BIO310 Lecture 2 PDF - University of Toronto Mississauga

BIO310 Lecture – 1 Physiology of Regulatory Systems Introduction Dr. Nagham Abdalahad September 6th, 2024 Readings Vander’s Human Physiology - Chapter 1 1  Course Instructor Assistant...

BIO310 Lecture – 1 Physiology of Regulatory Systems Introduction Dr. Nagham Abdalahad September 6th, 2024 Readings Vander’s Human Physiology - Chapter 1 1  Course Instructor Assistant Professor -Biology Department University of Toronto Mississauga Dr. Nagham Abdalahad MD, M.Sc, Human Anatomy and Embryology PhD Molecular Medicine- Human Genetics [email protected] 2  Land Acknowledgement https://images.app.goo.gl/VQtbnynx4HTKT8aRA I wish to acknowledge this land on which the University of Toronto operates. For thousands of years, it has been the traditional land of the Huron-Wendat, the Seneca and, most recently, the Mississaugas of the Credit River. Today, this meeting place is still the home to many Indigenous people from across Turtle Island and we are grateful to have the opportunity to work on this land. 3  Lecture outline Introduction to the course Course organization: communication, textbook, etc. Lecture 1: Introduction to Physiology: Regulation & Mechanisms What is physiology? Homeostasis 4  BIO310- Learning Outcomes 1. To learn the fundamental concepts of integrative animal physiology and the central role of homeostasis in the regulation of animal systems. 2. Analysis of the principles that underlie the functioning of a variety of organ systems in animals, such as the cardiovascular, renal and respiratory systems. To understand the fundamental role that the nervous and endocrine systems play in the regulation of homeostasis. 3. Apply knowledge to solve problems associated with maintaining and regulating systems in the body. 4. Communicate biological knowledge and concepts in a clear, concise and correct manner in written form using the appropriate terminology 5  Course Organization In-person Lectures All classes will be conducted in-person If you are not able to attend, a zoom link is posted to join online You must register for a UTM Zoom account using your UTORid and password. (https://utoronto.zoom.us ) Lectures will have limit access to registered users ONLY. You have enrolled in this course and your attendance is expected at lectures, tests and the in-class quizzes Mark your calendar Students are expected to join the class on time. Note that classes begin 10 minutes past the hour. If you are joining online, you are responsible to mute their mics unless otherwise requested by your instructor. A quiz by the end of almost each lecture (no quizzes at the days of term test) Lectures are supplemented with slide presentations that will be made available to you before each lecture in pdf format. Lecture recordings will be posted for one week download and re-use is prohibited 6  Course Organization-Textbook Vander's Human Physiology ISE 16th Edition 1265131813 · 9781265131814 By Eric P. Widmaier, Hershel Raff, Kevin T. Strang © 2023 | Published: January 6, 2022 978-1-260-19269-8 VANDERS PKG / HUMAN PHYSIOLOGY Text With CONNECT W/SMARTBOOK 1 YR Digital: https://www.campusebookstore.com/integration/AccessCode s/default.aspx?bookseller_id=96&Course=UTM+Fall2021+BIO310H5F+ CONNECT+W%2fSMARTBOOK+1YR&frame=YES&t=permalink (Links to an external site.) 7  Our Communication Announcements - Pay attention to your emails from this course as any changes or special announcements will be made on Quercus Online Office hours : Mondays @ 3:00-4:00 PM (Zoom meeting link has been posted) 8  Course Organization- Communication E mail policy: Your email has been ignored ? You may email your instructor MONDAY- FRIDAY between 8:00 AM- 5:00 PM (emails outside this timeline might be missed) Expect that your emails will be replied within 48 hours Include your name, student number , the course code and use your @mail.utoronto.ca email address. Any email missing these components will be ignored. Contents questions should be posted in the Discussion Board ONLY. Do not email content questions. Office hours are also a good place to ask your questions. 9 Course Organization-Evaluation 10  Evaluations In-person Term Tests: (90 min) Will cover material from the lectures, assigned readings and homework All the assigned readings are testable. Test will be a mixture of multiple choice and short answer questions. In class Quizzes: by the end of almost every lecture (Quercus quizzes- MCQ) Weekly homework: at the end of every week. Available for one week The Final Examination will be comprehensive and will be based on all material covered in lecture and the assigned readings. 