Digestive System Overview and Anatomy

The digestive system has a quality control system and eliminates wastes, ensuring proper functioning.

The mouth is responsible for ingestion, mechanical digestion, and initial chemical digestion of food.

<p>The muscularis layer controls movement (peristalsis) and secretion within the digestive tract.</p> Signup and view all the answers

<p>The peritoneum is a serous membrane that lines the abdominal cavity. Its two main components are the visceral peritoneum, which covers the abdominal organs, and the parietal peritoneum, which covers the abdominal wall.</p> Signup and view all the answers

<p>The omental bursa is a cavity formed by a double fold of mesentery that extends from the stomach and loops back to the transverse colon. It serves as a 'pocket' within the abdominal cavity.</p> Signup and view all the answers

<p>Duodenum, Pancreas, Ascending colon</p> Signup and view all the answers

<p>The tongue plays a key role in mechanical digestion, swallowing, and taste perception.</p> Signup and view all the answers

<p>Permanent teeth are the adult set of teeth that replaces primary teeth (also known as 'milk teeth' or 'baby teeth').</p> Signup and view all the answers

<p>Enamel is the hardest substance in the human body and serves as a protective outer layer for the dentin of the tooth.</p> Signup and view all the answers

<p>Periodontal ligaments are connective tissues that connect the tooth to the alveolar bone, holding the tooth securely in place.</p> Signup and view all the answers

<p>The alveoli are the sockets within the alveolar bone that house the roots of teeth.</p> Signup and view all the answers

<p>The gingiva, also known as the gums, covers the alveolar processes and provides a protective barrier for the teeth and underlying structures.</p> Signup and view all the answers

<p>Tooth decay occurs due to the breakdown of enamel by acids produced by bacteria on the tooth surface.</p> Signup and view all the answers

<p>Periodontal disease is an inflammation and degeneration of the periodontal ligaments, gingiva, and alveolar bone, often caused by bacterial infection.</p> Signup and view all the answers

<p>The palate acts as the roof of the oral cavity, preventing food from entering the nasal cavity during chewing and swallowing.</p> Signup and view all the answers

<p>The hard palate, the anterior portion of the palate, is composed of bone and provides rigidity for the roof of the mouth.</p> Signup and view all the answers

<p>The uvula is a grape-like extension of the soft palate that helps prevent food from entering the nasal cavity.</p> Signup and view all the answers

<p>Tonsils are lymphatic tissues that protect the body against pathogens from entering the nose and mouth.</p> Signup and view all the answers

<p>The major salivary glands are the parotid glands (serous), submandibular glands (serous and mucous), and sublingual glands (mucous).</p> Signup and view all the answers

<p>Saliva helps keep the oral cavity moist, contains digestive enzymes (like salivary amylase), and helps break down food.</p> Signup and view all the answers

<p>Salivary amylase breaks down starches (polysaccharides) into simpler sugars, initiating the digestion of carbohydrates.</p> Signup and view all the answers

<p>Lysozyme is an enzyme that possesses weak antibacterial properties, helping to protect the oral cavity from infections.</p> Signup and view all the answers

<p>Mastification, or chewing, breaks down large food particles into smaller ones and increases the efficiency of digestion.</p> Signup and view all the answers

<p>The pharynx acts as a passageway for food and air, connecting the mouth to the esophagus and the nasal cavity to the larynx.</p> Signup and view all the answers

<p>Esophageal sphincters, located at the top (upper esophageal sphincter) and bottom (lower esophageal sphincter) of the esophagus, regulate the flow of food into and out of the esophagus, preventing backflow.</p> Signup and view all the answers

<p>Swallowing, or deglutition, is a complex process involving three phases: the voluntary phase (forming the bolus and pushing it into the pharynx), the pharyngeal phase (reflexive movement of the bolus through the pharynx), and the esophageal phase (peristaltic waves moving the bolus down the esophagus).</p> Signup and view all the answers

<p>The stomach serves as a storage and mixing chamber for ingested food. It achieves this through muscular contractions and the secretion of digestive enzymes.</p> Signup and view all the answers

<p>The four main regions of the stomach are the cardia (junction with the esophagus), fundus (topmost region), body (main central region), and pylorus (bottom region).</p> Signup and view all the answers

<p>The pyloric sphincter acts as a valve, regulating the passage of food from the stomach into the small intestine.</p> Signup and view all the answers

<p>Chyme is a semifluid mixture formed in the stomach as a result of food being churned and mixed with gastric secretions (acid, enzymes, mucus).</p> Signup and view all the answers

