Week 10: Chapters 29-32
Week 10: Chapters 29-32 BIOL 1306/1106
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This 13 page Class Notes was uploaded by Hayley Lecker on Friday October 30, 2015. The Class Notes belongs to BIOL 1306/1106 at University of Texas at El Paso taught by Anthony Darrouzet-Nardi in Fall 2015. Since its upload, it has received 67 views. For similar materials see Organismal Biology in Biology at University of Texas at El Paso.
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Date Created: 10/30/15
Biology Week 10 Important Information Professor s Email aidarrouzetnardiutepedu or anthonvdnutepedu All vocabulary will be defined at the end of the notes Chapter 29 291 Animals Eat to Obtain Energy and Chemical Building Blocks Animals build new molecules and cells from ingested organic compounds A growing animal adds new cells to its body and all animals are constantly replacing wornout molecules ad cells An animal is characterized by the organization of its body s cells tissues and organs Energy can be seen as the capacity to create or maintain this organization 292 An Animal s Energy Needs Depend on Physical Activity and Body Size An animal s metabolic rate is defined as its rate of energy consumption the rate at which the animal uses chemical energy turning it into heat Metabolic rate can be quantified by measuring the rate of oxygen consumption or not common by measuring the rate of heat production Physical activity increases an animal s metabolic rate but the exact relationship between activity level and metabolic rate varies Basal metabolic rate BMR is the metabolic rate of a resting fasting individual in a comfortable thermal environment When BMR is expressed per unit of body weight in grams it is called BMRg Smaller mammals consistently have higher BMRg than larger mammals do This is an example of a scaling relationship An animal with a high BMRg must consume more food relative to its body weight than an animal with a lower BMRg 293 Metabolic Rates Are Affected by Homeostasis and by Regulation and Conformity Within the animal body cells exist in an internal environment of tissue fluids Conditions outside of the body are the external environment Animals that maintain a consistent internal environment despite variation in the external environment are called regulators Conformers are animals in which the internal environment varies to match the external environment Regulation of the internal environment is more energetically expensive than conformity Homeostasis refers to the stability of an animals internal environment and the mechanisms that maintain this stability Homeotherms exhibit thermoregulation maintaining a constant internal temperature by varying metabolic rate and insulation with external temperature Above or below a specific temperature range called the thermoneutral zone TNZ metabolic rate increases to compensate for increasing heat input or to offset heat loss respectively Most animals are poikilotherms Ectotherms with body temperature that vary with and match external temperature Metabolic rates decrease as temperature drops and increases as temperature rises The sensitivity of a reaction or process to changes of internal tissue temperature can be expressed as a numerical factor Q10 which usually has a value of 2 to 3 A poikilotherm can exert some control over its tissue temperature through behavior by moving to a more favorable location Homeothermy expends more energy than poikilothermy Homeothermic heatproducing mechanisms used by mammals include shivering the subtle contraction of the skeletal muscles to convert ATP to heat and the nonshivering thermogenesis NST in brown adipose tissue which produces heat directly in the mitochondria by shortcircuiting oxidative phosphorylation Insects sometimes regulate their thoracic temperature using heat generated from ATP by flight muscles in their throax n hot environments homeotheric animals increases their rate of heat loss by sweating or panting processes that increase heat transfer to the environment by evaporation of water Mammalian hibernation refers to a strategy of reducing energy and thus food needs by entering a state of thermoconformity during extended cold periods 294 Animals Exhibit Division of Labor but Each Cell Must Make Its Own ATP The fluids in an animals body are distributed among various body compartments Intracellular fluid is inside the body s cells and is said to be in the intracellular compartment Extracellular fluid which includes blood plasma and interstitial fluid is outside of the cells and is said to be in the extracellular compartment Different extracellular fluids are separated by epithelia sheets of cells that cover a body surface or organ or line a body cavity The boundary between intracellular fluids and extracellular fluids is formed by cells membranes Animals exhibit a high degree of division of labor This division of labor typically necessitates a rapid transport system to distribute materials among parts of the body Cells tissues organs and multiorgan systems represent evermorecomplex levels in the hierarchy of organization of the animal body Each cell must make its own ATP Cells may use aerobic with oxygen or anaerobic without oxygen processes to produce ATP 295 The Phenotypes of Individual Animals Can Change during Their Lifetime Phenotypic plasticity refers to an individual s ability to display two notypic plasticity is a way