Chapter 9- Digestive System Flashcards
Intracellular Digestion
Involves oxidation of glucose and fatty acid to make energy
Where does extra cellular digestion occur?
In the lumen of the elementary canal. (Runs from the mouth to the anus)
Mechanical versus chemical digestion
Mechanical digestion is the physical breakdown of large food particles into smaller food particles. Chemical digestion is an enzymatic cleavage of chemical bonds such as the peptide bonds of proteins or the glycosidic bonds of starches.
What is the path of food through the digestive system
Oral cavity > Pharynx > Esophagus > Stomach > Small intestine > Large intestine > Rectum
What are the accessory organs of the digestive system
Salivary glands, pancreas, liver, gallbladder.
What is the enteric nervous system?
In the wall of the elementary canal and controls peristalsis.
Which branch of the nervous system controls peristalsis
Both the sympathetic and parasympathetic nervous system‘s.
The parasympathetic nervous system upregulates the digestive system. The sympathetic nervous system downregulates the digestive system.
Which hormone promotes hunger? Which hormone promotes the satiety?
Ghrelin, Glucagon
Leptin, Cholecystokinin
What hormone promotes thirst?
ADH (vasopressin) and aldosterone
Mouth
Start of mechanical digestion through mastication.
Salivary amylase and lipase start a chemical digestion of food.
What enzymes chemically break down food in the mouth?
Salivary amylase and lipase
What is food called once it is broken down within the mouth?
Bolus
Pharynx
Connects the mouth and posterior nasal cavity to the esophagus
What sphincter separates the lower esophagus and the stomach?
The lower esophageal (cardiac) sphincter
What propels food down the esophagus
Peristalsis (contraction)
What are the four parts of the stomach?
Fundus-Top
Body-Long curved side
Antrum- thinner transition into small intestine
Pylorus- bottom portion that connects to small intestine
Cells that line the stomach 
Mucous cells
Chief cells
Parietal cells
G cells
Mucous cells
produces bicarbonate rich mucus to protect the stomach
Chief cells
Secretes pepsinogen, a protease activated by the acidic environment of the stomach
Parietal cells
Secretes hydrochloric acid and intrinsic factor for vitamin B12 absorption
G cells
Secrete gastrin a peptide hormone that increases HCl secretion and gastric motility
What is food particles called after mechanical and chemical digestion in the stomach?
Chyme
Food passes from the stomach into the duodenum of the small intestine through which sphincter?
Pyloric sphincter
What are the three parts of the small intestine?
The duodenum- site of chemical digestion
The jejunum-nutrient absorption
The ileum-nutrient absorption
The presence of chyme in the duodenum causes the release of which enzymes?
Brush border enzymes such as disaccharides (Maltase isomaltase lactase and sucrase) and peptidases (dipeptidase)
Responsible for breakdown of dimers and trimers of biomolecules into absorbable monomers.
Where a brush border enzymes present?
On the luminal surface of the cells lining the duodenum
Role of disaccharidaces in digestion
Disaccharidase digest disaccharides in the duodenum. Examples include maltase which digests maltose, lactase which digests lactose and sucrase that digests sucrose. Lack of a particular disaccharidase causes an inability to break down the corresponding disaccharide.
Undigestive disaccharides have an osmotic effect and pull water into the stool causing diarrhea.
What is bile
A complex fluid composed of bile salts, pigments, and cholesterol.
Aids in digestion and absorption of fats and fat-soluble vitamins in the small intestine.
Made up of pigments, bile salts, pigments such as bilirubin (from the breakdown of hemoglobin) and cholesterol
which can be stored in the gallbladder or secreted in the duodenum directly.
Bile salts
Derived from cholesterol.
Important role in the mechanical digestion of fats and facilitate the chemical digestion of lipids.
Emulsifies fats and cholesterol into micelles. 
Pancreatic juice
Complex mixture of several enzymes in a bicarbonate rich alkaline solution. Help neutralize acidic chyme and provides an ideal working environment for a digestive enzymes. 
Enteropeptidase
Activates trypsinogen and procarboxypeptidase initiating an activation cascade
Secretin
Stimulates the release of pancreatic juices into the digestive tract slows motility
Cholecystokinin
Stimulates
Aminar cells
Located in the pancreas, produces pancreatic juices that contain by carbonate, pancreatic amylase, pancreatic peptidases such as trypsinogen, chymotrypsinogen, carboxypeptidases and pancreatic lipase
What is the role of the liver in digestion?
Processes nutrients through glycogenesis and glycogenolysis, storage and mobilization of fats and gluconeogenesis
Produces urea. Detoxifies chemicals. Activates or in a activates medication. Produces bile. Synthesizes albumin and clotting factors.
Gallbladder
Stores and concentrates bile
The villi in the small intestine contain what two structures that interacts with the lymphatic system?
A capillary bed and a lack teal or a vessel of the lymphatic system
What compounds enter the capillary bed within the valet of the small intestine?
Water soluble compounds such as monosaccharides, amino acids, water soluble vitamins, small fatty acids, and water
What types of molecules enter the lack teals in the valley of the small intestine?
Fat soluble soluble such as fats cholesterol and fat soluble vitamins.
Large intestine
Absorbs water and salts, forming semisolid feces
Cecum
Out pocketing that accepts fluid from the small intestine through the ileocecal valve. Site of attachment of the appendix.
Parts of the colon
Ascending, transverse, descending, and sigmoid
What valve accepts fluid from the small intestine?
Ileocecal valve
Rectum
Stores feces to be excreted through the anus
Gut bacteria produces which vitamins?
Vitamin K and vitamin B7 a.k.a. biotin
