Chapter 3 Flashcards
Which of our senses influence eating?
Sight, smells, taste, texture, sound
Distinguish between appetite, satiety, anorexia and hunger.
Appetite- psychological desire to consume specific foods Anorexia-absence of appetite Hunger-physiologic sensation that prompts us to eat
Identify the region of the brain and body that is responsible for regulating hunger and thirst.
Hypothalamus
What is a hormone?
a regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action.
What is an enzyme?
a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.
How do the different macronutrients affect hunger & satiety?
x
What are the parts of a Cell?
x
Describe the structure of the human body from the atom to each of the systems.
Atoms
Molecules
Calls
Tissues
Organs
Organ systems,
Organisms
What are the 3 digestive processes associated with food in the human body?
Digestion
Absorbtion
Elimination
What are the functions of saliva?
The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach.
Identify the parts of the gastrointestinal tract, including all major and accessory organs.
The organs of the digestive system are classified into two parts:
- Gastrointestinal organs: stomach, small and large intestines, esophagus…basically organs that run the food from point of ingestion to defecation.
- Accessory organs: organs such as the gallbladder and the pancreas. These organs generally help with chemical digestion by secreting enzymes to catalyse the breakdown of food.
Describe the role of each of the following in digestion: Mouth
Cephalic phase-Brain thinks about and prepares the digestive organs for the consumption of food
Chewing
Saliva
Describe the role of each of the following in digestion: Esophagus
Propels food into the stomach
Bolus- chewed moistened mass
Describe the role of each of the following in digestion: Stomach
The stomach is a muscular, hollow, dilated part of the digestion system which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects (mid-gut), and molluscs. It is involved in the second phase of digestion, following mastication (chewing).
The stomach is located between the esophagus and the small intestine. It secretes protein-digesting enzymes called proteases and strong acids to aid in food digestion, (sent to it via esophageal peristalsis) through smooth muscular contortions (called segmentation) before sending partially digested food (chyme) to the small intestines.
Describe the role of each of the following in digestion: Small Intestine
is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. The small intestine is composed of a duodenum, jejunum, and ileum. It receives bile juice and pancreatic juice through the hepatopancreatic duct, controlled by Sphincter of oddi. The primary function of the small intestine is the absorption of nutrients and minerals found in food
Describe the role of each of the following in digestion: Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion.
This gland plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, hormone production, and detoxification. It lies below the diaphragm in the abdominal-pelvic region of the abdomen. It produces bile, an alkaline compound which aids in digestion via the emulsification of lipids. The liver’s highly specialized tissues regulate a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex molecules, many of which are necessary for normal vital functions.
Describe the role of each of the following in digestion: Gall bladder
is a small organ where bile is stored, before it is released into the small intestine. Humans can live normal lives without a gallbladder.
Describe the role of each of the following in digestion: Bile
dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the digestion of lipids in the small intestine. In many species, bile is stored in the gallbladder and, when the organism eats, is discharged into the duodenum.
Describe the role of each of the following in digestion: Pancreas
glandular organ in the digestive system and endocrine system of vertebrates. It is an endocrine gland producing several important hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide which circulate in the blood. The pancreas is also a digestive organ, secreting pancreatic juice containing digestive enzymes that assist digestion and absorption of nutrients in the small intestine. These enzymes help to further break down the carbohydrates, proteins, and lipids in the chyme.
Describe the role of each of the following in digestion: Large intestine
is the last part of the digestive system in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body
Describe the role of each of the following in digestion: Hormones
Stomach: Pepsin is an enzyme used to partially hydrolyze protein. Pepsin is released in an inactive form PEPSINOGEN. The pepsinogen reacts with HCl to form pepsin.
The hormone GASTRIN is secreted by the stomach cells to regulate the production of gastric juices.
Small Intestine: It is divided into 3 sections ( Duodenum, Jejunum, and ileum). Accessory Organs ( Pancreas, Liver, and Gall Bladder), add digestive enzymes, juices and hormones into the small intestine. As the acid chyme enters the duodenum (first 25 cm of the small intestine) a hormone called SECRETIN is released from the intestinal walls to siginal the pancreas to release a bicarbonate solution which neutralizes the acid.
The hormone CHOLECYSTOKININ (CCK), is released from the intestinal cells causing the gall bladder to release bile. It also causes the pancreas to release its digestive enzymes. The hormone ENTEROGESTRONE is also secreted to slow down peristalsis. Protein Digestion: Trypsin and Chymotrypsin are enzymes that break bonds next to specific amino acids. Carboxypeptidase splits off one amino acid at a time.
This enzyme works on the end with the free carboxyl group. Aminopeptidase works in the opposite direction. All the above enzymes are secreted in an inactive form. They are activated by the hormone ENTEROKINASE. Fat Digestion: Bile emulsifies fat. This creates a larger surface area for the enzyme lipase to digest it. Carbohydrate Digestion: Disaccharide digestion is under the control of the enzymes maltase, lactase, sucrase.
Describe the role of each of the following in digestion: Peristalsis
contraction and relaxation of muscles which propagates in a wave down a muscular tube, in an anterograde fashion. Peristalsis is often found in the contraction of smooth muscle tissue to propel food/chyme through a digestive tract, such as the human gastrointestinal tract. It is wave contraction of longitudinal and circular muscles preceded by wave relaxation of these muscles.
Describe the role of each of the following in digestion: gastro-esophageal sphincter and pyloric sphincter
gastroesophageal sphincter - a ring of smooth muscle fibers connecting the esophagus and stomach.
pyloric sphincter - A ring of smooth muscle fibers around the opening of the stomach into the duodenum.
Describe the role of each of the following in digestion: Mucus and Hydrochloric acid
Mucus - is a slippery secretion produced by, and covering, mucous membranes.
HCl breaks down fats, and emulsifies food
Describe the role of each of the following in digestion: Chyme
is the semifluid mass of partly digested food expelled by the stomach into the duodenum.
Describe the role of bicarbonate in the small intestine.
Bicarbonate’s main role is to help neutralize the very acidic contents coming out of the stomach and into the small intestine. This serves a protective role to help protect the lining of the small intestine from being eaten away aswell as a functional one – the digestive enzymes at work in the small intestine operate better at a higher pH (less acidic).
What does lymph do relative to food digestion?
Pics up most fats, fat-soluble vitamins, and fluids that have excaped from the cardiovascular system, and transport them to the lymph. The lymph filters and destroys harmful microbs
Identify the two pancreatic hormones responsible for maintaining blood glucose levels.
insulin will lower your sugar, glucagon will raise it.
Where does most digestion and absorption take place?
The greatest amount of digestion occurs in the upper portion of the small intestine called the duodenum. The small intestine is also where about 95% of nutrients are absorbed.
What are Heartburn and gastro-esophageal reflux disease (GERD)
Heartburn (GER)- a painful sensation that occurs over the sternum when HCl back up into the lower esophagus GERD-a more painful type of GER that occurs more than 2x per week
What causes ulcers?
The bacteria H. pylori,
Describe Food allergies vs intolerances?
Allergy - Inflamitory reaction caused by an immune system hypersensitivity Intolerance-gastrointestinal discomfort caused by certain foods that is not a result of an immune systems reaction
What is Celiac disease?
a disease in which the small intestine is hypersensitive to gluten, leading to difficulty in digesting food. Autoimune
