Exam 2 Study Guide
Exam 2 Study Guide BIO 123
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This 10 page Study Guide was uploaded by Andrea Yip on Thursday March 3, 2016. The Study Guide belongs to BIO 123 at Syracuse University taught by Jason Wiles in Winter 2016. Since its upload, it has received 82 views. For similar materials see General Biology II in Biology at Syracuse University.
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Date Created: 03/03/16
Exam 2 Study Guide 1 Basic tissue types: Epithelial, Muscle, Connective and Nervous. Epithelial tissue (epithelium) A continuous layer (sheet) of cells covering a body surface/lining a body cavity. functions in protection, absorption, secretion, or sensation. In both invertebrates and vertebrates protects underlying tissues with specialized sensory or respiratory functions Outer epithelium specialized to secrete lubricants/adhesives and odorous/poisonous substances. Epithelial tissue in invertebrates: cuticle is a protective shell secreted by outer epithelium. Stratified epithelium would be found covering a surface subject to physical forces. Simple columnar epithelium is found in the intestines and absorbs nutrients. Simple squamous epithelium is found in the lungs and permits gas exchange by diffusion. Simple cuboidal cells are the type of epithelial tissue lining the kidney tubules. Connective Tissue Relatively few cells separated by intercellular substance. Fibers scattered throughout a matrix, which generally consists of a web of fibers embedded in a liquid, jellylike or solid foundation. Collagenous fibers, reticular fibers and elastic fibers are the three types of fibers found within the matrix. Differs from other 3 major tissue types in that it often consists of relatively few cells embedded in an extracellular matrix. Blood is the connective tissue specialized for transport. It has a liquid matrix. Bone is an example of connective tissue that has a solid matrix. Adipose tissue and cartilage are examples of connective tissue that have a more jellylike matrix. Intercellular substance fibers: collagen fibers elastic fibers reticular fibers Contains specialized cells such as fibroblasts and microphages Functions: Joins other body tissues Supports body and organs Protects underlying organs Muscle Tissue Consists of cells specialized to contract Each cell is an elongated muscle fiber (many contractile units; myofibrils) Smooth muscle is responsible for contractions of the digestive tract and arteries. Cardiac muscle is the only muscle composed of branched fibers. Nervous Tissue Neurons are elongated cells specialized for transmitting impulses. They consist if dendrites, a cell body and axons. Glial cells support and nourish neurons. Nervous tissue functions to sense stimuli. Organ Systems: Integumentary, Skeletal, Muscular, Digestive, Cardiovascular, Immune (lymphatic), Respiratory, Urinary, Nervous, Endocrine, Reproductive System Consists of: Function(s) Integumentary Skin and structures Protect body derived from it Regulate body temperature Receives stimuli Skeletal Bones and cartilage Support and protect body Muscular Large skeletal muscles, Movement, heart, internal cardiac muscle, internal organs organs Digestive Digestive tract and Mechanically and glands that secrete systematically breaks digestive juices into down food digestive tract Functions in nutrient absorption Eliminates wastes Cardiovascular Heart and blood vessels Transport materials throughout the body Immune Thymus, thoracic duct, Returns excess tissue fluid lymph node, spleen, to blood and defends lymph vessels against disease Respiratory Lung and air Supplies oxygen to blood passageways and excretes carbon dioxide. Urinary Kidney, ureter, urinary Main excretory system bladder, urethra Helps regulate blood chemistry (kidneys remove waste from blood and produce urine) Nervous Brain, spinal cord, sense Principal regulatory organ organs, nerves Endocrine Ductless glands that release Works with nervous system hormones in regulating metabolic activities Reproductive Gonads and associated Maintains secual structures characteristics and passes on genes to next generation Homeostasis is a balanced internal environment (steady state) Homeostatic mechanisms control processes that maintain conditions. Negative feedback- a stressor causes deviation from set point, sensor detects deviation and signals integrator (control center) which activated effectors (homeostatic mechanisms) so normal condition (set point) is restored. In positive feedback, deviation from steady state causes changes that intensify (rather than reverse) the changes. Thermoregulation is the process of maintaining body temperature with certain limits despite changes in surrounding temperature. It relies on negative feedback. In mammals the temperature control system is located in the hypothalamus. When cells