11  Missed Course Component Policy If you miss a term test for whatever reason (including medical reasons and other justifiable reasons), inform your instructor within 48 hours of the missed component. If your reason for missing a test is verifiable and justifiable, your grade will be re-distributed to the other term test If you missed both term tests, you must write a cumulative makeup test at the end of the course ( short answers only). If you miss the makeup test, an oral test will be offered. Documentation and Procedures for missing any of the above assessments: 1. If you missed a test, declare your absence on ACORN/ROSI on the day of the missed 2. Contact your instructor by email within 48 hours of the missed assessment; and Submit your Absence declaration from Acorn Students who enroll in courses with conflicting lectures, tutorials or practical will not receive accommodations for conflicting exams, assignments, lecture material, in-class participation, etc. 12  Missed Course Component If you missed an online lecture quiz : the least 5 quizzes will be dropped. You can miss 5 quizzes without penalty If you missed an online Homework: ALL homework assignments should be submitted. No need for medical documentation 13  Academic Integrity Academic Integrity The code of Behaviour on Academic Matters states that: The University and its members have a responsibility to ensure that a climate that might encourage, or conditions that might enable, cheating, misrepresentation or unfairness not be tolerated. To this end all must acknowledge that seeking credit or other advantages by fraud or misrepresentation or seeking to disadvantage others by disruptive behaviour is unacceptable, as is any dishonesty or unfairness in dealing with the work or record of a student. It is your responsibility as a student at the University of Toronto, to familiarize yourself with, and adhere to, both the Code of Student Conduct and the Code of Behaviour on Academic Matters. This means, first and foremost, that you should read them carefully. The Code of Student Conduct is available from the U of T Mississauga website (Registrar > Academic Calendar > Codes and Policies) or in your print version of the Academic Calendar. The Code of Behaviour on Academic Matters is available from the U of T Mississauga website (Registrar > Academic Calendar > Codes and Policies) or in your print version of the Academic Calendar. Another helpful document that you should read is How Not To Plagiarize, by M. Proctor. 14  Tips For Success in BIO310 Attend Have all Have a Maintain a Schedule Get all required personal calendar or personal information classes materials network of planner appointments, through peers includes due work so they do emails and dates not conflict with Quercus your classes https://images.app.goo.gl/GCFRZ7gzVvmUD85MA 15  Accessibility Students with diverse learning styles and needs are welcome in this course. In particular, if you have a disability or health consideration that may require accommodations, please feel free to approach the Accessibility Services Office as soon as possible. The Accessibility Services staff are available by appointment to assess specific needs, provide referrals and arrange appropriate accommodations. The sooner you let them and me know your needs, the quicker we can assist you in achieving your learning goals in this course. 16  Lecture Outline Introduction to the course Course organization: communication, textbook, etc. Lecture 1: Introduction to Physiology: Regulation & Mechanisms What is physiology? Homeostasis 17  Why Physiology is so cool! Integrative physiology: is the study of how cells, tissues, organs and organ systems function in living organisms The study of physiology integrates knowledge at all levels of organization 18  Levels of Cellular Organization Important relationship between structure and All muscle cells are specialized to function. generate mechanical force. There are 3 types of muscle cells in the human body: cardiac, skeletal, and smooth. Connective-tissue cells connect, anchor, and support the structures of the body. Control of cardiac and smooth muscle is involuntary, while skeletal muscle control is voluntary. Types of connective tissues include: Loose Connective Dense Connective A neuron is a cell of the nervous Blood system that is specialized to initiate, Bone integrate, and conduct electrical Cartilage signals to other cells, sometimes over Adipose long distances. Cellular extensions from many neurons are packaged together along with connective tissue to form a nerve. Vander’s Human Physiology Figure 1.1 19  Epithelial Cells and Epithelial Tissue Epithelial cells are specialized for the selective secretion and absorption of ions and organic molecules, and for protection. These cells are characterized and named according to their unique shapes, including cuboidal (cube-shaped), columnar (elongated), squamous (flattened), and ciliated. Epithelial tissue (known as an epithelium) may form from any type of epithelial