<p>Parietal cells in the stomach produce hydrochloric acid (HCl) and intrinsic factor.</p> Signup and view all the answers

<p>Chief cells produce pepsinogen, an inactive precursor of the digestive enzyme pepsin.</p> Signup and view all the answers

<p>Endocrine cells in the stomach produce regulatory chemicals that influence digestion and other functions.</p> Signup and view all the answers

<p>Gastric secretions, including hydrochloric acid, pepsin, mucus, and intrinsic factor, play crucial roles in breaking down food, protecting the stomach lining, and aiding in nutrient absorption.</p> Signup and view all the answers

<p>The three phases of gastric secretion regulation are the cephalic phase (triggered by anticipation of food), the gastric phase (stimulated by food in the stomach), and the intestinal phase (regulated by signals from the small intestine).</p> Signup and view all the answers

<p>Motility in the stomach is crucial for mixing food with gastric secretions to form chyme and propelling chyme towards the small intestine.</p> Signup and view all the answers

<p>The two main types of movement are mixing waves (thorough mixing) and peristaltic waves (propelling chyme towards the pyloric sphincter), both working together to facilitate digestion.</p> Signup and view all the answers

<p>The small intestine is the primary site for digestion and absorption of nutrients from food.</p> Signup and view all the answers

<p>The three sections are the duodenum (shortest, initial section), jejunum (middle section, responsible for most digestion and absorption), and ileum (final section, further absorption).</p> Signup and view all the answers

<p>Circular folds, villi, microvilli</p> Signup and view all the answers

<p>The lacteal is a lymphatic capillary that transports absorbed fats from the small intestine to the lymphatic system.</p> Signup and view all the answers

<p>The four primary cell types are absorptive cells (absorbing digested nutrients), goblet cells (producing mucus for protection), granular cells (protecting against bacteria), and endocrine cells (producing hormones for regulation).</p> Signup and view all the answers

<p>Intestinal glands are responsible for producing and secreting digestive enzymes and other substances that aid in digestion and absorption.</p> Signup and view all the answers

<p>Duodenal glands, found in the submucosa of the duodenum, secrete mucus to protect the lining from acidic chyme entering from the stomach.</p> Signup and view all the answers

<p>Peyer's patches are clusters of lymphatic nodules found along the ileum of the small intestine. They are crucial for immune surveillance and defense against pathogens.</p> Signup and view all the answers

<p>The ileocecal junction is the point where the small intestine (ileum) connects with the large intestine (cecum). The ileocecal valve, a ring of smooth muscle, controls the flow of material from the ileum into the cecum, preventing backflow.</p> Signup and view all the answers

<p>These enzymes are peptidases (breaking down protein chains into amino acids) and disaccharidases (breaking down complex sugars into simpler sugars).</p> Signup and view all the answers

<p>The primary movements are peristaltic contractions (propelling food contents along the length of the intestine) and segmental contractions (mixing intestinal contents), working together to facilitate both movement and efficient digestion.</p> Signup and view all the answers

<p>The liver is a vital organ with numerous functions, including digestion (producing bile), detoxification of harmful substances, nutrient conversion, storage, and synthesis of essential molecules. It plays a crucial role in overall health and maintaining homeostasis.</p> Signup and view all the answers

<p>The liver has two main lobes: the right lobe and the left lobe. The falciform ligament acts as a septum that separates these two lobes.</p> Signup and view all the answers

<p>The hepatic triad consists of a hepatic artery (supplying oxygenated blood), hepatic portal vein (carrying nutrient-rich blood from the digestive system), and a hepatic duct (carrying bile from the liver).</p> Signup and view all the answers

<p>Bile is a fluid produced by the liver that plays a crucial role in the digestion of fats. It emulsifies fats, breaking them down into smaller droplets for easier digestion by enzymes.</p> Signup and view all the answers

<p>The gallbladder is a small organ beneath the liver that stores and concentrates bile produced by the liver, releasing it into the small intestine when needed.</p> Signup and view all the answers

<p>The duodenal papilla is a small opening in the duodenum where the common bile duct and the pancreatic duct join, allowing bile and pancreatic juices to flow into the small intestine.</p> Signup and view all the answers

<p>The pancreas has two main parts: the exocrine part (producing digestive enzymes) and the endocrine part (producing hormones like insulin and glucagon).</p> Signup and view all the answers