in the hypothalamus detect a body temperature below the normal range, the hypothalamus will activate mechanisms such as vasoconstriction. When cells in the hypothalamus detect a body temperature above normal range, the thermostat activates mechanisms such as vasodilation. Animals have different structural, behavioral and physiological strategies. Animals can be described according to whether they maintain a relatively constant body temperature (homeothermic) or allow the body temperature to fluctuate with the environment (poikilothermic). Metabolic rate is the total amount of energy an animal uses in a unit of time. Small mammals have lower BMR (basal metabolic rate), but use more calories per kilogram than large mammals. In ectotherms, body temperature depends on the temperature of the environment. Use behavioral strategies to adjust body temperatures. They are more abundant and diverse than endotherms. Benefits very little energy used to maintain the metabolic rate can survive on less food Disadvantage activity limited by daily and seasonal temperature conditions Endotherms have homeostatic mechanisms. Regulate body temperature within a narrow range. Benefits High metabolic rate Constant body temperature allows higher rate of enzyme activity Active even in low winter temperatures Disadvantage: High energy cost Feathers of birds and hair mammals form insulating layer that helps maintain constant body temperature. Mammalian skin includes hair, claws or nails, sweat glands, oil glands, sensory receptors. Epidermis Protects body from outer environment Stratum corneum is the most superficial layer that consists of dead cells filled with keratin (insoluble protein that gives mechanical strength to skin and reduces water loss) Stratum basale cells divide, are pushed up to skin surface. cells mature, flatten, produce keratin, eventually die and slough off. Dermis Consists of dense, fibrous connective tissue Rests on layer of subcutaneous tissue composed largely of insulating fat. Food Processing Feeding: selection, acquisition and ingestion of food. Digestion: breaking down food mechanically, chemically. Absorption: nutrients pass from digestive tract into blood. Egestion (elimination): undigested, unabsorbed food is discharged. Cnidarians and flatworms digest food in gastrovascular cavity. Only one opening that serves both as mouth and anus. An alimentary canal has two openings and moves food unidirectionally. Carbohydrates Most are ingested as polysaccharides (starch and cellulose) Used mainly as energy source Glucose concentration in blood is carefully regulated. Excess glucose is stored as glycogen. Polysaccharides are complex carbohydrates. Fiber is a mixture of cellulose, other indigestible carbohydrates. Your small intestine can absorb fructoses without their being further digested because it is a monosaccharide and monosaccharides can be absorbed without having to be broken down into smaller units. Starch can be broken down into the disaccharide known as maltose. Fats Lipids are used to provide energy, form components of cell membranes and synthesize steroid hormones, other lipid substances. A fat molecule is composed of two types of smaller molecules, including only one molecule of glycerol. A fat molecule also includes one, two or three fatty acid molecules. A fat molecule with only one fatty acid is called a monoglyceride, one with three fatty acids is called a triglyceride. A fatty acid includes a carboxyl group at one end as well as a long hydrocarbon chain. These chains found in fats store a lot of inert and make fats hydrophobic. The absorption of fats from the small intestine requires a series of steps: In the lumen of the small intestine, bile salts keep fat droplets small. With more surface area exposed, lipase is able to break down triglycerides into smaller molecules of monoglycerides and fatty acids in order to facilitate absorption by epithelial cells. Monoglycerides and fatty acids diffuse into epithelial cells, where they are assembled back into triglycerides. The triglycerides are then coated with phospholipids, cholesterol, and proteins to form structures called chylomicrons. Chylomicrons leave epithelial cells via exocytosis, move into lacteals and enter the bloodstream. Fats, fatty acids and monoglycerides are hydrophobic. Chylomicrons have a hydrophilic surface. Fat digestion is not complete until pancreatic lipase finalizes fat digestion in the small intestine. Proteins Serve as enzymes and essential structural components of cells. Best distribution of essential amino acids in complete proteins of animal foods. Excess amino acids are deaminated by liver cells. Amino groups are converted to urea (excreted in urine). Remaining kept acids are converted to carbohydrate and used as fuel or converted to lipid and stored in fat cells. Vitamins Organic compounds required in small amounts