cell. Epithelia may be arranged in single-cell-thick tissue, called a simple epithelium, or a thicker tissue consisting of numerous layers of cells, called a stratified epithelium. The type of epithelium that forms in a given Vander’s Human Physiology Figure 1.2 region of the body reflects the function of that particular epithelium. For example, the epithelium that lines the inner surface of the main airway, the trachea, consists of ciliated epithelial cells 20  What Surrounds the Cells? The immediate environment that surrounds each individual cell in the body is the extracellular fluid and extracellular matrix (ECM). ECM consists of a mixture of proteins, polysaccharides, and in some cases, minerals. The ECM serves two general functions: (1) it provides a scaffold for cellular attachments (2) it transmits information in the form of chemical messengers to the cells to help regulate their activity, migration, growth, and differentiation. Some proteins of the ECM consist of fibers, rope-like collagen fibers, and rubber band-like elastin fibers; others are a mixture of nonfibrous proteins that contain carbohydrate. 21  Organs and Organ Systems Organs are composed of two or more of the four tissue types (for example: blood vessels have layers of smooth muscle cells, endothelial cells and fibroblasts). Organ systems are a collection of organs that together perform an overall function (for example: the urinary system includes the kidney, ureters, bladder, and urethra). 22 Vander’s Human Physiology Figure 1.1  Table 1.1 Organ Systems of the Body System Major Organs or Tissues Primary Functions Circulatory Heart, blood vessels, blood Transport of blood throughout the body Digestive Mouth, salivary glands, pharynx, Digestion and absorption of nutrients esophagus, stomach, small and large and water; elimination of wastes intestines, anus, pancreas, liver, gallbladder Endocrine All glands or organs secreting hormones; Regulation and coordination of many pancreas, testes, ovaries, hypothalamus, activities in the body, including growth, kidneys, pituitary, thyroid, parathyroids, metabolism, reproduction, blood adrenals, stomach, small intestine, liver, pressure, water and electrolyte balance, adipose tissue, heart, and pineal gland; and others and endocrine cells in other organs Immune White blood cells and their organs of Defense against pathogens production Integumentary Skin Protection against injury and dehydration; defense against pathogens; regulation of body temperature Lymphatic Lymph vessels, lymph nodes Collection of extracellular fluid for return to blood; participation in immune defenses; absorption of fats from digestive system 23  Table 1.1 Organ Systems of the Body System Major Organs or Tissues Primary Functions Musculoskeletal Cartilage, bone, ligaments, tendons, joints, Support, protection, and movement of skeletal muscle the body; production of blood cells Nervous Brain, spinal cord, peripheral nerves and Regulation and coordination of many ganglia, sense organs activities in the body; detection of and response to changes in the internal and external environments; states of consciousness; learning; memory; emotion; others Reproductive Male: testes, penis, and associated ducts Male: production of sperm; transfer of and glands sperm to female Female: ovaries, fallopian tubes, uterus, Female: production of eggs; provision of vagina, mammary glands a nutritive environment for the developing embryo and fetus; nutrition of the infant Respiratory Nose, pharynx, larynx, trachea, bronchi, Exchange of carbon dioxide and oxygen; lungs regulation of hydrogen ion concentration in the body fluids Urinary Kidneys, ureters, bladder, urethra Regulation of plasma composition through controlled excretion of ions, water, and organic wastes 24  Body Fluid Compartments The term “body fluid,” refers to the watery solution of dissolved substances (oxygen, nutrients, and wastes) present in the body. The fluid in the blood and in spaces surrounding the cells is called extracellular fluid (all fluid outside of cells). Of this, 20 to 25% is in the fluid portion of blood (plasma); the remaining 75 to 80% lies around and between cells and is called the interstitial fluid. The space containing interstitial fluid is called the interstitium. Therefore, the total volume of extracellular fluid is the sum of the plasma and interstitial fluid volumes. Vander’s Human Physiology Figure 1.3 25  Homeostasis Homeostasis refers to physiological variables in a state of dynamic constancy; it is not a static process. Most physiological variables such as blood pressure, body temperature, and blood gases, are maintained within a predictable Physiological range. Physiological variables can change dramatically over a 24-hour period, but the body is still in overall balance. When homeostasis is maintained, we refer to physiology; when it is not, we refer to pathophysiology. 