Tissues: systems of cells working together to perform specialized tasks. Ex muscles, nerves, blood

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1 Chapter 3 Cells: the smallest units in which independent life can exist. All living things are single cells or organisms made of cells. Need water and nutrients to survive Enzyme: any of the great working proteins that speed up specific chemical reaction, such as breaking the bonds of a nutrient, without undergoing change themselves. Fat cells: cells that specialize in the storage of fat and form the fat tissue. Fat cells also produce enzymes that metabolize fat and hormones involved in appetite and energy balance Cell: each cell contains a complete set of genes but different ones are active in different types of cells. Genes affect the body s handling of nutrients Nutritional Genomics: the science of how nutrients affect the activities of genes and how genes affect the activities of nutrients. Also called molecular nutrition or nutrigenomics Tissues: systems of cells working together to perform specialized tasks. Ex muscles, nerves, blood Organs: discrete structural units made of tissues that perform specific jobs. Ex the heart Body system: a group of related organs that work together to perform a function ex. Circulatory system Lymph: the fluid that moves from the bloodstream into tissue spaces and then travels in it own vessel, which eventually drain back into the bloodstream Blood: the fluid of the cardiovascular system; composed of water, red and white blood cells, other formed particles, nutrients, oxygen and other constituents Veins: blood vessels that carry blood, with the carbon dioxide it has collected, from the tissues back to the heart Arteries: blood vessels that carry blood containing fresh oxygen supplies to from the heart to the tissues Capillaries: minute, weblike blood vessels that connect arteries to veins amd permit transfer of materials between blood and tissues Plasma: the cell-free fluid part of blood and lymph Extra-cellular fluid: fluid residing outside cells that transport materials to and from the cells Intracellular Fluid: fluid residing inside the cells that provides the medium for cellular reactions Lungs: the body s organs of gas exchange. Blood circulating through the lungs releases its carbon dioxide and picks up fresh oxygen to carry to the tissues Intestine: the body s long tubular organ of digestions and the sites of nutrients

2 Liver: a large, lobed organ that lies just under the ribs. It filters the blood, removes and processes nutrients, manufactures materials for export to other parts of the body, destroys toxins or stores them to keep them out of the circulation, and excretes fat-soluble waste products into the small intestine Kidneys: a pair of organs that filter wastes from the blood, makes urine and release it to the bladder for excretion from the body Hormones: chemicals that are secreted by the glands into the blood in response to conditions in the body that require regulation. These chemicals serve as messengers, acting on other organs to maintain constant conditions Pancreas: an organ with 2 functions; endocrine function (the making of hormones) and exocrine function (making of digestive enzymes) Insulin: a hormone from the pancreas that helps glucose enter the cells from the blood Glucagon: a hormone from the pancreas that stimulates the liver to release glucose into the bloodstream when blood glucose concentration dips Cortex: the outermost layer of something. The brain s cortex is the part of the brain where conscious thought takes place Hypothalamus: a part of the brain that senses a variety of conditions in the blood such as temperature, glucose and salt. It signals other parts of the brain or body to adjust those conditions Flight-or-fight response: the body s instinctive hormone- an nerve-mediated reaction to danger. Neurotransmitters: chemicals that are released at the end of a nerve cell when a nerve impulses arrives there. Diffuse across the gap to the next cell Epinephrine: the major hormone that elicits the stress response Norepinephrine: a compound related to epinephrine that helps elicit the stress response Metabolism: sum of physical and chemical changes taking place in living cells Microbes (micro-organisms): bacteria, viruses or other organisms invisible to the naked eye which can cause diseases Antigen: a microbe or substance that is foreign to the body Immune System: system of tissues and organs that defend the body against antigens, foreign materials that have gotten into the body Lymphocytes: white blood cells that help in immune response; b-cells and t-cells

