical digestion that follows. types of mechanical digestion include mastication, gastric churning, segmented peristalsis, and haustral churning

mastication

the process of chewing with teeth - incisors are able to slice, canines can puncture, and premolars and molars are use to grind food

the enteric nervous system independently regulates digestion through the activity of two plexuses:

the submucosal plexus & the myenteric plexus

chemical digestion within the oral cavity occurs through secretions from ____ main salivary glands, each of which produces saliva of different composition

three

The pancreas has both an endocrine and an exocrine function (t/f)

true

each salivary gland produces saliva of a different composition. they have the same basic components but their concentrations differ depending on the gland (t/f)

true

pancreatic juice consists of precursors to the proteases _________, ____________, ____________,

trypsin chymotrypsin pancreatic amylase pancreatic lipase ribonuclease deoxyribonuclease

chemical digestion in the large intestine is associated with several bacterial enzymes that are responsible for producing _______________

vitamins B and K

once surrounded by bile salts, fatty acids become temporarily ____________ and are absorbed by lacteals

water-soluble

mucous cells

within the neck of the gland secrete mucus for lubrication and protection of the gastric mucosa


Ensembles d'études connexes

Additional TB Health Assessment Questions chapters

View Set

HS 354 Sources of Retirement Income

View Set

Comptia Security+ - Chapter 1 Quiz -Mastering Security Basics

View Set

Intl Econ Exam 2- Ch 13, 14, ,15, 16, 18, 19

View Set