26  Blood Glucose Concentration Changes in Blood Glucose Concentration During a Typical 24-Hour Period Blood glucose levels increase after eating, and then levels return to their set point via homeostasis. This is an example of dynamic constancy. Levels change over short periods of time but remain relatively constant over long periods of time. 27 Vander’s Human Physiology Figure 1.4  Control Systems Feedback loops or systems are a common mechanism to control physiological processes. A negative feedback system brings about responses that move a variable opposite to the direction of its original change. A positive feedback system enhances the production of the product or accelerates a process. 28  Negative Feedback A Homeostatic Control System Maintains Body Temperature When Room Temperature Decreases Response that moves leads to Room temp is 20 degrees the variable opposite Body temp is 37 degrees (negative to) the direction of the original change Resetting the set point to higher value. Shivering and chills before fever Set point or steady state 29 Vander’s Human Physiology Figure 1.5  Negative Feedback at Cellular Level Example accumulation of ATP inside the cells “Active product” controls the sequence of chemical reactions by inhibiting the rate-limiting enzyme, “Enzyme A.” 30 Vander’s Human Physiology Figure 1.6  Homeostatic Control Systems In negative feedback, a change in the variable being regulated brings about responses that tend to move the variable in the direction opposite the original change – that is, back toward the initial value (set point). Stability of an internal environmental variable is achieved by balancing inputs and outputs. It is not the absolute magnitudes of the inputs and outputs that matter but the balance between them. Homeostatic control systems cannot maintain complete constancy of any given feature of the internal environment. Therefore, any regulated variable will have a more or less narrow range of normal values depending on the external environmental conditions. The set point of some variables regulated by homeostatic control systems can be reset – that is, physiologically raised or lowered. It is not always possible for homeostatic systems to maintain every variable within a narrow normal range in response to an environmental challenge. There is a hierarchy of importance, so that certain variables may be altered markedly to maintain others within their normal range. 31  Mixed Conformity and Regulation in a Single Species Salmon are temperature conformers but chloride regulators. the presentation of Cl – regulation is diagrammatic; the blood Cl– concentration is not in fact absolutely constant but is a little higher when the fish are in seawater than when they are in freshwater. 32  Positive feedback does not lead to regulation! https://images.app.goo.gl/dfaAvFryL64SJFQNA Vander’s Human Physiology Figure 1.7 Positive feedback occurs infrequently in biological systems but is involved in important processes: the action potential clot production 33  Reflexes General Components of a Reflex Arc that Functions as a Negative Feedback Control System A reflex is a specific, involuntary, unpremeditated, “built-in” response to a particular stimulus. Example: pulling your hand away from a hot object or shutting your eyes as an object rapidly approaches your face. A reflex arc has several components: stimulus, receptor, afferent (incoming) pathway, integrating center, efferent (outgoing) pathway, and effector. A stimulus is defined as a detectable change in the internal or external environment, and a receptor detects the environmental The reflex arc change. The signal travels between the receptor and the integrating Vander’s Human Physiology Figure 1.8 center along the afferent pathway. The information going from the integrating center to the effector travels along the efferent pathway. An integrating center often receives signals from many receptors, some of which may respond to quite different types of stimuli. Thus, the output of an integrating center reflects the net effect of the total afferent input; that is, it represents an integration of numerous bits of information. 34  Reflex for Minimizing the Decrease in Body Temperature that Occurs on Exposure to a Reduced External Environmental Temperature Feedforward Regulation ? Physiological changes that occur in anticipation of a future change to a variable. Vander’s Human Physiology Figure 1.9 35  Hormones and Glands Can Be Reflex Components Almost all body cells can act as effectors in homeostatic reflexes. Muscles and glands are the major effectors of biological control systems. Glands may be both a receptor and an integrating center, and they secrete hormones into the blood that act as effectors. A hormone is a type of chemical messenger secreted into the blood by cells of the endocrine system. Hormones may act on many different cells simultaneously because they circulate throughout the body. Vander’s Human Physiology Figure 1.8 36  Intercellular Chemical Messengers Hormones are produced in and secreted from endocrine glands or in scattered cells that are distributed throughout another organ. Hormones travel through the blood to their target cells. Neurotransmitters are chemical messengers that are released from the endings of neurons onto other neurons, muscle cells, or gland cells. 