Exam 4 study guide
Exam 4 study guide Biol 2230-001
Popular in Human Anatomy & Physiology II
verified elite notetaker
Popular in Biological Sciences
80887 - BIOL 3150 - 001
verified elite notetaker
This 15 page Study Guide was uploaded by Madeline Notetaker on Friday April 1, 2016. The Study Guide belongs to Biol 2230-001 at Clemson University taught by Dr. John Cummings in Spring 2016. Since its upload, it has received 48 views. For similar materials see Human Anatomy & Physiology II in Biological Sciences at Clemson University.
Reviews for Exam 4 study guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/01/16
Digestive Lecture Objectives List the organs of the digestive system, differentiating the alimentary canal organs from the accessory organs. ORGANS: 1. Alimentary canal: continuous, muscular tube; has an entry hole (mouth) exit hole (anus) o Includes mouth, esophagus, intestines, stomach 2. Accessory organs: any organ that is not part of the muscular tube o Ex: teeth, tongue, gallbladder, liver Describe the major actions of the digestive process. Ingestion § There is one site that this action happens- the mouth Propulsion • Deglutition: swallowing; voluntary • Peristalsis: wave like smooth muscle contractions that move food through tube; involuntary Mechanical digestion • The physical breakdown of food o Mastication: chewing (voluntary) o Mixing: tongue mixes food with juices (saliva) § Also have churning/mixing in stomach with juices o Segmentation: move things back and forth which breaks down food because it is being squeezed Chemical digestion • Enzymatic breakdown of food o Is done before absorption begins; begins in mouth but basically completed before small intestines Absorption § Moving nutrients from lumen of alimentary canal into body § Mainly happens in small intestine Defecation § Elimination of waste Describe the mechanisms of control of the digestive process, differentiating short and long reflexes. Sensors: mechanical and chemical sensors that are stimulated/ respond to… o Stretch of stomach o Change in pH o Change in osmolality (concentration) o Presence of specific molecules When stimulated, these sensors initiate the following reflexes… Nerve Plexuses: o Can activate or inhibit glandular secretions, smooth muscle contraction, or the release of hormones § Short reflexes o Intrinsic o The sensor within digestive tract detects stimuli and causes an action within digestive tract § Long reflexes o Extrinsic 1 o Sensor sends a signal that goes out of digestive system (most likely goes to brain) to initiate a response Hormones: chemical messengers that change activity Define mesentery, and discuss its relationship to the peritoneum. Mesentery: double layered peritoneum, visceral layer lines organ and parietal layer lines cavity • Function to anchor abdominal organs to wall of cavity List the four tunics of the digestive tract, and describe their composition and action mucosa Functions in protection, secretion and absorption Made up of epithelial tissue, predominantly goblet cells submucosa Possesses blood vessels, lymph vessels and nerves Made up of dense connective tissue Muscularis externa • Performs peristalsis and segmentation • Smooth muscle with 2 layers o Circular layer- changes diameter o Longitudinal layer- changes length of tube Serosa Same as visceral peritoneum • Called adventitia in the esophagus Describe the enteric nervous system. ENTERIC NEURONS (both are intrinsic plexi within digestive system) § Submucosal o Nerves activate different glandular secretions of mucosa and submucosa § Myenteric o In between 2 layers of muscle (circular and longitudinal) o Involved in motility by stimulating muscle contraction when activated Describe the anatomy and function of each organ (alimentary and accessory) of the digestive system. Oral (Buccal) Cavity • DIGESTIVE ACTIONS= ingestion, propulsion, mechanical digestion, chemical digestion • Palate o Can also be called the roof of the mouth o Tongue uses palate to push against to form bolus and mix food o Uvula shuts off entrance to nasopharynx when we swallow • Tongue o Helps form bolus by using saliva and palate o Papillae § Circumvallate • Large taste buds on back of tongue § Fungiform • Bumps that will provide grip, located all over the tongue’s surface • Salivary Glands o 2 types of tissues within the salivary glands: mucous or serous (secretes enzymes) tissue § Sublingual cells • Located under tongue • Consists of mucous tissue § Parotid cell 2 • Located on sides of face • Consists of serous tissue § Submandibular cell • Located under jaw • Consists of both tissues • Teeth o Involved in mastication o 20 primary teeth and 32 permanent teeth; primary is replaced