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BSc (Veterinary Biosciences) Level 2 Body Systems Physiology - 2 (2009-10) 30 Credits Course Co-ordinator: Dr I.A. Jeffcoate Position in Course: Year 2 (both semesters) Course prerequisites: To have achieved a minimum of Grade D in all Level 1 courses to total 120 credits Courses Chemistry 1 (402B) (Chemistry) Biology 1A (Animal biology) (KNPU) (FBLS) Biology 1B (Cell biology) (KNMU) (FBLS) Animal Production and Management 1 (FVM) Basic mammalian body plan 1 (FVM) Comparative vertebrate morphology 1 (FVM) Body systems physiology 1 (FVM) Credits 40 20 20 10 10 10 10 Course corequisites: Courses Veterinary Bioinformatics 2 (FVM) Proteins, DNA & basic genetics 2 (FVM) Animal Science, Behaviour and Nutrition 2 (FVM) Other Level-2 FBLS courses (usually 6 x 10 credits) Excluded courses or course combinations: Credits 10 10 10 60 None 1 Aims of the Course The aims of this course are to give participants the means of acquiring knowledge and understanding of systems confined to mammals: 1) temperature regulation and metabolism 2) the digestive system and control of food intake 3) the respiratory system and how it is regulated 4) body fluids, blood and the cardiovascular system and how the circulation is adjusted according to need 5) the renal system and body fluid regulation 6) the reproductive system and how it is regulated Overall Intended Learning Outcomes After completing this course you should be able to: 1) explain the effect of body temperature on living cells 2) describe how animals are either able to closely achieve a constant body temperature or if not are prone to variation depending on environmental conditions 3) define homeothermy as opposed to poikilothermy and show metabolic rate is a function of body size 4) define digestion and absorption 5) describe how food is eaten and digested 6) describe how food components are absorbed 7) describe that food residues are excreted 8) explain what normally limits food intake, appetite versus satiety 9) explain how cells require oxygen and must void carbon dioxide 10) explain how increased body size has necessitated development of internal gas exchange and internal gas distribution 11) explain how gas exchange is achieved and regulated so as to maintain homeostasis 12) explain how impairment of gas exchange is harmful 13) describe why cells exist in an aqueous environment and that the bulk of body mass is water 14) describe why the precise ionic and osmotic balance of the cellular environment is vital to cellular viability 15) describe the two major body water compartments, intracellular and extracellular, which are in equilibrium 16) define that portion of extracellular fluid comprising blood plasma 17) describe the circulatory system and account for pressure differences between arterial and venous circuits 18) illustrate the structure and activity of the heart and the circulatory pattern through pulmonary and systemic circuits 19) describe how blood pressure is monitored and regulated in the systemic circuit 20) explain the need for the renal system to regulate volume and composition of body water and blood volume 21) describe the activities of the renal nephron 22) describe how nephronal activity is regulated to achieve body water homeostasis 23) describe the chromosomal basis of sex determination 24) explain the function of the male and female gonads and accessory reproductive structures 25) describe hormonal control of reproductive function in male and female 26) explain the female oestrous cycle 27) explain pregnancy establishment and the need for an altered hormonal background 2 28) 29) 30) explain gestational term and parturition account for mammary development during gestation and onset of milk secretion after parturition account for inhibition of oestrous cycles during lactation and the effect of weaning Lecturing Staff - to be agreed Teaching Methods and Hours: Body systems Physiology 2 will be taught during the first and second semesters of Year 2 with an end of course examination. The course will comprise three lectures per week complemented by homework and practical assignments involving about 300h work as shown in Table 1. The FVM Moodle system will be used to communicate these assignments and to allow a discussion forum around each topic. The course is organised around the 6 main topics as shown above under ‘aims’. A homework essay assignment will generally be given near the end of each topic, the marks from which will contribute towards the course exam mark as shown in table 2. The course will also include 2 computer simulations of laboratory experiments. Following each of these classes there will be a summary test to be completed in the student’s own time and submitted for marking, again for a contribution to the overall course mark as shown in Table 2. TABLE 1 Lectures Laboratory Computer Lab. Essay Private study TOTAL Formal teaching (hours) 75 2x2 2x2 83 Homework (hours) 4x8 7.5h / week ( upto 25 weeks) 220 Course textbooks: No single textbook is likely to be ideal for all students of Animal Physiology. Students are recommended to possess one of the following:‘Textbook of Veterinary Physiology’ by J.G. Cunningham & B. Klein; fourth Edition. ‘Physiology’, by R.M. Berne and M.N. Levy; Fifth Edition, 2004. ‘Color Atlas of Physiology’ by A. Despopoulos & S. Silvernagl, Fourth Edition, Thieme Medical Publications, 1991. New York The following textbooks are recommended additional reading. ‘Physiology of Domestic Animals’ by Sjaastad, Hove and Sand (2003), Scandanavian Veterinary Press, Oslo. ‘Dukes Physiology of Domestic Animals’ (12th Ed, W.O.Reece, ed). 