Digestive System and Metabolism Overview

Carbohydrates provide the primary source of energy through glycolysis and the Krebs cycle.

Essential amino acids are crucial as the body cannot synthesize them; they must be obtained from dietary protein.

Minerals act as cofactors for enzymes, facilitating biochemical reactions essential for metabolism.

<p>Vitamins often function as coenzymes, enhancing the activity of enzymes in metabolic pathways.</p> Signup and view all the answers

<p>Lipids are primarily sourced from animal products (saturated fats) and plant sources like nuts and oils (unsaturated fats).</p> Signup and view all the answers

<p>Complete proteins, from animal sources, contain all essential amino acids, while incomplete proteins, found in legumes, lack some essential amino acids.</p> Signup and view all the answers

<p>Fruits and vegetables are rich in vitamins that serve as coenzymes, vital for various enzymatic reactions.</p> Signup and view all the answers

<p>Foods richest in minerals include vegetables, legumes, milk, and certain meats.</p> Signup and view all the answers

<p>Amino acids are oxidized to form ATP mainly when glucose and fats are not available.</p> Signup and view all the answers

<p>The liver detoxifies ammonia by combining it with carbon dioxide to form urea.</p> Signup and view all the answers

<p>Functional proteins include enzymes and antibodies, while structural proteins consist of connective tissue fibers and muscle proteins.</p> Signup and view all the answers

<p>Amino acids are primarily used for ATP formation when other fuel sources, like glucose and fats, are insufficient.</p> Signup and view all the answers

<p>Proteins are digested into amino acids through gastrointestinal digestion.</p> Signup and view all the answers

<p>Fats provide insulation and cushion to protect body organs.</p> Signup and view all the answers

<p>Inadequate essential amino acids can lead to decreased protein synthesis, affecting normal bodily functions.</p> Signup and view all the answers

<p>Proteins are carefully conserved by body cells to maintain structural and functional integrity.</p> Signup and view all the answers

<p>Resident bacteria in the large intestine help digest remaining nutrients and produce vitamin K and some B vitamins.</p> Signup and view all the answers

<p>The presence of feces in the rectum triggers a defecation reflex, relaxing the internal anal sphincter.</p> Signup and view all the answers

<p>The energy value of food is measured in kilocalories (kcal) or Calories (C), which represent the metabolic fuel for ATP production.</p> Signup and view all the answers

<p>The major nutrients are carbohydrates, lipids, proteins, and water; they are crucial for growth, maintenance, and repair of body tissues.</p> Signup and view all the answers

<p>The large intestine exhibits sluggish peristalsis along with frequent haustral contractions and slow, powerful mass movements occurring three to four times daily.</p> Signup and view all the answers

<p>Minerals serve as essential cofactors for enzymes, aiding in various biochemical reactions necessary for metabolism.</p> Signup and view all the answers

<p>Vitamins serve as precursors to coenzymes, which are necessary for the proper functioning of enzymes involved in metabolic pathways.</p> Signup and view all the answers

<p>A balanced diet from the five food groups ensures adequate intake of all necessary nutrients for optimal health.</p> Signup and view all the answers

<p>Submucosal nerve plexus and Myenteric nerve plexus.</p> Signup and view all the answers

<p>Food enters the stomach at the cardioesophageal sphincter.</p> Signup and view all the answers

<p>The stomach is C-shaped and located on the left side of the abdominal cavity.</p> Signup and view all the answers

<p>The pyloric sphincter regulates the emptying of food from the stomach into the small intestine.</p> Signup and view all the answers

<p>The peritoneal cavity consists of structures such as the visceral peritoneum, parietal peritoneum, and ligaments like the falciform ligament.</p> Signup and view all the answers

<p>The peritoneum supports abdominal organs and provides a friction-reducing surface for organ movement.</p> Signup and view all the answers