for biochemical processes; components of coenzymes. Folic acid is a vitamin that helps reduce the risk of birth defects such as spina bifida and cleft lip. Vitamin C is involved in the formation of important amino acids and part of the collagen that forms the connective tissues. Lack of this vitamin causes scurvy. The fatsoluble vitamins (A, D, E, K) are not involved as coenzymes, but are involved in important processes such as vision, bone formation, protection from oxidation and blood clotting. The watersoluble (B and C) vitamins act as coenzymes in the body and do not stay bonded to only one enzyme but are used over and over again by many enzymes. Vitamin A is absorbed from some foods in the form of carotene. The vitamin accumulates in the rods and cones of the eyes and plays a role in vision. Minerals Inorganic nutrients ingested as salts, dissolved in food and water. Required in small amounts. (<100 mg/day) The “essential nutrients” for proper human nutrition include calcium, sodium, potassium and other minerals. Human Digestive System Mammalian teeth have incisors for biting, canines for tearing food and premolars&molars for crushing and grinding Three pairs of salivary glands secrete saliva (enzyme salivary amylase digests starch) Salivary glands are not part of the alimentary canal but contribute digestive enzymes to break down food in the mouth. An advantage of having a tubelike digestive tract is that digestive processes with different requirements can be separated within the tract. The main component of gastric juice is water In ruminant animals it is usually true that cellulose digestion occurs before the ingested foods reach the small intestine. Pharynx and esophagus carry food to the stomach Peristalsis: waves of muscular contraction push bolus of food along digestive tract Stomach: mechanical digestion by vigorous churning. Enzyme pepsin in gastric juice digests proteins. Rugae: folds in stomach wall; expand as stomach fills with food. The stomach lining secretes mucus, a mixture of glycoproteins, cells, salts and water. Gastric glands secrete hydrochloric acid and pepsinogen (precursor of pepsin). Hal is responsible for stomach acidity. Chyme: soup of partly digested food leaves the stomach through the pyloric sphincter and enters small intestine in spurs. Duodenum: shortest part of small intestine; location of most enzymatic digestion, produces several digestive enzymes, receives secretions from liver and pancreas. Jejunum is specialized for absorption of small nutrient particles previously digested by enzymes in duodenum Bile is secreted by the liver and acts to emulsify fats in the small intestine. It is stored in the gallbladder until it is secreted into the small intestine. The liver is an accessory organ of digestion and is not part of the actual alimentary canal through which food passes. The liver converts fructose to fat Fat accumulation, insulin resistance and metabolic syndrome lead to heart disease. From the oral cavity, food gives to the pharynx, then to the stomach via the esophagus, then the small intestine and finally the large intestine. The lower esophageal sphincter guards the junction between the esophagus and stomach. If this sphincter failed to properly constricts then there might be a problem with regurgitation of acidic stomach contents into the esophagus, commonly called heartburn. Pancreas produces enzymes (digest protein, lipid, carbohydrate, RNA, DNA) The acidity of the stomach contents trigger the small intestine to secrete secretin, which stimulates the pancreas to secrete bicarbonate to neutralize this acidity. The presence of fatty acids and amino acids in the stomach contents tigers the small intestine to secrete cholecystokinin (CKK) stimulates the pancreas to secrete pancreatic enzymes. Large intestine: (cecum, colon, rectum, anus) eliminates undigested wastes and incubates bacteria (produce vitamin K, certain B vitamins). Surface area of the small intestine is greatly expanded by folds in wall (rugae), intestinal villi (projections of mucosa) and microvilli (plasma membrane projections of epithelial cells of villi). Carbohydrate Digestion Polysaccharides are digested to disaccharide maltose by salivary and pancreatic amylases. Maltase in small intestine splits maltose into glucose (main product of carbohydrate digestion). Mechanical, enzymatic digestion of carbohydrates begins in the mouth Pancreatic amylase digests complex carbohydrates Protein Digestion Protein digestion begins in the stomach Trypsin and chymotrypsin digest polypeptides to dipeptides Proteins are split by pepsin in the stomach and by proteolytic enzymes in pancreatic juice. Dipeptidases split small peptides into amino acids. Lipid Digestion Lipids are emulsified by bile salts then hydrolyzed by pancreatic lipase (degrades fats).
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