2004 ‘Neurophysiology’ by R.H.S. Carpenter, Fourth Edition, Arnold, London (2003). In addition: Textbooks and other literature will be referenced in lectures and Students are expected to fully consult library resources for books and journal texts Evidence of wide reading will be required when marking assignments. As a starting point, some references to the above texts are given under ‘study guide’ below. 3 ITEMS OF SUMMATIVE ASSESSMENT Coursework Assessments The grades you gain from coursework will be used as 30% of your final assessment. These coursework grades will also count towards your final grade if you have to resit the end‐of‐course examination. Consequently it is vital for you to obtain a decent grade for your coursework, which means you must hand in all the required assignments. The deadlines for submission of coursework are listed in the Timetable and in the laboratory schedules. End‐of‐course Examination An end‐of‐course examination will count as 70% of your final assessment. The format will be provided in advance and you will have an opportunity to practise example questions. The examination timetables are published on the Registry website. Normally you must sit the end‐of‐course examination at the first set (diet) of examinations after the end of the course. For Body Systems Physiology 2, the first diet of end‐of‐course examinations will be held in the May / June examination period. Relative Weighting of Assessments Body Systems physiology 2 Item of assessment Completed during End-of-course examination (2 hours) May diet Weighting 70% Home Essay Assignment, Thermoregulation Week 3 4% Home Essay Assignment, Digestion Week 6 4% Laboratory & test, Respiration Week 9 4% Laboratory simulation & test, Respiration Week 10 3% Laboratory & test, ECG Week 13 4% Laboratory simulation & test, Circulation Week 14 3% Home essay assignment, Kidney Week 17 4% Home Essay Assignment, Reproduction Week 22 4% TOTAL 100% Table 2. Showing value of coursework assessments and the end-of-course examination in the overall course mark. 4 Intended learning outcomes, Lecture synopses and Study guides Temperature regulation and metabolism Lecture 1 Lecture 2 Effect of temperature on cell metabolism and concept of internal heat production to achieve a constant body temperature Basal metabolic rate is governed by body size and may be altered to maintain stable body temperature Intended learning outcomes: a) b) c) d) e) a) b) Explain inefficiency of metabolism and waste heat Describe the concept of metabolic mass Show examples where body temperature fluctuates with ambient Explain zone of thermoneutrality and costs of keeping warm or losing heat Active versus passive mechanisms Explain long-term adaptations to raise heat production Explain diverse approaches to minimising costs of maintaining constant body temperature eg hibernation Synopsis: Temperature is one of the important variables affecting cell function and viability. Animals have evolved to regulate body temperature actively by harnessing metabolic waste heat. Poikilotherms rely on behavioural adaptations to match body and environmental temperature. Homeotherms exibit a range of environmental temperature, the thermoneutral zone (TNZ), over which body temperature can be kept constant by balancing basal metabolic rate with passive adaptations such as insulation effectiveness and diurnal feeding. Above TNZ energy is wasted in efforts to lose body heat eg panting. Below TNZ energy is wasted in efforts to raise body temperature eg shivering. Sometimes it may be energetically more favourable to give up the fight to maintain body temperature whereupon it will revert to environmental temperature eg hibernation Study Guide: Cunningham & Klein, Chapter 53. Berne & Levy, Page 217. 5 Intended learning outcomes, Lecture synopses and Study guides Digestion and control of food intake, functions of gastrointestinal tract Lecture 1 Lecture 2 Lecture 3 Lecture 4 Lecture 5 Introduction to GI tract and concept of digestion to allow absorption of nutrients. Comparative gut design and main features. Digestion involves mastication, maceration by muscular contraction and mixing with digestive secretions containing enzymes in acid or alkaline environment. Exocrine GI glands regulated by neurohumoral reflexes Absorption is a function of the epithelium of the small intestine and also from the rumen and large intestine depending on species. Non absorbed food/secretions excreted. Diarrhoea. Food intake and appetite, roles of gut fill and neurohumoral feedback Intended learning