<p>The diaphragm separates the thoracic cavity from the abdominal cavity and plays a key role in respiration.</p> Signup and view all the answers

<p>The greater omentum serves to insulate and protect the abdominal organs, as well as store fat.</p> Signup and view all the answers

<p>Teeth masticate (chew) food into smaller fragments.</p> Signup and view all the answers

<p>By age 2.</p> Signup and view all the answers

<p>Incisors (cutting), canines (tearing), premolars (grinding), molars (grinding).</p> Signup and view all the answers

<p>Deciduous teeth are replaced by permanent teeth.</p> Signup and view all the answers

<p>Lower central incisors.</p> Signup and view all the answers

<p>Crown and root.</p> Signup and view all the answers

<p>32 teeth, including the wisdom teeth.</p> Signup and view all the answers

<p>Grinding food.</p> Signup and view all the answers

<p>The pylorus acts as a funnel-shaped terminal end that regulates the passage of partially digested food into the duodenum.</p> Signup and view all the answers

<p>The stomach can stretch to hold about 4 liters (1 gallon) of food, facilitating the storage and gradual processing of food during digestion.</p> Signup and view all the answers

<p>The greater curvature is the convex lateral surface, while the lesser curvature is the concave medial surface of the stomach.</p> Signup and view all the answers

<p>Rugae are internal mucosal folds that allow the stomach to expand when full and increase its surface area for digestion.</p> Signup and view all the answers

<p>The lesser omentum connects the liver to the lesser curvature of the stomach, while the greater omentum extends over the abdominal organs for protection and insulation.</p> Signup and view all the answers

<p>The primary regions of the stomach include the cardial region near the heart, the fundus lateral to the cardiac region, the body as the midportion, and the pylorus as the terminal end.</p> Signup and view all the answers

<p>The stomach contains longitudinal, circular, and oblique muscular layers that facilitate churning and mixing of food, aiding in mechanical digestion.</p> Signup and view all the answers

<p>The stomach plays a crucial role in breaking down food both mechanically and chemically, preparing it for absorption in the small intestine.</p> Signup and view all the answers

<p>Pepsin and rennin.</p> Signup and view all the answers

<p>Peristalsis moves food toward the pylorus, while retropulsion forces food back into the stomach.</p> Signup and view all the answers

<p>To regulate the passage of chyme into the small intestine.</p> Signup and view all the answers

<p>Alcohol and aspirin.</p> Signup and view all the answers

<p>Breakdown of double sugars into simple sugars and completion of protein digestion.</p> Signup and view all the answers

<p>Chyme is gradually pushed through the pyloric sphincter into the duodenum.</p> Signup and view all the answers

<p>Grinding vigorously mixes food and prepares it for further digestion.</p> Signup and view all the answers

<p>About 4 to 6 hours.</p> Signup and view all the answers

<p>Feces primarily contains undigested food residues, mucus, bacteria, and water.</p> Signup and view all the answers

<p>Resident bacteria digest remaining nutrients, produce some vitamin K and B vitamins, and release gases.</p> Signup and view all the answers

<p>Defecation is triggered by the presence of feces in the rectum causing the internal anal sphincter to relax, followed by the relaxation of the voluntary external anal sphincter.</p> Signup and view all the answers

<p>Haustral contractions are frequent, sluggish movements, while mass movements are powerful contractions occurring three to four times per day.</p> Signup and view all the answers

<p>The body oxidizes food to transform it into adenosine triphosphate (ATP), which is the chemical energy driving cellular activities.</p> Signup and view all the answers

<p>The major nutrients are carbohydrates, lipids, proteins, and water.</p> Signup and view all the answers

<p>A balanced diet ensures adequate amounts of all needed nutrients for proper body function and health maintenance.</p> Signup and view all the answers

<p>Kilocalories measure the energy value of food, indicating how much energy that food provides to the body.</p> Signup and view all the answers

<p>Amino acids and urea are the main components produced during protein metabolism.</p> Signup and view all the answers