by permanent o Incisors § Cutting o Cuspids/canines § Piercing o Bicuspids/premolars § Piercing/sheering o Molars § Grinding Tooth structure Crown Tooth above the gumline -rich in enamel Neck The gum or “gingiva” -between crown and root Root Peg and socket joint -embedded in jaw -covered and secured by cementum Pulp Center of tooth -contains blood vessels and nerves Root canal Canal in center of root -contains an extension of the pulp Pharynx • DIGESTIVE ACTIONS: propulsion o Bolus is pushed into the oropharynx after leaving the mouth Larynx • Manipulates pathway/direction of food by using the epiglottis Esophagus • Muscular tube connecting mouth and stomach • DIGESTIVE ACTIONS: propulsion • Physiological sphincters (missing valves, really just constrictions) 1. upper esophageal 2. gastroesophageal Stomach o Muscular storage sac of alimentary canal o DIGESTIVE ACTIONS: propulsion, mechanical digestion, chemical digestion o Breakdown of starch stops when the bolus enters stomach o Breakdown of proteins is activated when the bolus enters the stomach • Sphincters Cardiac Prevents material from entering esophagus Pyloric Regulates movement of material in stomach into the small intestine 3 Discuss the composition and function of saliva § Saliva functions: 1. chemical breakdown 2. dissolve/moisten food 3. cleans mouth § Saliva composition 1. Water 2. Electrolytes 3. Amylase – an enzyme 4. Mucin – a lubricant 5. Lysosome 6. IgA antibodies 7. Metabolic wastes List the cells of the stomach, and identify the functions of each. Stomach cells o Goblet o Mucous neck o Parietal o Chief o Eneteroendocrine (G-cells) Cell Function/Secretion Goblet secrete mucus, collects on the surface of cells and forms a protective barrier Mucus has bicarbonate with it… helps stomach protect itself Mucous neck Located at neck of the gland, produce mucus that’s slightly acidic Helps protect other cells of the stomach from secretions coming from deeper within the pit Parietal Secrete HCl (part of gastric juice- very acidic) and intrinsic factor (super important glycoprotein- enhances B12 absorption in small intestine.. B12 is necessary to produce RBCs ) Chief 2 to most deep layer Produce protein pepsinogen (inactive enzyme) Becomes activated by HCl and turns into pepsin (breaks down proteins) Can also become activated by pepsin (a cascade of activation) Also produce very small amount of lipase (breaks down lipids) Eneteroendocrine (G-cells) often called G cells- because they secrete gastrin) Deepest, at the very bottom of the gland Secrete a hormone called gastrin (regulates stomach activity) 4 Describe the mechanism of deglutition. DEGLUTITION: swallowing 1. Food within the mouth is compacted into a bolus 2. Buccal phase • Voluntary phase • Tip of tongue is placed against the hard palate • Skeletal muscle in tongue contracts and forces bolus into the oropharynx • Bolus stimulates tactile receptors in the oropharynx to initiate the pharyngeal-esophageal phase 3. Pharyngeal-esophageal phase • Involuntary phase • Activated tactile receptors stimulate medulla and pons • Motor impulse is sent down autonomic nerves to the muscles in pharynx and esophagus • Peristalsis moves bolus towards the stomach Explain the processes of gastric secretion and motility. Cephalic (reflex) phase • Under nervous control • Activation of stomach due to thinking about food o This is a conditioned stimulus Gastric Phase • Food has now entered the stomach • 2 controls of this phase… o Nerves § Stretch occurs and sends a signal to the brain § Brain sends parasympathetic impulse § Arrival of ACh to stomach will activate parietal cells to produce HCl o Hormones § Arrival of food with protein in it will activate the G cells § G cells secrete gastrin § Stimulates stomach cells (especially parietal cells) to make more gastric juice ***Gastrin is inhibited by low pH Intestinal Phase (start to empty into small intestine) • Excitatory (begin to empty into small intestine) o Gastric juice production is stimulated as stomach initially expels chyme via pyloric sphincter into duodenum • Inhibitory o As duodenum gets stretched, continued stretch cuts off parasympathetic activity of the stomach and suppresses gastric juice production o Stretch of duodenum also stimulates sympathetic nervous activity shuts off stomach activity and closes the pyloric sphincter o Makes it so that only a small amount of chyme can be in the duodenum at one time. Gastric Filling/Emptying Description 1. Receptive Relaxation Occurs in preparation for arrival of food; rugae flatten to prevent stretch 2. Adaptive Relaxation Food has now arrived; can hold up to 1L before stretching 5 3. Gastric Contraction • Basic electrical rhythm= 3 waves/ min • Starts to turn the bolus into chyme and breaking down of proteins begins • Pace is controlled by auto-rhythmic cells called interstitial cells of Cajal à activation of these cells cause the stomach to contract o Pushes toward pylorus into the first part of the small intestine (duodenum) o Pushes about 30 mL of chyme into the duodenum; the duodenum then contracts and 27 mL of chyme enter back into the stomach. § = A net passage of about 3 mL of chyme into the duodenum making digestion efficient § Empties slowly to improve efficiency of digestion; so intestinal cells can come in contact with all of it 4. Gastric Emptying 1. Chyme enters duodenum 2. Activates stretch receptors and chemoreceptors in the duodenum which initiate… o Enterogastric reflex: reduce stomach activity by activating receptors in duodenum o Enterogastrone reflex: stimuli causes hormones to be released to shut off stomach activity o Sympathetic impulses: sent to pyloric sphincter at end of stomach to close it 3. What happens as a result of these reflexes? Gastric activity is reduced Discuss the protective barrier that prevents the stomach from digesting itself. MUCOSAL BARRIER o Bicarbonate rich mucus o Acts as a buffer o Tight junctions in mucosal epithelium o Gastric gland plasma membranes that are impermeable to HCl o Undifferentiated stem cells o Can continue to divide and replace cells in the pits o Lining of stomach is replaced every 3-6 days Differentiate the various regions of the small intestine. Small Intestine o DIGESTIVE ACTIONS: propulsion, chemical digestion, absorption o Runs from pyloric sphincter to ileocecal valve Regions o Duodenumà jejunumà ileum Identify the structural modifications on the wall of the small intestine, and discuss how each enhances the digestive process. § Length o Long tube with lots of surface area to allow more interaction § Plicae circulares o Folds of mucosa and submucosa that slow movement of chyme and increase surface area 6 § Villi o Fingerlike projections of mucosa on Plicae circulares § Microvilli o Extensions off villi o “Brush border”= lining of small intestine; looks like a brush; secretions are slightly basic to neutralize chyme and protect enzymes State the roles of bile and pancreatic juice in digestion, and identify their point of entry into the alimentary canal. BILE • Bile comes from the liver (through the common hepatic duct) and gallbladder (through the cystic duct), these ducts both meet and form the bile duct, bile then flows into the alimentary canal via the hepatopancreatic ampulla • Bile is result of the processing of red blood cells; comes from the breakdown of hemoglobin pigment • Functions as an emulsifier (mechanically digests fats) • Composed of: o Water, bile salts, pigments (bilirubin broken down to urobilinogen from digestion and makes feces brown), cholesterol, neutral fats, phospholipids, electrolytes o Major digestive component of bile is bile salts • Stored in the gallbladder if the liver makes too much and it cannot pass the hepatopancreatic sphincter; backs up the cystic duct into the gallbladder o Gall bladder also concentrates the bile PANCREATIC JUICE • Secreted by the acinar cells of the pancreas into the pancreatic duct o This duct fuses with the bile duct right near where it will empty into the duodenum via the hepatopancreatic ampulla • Composed of: o Mostly water o Enzymes that break down macromolecules o Bicarbonate § What cells produce this component? § Why is this component important? Describe the regulation of pancreatic juice and bile into the small intestine. • Bile release o Fatty chyme entering duodenum stimulates production of cholecystokinin (CCK) by small intestine o CCK (hormone) causes parasympathetic impulses to promote gallbladder contraction o CCK also relaxes hepatopancreatic sphincter • Pancreatic Juice o Secretin § Secreted by the intestine, stimulated to be produced by high acidity of the chyme o CCK § Secreted in response to fats and proteins in the duodenum § Stimulates the acinar portion of the pancreas to produce the enzymes o Parasympathetic impulses § ANS sends signals to pancreas that cause it to… Intestinal Emptying • Gastroileal (long) reflex in the small intestine 7 o Action of the stomach will send signals to the brain which cause segmentation impulses to come down and stimulate parasympathetic in small intestine § Helps empty products into the cecum • Gastrin hormone produced from the stomach relaxes the ileocecal valve and allows the contents of the small intestine to empty into the large intestine • Pressure o Buildup of waste in the cecum will eventually cause too much pressure and the ileocecal valve will close. List the pancreatic enzymes, and