for an animal to acclimate or acclimatize to changes in its environment At a biochemical level phenotypic plasticity often involves inducible enzymes enzymes that change in abundance or type in response to an animal s environment Phenotypic plasticity also occurs at the level of tissues and organs The capacity for phenotypic plasticity is genetically based and is subject to natural selection 296 Animal Function Requires Control Mechanisms The four essential elements of a control system are controlled variable sensors effectors and control mechanisms The controlled variable is the property of characteristic of animal that is being controlled Sensors detect the current level of the controlled variable Effectors are tissues or organs that can change the level of the controlled variable The control mechanism uses information from the sensors to determine which effectors to activate and how intensely to modify the controlled variable A controlled mechanism may involve negative feedback in which the control mechanism activates effectors in ways that reduce or negate any difference that exists between the controlled variable s actual state and its set point Negative feedback is stabilizing Positive feedback occurs when deviations of a controlled variable from its existing level are increases or amplified by the action of the control mechanism Positive feedback is destabilizing but still can be advantageous Animals have selfcontained mechanisms of keeping track of time known as a biological clocks that allow the animals to anticipate future events Biological clocks that have freerunning timing cycles of about 24 hours are called circadian clocks Some animals also have circannual or circatidal clocks Chapter 30 301 Food Provides Energy and Chemical Building Blocks Animals are heterotrophs that derive their energy and chemical building blocks from eating other organisms A measure of the energy content of food is the calorie cal the amount of heat required to raise the temperature of 1 gram of water by 1C What we typically refer to as calories in our food are actually kilocalories kcal The metric unit for measuring energy is the joule There are three major types of food molecules lipidsfats and oils carbohydrates and proteins Lipids contain about twice as many calories per unit of weight as carbohydrates and proteins Animals store extra energy as lipids and glycogen Food provides carbon skeletons termed essential that animals cannot synthesize themselves Adult humans require eight essential amino acids and at least two essential fatty acids Vitamins are essential carbon molecules needed in tiny amounts There are either watersoluble or lipid soluble Essential minerals are chemical elements that are required in the diet in addition to carbon hydrogen oxygen and nitrogen Malnutrition results when any essential nutrient is lacking from the diet Chronic malnutrition causes deficiency diseases 302 Animals Get Food in Three Major Ways Animals can be characterized by how they acquire their food Some animals feed on easily visible food items that they eat by targeting them individually Suspension feeders are aquatic animals that feed indiscriminately on large numbers of tiny food particles that they collect from the surrounding water Some animals rely on symbiosis with microbes to obtain at least some of their nutrients Reefbuilding corals for examples contain photosynthetic algae that supply carbon compounds to the coral Microbes in the rumen of ruminants break down cellulose that the animals are unable to digest 303 The Digestive System Plays A Key Role in Determining the Nutritional Value of Foods In most animals digestion takes place in a tubular gut that has two openings the mouth and the anus Food is processed within the gut lumen Digestion is the enzymatic breakdown of food molecules into smaller molecules that can cross the gut epithelium The process of transporting molecules from the gut lumen into the blood is called absorption Each digestive enzyme can break only specific types of chemical bonds in food molecules For ex the sugars trehalose and lactose are broken down by trehalase and lactase respectively The nutritional value of food depends on the ability of the animal s digestive track to process the food in such a way that nutrients in the food can be absorbed Animal species vary in the digestive enzymes they produce and this in their ability to gain nutritional value from specific food molecules An individual animal can adjust its digestive and absorptive capabilities in response to changes in its diet 304 The Vertebrate Digestive System is a Tubular Gut with Accessory Glands The vertebrate digestive system consists of a tubular gut and several secretory organs notably the liver and pancreas that aid in digestion The gut consists of an inner gut epithelium that secretes mucus enzymes and hormones and absorbs nutrients A submucosa containing blood and lymph vessels and two layers of smooth muscle and a nerve network called the enteric nervous system which is part of the autonomic nervous system Peristalsis moves food along the length of the gut Sphincters block food passage at certain locations but relax at controlled moments to let food through Digestive enzymes are categorized on the basis of the types of food molecules they hydrolyze and by where they functions The vertebrate gut can be divided into several compartments with different functions The foregut