<p>Fats provide cushioning to protect body organs from physical impact.</p> Signup and view all the answers

<p>The liver combines ammonia with carbon dioxide to form urea, detoxifying ammonia.</p> Signup and view all the answers

<p>Amino acids are oxidized to form ATP for energy when other sources are lacking.</p> Signup and view all the answers

<p>Functional proteins (like enzymes and antibodies) and structural proteins (like muscle proteins).</p> Signup and view all the answers

<p>Myelin sheaths are built from fats and serve to insulate nerve fibers for optimal signal transmission.</p> Signup and view all the answers

<p>Ammonia is detoxified in the liver, where it is converted to urea.</p> Signup and view all the answers

<p>Amino acids can be oxidized to produce ATP when carbohydrates and fats are insufficient.</p> Signup and view all the answers

<p>Incisors are primarily used for cutting food.</p> Signup and view all the answers

<p>Deciduous teeth are temporary and replaced by permanent teeth, which are meant to last a lifetime.</p> Signup and view all the answers

<p>Permanent molars generally begin to emerge between the ages of 6 and 13.</p> Signup and view all the answers

<p>Canines are used for tearing and piercing food.</p> Signup and view all the answers

<p>The two major regions of a tooth are the crown and the root.</p> Signup and view all the answers

<p>In a full set of permanent teeth, there are 12 molars.</p> Signup and view all the answers

<p>Premolars are called bicuspids because they typically have two cusps that aid in grinding food.</p> Signup and view all the answers

<p>By the age of two, a child typically has 20 deciduous teeth.</p> Signup and view all the answers

<p>CCK and secretin.</p> Signup and view all the answers

<p>By active transport through cell membranes.</p> Signup and view all the answers

<p>Segmental movements.</p> Signup and view all the answers

<p>To propel food through the digestive tract.</p> Signup and view all the answers

<p>The hepatic portal vein.</p> Signup and view all the answers

<p>Diffusion.</p> Signup and view all the answers

<p>It helps maintain hydration and nutrient concentration for absorption.</p> Signup and view all the answers

<p>It induces the secretion of enzyme-rich pancreatic juice.</p> Signup and view all the answers

<p>Glycerol and short-chain fatty acids.</p> Signup and view all the answers

<p>They are transported via the hepatic portal vein.</p> Signup and view all the answers

<p>Mucosal cells allow food to enter them before transferring it into blood or lymph capillaries.</p> Signup and view all the answers

<p>Defecation is the elimination of indigestible substances from the GI tract as feces.</p> Signup and view all the answers

<p>Absorption involves the transfer of digested nutrients into the bloodstream or lymphatic system.</p> Signup and view all the answers

<p>Saliva aids in lubricating food and contains salivary amylase, which initiates the digestion of starch.</p> Signup and view all the answers

<p>The small intestine is where most nutrient absorption occurs due to its villi and microvilli.</p> Signup and view all the answers

<p>Segmentation refers to the rhythmic contractions that mix food in the small intestine.</p> Signup and view all the answers

<p>The buccal phase is voluntary, occurring in the mouth where food is formed into a bolus and pushed into the pharynx by the tongue.</p> Signup and view all the answers

<p>Mechanical breakdown facilitates digestion and increases the surface area for enzymatic action.</p> Signup and view all the answers

<p>This involuntary phase transports the bolus through the pharynx and esophagus to the stomach via peristalsis.</p> Signup and view all the answers

<p>Water is primarily absorbed in the large intestine, contributing to stool formation.</p> Signup and view all the answers

<p>The cardioesophageal sphincter opens when food presses against it, allowing the bolus to enter the stomach.</p> Signup and view all the answers

<p>Chewing physically breaks down food into smaller pieces, increasing the surface area for enzymes to act upon.</p> Signup and view all the answers