identify what each digests. Protease Enzymes Active Enzyme Inactive Form Activator Trypsin trypsinogen enterokinase carboxypeptidase procarboxypeptidase Trypsin Chymotrypsin chymotrypsinogen Trypsin Other Pancreatic Enzymes Enzyme Function Amylase For short chain (BREAKS DOWN STARCH/CARBS) Lipase Breakdown fat/Triglycerides Nucleases Breakdown nucleic acids Identify the structural modifications of the large intestine, and discuss how each is associated the digestive process. LARGE INTESTINE o Pathway of section movement through large intestine: o Two sphincters at the anus; internal (smooth muscle) and external (skeletal muscle) o Haustra: sac like puckerings; constricted segments of large intestine o Epiploic appendages: fatty deposits along surface of large intestine o Propels feces to rectum to be expelled § Feces components: undigested food residue, epithelial cells, bacteria, water o Rectal valves: separates the gas from the solids o Vermiform appendix § Doesn’t function for us anymore § Prone to being plugged up and inflamed § Contains intestinal bacteria that… • Ferment indigestible carbohydrates o Creates flatulence o Process of fermenting… § Synthesizes B vitamins • B12 is required for blood cell production § Synthesizes vitamin K • Vitamin K important for production of clotting proteins by the liver • Motility o Haustral contractions slow § Haustra contract and move fecal material from one to the next § About every 30 mins o Mass Movements 8 § Long range movements; large waves of peristaltic contractions § 3-4 times per day § Can be stimulated by filling in the stomach Describe the defecation process. 1. Mass movements cause stretch 2. Stretch triggers parasympathetic stimulation of sigmoid colon and rectum and inhibits anal sphincters a. Both external and internal sphincters are inhibited but external is voluntarily closed until we have to go 3. Valsalva’s maneuver assists emptying; closing of valves and contract abdominal muscles. Chemical Digestion *Chemical Digestion: the catabolic process of breaking things down (polymersà monomers) *Most breaking down of macromolecules occurs through hydrolysis where a macromolecule is hydrated, which cleaves the bond, and splits the molecule into its smaller parts. List the enzymes involved in chemical digestion, their location of action and/or production, and the macromolecules they act on. 1. Carbohydrate Digestion *starts in mouth, stops in stomach, finishes in small intestine a. Salivary amylase i. Acts in mouth, produced by salivary gland ii. Substrate is starch b. Pancreatic amylase i. Acts in small intestine, produced by pancreas ii. Substrate is starch c. Dextrinase i. Acts in small intestine, produced by brush border ii. Substrate is oligosaccharides d. Glycoamylase i. Acts in small intestine, produced by brush border ii. Substrate is oligosaccharides e. Maltase i. Acts in small intestine, produced by brush border ii. Substrate is maltose f. Sucrose i. Acts in small intestine, produced by brush border ii. Substrate is sucrose g. Lactase i. Acts in small intestine, produced by brush border ii. Substrate is lactose 2. Protein Digestion *starts un stomach, continues in small intestine Ø Dietary proteins are taken in through digestion Ø Intrinsic proteins are already apart of our bodies a. Pepsin i. Acts in stomach, produced by chief cells ii. Substrate is long chains of amino acids b. Rennin 9 i. Only in babies ii. Acts on milk c. Trypsin i. Acts in small intestine, inactive form secreted by pancreas ii. Acts on substrates from pepsin d. Chymotrypsin i. Acts in small intestine, inactive form secreted by pancreas ii. acts on substrates from trypsin e. Carboxypeptidase i. Produced by brush border OR pancreas ii. Splits off single amino acid from the end f. Aminopeptidase i. Brush border ii. Splits off single amino acid from the end g. Dipeptidase i. Brush border ii. Only work son dipeptides 3. Lipid Digestion *starts in small intestine a. Lipase i. Requires bile to work ii. Acts in small intestine, produced by pancreas iii. Breaks apart lipid into free fatty acid and monoglyceride 4. Nucleic Acid Digestion (breaking down of RNA and DNA into individual nucleotides; Adenine, cytosine, thymine, guanine) *starts in small intestien a. Pancreatic nuclease i. Made in pancreas ii. Substrate is nucleic acids b. Nucleosidase i. Brush border ii. Substrate is nucleoside c. Phosphatase i. Brush border ii. Substrate is nucleotide Describe the process of absorption in the small intestine • Active transport • It requires energy to move nutrients into bloodstream and deliver them to liver • Simple diffusion • Does not require energy to move nutrients into villi lacteals (special lymphatic vessels) and