includes the mouth esophagus and the stomach The midgut is the principle site of digestion and absorption The hindgut stores waste between defecations and reabsorbs water and salts from the feces Digestions begins in the mouth in mammals Mammals chew their food and their saliva contains the starchdigesting enzyme amylase The stomach breaks break up food and begins the process of protein digestion and controls the flow of food materials to the small intestine Stomach cells secret HCl pepsinogen inactive form of pepsin and mucus that protects the stomach wall In most vertebrates absorptive areas of the gut are characterized by a large surface area produced by extensive folding including villi and microvilli Digestive juices secreted by the pancreas and emulsifying bile secreted by the liver flow into the lumen of the early part of the midgut Bicarbonate ions from the pancreas neutralize the pH of the food entering from the stomach Some animals have fermentation chambers where symbiotic microbes help break down foods synthesize B vitamins and recycle nitrogen The host animal is classified as a foregut fermenter midgut fermenter or hindgut fermenter based on the location of the fermentation compartment within the digestive tract 305 The Processing of Meals Is Regulated Animals alternate between an absorptive state food in the gut and postabsorptive state no food in the gut The actions of the stomach and small intestine are controlled by formones such as gastrin secretin and cholecystokinin CCK Food intake is governed by sensations of hunger and satiety which are determined by brain mechanisms responding to feedback signals provided in part by the hormones ghrelin and leptin Insulin and glucagon from the pancreas control the glucose concentration of the blood Insulin stimulates the uptake and use of glucose by many cells of the body If the blood glucose concentration falls glucagon secretions increases stimulating the liver to break down glycogen and release glucose to the blood Chapter 31 311 Respiratory Gas Exchange Depends on Diffusion and Bulk Flow Most cells require a constant supply of 02 and continuous removal of C02 These respiratory gases are exchanged between an animal s cells and the animal s environment by a combination of diffusion and bulk flow A gas diffuses from where its partial pressure is high to where its partial pressure is low The law of diffusion for gases show how various physical factors influence the diffusion rate of gases Adaptation to maximize respiratory gas exchange influence one or more variables in the law of diffusion for gases Fick s Law As they move between an animal s internal tissues and the environment respiratory gases diffuse acorss gas exchange membranes Breathing organs are classified based on their structures lungs fold inward into the body gills fold outward from the body In water gas exchanged is limited by the low diffusion rate and low solubility of 02 in water 02 becomes less soluble in water as water temperature increases 312 Animals Have Evolved Diverse Types of Breathing Organs Adaptations to maximize gas exchange include increasing the surface area for gas exchange and maximizing both ventilation with the respiratory medium and perfusion with blood The gas exchange membranes are also very thin which minimizes the distance gases must diffuse Cocurrent gas exchange occurs when perfusion flows in the same direction as ventilation flows in opposite directions result in countercurrent gas exchange The most efficient transfer of gases is achieved by countercurrent systems such as those found in fish Internal partitioning of the lungs is greater in mammals than in nonavian reptiles like lizards and greater in these reptiles than in amphibians Ventilations in all these groups is tidal The breathing system of birds includes air sacs that are filled and emptied tidally and act as bellows to ventilate the lungs Air flows unidirectionally and continuously through the parabronchi of the birds lungs Insects distribute air throughout their bodies in a system of tracheae and tracheoles The circulatory system is not involved in gas exchange because all cells are supplied directly by the tracheal system 313 The Mammalian Breathing System Is Anatomically and Functionally Elaborate In mammalian lungs the gas exchange surface area provided by the millions of alveoli is enormous and the diffusion path length is short The tidal volume is the amount of air that moves in and out of the lungs per breath The respiratory minute volume is the total volume of air that is inhaled and exhaled per minute Inhalations occurs when contractions of the diaphragm and some of the intercostal muscles expand the thoracic cavity In a resting person when the diaphragm and intercostal muscles relax the thoracic cavity contracts by elastic recoil resulting in exhalation During exercise greater muscular forces are used increasing the volume of air inhaled and exhaled per breath and the rate of breathing The breathing rhythm is generated by neurons in rhythm generating centers in the medulla oblongata The most important feedback stimulus for breaking is the level of C02 in the blood which is detected by chemosensitive neural centers on the surface of the medulla oblongata These centers detect both the blood C02 partial pressure and the blood pH which indirectly reflects the level of C02 Breathing rate can also be affected by the onset of exercise and by