<p>Absorption does not occur in the mouth because its primary functions are ingestion and mechanical breakdown of food, rather than nutrient uptake.</p> Signup and view all the answers

<p>The body blocks the nasal passages and respiratory pathways to ensure safe swallowing and prevent aspiration.</p> Signup and view all the answers

<p>Saliva is released in response to mechanical pressure of chewing and psychic stimuli such as the sight or smell of food.</p> Signup and view all the answers

<p>It prevents air from entering the esophagus and keeps food from entering the trachea.</p> Signup and view all the answers

<p>Gastrin triggers the production of protein-digesting enzymes, mucus, and hydrochloric acid in the stomach.</p> Signup and view all the answers

<p>Pepsinogen is activated into pepsin by the acidic pH created by hydrochloric acid in the stomach.</p> Signup and view all the answers

<p>Hydrochloric acid creates an acidic environment essential for activating digestive enzymes and killing harmful microorganisms.</p> Signup and view all the answers

<p>The epiglottis covers the glottis to prevent food from entering the trachea and directs it into the esophagus.</p> Signup and view all the answers

<p>The cardioesophageal sphincter relaxes to allow the bolus of food to enter the stomach from the esophagus.</p> Signup and view all the answers

<p>The presence of food raises the pH, leading to the release of gastrin, which then decreases the pH through acid production.</p> Signup and view all the answers

<p>A hostile environment in the stomach helps activate digestive enzymes and inhibits the growth of harmful microorganisms.</p> Signup and view all the answers

<p>LDLs transport cholesterol to body cells and are considered 'bad' due to atherosclerosis risk, while HDLs carry cholesterol from cells to the liver for breakdown and are deemed 'good.'</p> Signup and view all the answers

<p>Body weight remains stable when energy intake equals energy output, ensuring no excess energy is stored.</p> Signup and view all the answers

<p>Fats yield 9 kcal/gram, while carbohydrates and proteins yield 4 kcal/gram each.</p> Signup and view all the answers

<p>The levels of nutrients in the blood and certain hormones can regulate food intake.</p> Signup and view all the answers

<p>Interference can lead to obesity and malnutrition, causing various health issues.</p> Signup and view all the answers

<p>Energy is produced during glycolysis, the citric acid cycle, and the electron transport chain.</p> Signup and view all the answers

<p>Lipoproteins, like LDLs and HDLs, facilitate the transport of cholesterol since it cannot circulate freely in the bloodstream.</p> Signup and view all the answers

<p>LDLs are termed 'bad' because their accumulation can lead to atherosclerosis, increasing cardiovascular disease risk.</p> Signup and view all the answers

<p>The pancreas produces digestive enzymes that break down food and secretes hormones like insulin and glucagon that regulate blood sugar levels.</p> Signup and view all the answers

<p>The pancreas secretes alkaline fluid along with digestive enzymes to neutralize the acidic chyme that enters the duodenum from the stomach.</p> Signup and view all the answers

<p>The two primary hormones are insulin, which lowers blood sugar levels, and glucagon, which raises blood sugar levels.</p> Signup and view all the answers

<p>The pancreas is significant because it produces a wide range of digestive enzymes that are essential for breaking down carbohydrates, proteins, and fats.</p> Signup and view all the answers

<p>The pancreas is located on the right side of the body under the diaphragm, consisting of four lobes held by the falciform ligament.</p> Signup and view all the answers

<p>The falciform ligament anchors the liver to the anterior abdominal wall and the diaphragm.</p> Signup and view all the answers

<p>The greater omentum hangs down from the greater curvature of the stomach and extends to cover the intestines, providing insulation and immune defense.</p> Signup and view all the answers

<p>Mesenteries support the small intestine by anchoring it to the posterior abdominal wall and containing blood vessels and nerves.</p> Signup and view all the answers

<p>The visceral peritoneum covers and protects the abdominal organs while facilitating movement within the abdominal cavity.</p> Signup and view all the answers