37  Categories of Chemical Messengers A given chemical messenger can fit into more than one category. For example, the steroid hormone cortisol affects the very cells in which it is made, the nearby cells that produce other hormones, and many distant targets, including muscles and liver. In some cases, a particular messenger may function as a neurotransmitter, a hormone, or a paracrine or autocrine substance, Norepinephrine. Vander’s Human Physiology Figure 1.10 38  Other Types of Cell Communication There are two important types of chemical communication between cells that do not require secretion of a chemical messenger. Gap junctions are physical linkages connecting the cytosol between two cells, which allow molecules to move from one cell to an adjacent cell without entering the extracellular fluid. Juxtacrine signaling is the chemical messenger not actually being released from the cell producing it, but rather is located in the plasma membrane of that cell. When the cell encounters another cell type capable of responding to the message, the two cells link up via the membrane-bound messenger. 39  Balance of Chemical Substances in the Body Many homeostatic systems regulate the balance between addition and removal of a chemical substance from the body. Two important generalizations concerning the balance concept are: : (1) during any period of time, total-body balance depends upon the relative rates of net gain and net loss to the body; and (2) the pool concentration depends not only upon the total amount of the substance in the body, but also upon exchanges of the substance within the body. Three states of total-body balance are possible: Negative balance loss > gain Positive balance (gain > loss) These are some of the potential inputs and outputs that Stable balance gain = loss can affect the “pool” of a substance (like glucose), which is a dynamically regulated physiological variable. Vander’s Human Physiology Figure 1.12 40  Adaptation and Acclimatization Adaptation denotes a characteristic that favors survival in specific environments. Acclimatization refers to the improved functioning of an already existing homeostatic system; in some cases, this is due to prolonged exposure to an environmental change. The five-time frames in which physiology changes 41  Biological Rhythms Circadian Rhythm Body Temperature in a Human Subject with Light On and Off Many body functions are associated with rhythmical changes. The most common type is the circadian rhythm, which cycles approximately once every 24 hours. Waking and sleeping, body temperature, hormone concentrations in the blood, the excretion of ions into the urine, and many other functions undergo circadian variation. Vander’s Human Physiology Figure 1.11 42  Relationship Between Biological Rhythms and Homeostasis Biological rhythms add an anticipatory component to homeostatic control systems, and in effect, are a feedforward system operating without detectors. Negative feedback homeostatic responses are corrective responses. They are initiated after the steady state of the individual has been perturbed. Biological rhythms enable homeostatic mechanisms to be utilized immediately and automatically by activating them at times when a challenge is likely to occur but before it actually does occur. 43  Case Study A 64-year-old, fair-skinned man in good overall health spent a very hot, humid summer day gardening in his backyard. After several hours in the sun, he began to feel light-headed and confused as he knelt over his vegetable garden. Although earlier he had been perspiring profusely and appeared flushed, his sweating had eventually stopped. Because he also felt confused and disoriented, he could not recall for how long he had not been perspiring, or even how long it had been since he had taken a drink of water. He called to his wife, who was alarmed to see that his skin had turned a pale-blue color. She asked her husband to come indoors, but he fainted as soon as he tried to stand. The wife called for an ambulance, and the man was taken to a hospital and diagnosed with a condition called heatstroke. What happened to this man that would explain his condition? How does it relate to homeostasis? Vander’s Human Physiology Figure 1.13 44