outcomes: c) Describe generalised gut structure and define digestion as opposed to absorption d) Account for movement of digesta and enzyme/fluid secretion into GI tract e) Note gut surface area and effect on absorption and Explain absorption for each food group and the fate of absorbed nutrients f) Note the extent of fluid flux across gut wall and normal recovery rate and diarrhoea g) Appetite is regulated by hypothalamus in response to afferent neural/humoral signals Synopsis: Food obtained by eating must be digested to make molecules accessible to the body after absorption into the circulatory system. GI plans differ between species depending on diet, reflecting adaptation to particular food sources. When food is swallowed it is conveyed to the stomach and intestines where enzymes and muscular activity break it into substances of simple chemical composition ready for absorption. This occurs across an epithelial surface and then into the blood. Blood draining gut passes exclusively to the liver where modification and storage of nutrients may occur. Gut motility and exocrine secretion are controlled by neural and endocrine signals in response to food type and also psychic signals. Large volumes of secretions are normal but recovery rates must be high to avoid diarrhoea. Rumen and large intestine may be important as fermentation chambers to provide microbially-derived nutrients. Appetite may be stimulated or inhibited depending on neurohumoral traffic to the hypothalamus. Study Guide: Cunningham & Klein, Chapters 27 - 31. Berne & Levy, Chapters 31 - 33. 6 Intended learning outcomes, Lecture synopses and Study guides Respiration and the roles of the lungs in gas exchange Lecture 1 Lecture 2 Lecture 3 Lecture 4 Lecture 5 Lecture 6 Respiration, airways and movement of air to and from lungs and into blood Concept of tidal volume and adequate alveolar ventilation Brain respiratory centre and chemoreceptor regulation Gas transport between lung and tissues, haemoglobin Effects of exercise and lung pathology on blood gases Lungs and acid-base balance Intended learning outcomes: h) Explain the need for lungs in large animals for oxygen and carbon dioxide exchange between atmosphere and blood i) Describe lung and airway structure and function and detail the gas exchange barrier. How is gas transported to and from lungs? j) Chemoreceptors monitor blood gas content and by feeding back to the medulla can signal changes in respiration pattern k) How does exercise stimulate breathing? l) Explain how pulmonary and circulatory disease reduces gas exchange/transport efficiency and can alter blood gas levels m) Explain the involvement of the respiratory system in acid-base balance Synopsis: Cell metabolism requires O2 and releases CO2. Both gases must be transported in blood to and from the lungs and the air in the lungs must be continually refreshed with atmospheric air. Breathing movements act as bellows to move air in the lung airways. Gaseous diffusion is responsible for gas transfer from blood to air. The gas blood barrier is so thin to allow rapid equilibration but disease can impair the process. Chemoreceptors in blood and cerebral fluid detect gas levels and their feedback helps regulate ventilation of the lungs to maintain homeostasis. Respiratory changes at exercise can anticipate requirements but also rely on other sensory inputs to the respiratory control centre. The circulation is vital for blood gas transport and changes such as anaemia will prejudice against satisfactory cell respiration. CO2 yields hydrogen ions in solution in plasma so the correct respiration rate is vital for normal blood pH. Altered respiration may be able to compensate for metabolic acid-base change. Study Guide: Cunningham & Klein, Chapter 53. Berne & Levy, Chapter 25, Pages 464-468, Chapters 27 - 30. 7 Intended learning outcomes, Lecture synopses and Study guides Body fluids and the cardiovascular system Lecture 1 Lecture 2 Lecture 3 Lecture 4 Lecture 5 Body fluids form the bulk of body mass and most of this is located intracellularly Extracellular fluid is continuously formed from and reabsorbed into the blood circulatory system. It acts to link cells to the circulatory system and is in equilibrium with the water of the intracellular compartment The heart structure and function – correlation of electrical and pressure cycles Pressure gradient in the systemic circuit, feedback and autonomic control Cardiac disease Intended learning outcomes: n) Appreciate the importance of body water and show differences between intra- and extra-cellular water and their origins o) Describe the heart and pressure and electrical p) Describe blood pressure variation within the circulatory system and explain pressure differences q) Explain blood pressure feedback and control in the systemic circuit r) What is cardiac failure and how does it affect the circulatory system and body water content and disposition Synopsis: Water accounts for some 2/3 body mass of which 2/3 is contained within cells or intracellularly. The remainder forms the fluid bathing the cells and a small