Digestive System Flashcards
Describe the role of the oral cavity in the digestive process
The oral cavity is where food is chewed and mixed with saliva, which contains enzymes that begin breaking down carbohydrates. Chewing increases the surface area of the food, allowing for the formation of an appropriately sized bolus
Explain the function of the pharynx in digestion
The pharynx serves as a passageway for food, liquid, and air, facilitating the movement of food from the mouth to the esophagus
How does the esophagus contribute to the digestive process?
The esophagus transfers food from the mouth to the stomach through peristaltic contractions, propelling the food along its length
Define the primary functions of the stomach in digestion
The stomach is responsible for the mechanical and chemical breakdown of food, producing chyme, and secreting glycoprotein B12
Describe the process of segmentation in the small intestine
Segmentation in the small intestine consists of localized contractions that move food back and forth, mixing it with digestive juices and facilitating absorption
What is the role of the cecum in the large intestine?
The cecum receives digested food from the small intestine, continues the absorption of water and salts, and begins compacting undigested materials into waste.
Outline the journey of fecal matter through the colon
Fecal matter travels from the cecum to the ascending colon, then to the transverse colon, followed by the descending colon, and finally enters the sigmoid colon
Explain the function of the rectum in the digestive system
The rectum is the final segment of the GI tract, featuring internal transverse folds called rectal valves that help separate feces from gas, preventing simultaneous passage
Identify the accessory organs of the digestive system and their roles
the liver, pancreas, and gallbladder. Which contribute to digestion by producing bile, digestive enzymes, and aiding in the digestion and absorption of nutrients
Compare the digestion of macronutrients across different organs of the digestive system
The mouth begins the carbohydrate digestion
The stomach focuses on protein breakdown
The small intestine completes digestion and absorption of carbohydrates, proteins and fats
How does the liver contribute to digestion?
The liver produces bile, which is essential for the emulsification and digestion of fats
What is the function of the pancreas in the digestive system?
Produces digestive enzymes that help break down carbohydrates, proteins, and fats in the small intestine
Describe the role of the gallbladder in digestion
Stores and concentrates bile produced by the liver, releasing it into the small intestine to aid in fat digestion
Describe the role of accessory digestive organs
Suppor digestion by producing and storing enzymes and chemicals vital for breaking down food
How do salivary glands contribute to digestion?
Salivary glands produce saliva, which contains enzymes like amylase that begin carbohydrate digestion and moistens food for easier passage through the esophagus
Define the function of the liver in digestion
Produces bile, crucial for digesting and absorbing fats, processes nutrients from the digestive tract, and detoxifies chemicals
What is the role of the gallbladder in the digestive process?
stores and concentrates bile produced by the liver and releases it into the small intestine to aid in fat digestion
Explain the function of the pancreas in digestion
Secretes digestive enzymes and bicarbonate into the small intestine, breaking down proteins, fats, and carbohydrates while neutralizing stomach acid
How do teeth assist in the digestive process
Teeth mechanically break down food into smaller pieces, increasing the surface area for enzymes to act upon, facilitating easier swallowing and digestion
What is the role of the tongue in digestion?
manipulating food during chewing and swallowing and is essential for taste and speech
Define ingestion in the context of the digestive system
Ingestion is the process of taking food into the GI tract through the mouth
What is propulsion in the digestive system?
The movement of food through the digestive tract, involving voluntary processes like swallowing and involuntary processes like peristalsis
Describe mechanical digestion
A physical process that reduces food size to increase surface area and mobility without changing its chemical nature, i.e., chewing
What is chemical digestion?
The enzymatic breakdown of food
Explain the process of absorption in digestion
The process where most nutrients are taken from the lumen of the alimentary canal into the bloodstream through epithelial cells, while lipids are absorbed into lacteals and transported via lymphatic vessels
Define defecation in the digestive process
The elimination of undigested substances from the body in the form of feces
List the layers of the GI tract wall from superficial to deep
Serosa, musculares externa, tunica submucosa, and tunica mucosa
What is the function of the enteric nervous system? (ENS)
Directly controls motility, secretion, and blood flow. Regulates peristalsis, coordinates complex reflexes, and processes sensory information from the gut.