<p>The diaphragm contracts and flattens during inhalation, increasing the thoracic cavity's volume and helping to draw air into the lungs while also impacting abdominal pressure.</p> Signup and view all the answers

<p>The two primary nerve plexuses are the submucosal nerve plexus and the myenteric nerve plexus.</p> Signup and view all the answers

<p>The cardioesophageal sphincter prevents backflow into the esophagus.</p> Signup and view all the answers

<p>The pyloric sphincter controls the passage of food from the stomach into the small intestine.</p> Signup and view all the answers

<p>The stomach's ability to stretch is facilitated by its rugae, which are folds in the stomach lining.</p> Signup and view all the answers

<p>The greater omentum stores fat and provides insulation while the lesser omentum connects the stomach to the liver.</p> Signup and view all the answers

<p>The intrinsic nerve plexuses, specifically the submucosal and myenteric plexuses, are crucial.</p> Signup and view all the answers

<p>The stomach is C-shaped and located on the left side of the abdominal cavity.</p> Signup and view all the answers

<p>The visceral peritoneum covers abdominal organs, while the parietal peritoneum lines the abdominal wall.</p> Signup and view all the answers

<p>Bile contains bile salts, bile pigments (mainly bilirubin), cholesterol, phospholipids, and electrolytes.</p> Signup and view all the answers

<p>The cystic duct allows the bile to flow back to the gallbladder for storage when digestion is not occurring.</p> Signup and view all the answers

<p>The gallbladder contracts and spurts out stored bile into the duodenum to aid in fat digestion.</p> Signup and view all the answers

<p>Bile leaves the liver via the common hepatic duct, travels through the bile duct, and enters the duodenum.</p> Signup and view all the answers

<p>Bile emulsifies fats, breaking them down into smaller droplets for easier digestion by enzymes.</p> Signup and view all the answers

<p>Bile is concentrated in the gallbladder through the removal of water.</p> Signup and view all the answers

<p>The right and left hepatic ducts converge to form the common hepatic duct, which transports bile from the liver.</p> Signup and view all the answers

<p>Bilirubin is a bile pigment derived from the breakdown of hemoglobin and is a key component of bile.</p> Signup and view all the answers

<p>Pepsin is the enzyme that primarily digests proteins in the stomach.</p> Signup and view all the answers

<p>The pylorus acts as a pump that meters out chyme into the small intestine.</p> Signup and view all the answers

<p>Alcohol and aspirin are virtually the only substances absorbed in the stomach.</p> Signup and view all the answers

<p>The stomach typically empties its contents in 4 to 6 hours.</p> Signup and view all the answers

<p>This process is called retropulsion.</p> Signup and view all the answers

<p>Intestinal enzymes break down double sugars into simple sugars and complete some protein digestion.</p> Signup and view all the answers

<p>Rennin is the enzyme that digests milk protein in infants.</p> Signup and view all the answers

<p>The stomach has muscular layers and rugae that allow it to stretch.</p> Signup and view all the answers

<p>About 60 to 72 kcal/hour.</p> Signup and view all the answers

<p>Surface area; a smaller body typically has a higher BMR because of a higher heat loss relative to body mass.</p> Signup and view all the answers

<p>Higher levels of thyroxine result in a higher metabolic rate.</p> Signup and view all the answers

<p>TMR is the total kilocalories the body must consume, and it must equal the calories consumed to maintain homeostasis.</p> Signup and view all the answers

<p>Through the radiation of heat from the skin and the evaporation of sweat.</p> Signup and view all the answers

<p>The hypothalamus; it initiates mechanisms to maintain body temperature through heat loss or heat-promoting methods.</p> Signup and view all the answers

<p>Between 35.6ºC and 37.8ºC (96ºF and 100ºF).</p> Signup and view all the answers

<p>Muscle activity dramatically increases the total metabolic rate.</p> Signup and view all the answers