deliver to blood by the lymph • Aided by micelles • Most absorption is finished by the time we get to the ileum List the nutrients necessary for life, and identify where they are obtained. Nutrients: substance used in the body for growth, maintenance, or repair Nutrient Description 1. Water • Absorbed in the large intestine 10 • 60% of the food we take in is water; even so we need water consumption beyond food water content • Puts nutrients into solution to be biologically active 2. Carbohydrates • Major source of carbs from diet is plants • Monomer is glucose 3. Lipids • Most lipids important with nutrition are neutral fats also called triglycerides • Saturated fat: o solid at room temp o Come from animals • Unsaturated fat: o Liquid at room temp o Come from plants 4. Proteins • We can get protein from animals and plants • Animal proteins are “complete” proteins; contain all the essential amino acids we need • Plant proteins are missing 1 or more essential amino acids 5. Vitamins • Occur naturally in the food we eat • Function as coenzymes in the building or materials or breaking down of materials (ex. NAD, FADH) • Not energy source • Two classes: o Water soluble- if too much is ingested we excrete it through urine. Cant accumulate o Fat soluble- we can accumulate these and if too much is absorbed it can be toxic. 6. Minerals • K, Ca, Na, etc • Not energy source • Big example of minerals contributing to growth and repair can be seen with minerals being stored in bone and helping them grow/repair themselves Define metabolism, then define the contributing roles of anabolism, catabolism, oxidation and reduction. Metabolism: biochemical conversion in body; the sum of anabolism and catabolism; highly linked to energy production Overview of chemical digestion and transport of products to cells a. Anabolism of lipids, proteins and glycogen b. Catabolism of pyruvic acid and Acetyl-CoA c. Cellular respiration in mitochondria • Anabolism: buildup • Catabolism: breakdown • Reduction: addition of hydrogen to a coenzyme, requires addition of energy o If undergone the products are at a higher energy state than reactants • Oxidation: adding oxygen or removing hydrogen o If undergone the products are at a lower energy state than reactants 11 Identify the enzymes and coenzymes used for redox reactions. • Redox Enzymes o Dehydrogenases: removes a hydrogen, catalyzing oxidation § Ex. Alcohol dehydrogenase breaks down alcohol through oxidation o Oxidases: adds oxygen, also catalyzing oxidation o Coenzymes: hydrogen acceptors § Examples= NAD, FADH Differentiate substrate-level and oxidative phosphorylation. • Substrate level o Happens in cytoplasm o Makes small amount of ATP o Direct transfer of phosphate to ADP o Also known as glycolysis • Oxidative o Oxygen is present o Larger amounts of ATP o Indirect mechanism-‐ uses protein gradient in electron transport chain o Happens in mitochondria Summarize the important events in the oxidation of glucose, including the phases of glycolysis, Kreb’s cycle and electron transport. 1. Glucose enters cells by facilitated diffusion 2. Glucose immediately phosphorylated to *glucose 6 phosphate* a. This keeps a constant gradient and makes flow of glucose one directional 3. Glycolysis continues and results in the formation of: a. 2 molecules pyruvic acid b. 1 molecules of NADH c. Net gain 2 molecules of ATP 4. *if oxygen is present, 2 pyruvic acid will go into mitochondria and undergo oxidative phosphorylation 5. Each pyruvic acid converted to acetyl-CoA in mitochondria a. Generates CO and2NADH 6. Each Acetyl-CoA enters Krebs cycle generates a. 2 CO 2 b. 2 NADH c. 1 ATP d. 1 FADH 2 7. Reduced Kreb’s cycle coenzymes (NADH/FADH ) enter electron transport chain 2 8. Hydrogen are used to phosphorylate ADP to ATP a. Generates: i. H 2 ii. 34 ATP Name and describe the process that results when there is an excessive of glucose, describe how this process is reversed when glucose becomes rare, and how glucose is made from non-carbohydrate molecules. • Metabolism involving Glucose o High ATP levels stop glycolysis; stop importing glucose into cells 12 o Glucose converted to glycogen by the liver (glycogenesis) § Glycogen is stored until energy is needed o If drop in blood glucose occurs stimulates conversion of glycogen into glucose (glycogenolysis) o If there is insufficient glucose available or none in storage § Glucose is made out of glycerol or amino acids called (gluconeogenesis) Describe the process by which lipids are oxidized for energy, stored when in excess and freed when needed. • Lipids broken down by plasma enzymes into glycerol and fatty acids • Glycerol converted to glyceraldehyde phosphate o Glyceraldehyde phosphate