fraction of this extracellular fluid is located within the branching network of the circulatory system as blood plasma. A powerful 2-sided pump, the heart, forces blood through the circulatory system and also provides energy for its ultrafiltration to form the extracellular fluid. Extracellular fluid is vital as a solvent to carry a very varied collection of substances including nutrients and respiratory gases between blood and body cells. The heart comprises separate right and left sides which deliver blood to the pulmonary circuit for oxygenation and systemic arterial circuit simultaneously. The arterial circuit is through thick-walled muscular vessels under substantial pressure which is required for tissue perfusion and to ensure venous return to the right heart. There is great capacity for selective distribution of blood to tissue beds depending on relative tone in the autonomic nervous system. The most marked drop in blood pressure occurs across the great many arterioles prior to capillary and tissue distribution. The venous system collects blood from the capillaries and is characterised by large-bore low-pressure vessels. Extracellular fluid formation and resorption depends on these capillary pressure differences. Certain heart and metabolic diseases can lead to increased extracellular fluid formation. Study Guide: Cunningham & Klein, Section 3. Berne & Levy, Chapters 14 - 24. 8 Intended learning outcomes, Lecture synopses and Study guides The renal system and body fluid regulation Lecture 1 Lecture 2 Lecture 3 Lecture 4 Lecture 5 Show the need for a system to regulate the volume and composition of body fluids and the circulatory system Describe the activities of the renal nephron Explain glomerular filtration rate (GFR) Identify sites of selective reabsorption and show mechanism Link renal function, body fluid volume, aldosterone and ADH Intended learning outcomes: s) t) u) v) w) Show suitability of renal system for the purpose of body fluid regulation Describe the nephron, its components and activities Explain GFR, its measurement and relevance in renal function Show importance of reabsorption and the mechanisms involved Explain coordination of renal body fluid regulation Synopsis: The fluid environment of the cell must be regulated to control exchange of materials and preserve the fluid environment within the cell. Water is gained and must also be lost daily to preserve this fluid homeostasis. It is the role of the kidneys to balance water gains and losses by regulating urine volume. The kidneys take a large share of the arterial blood flow to allow them adjust plasma water and solute content. This works because ECF and ICF are in equilibrium with plasma. The nephron is the basic renal functional unit and its main processes involve filtration and selective reabsorption. Quantification of these processes shows how body fluid composition could be regulated but fine tuning of the process is vital and requires communication between kidney and circulatory system. This is provided by endocrine means through aldosterone and ADH. Study Guide: Cunningham & Klein, Section 7. Berne & Levy, Chapters 34 - 38. 9 Intended learning outcomes, Lecture synopses and Study guides Reproduction, maintenance of the species Lecture 1 Lecture 2 Lecture 3 Lecture 4 Lecture 5 Lecture 6 The chromosomal basis of sex and the roles of the gonads and accessory structures Describe hormonal control of reproduction in male and female Explain the purpose of the breeding season and the oestrous cycle Explain pregnancy and parturition Account for mammary development and onset of lactation after parturition Account for lactational anoestrus and effect of weaning Intended learning outcomes: x) y) z) aa) bb) cc) dd) Explain sex differences and gametogenesis Demonstrate the endocrine hierarchy in control of reproduction Detail the control of spermatogenesis and libido/20 sexual function in male Explain the oestrous cycle, its follicular and luteal phases and effects of season Explain gestation and determination of gestation length Account for mammary development and onset and maintenance of function Account for effects of lactation on ovulation and oestrous cycles Synopsis: Half of male gametes carry the male determining Y-chromosome. These and gametes carrying X-chromosomes must be deposited in the female tract precisely when female gametes are ready to be fertilised. This requires much synchronisation of reproductive events in the sexes and requires a cyclic pattern of ovarian activity both to produce the hormones necessary to both encourage sexual liaison between sexes and also to promote development of any resulting embryos. Gestation is the prolongation of embryonic development and usually inactivates the cyclic ovary. Gestational hormones promote mammary development but full lactation is delayed until birth. Continued lactation requires young to suckle, which signal usually postpones resumption of ovarian cyclicity. Termination of suckling at weaning allows resumption of oestrous cycles. Study Guide: Cunningham & Klein, Section 6. Berne & Levy, Chapter 46. 10