<p>The three key proteolytic enzymes are trypsin, chymotrypsin, and carboxypeptidase. They are crucial for breaking down proteins into smaller peptides, continuing the process of protein digestion initiated in the stomach.</p> Signup and view all the answers

<p>Pancreatic amylase is an enzyme that continues the digestion of carbohydrates (polysaccharides) into simpler sugars. It plays a crucial role in completing the breakdown of starches initiated by salivary amylase in the mouth.</p> Signup and view all the answers

<p>Pancreatic lipase is a digestive enzyme that breaks down fats (lipids) into smaller molecules (fatty acids and glycerol), facilitating their absorption by the small intestine.</p> Signup and view all the answers

<p>Micelles are tiny structures formed by the aggregation of bile salts around small droplets of digested fats (lipids). They help transport these fats from the small intestine for absorption into the bloodstream.</p> Signup and view all the answers

<p>Chylomicrons are lipid-protein complexes that carry absorbed fats (lipids) from the small intestine into the lymphatic system, eventually transporting them to the bloodstream.</p> Signup and view all the answers

<p>The large intestine's main function is to absorb water and electrolytes, forming feces for elimination. Its four parts are the cecum, colon (ascending, transverse, descending, and sigmoid portions), rectum, and anal canal.</p> Signup and view all the answers

<p>The appendix is a small, finger-like projection attached to the cecum. While its exact function is still debated, it is thought to play a role in immune system development.</p> Signup and view all the answers

<p>Teniae coli are three bands of smooth muscle that run along the length of the large intestine. These bands create a contraction pattern that helps propel feces through the colon.</p> Signup and view all the answers

<p>The rectum is the final part of the large intestine, receiving feces from the sigmoid colon. The anal canal connects the rectum to the exterior of the body, allowing for the elimination of feces.</p> Signup and view all the answers

<p>The two anal sphincters are the internal anal sphincter (smooth muscle, involuntary control) and the external anal sphincter (skeletal muscle, voluntary control). They work together to regulate the passage of feces during defecation.</p> Signup and view all the answers

<p>The large intestine absorbs water from the digested food material, concentrating the waste products and forming solid feces for elimination.</p> Signup and view all the answers

<p>Defecation is the elimination of feces from the body through the anus. It is triggered by a complex reflex involving both local (weak) and parasympathetic (strong) contractions of the colon and rectum.</p> Signup and view all the answers

<p>Mechanical digestion is the physical breakdown of food into smaller pieces, while chemical digestion involves the use of enzymes to break down food molecules into smaller units.</p> Signup and view all the answers

<p>Carbohydrates are primarily found in starches (like potatoes and grains), sugars (like sucrose, fructose, and lactose), and cellulose (found in plant fibers). The main types of carbohydrates are monosaccharides, disaccharides, and polysaccharides.</p> Signup and view all the answers

<p>Salivary amylase initiates the breakdown of carbohydrates in the mouth, while pancreatic amylase continues this process in the small intestine, ultimately breaking down complex carbohydrates into simpler sugars for absorption.</p> Signup and view all the answers

<p>Disaccharidases are enzymes that break down disaccharides (complex sugars) into simpler monosaccharides (single sugars) for absorption by the small intestine.</p> Signup and view all the answers

<p>The three main types of lipids are triglycerides (most common, composed of three fatty acids bound to glycerol), saturated fatty acids (with only single bonds), and unsaturated fatty acids (with one or more double bonds).</p> Signup and view all the answers

<p>Lipase is the primary enzyme responsible for digesting fats (lipids). It is secreted by the pancreas and breaks down triglycerides into fatty acids and glycerol, facilitating their absorption.</p> Signup and view all the answers

<p>Emulsification is the process of breaking down large lipid droplets into smaller droplets. Bile salts produced by the liver aid in this process. Emulsification increases the surface area of fats, allowing for more efficient contact with lipase and enhancing their digestion and absorption.</p> Signup and view all the answers

<p>Pepsin is a protein-digesting enzyme secreted by the stomach. It breaks down proteins into smaller peptides, initiating the process of protein digestion.</p> Signup and view all the answers

<p>These protein-digesting enzymes, produced by the pancreas, continue the breakdown of proteins into smaller peptides, completing the process of protein digestion.</p> Signup and view all the answers

<p>Peptidases are enzymes that further break down small peptides into individual amino acids, the building blocks of proteins.</p> Signup and view all the answers

<p>Water is essential for the digestive system because it is necessary for dissolving food, lubricating the digestive tract, and transporting nutrients and waste products.</p> Signup and view all the answers