large changes in blood 02 partial pressure Chapter 32 321 Circulatory Systems Can Be Open or Closed Animals with a high degree of division of labor need a circulatory system that transport respiratory gases nutrients hormones and metabolic wastes throughout the body at high rates 02 transport is the most urgent function of the circulatory system in most types of animals In closes circulatory systems found in vertebrates annelid worms squid and octopuses the blood never leaves a system of vessels In open systems found in arthropods and most mollusks the blood leaves vessels and bathes tissue cells directly Closed have an advantage that they can direct blood selectively to specific tissues In closed the blood flows from the heart through arteries to the microscopic vessels of the microcirculation which consists of arterioles capillaries and venules Veins then carry blood back to the heart Capillaries are the smallest vessels and are the principal sites of exchange of gases nutrients and other substances between blood and tissues Arterioles control the rate of blood flow into the capillaries n open systems the heart typically pumps blood into arteries that carry the blood for at least a short distance These vessels then end and the blood flows out into the animals tissues The blood makes its way back to the heart through channels between the tissue cells called sinuses and lacunae n open systems there is no distinction between blood and interstitial fluid 322 The Breathing Organs and Systemic Tissues Are Usually but Not Always in Series The systemic circuit consists of the blood vessels that carry blood to and from the systemic tissues The breathing organ circuit consists of the blood vessels that carry blood to and from the breathing organs Arteries are vessels that carry blood away from the heart veins carry to the heart In most animals the systemic circuit and breathingorgan circuit are connected in series the blood flows from one circuit to the other sequentially Circulation in series is the most efficient way to deliver 02 to the systemic tissues 323 A Beating Heart Propels the Blood Vertebrate hearts are multichambered and myogenic heartbeats are initiated by specialized muscle cells within the heart The simplest vertebrate heart found in fish is twochambered it has an atrium that receives blood from the body and ventricle that pumps blood out of the heart Amphibians and nonavian reptiles have a threechambered heart with two atria and one partially divided ventricle The heart of mammals and birds has four chambers two atria and two ventricles with valves to prevent backflow Blood flows from the right atrium and ventricle to the lungs then to the left atrium and ventricle and then to the rest of the body The cardiac cycle has two phases systole when the ventricles contract and diastole when the ventricles relax The heartbeat is mammals is initiated by pacemaker cells in the sinoatrial node that spontaneously depolarize triggering a wave of depolarization that spreads through the atria and then spreads with a brief delay into the ventricles via the atrioventricular node and the conducting system The autonomic nervous system controls heart rate by changing the rate of depolarization of the pacemaker cells Norepinephrine from sympathetic nerves increases heart rate and acetylchline from parasympathetic nerves decreases it In mammals and many other vertebrates a coronary circulatory system supplies 02 to the cells of the heart muscle The depolarization of heart muscle cells can be detected on the surface of the body and recorded as an ECG or EKG The hearts of crustaceans have one chamber and are neurogenic the muscle cells of the heart require nervous stimulation to beat 324 Many Key Processes Occur in the Vascular System Arteries are composed of muscle fibers and elastic fibers that enable them to dampen the surge in pressure when the heart beasts and store their stretched state some of the energy imparted to the blood by the heart Veins have thinner walls and have a high capacity for storing blood The pressure and linear velocity of blood vary greatly as it flows through the vascular system Blood pressure is high in arteries and low in veins Blood velocity is lowest in capillary beds Veins have one way valves that assist in returning blood to the heart under low pressure Heat loss from certain regions of an animal s body such as extremities of the arctic fox and red swimming muscles of tuna can be reduced by countercurrent heat exchange High blood pressure forces fluid out of the blood as it travels through the initial part of the capillary bed osmotic pressure draws some of the fluid back into the blood as blood pressure falls The excess fluid that does reenter the blood as it travels through capillary beds is called lymph The lymphatic system collects the fruit and returns it to the blood 325 The Blood Transports 02 and C02 In vertebrates blood consists of a liquid plasma and cellular components Red blood cells are produced in the bone marrow Hemoglobin the respiratory pigment in red blood cells binds 02 reversibly Each hemoglobin molecule can carry a maximum of four 02 molecules Hemoglobin binds 02 when the partial pressure of 02 is high and releases it when the partial pressure is low Hemocyanin is the respiratory pigment in mollusks and arthopods C02 reacts with the blood water to form bicarbonate ions HC03 and is transported mostly in the form of