3 Phagocytes: white blood cells that ingest and destroy antigens. This process is called phagocytosis T-cells: attack antigens; T refers to the thalamus gland where the T-cells are stored and matured B-cells: lymphocytes that produce antibodies; B refers to the bursa organ in the chicken where B-cells were first identified Antibodies: proteins, made by cells of the immune systems, that are expressly designed to combine with and inactivate specific antigens Grehlin: a hormone secreted by the stomach that is thought to be the hunger hormone Digestive system: system composed of organs that break down complex food particles into smaller, absorbable products. Called the gastrointestinal or GI system Digest: to break down molecules to smaller molecules; main function of the digestive system Absorb: to take in; main function of digestive tract with respect to nutrients Peristalsis: the wavelike muscular squeezing of the esophagus, stomach and intestine that pushes their contents along Segmentation: alternating forward and backward movement that allows for greater contact between the partially digested food and intestinal juices and enzymes; results in greater and more complete digestion Stomach: muscular, elastic, pouch-like organ, of the digestive tract that breaks down swallowed food with acid Sphincter: circular muscle surrounding and able to close a body opening Chyme: fluid resulting from the action of the stomach upon a meal Pyloric valve: circular muscle of the lower stomach that regulates the flow of partly digested food into small intestine Small intestine: 7m length, major site of digestion of food and absorption of nutrients Large intestine (colon): portion of the intestine that completes the absorption process Feces: waste material remaining after digestion and absorption is complete; is discharged Gastric Juice: the digestive secretion of the stomach ph: a measure of acidity on a point scale. 1 is strong acid, 7 neutral, 14 strong base Mucus: slippery coating of the digestive tract lining that protects the cells from exposure to digestive juices

4 Bile: cholesterol-containing digestive fluid made by the liver, stored in the gall bladder and release into the small intestine; emulsifies fats and oils so they can be digestion Emulsifier: a compound with both water-soluble and fat-soluble portions that can attract fats and oils into water combining them Pancreatic juice: fluid secreted by pancreas; contains enzymes and proteins to digest carbs, fat and proteins and sodium bicarbonate Bicarbonate: a secretion of the pancreas Villi: finger-like projections of the sheets of cells that line intestinal tract. Make surface area greater than it would be Microvilli: tiny, hair-like projections on each cell of every villus to expand surface area therefore increasing more nutrient particles and absorbing more Hiccups: spasm of vocal cords and diaphragm causing audible short inhaled coughs. Caused by irritation of diaphragm, indigestion, etc. Resolve itself in a few minutes but prolonged hiccups may have serious effects. Breathing into paper bag/ teaspoon of school may help them Heartburn: burning sensation in the chest caused by backflow of stomach acid into esophagus Antacids: meds that react with stomach acid immediately. Treat heartburn by neutralizing Acid reducers: drugs that reduce the acid output of the stomach. Treats persistent heart burn but not if a neutralizing acid is already present. Side effects: diarrhea, GI complications, reduction of stomachs ability to destroy alcohol Ulcer: erosion in topmost/ sometimes underlying layers of cells that for a lining. Commonly found in digestive tract at the esophagus, stomach and upper small intestine Hernia: protrusion of an organ or part of organ through the wall of body chamber that contain the organ. i.e hiatal hernia is when stomach protrudes through diaphragm into chest cavity Gastroesophageal reflux disease (GERD): severe chronic splashing of stomach acid and enzymes into the esophagus, throat, mouth or airway that causes injury or inflammation. Leads to a higher risk of esophageal cancer. May require surgery or medication Constipation: infrequent, difficult bowel movement. Causes: diet, inactivity, dehydration, medication Diarrhea: frequent, watery bowel movement. Causes: diet, stress, irritation of colon. Severe or prolonged diarrhea robs body of fluids or minerals Irritable Bowel Syndrome: intermittent disturbance of bowel function, alternating periods of diarrhea and constipation. Linked to diet, inactivity and stress Nephrons: working units in the kidneys (intermeshed blood vessels and tubules)

5 Bladder: sac that holds urine until time for elimination Glycogen: storage form of carb energy (glucose) Adipose Tissue: body s fat tissue consisting of masses of fat-storing cells and blood vessels to nourish them