Ch 3 - The Human Body: Are We Really What We Eat? Flashcards
Cell
The smallest unit of matter that exhibits the properties of living things, such as growth, reproduction, and metabolism.
Enterocytes
The cells lining the wall of the intestine.
Cell membrane
The boundary of an animal cell that separates its internal cytoplasm and organelles from the external environment.
Cytoplasm
The interior of an animal cell, not including its nucleus.
Organelle
A tiny “organ” within a cell that performs a discrete function necessary to the cell.
Tissue
A grouping of like cells that performs a function; for ex: muscle tissue.
Organ
A body structure composed of 2/more tissues and performing a specific function; for ex: the esophagus.
System
A group of organs that work together to perform a unique function; for ex: the gastrointestinal system.
Hunger
A physiological drive for food
Anorexia
An absence of appetite
Hypothalamus
A region of the forebrain above the pituitary gland, where visceral sensations, such as hunger and thirst are regulated.
Hormone
A chemical messenger secreted into the bloodstream by one of the many glands from the body, which acts as a regulator of physiological processes at a site remote from the gland that secreted it.
Digestion
The process by which foods are broken down into their component molecules, either mechanically or chemically.
Absorption
The physiological process by which molecules of food are taken form the gastrointestinal tract into the circulation.
Elimination
The process by which undigested portions of food and waste products are removed from the body.
Gastrointestinal (GI) tract
A long, muscular tube consisting of several organs: the mouth, esophagus, stomach, small intestine, and large intestine.
Sphincter
A tight ring of muscle separating some of the organs of the GI tract and opening in response to nerve signal indicating that food is ready to pass into the next section.
Cephalic phase
The earliest phase of digestion, in which the brain thinks about and prepares the digestive organs for the consumption of food.
Saliva
A mixture of water, mucus, enzymes, and other chemicals that moistens the mouth and food, binds food particles together, and begin the digestion of carbohydrates.
Salivary glands
A group of glands found under and behind the tongue and beneath the jaw that release saliva continually as well as in response to the thought, sight, smell, or presence of food.
Enzyme
Small chemicals, usually proteins, that act on other chemicals to speed up body processes but are not apparently changed during those processes.
Bolus
A mass of food that has been chewed and moistened in the mouth.
Esophagus
A muscular tube of the GI, tract connecting the back of the mouth to the stomach.
Peristalsis
Waves of squeezing and pushing contractions that move food in one direction through the length of the GI tract.
Stomach
A J-shaped organ where food is partially digested, chumed, and stored until it is released into the small intestine.
Gastric juice
Acidic liquid secreted within the stomach; it contains hydrochloric acid and other compounds.
Denature
The action of the unfolding of proteins in the stomach. Proteins must be denatured before they can be digested.
Chyme
A semifluid mass consisting of partially digested food, water, and gastric juice.
Small intestine
The longest portion of the GI tract, where most digestion and absorption take place.
Gallbladder
A sac-like accessory organ of digestion, which lies beneath the liver; it stores bile and secretes it into the small intestine.
Bile
Fluid produced by the liver and stored in the gallbladder; it emulsifies fats in the small intestine.
Pancreas
An accessory organ of digestion located behind the stomach; it secretes digestive enzymes as well as hormones that help regulate blood glucose.
Lacteal
A small lymph vessel located inside the villi of the small intestine.
Brush border
The microvilli projecting from the membrane of enterocytes of the small intestine’s villi. These microvilli tremendously increase the small intestine’s absorptive capacity.
Liver
The largest accessory organ of digestion and one of the most important organs of the body. Its functions include the production of bile and the processing of nutrient-rich blood from the small intestine.
Large intestine
The final organ of the GI tract, consisting of the cecum, colon, rectum, and anal canal and in which most water is absorbed and feces are formed.
Enteric nervous system (ENS)
The autonomic nerves in the walls of the GI tract.
Heartburn
A painful sensation that occurs over the sternum when gastric juice pools in the lower esophagus.
Gastroesophageal reflux disease (GERD)
A chronic disease in which episodes of gastroesophageal reflux cause heartburn or other symptoms more than twice per week.
Peptic ulcer
An area of the GI tract that has been eroded away by the acidic gastric juice or the stomach.
Vomiting
The involuntary expulsion of the contents of the stomach and duodenum from the mouth.
Diarrhea
A condition characterized by the frequent passage of loose, watery stools.
Constipation
Absence of bowel movements for a period of time that is significantly longer than normal for the individual. When a bowel movement does occur, stools are usually small, hard, and difficult to pass.
Irritated bowel syndrome (IBS)
A bowel disorder that interferes with normal functions of the colon.
Food intolerance
Gastrointestinal discomfort caused by a certain foods that is not a result of an immune system reaction.
Lactose intolerance
A disorder in which the body does not produce enough lactase enzyme to break down the sugar lactose, which is found in milk and milk products.
Food allergy
An inflammatory reaction to food caused by an immune system hypersensitivity.
Celiac disease
An autoimmune disorder characterized by an inability to absorb a component of gluten called gliadin. This causes an inflammatory immune response that damages the lining of the small intestine.
Satiety
A physiologic sensation of fullness