bicarbonate Lecture Notes Platyhelminthes Flatworms unsegmented no circulations respiration or internal organs They have eyes Annelid Worms segmented ex an earthworm they have tiny lines that segment their body A Neres succnea All of the segments of this marine annelid are similar Tail segments are modified for hunting and defense L 7 y I l x1 I39igxgigj xn g39p39ifM quot ii I Abdominal segments are modified for digestion and reproduction I L I l The muscles of the human abdomen are segmented Anterior segments have fused and bear appendages for locomotion and feeding B Hadrurus arzonenss C Homo sapens PRINCIPLES OF LIFE 2e Figure 235 r 2014 Sinauer Associates Inc Bryozoa Sessile rooted in place filter feeders colonial Rotifers Small only 15mmong Mostly asexual reproduction which is unusual in most animals Dessication resistant they can repair their DNA Evidence that genes are acquired by horizontal gene transfer Arthropods there are a million described species 23 of all organisms are arthropods They have a hard exoskeleton made of protein and chitin which is strong impermeable to water It facilitated movement onton land and they molt ecdysis There is segmentation and they have jointed specialized appendages They use cephalization eye antennae for touch and smells They have an open circulation abdomon cephalothorax Iquot eyes 392 i A 0476 d 39 Kquot 1 i A cheliccra r i s j 39 4 pedipalp 5 b kl quot xquot coxae of legs 00 ung spinneretcs Arachnids are arthropods these include spiders scorpions ticks mites and solifuges There is roughly 100000 species They are characterized by 8 legs and 2 bodt segments antenna simple eye compound eye front wing Q l I f abdomen lt leg wing 2010 Encyclopaedia Britannica Inc nsects are the only invertebrates with wings they have threepart body characterized by a head thorax and abomen Six legs compound eyes and antennae Major Insect Groups Anoplura sucking lice Coleoptera beetles 500000 species Dermaptera earwigs Diptera flies mosquitoes 120000 Hemiptera true bugs 55000 Hymenoptera ant bee wasp 100000 Isoptera termites Lepidoptera butterfly moth 140000 Odonata damselflies dragonflies Orthoptera crickets roaches grasshoppers mantids Siphonaptera fleas Trichoptera caddisflies Epithelial cell Epithelium Nucleus Intercellular space Basement Blood Tissue on which the membrane capillary epithelium rests LVIFOEVZe Figure 2913 Human ORGAN systems Digestive system mechanical and chemical processes that provide nutrients via the mouth esophagus stomach and intestines Respiratory system the lungs and the trachea that bring air into the body CardiovascularCirculatory system circulates blood around the body via the heart arteries and veins delivering oxygen and nutrients to organs and cells and carrying their waste products away Lymphatic system supplies and drains lymph fluid in support of the cardiovascular and immune systems Urinary system the system where the kidneys filter blood Excretory system eliminates waste from the body Endocrine system provides chemical communications within the body using hormones Reproductive system the sex organs required for the production of offspring Nervous system collects and processes information from the senses via nerves and the brain and tells the muscles to contract to cause physical actions Skeletal system bones supporting the body and its organs Muscular system enables the body to move using muscles Integumentary system skin hair nails sweat and other exocrine glands Immune system defends the body against diseasecausing agents Vocab Metamorphsis Biological process by which an animal physically develops after birth or hatching involving a conspicuous and relatively abrupt change in the animal s body structure through cell growth and differentiation Animal Tissues Epithelial cells that line a body cavity organ or external surfaces providing barrier and controlling material flow ex skin Connective cells that function to bind and support other tissues typically secreting a matrix eg blood bone Muscle long muscle cells that can contract to produce force Nervous neurons and supporting cells that transmit and receive impulses Organ system A group of organs that work together to perform vital body functions Basal metabolic rate metabolic rate of resting fasting and nonstressed endotherm at a comfortable temperature Homeostasis Regulation of an organism s body to maintain internal conditions that are stable and relatively constant Homeotherm An organism in which thermoregulation maintains a consistent body temperature endoterm warmblooded Poikiloterm An organisms whose body temperature matches the ambient environment ectoterm cold blooded Hibernation A state of inactivity and metabolic depression in endotherms during winter months Estivation Similar to hibernation but during summer months Torpor Decreased activity in an animal accompanied by a substantial decline in body temperature Circadian rhythm A physiological cycle of about 24hours that persists even in the absence of external cues Ruminant Mammals that are able to acquire nutrients from plantbased food by fermenting it with the help of microbial symbionts in a specialized stomach prior to digestion Vitamin An organic compound and vital nutrient that an organism requires in limited amounts Dietary minerals Chemical elements such as calcium phosphorus and potassium that an organism requires for growth
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