converted to pyruvic acid in glycolysis o Enters Kreb’s cycle • Fatty acids broken into acetic acid in mitochondria o Acetic acid fused with CoA to form acetyl-CoA Excess Lipids o High ATP and glucose levels trigger conversion of glycerol and fatty acids into triglycerides for storage o Lipolysis reverses the process (converts triglycerides into glycerol and fatty acids) Describe protein metabolism. Protein used as energy • Protein will only be used as energy source if…. • Amino acids deaminated (lose the ammonia) • Deaminated molecules converted to pyruvic acid or to Kreb’s cycle intermediates Excess protein • If high ATP levels are reached the pyruvic acid formed through deamination to be converted to glucose • Glucose will then be converted to glycogen via glycogenesis Temperature Regulation Explain the concept of nutrient pools, and describe pathways for the inter-conversions of materials in these pools. • Nutrient Pools: The food we eat can be….. o Put into storage o Used for energy o Used by cell for structure etc. o Converted to different molecules/nutrients Differentiate the absorprtive and postabsorptive states, and discuss the hormonal and neural regulation of these conditions. • Absorptive o During or right after a meal o High levels of circulating nutrients o Anabolic activity • Post-‐absorptive o In between meals 13 o Low circulating nutrient levels o Catabolic activity Controlled by: • Monitoring of blood glucose levels o Hormones that control the blood glucose levels are: § Insulin: (fills storage pool) • Active during the absorptive state o Released when glucose and amino acid levels are high • Promotes: o movement of glucose into a cell o oxidative phosphorylation o glycogenesis o protein synthesis § Glucagon: (drains storage pool) • Active during the postabsorbtive state o Released when glucose and amino acid levels are low • Promotes: o glycogenolysis o gluconeogenesis o lipolysis o Nervous control § Sympathetic stimulation: low blood glucose levels so sympathetic signal is sent to areas of storage (especially adipose tissue) § Epinephrine: also sympathetic signal, adrenal medulla releases epinephrine which causes lipolysis and glycogenolysis Describe the role of the liver in cholesterol regulation. • Functions: o Primarily controls the breakdown of blood cells/recycling o Produces cholesterol § 85% of the cholesterol is produced by the body • Cholesterol o Produce very low density lipoproteins (VLDL) § These gets converted to LDL and then released from liver into blood o LDLs go to tissues and deliver cholesterol where it is needed § Cholesterol is pulled off LDL ; this breaking it down and makes HDL o HDL is delivered back to the liver with much less cholesterol/ fat in it Define basal and total metabolic rates. • Basal metabolic rate (BMR): must be at rest and relaxed to measure o Calculated using: § Colorimeter: direct measurement of heat § Respirometer: more common, indirectly measures heat by using oxygen or CO2 • Total metabolic rate (TMR): all of the metabolic activity, not just the essential Describe how body temperature is regulated, identifying factors stimulating its increase or decrease. Regulation of body temperature • Function of the hypothalamus; sets the temperature point (37c, 98.6F) • Body temperature is the balance between heat production and heat loss 14 Radiation movement of heat to or from environment; always from high to low Conduction heat exchange from contact Convection Movement of air Evaporation Conversion of liquid water to gaseous water Heat-promoting mechanisms • Vasoconstriction o Redirects blood flow to the core; lose less heat from less surface area • Increased metabolic activity (non-shivering thermogenesis) o Production of norepinephrine • Shivering thermogenesis o Contraction of skeletal muscle; produces heat • Thyroxine o Only babies have this response. o Thyroxine increases thyroid hormone which increases heat production • Behavioral mechanisms o Behavioral things that promote body heat o Drinking hot drinks, curling into a ball, wearing cloths etc Heat-loss mechanisms • Vasodilation o More blood is sent to the surface which increases the surface area that the blood heat can dissipate • Sweating o Water sent to surface of skin to be heated and evaporated • Behavioral mechanisms o Behavioral things that promote cooling o Finding shade, fanning, dumping cool water on head etc. Describe the mechanism for the generation of a fever. 1. Infected cells release pyrogens 2. Pryogens cause hypothalamus to release prostaglandins 3. Prostaglandins reset thermostat 4. Vasoconstriction and shivering result 5. Body temperature increase 15
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'