How does the ANS affect digestion?
It modulates the activity of the ENS and directly affects the digestion through its branches, particularly promoting digestion via the parasympathetic branch
Contrast the ENS and ANS in terms of their independence in digestive functioning
The ENS can function independently of the CNS, directing basic digestive functions
The ANS operates throughout the body and modulates ENS activity
Describe the function of the parasympathetic nervous system in digestion
Enhances blood flow to the digestive tract, stimulates secretions, and promotes peristalsis
Explain the role of the sympathetic nervous system in digestion
Generally inhibits digestion in stressful situations, reducing blood flow to the digestive organs, slowing peristalsis, and decreasing digestive secretions
Define parietal peritoneum
Lining of the inner surfaces of the peritoneal or abdominopelvic cavity and is continuous with the serosa of the GI tract, producing lubricating fluid
Describe the greater omentum
A large, fatty structure hanging from the stomach and draping over the intestines, extending from the greater curvature of the stomach and the beginning of the duodenum
What is the function of the lesser momentum?
A smaller peritoneal fold that extends from the liver to the stomach and duodenum, stabilizing the position of the stomach and li8ver while allowing blood vessel and duct passage
How does the mesentery support the intestines?
It is a continuous set of tissues formed by a double fold of the peritoneum that anchors the intestines to the posterior abdominal wall and supplies blood vessels, lymphatics, and nerves
Describe the role of the mesocolon
Anchors the colon to the abdominal wall, supports and conduits blood vessels to the colon, and assists in maintaining the colons structure and positioning
Outline the pathway of food through the GI tract
oral cavity –> pharynx–> esophagus–> stomach–> small intesting–> large intesting–> rectum
Explain how mechanical digestion occurs in the mouth
Involves mastication, where buccinator muscle4s compress the cheeks to aid in churning food while chewing, and the tongue manipulates the food
Describe the chemical digestion process in the mouth
Salivary glands release saliva, containing amylase which breaks down complex carbohydrates into simple sugars
What is deglutition?
The process of transferring food from the oral cavity to the esophagus, Starting out as a voluntary process and becomes an autonomic reflex
Compare peristalsis and segmentation in digestion
Peristalsis is a coordinated series of smooth muscle contractions for propulsion
Segmentation separates chyme and mixes it for digestion and absorption
Identify enzymes responsible for breaking down carbohydrates and their sources
Amylase breaks down carbohydrates into sugars and is released from the salivary glands and pancreas
Name the proteases involved in protein digestion and their sources
Pepsin, trypsin, and chymotrypsin which are released from the stomach and pancreas
Describe the process of protein digestion in the body
Proteins are broken down into smaller peptides and amino acids by enzymes such as pepsin, trypsin, and chymotrypsin
Identify the source of pepsin and its role in digestion
Pepsin is secreted by the stomach and help s to break down proteins
Explain the function of lipase in digestion
Lipase breaks down lipids or fats into fatty acids and glycerol, and is released by the pancreas and small amounts from the stomach
What is the role of nucleases in the digestive system?
Nucleases break down nucleic acids into nucleotides and are released from the pancreas
List the major anatomical structures of the oral cavity
Lips, gingivae, hard palate, soft palate, uvula, cheeks, teeth, and tongue
Describe the function of molars in the mouth
Serve as grinders for breaking down food
How do bicuspids contribute to the digestive system?
involved with crushing and grinding food
What is the function of cuspids/ canines?
designed for tearing food
Function of incisors in the oral cavity
cutting food to bring into the mouth
Describe lingual papillae and their function
Mound like structures on the surface of the tongue that contain chemoreceptors involved in taste
List the 3 pairs of salivary glands and their locations
Parotid- anterior to the ear lobes
Sublingual- deep in the tongue
Submandibular- medial to the mandible
What is the function of the esophagus?
A muscular tube that extends from the pharynx to the stomach, pushing the bolus down by peristalsis
Describe the structure and function of gastric glands
Located in the stomach mucosal epithelium and produce gastric juices
Identify the 3 cell types found in gastric glands and their secretions
-Parietal cells- produce hydrochloric acid
-Chief cells- secrete pepsinogen
-G cells- produce hormones like gastrin
Define the cephalic phase of gastric digestion
Begins when you think, smell, or taste food. Triggering an increase in gastric juice secretions
What occurs during the gastric phase of digestion?
