Biology Chapter 9: The Digestive System (2 Stars) Flashcards
Intracellular digestion involves the _____ of glucose and fatty acids to make energy.
oxidation
______ digestion is the physical breakdown of large food particles into smaller food particles.
Mechanical
_______ digestion is the enzymatic cleavage of chemical bonds, such as the peptide bonds of proteins or the glycosidic bonds of starches.
Chemical
The pathway of the digestive tract is: oral cavity → pharynx → ______ → stomach → small intestine → large intestine → rectum
esophagus
The ______ organs of digestion are the salivary glands, pancreas, liver, and gallbladder.
accessory
The ______ nervous system is in the wall of the alimentary canal and controls peristalsis. Its activity is upregulated by the parasympathetic nervous system and downregulated by the sympathetic nervous system.
enteric
Multiple hormones regulate feeding behavior, including _______ and aldosterone, which promote thirst; glucagon and ghrelin, which promote hunger; and leptin and cholecystokinin, which promote satiety.
antidiuretic hormone (ADH or vasopressin)
In the ______, mastication starts the mechanical digestion of food, while salivary amylase and lipase start the chemical digestion of food.
oral cavity
The _____ connects the mouth and posterior nasal cavity to the esophagus.
pharynx
The _____ propels food to the stomach using peristalsis.
esophagus
Food enters the stomach through the lower esophageal (cardiac) sphincter.
The stomach has four parts: fundus, body, antrum, and ______. The stomach has a lesser and greater curvature and is thrown into folds called rugae.
pylorus
_____ cells produce bicarbonate-rich mucus to protect the stomach.
Mucous
_____ cells secrete pepsinogen, a protease activated by the acidic environment of the stomach.
Chief
_____ cells secrete hydrochloric acid and intrinsic factor, which is needed for vitamin B12 absorption.
Parietal
_____ secrete gastrin, a peptide hormone that increases HCl secretion and gastric motility.
G-cells
After mechanical and chemical digestion in the stomach, the food particles are now called _____
Food passes into the duodenum through the pyloric sphincter.
chyme
The ______ is the first part of the small intestine and is primarily involved in chemical digestion.
duodenum
______ are brush-border enzymes that break down maltose, isomaltose, lactose, and sucrose into monosaccharides.
Disaccharidases
Brush-border _______ include aminopeptidase and dipeptidases.
peptidasess.
_______ activates trypsinogen and procarboxypeptidases, initiating an activation cascade.
Enteropeptidase
_______ stimulates the release of pancreatic juices into the digestive tract and slows motility.
Secretin
Cholecystokinin stimulate ____ release from the gallbladder, release of pancreatic juices, and satiety.
bile
____ cells in the pancreas produce pancreatic juices that contain bicarbonate, pancreatic amylase, pancreatic peptidases (trypsinogen, chymotrypsinogen, carboxypeptidases A and B), and pancreatic lipase.
Acinar
The ____ synthesizes bile, which can be stored in the gallbladder or secreted into the duodenum directly.
liver
___ emulsifies fats, making them soluble and increasing their surface area.
Bile
The main components of bile are _____, pigments (especially bilirubin from the breakdown of hemoglobin), and cholesterol.
bile salts
The liver also processes _____ (through glycogenesis and glycogenolysis, storage and mobilization of fats, and gluconeogenesis), produces urea, detoxifies chemicals, activates or inactivates medications, produces bile, and synthesizes albumin and clotting factors.
nutrients
The ______ stores and concentrates bile.
gallbladder
The jejunum and _____ of the small intestine are primarily involved in absorption.
ileum
The _______ is lined with villi, which are covered with microvilli, increasing the surface area available for absorption.
small intestine
____ contain a capillary bed and a lacteal, a vessel of the lymphatic system.
Villi
Water-soluble compounds, such as monosaccharides, amino acids, watersoluble vitamins, small fatty acids, and water, enter the _____ bed.
capillary
Fat-soluble compounds, such as fats, cholesterol, and fat-soluble vitamins, enter the _____
lacteal
The large intestine absorbs water and salts, forming semisolid _____
feces.
The ____ is an outpocketing that accepts fluid from the small intestine through the ileocecal valve and is the site of attachment of the appendix.
cecum
The _____ is divided into ascending, transverse, descending, and sigmoid portions.
colon
The _____ stores feces, which are then excreted through the anus.
rectum
____ bacteria produce vitamin K and biotin (vitamin B7)
Gut
Extracellular digestion occurs in the lumen of the _____ canal.
alimentary
____ is formed into a bolus and swallowed.
Food
The fat-soluble vitamins are (4).
A, D, E, and K.
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