Starts when food enters the stomach, activating stretch and chemoreceptors that stimulate gastric activity
Describe the intestinal phase of gastric digestion
Starts when chyme enters the duodenum
List the major digestive functions of the liver
Bile production, carbohydrate metabolism, lipid metabolism, amino acid metabolism, plasma protein synthesis, and removal of toxins and wasts
Where is the gallbladder located and what is its function?
Located in the upper right quadrant of the abdomen beneath the liver
Stores bile
Describe the location and connection of the gallbladder
The gallbladder sits just below the liver’s right lobe and is attached to it by the cystic duct, which connects to the common bile duct
Explain the primary function of the gallbladder
The gallbladder stores and concentrates bile produced by the liver, releasing it when a meal high in fat is consumed
List the pancreatic enzymes and their functions
Carbohydrases (amylase) break down carbohydrates into simple sugars
Lipases break down lipids
Nucleases digest nucleic acids
Proteases digest proteins into peptides and amino acids
Distinguish between the 3 segments of the small intestine
Duodenum connects to the stomach
Jejunum is the middle part between the duodenum and the ileum
Ileum is the end of the small intestine, anding at the ileocecal valve
Describe the circular folds (Plicae circulars) in the small instestine
Large, deep folds in the mucosal and submucosal layer that slow down the movement of chyme, allowing more time for nutrient absorption and increasing surface area
What are villi and their role in the small intestine?
finger like projections that protrude from the epithelial lining, significantly increasing surface area and containing blood vessels and lacteals for nutrient transport
Explain the function of microvilli in the small intestine
Tiny hairlike structures on the apical surface of t6he epithelial cells that further increase surface area and contain enzymes for the final stages of nutrient digestion and absorption
How are nutrients absorbed into the body?
Segmentation and peristalsis that mix chyme with bile and pancreatic enzymes, allowing brush border enzymes to break down macromolecules into smaller nutrients for absorption
Describe the function of gastrin in the digestive system
A peptide hormone that stimulates the secretion of hydrochloric acid by the parietal cells of the stomach
What is the role of CCK (Cholecystokinin)?
produced in response to chyme rich in fats and proteins, stimulating the pancreas to increase digestive enzyme secretion, contracting the gallbladder to release bile, and relaxing the hepatopancreatic sphincter
Explain the function of GIP (Gastric Inhibitory Peptide)
Produced by the duodenum, inhibiting gastric motility and emptying while stimulating insulin production in response to fats and carbohydrates
What is the role of secretin in the digestive process?
a hormone produced by the duodenum that stimulates the pancreas to secrete a water solution of bicarbonate
Describe the anomy of the large intesting
Thicker and shorter that the small intestine, arranged in a loop that frames the small intestine, and consists of the main segments: cecum, colon, and rectum
Explain the physiological role of the large intestines in water absorption
The LI absorbs water and electrolytes, transforming the chyme from a liquid state into solid feces
What is the function of bacterial flora in the large intestine
Bacterial flora in the large intestine helps break down materials and synthesize specific vitamins
Describe the process of compaction in the large intestine
Involves absorbing water, electrolytes, and vitamins to compact fecal matter
How does the large intestine contribute to mucos production>
Glands in the colon secrete mucus to facilitate the smooth passage of feces
What is the process of defecation?
Involves complex reflex activities that lead to the expulsion of feces through the anus
Define the gut microbiome and its significance
The gut microbiome consists of organisms living in the digestive tract that impact physical and mental health, influencing infection resistance, immune function, mucosa maintenance, and behavior
What are the consequences of disrupting healthy gut flora?
Disruption of healthy gut flora has been correlated with inflammatory and autoimmune diseases
Describe appendicitis
An inflammation of the appendix that can be painful and potentially fatal if it ruptures, leaking bacteria into the abdominal cavity
What is the typical treatment for appendicitis?
Appendectomy and antibiotics
How are proteins digested throughout the digestive tract?
Proteins are initially denatured in the stomach by gastric acid, then broken down into peptides by enzymes and further digested into amino acids in the small intestine
