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PowerPoint® Lecture Slides prepared by Barbara Heard, Atlantic Cape Community College CHAPTER 1 The Human Body: Modified by Dr. Par Mohammadian © Annie Leibovitz/Contact Press Images © 2013 Pearson Education, Inc. About This Chapter • • • • Definition Organizational levels: Systems Homeostasis & Control systems The science of physiology Overview of Anatomy and Physiology Physiology: Study of the functions of a living organism and its components, including all chemical and physical processes. Derived from scientific experiments Anatomy: Study of structure, with much less emphasis on function. Pathophysiology: Study of body function in a disease state (pathos: suffering) Levels of Structural Organization Atoms Organelle Smooth muscle cell Molecule Chemical level Atoms combine to form molecules. Cellular level Cells are made up of molecules. Cardiovascular system Heart Blood vessels Smooth muscle tissue Tissue level Tissues consist of similar types of cells. Blood vessel (organ) Smooth muscle tissue Connective tissue Epithelial tissue Organ level Organs are made up of different types of tissues. Organ system level Organismal level The human organism is made Organ systems consist of different organs that work together closely. up of many organ systems. Slide 1 Figure 1.3a The body’s organ systems and their major functions. Hair Skin Nails Integumentary System Forms the external body covering, and protects deeper tissues from injury. Synthesizes vitamin D, and houses cutaneous (pain, pressure, etc.) receptors and sweat and oil glands. Skeletal muscles Bones Joint Skeletal System Protects and supports body organs, and provides a framework the muscles use to cause movement. Blood cells are formed within bones. Bones store minerals. (c) Muscular System Allows manipulation of the environment, locomotion, and facial expression. Maintains posture, and produces heat. Pineal gland Brain Pituitary gland Thyroid gland Thymus Adrenal gland Pancreas Testis Spinal cord Nerves Nervous System As the fast-acting control system of the body, it responds to internal and external changes by activating appropriate muscles and glands. © 2013 Pearson Education, Inc. Ovary Endocrine System Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells. Red bone marrow Heart Thymus Lymphatic vessels Thoracic duct Spleen Lymph nodes Blood vessels Cardiovascular System Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood. © 2013 Pearson Education, Inc. Lymphatic System/Immunity Picks up fluid leaked from blood vessels and returns it to blood. Disposes of debris in the lymphatic stream. Houses white blood cells (lymphocytes) involved in immunity. The immune response mounts the attack against foreign substances within the body. Figure 1.3h The body’s organ systems and their major functions. Nasal cavity Pharynx Larynx Bronchus Trachea Lung Respiratory System Keeps blood constantly supplied with oxygen and removes carbon dioxide. The gaseous exchanges occur through the walls of the air sacs of the lungs. © 2013 Pearson Education, Inc. Figure 1.3i The body’s organ systems and their major functions. Oral cavity Esophagus Liver Stomach Small Intestine Large Intestine Rectum Anus Digestive System Breaks down food into absorbable units that enter the blood for distribution to body cells. Indigestible foodstuffs are eliminated as feces. © 2013 Pearson Education, Inc. Figure 1.3j The body’s organ systems and their major functions. Kidney Ureter Urinary bladder Urethra Urinary System Eliminates nitrogenous wastes from the body. Regulates water, electrolyte and acid-base balance of the blood. © 2013 Pearson Education, Inc. Figure 1.3k–l The body’s organ systems and their major functions. Mammary glands (in breasts) Prostate gland Ovary Penis Testis Scrotum Ductus deferens Uterus Vagina Male Reproductive System Overall function is production of offspring. Testes produce sperm and male sex hormone, and male ducts and glands aid in delivery of sperm to the female reproductive tract. Ovaries produce eggs and female sex hormones. The remaining female structures serve as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn. © 2013 Pearson Education, Inc. Uterine tube Female Reproductive System Overall function is production of offspring. Testes produce sperm and male sex hormone, and male ducts and glands aid in delivery of sperm to the female reproductive tract. Ovaries produce eggs and female sex hormones. The remaining female structures serve as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn. Homeostasis • Homeostasis – Maintenance of relatively stable internal conditions despite continuous changes in environment – A dynamic state of equilibrium – Maintained by contributions of all organ systems © 2013 Pearson Education, Inc. Homeostasis Organism in homeostasis Internal change External change Internal change results in loss of homeostasis Organism attempts to compensate Compensation fails Illness or disease Compensation succeeds Wellness Components of a Control Mechanism • Receptor (sensor) – Monitors environment; Responds to stimuli • Control center – Determines set point – Receives input from receptor – Determines appropriate response • Effector – Receives output from control center – Provides the means to respond – Response either reduces (negative feedback) or enhances stimulus (positive feedback) Input signal Integrating center Output signal Response Figure 1.4 Interactions among the elements of a homeostatic control system maintain stable internal conditions. 3 Input: Information sent along afferent pathway to control center. 2 Receptor detects change. 1 Stimulus produces change in variable. © 2013 Pearson Education, Inc. Receptor Control Center Afferent pathway Efferent pathway BALANCE Slide 1 4 Output: Information sent along efferent pathway to effector. Effector 5 Response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level. Negative Feedback • Most feedback mechanisms in body • Response reduces or shuts off original stimulus – Variable changes in opposite direction of initial change • Examples – Regulation of body temperature (a nervous system mechanism) – Regulation of blood glucose by insulin (an endocrine system mechanism) © 2013 Pearson Education, Inc. Figure 1.5 Body temperature is regulated by a negative feedback mechanism. Control Center (thermoregulatory center in brain) Afferent pathway Efferent pathway Receptors Effectors Sweet glands Temperature-sensitive cells in skin and brain) Sweat glands activated Response Evaporation of sweat Body temperature falls; stimulus ends Body temperature rises BALANCE Stimulus: Heat Stimulus: Cold Response Body temperature falls Body temperature rises; stimulus ends Receptors Temperature-sensitive cells in skin and brain Effectors Skeletal muscles Shivering begins Efferent pathway Afferent pathway Control Center (thermoregulatory center in brain) © 2013 Pearson Education, Inc. Negative Feedback: Regulation of Blood Glucose by Insulin • Receptors sense increased blood glucose (blood sugar) • Pancreas (control center) secretes insulin into the blood • Insulin causes body cells (effectors) to absorb more glucose, which decreases blood glucose levels © 2013 Pearson Education, Inc. Positive Feedback • Response enhances or exaggerates original stimulus • May exhibit a cascade or amplifying effect • Usually controls infrequent events that do not require continuous adjustment – Enhancement of labor contractions by oxytocin (chapter 28) – Platelet plug formation and blood clotting © 2013 Pearson Education, Inc. Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug. 1 Break or tear occurs in blood vessel wall. Positive feedback cycle is initiated. 3 Released chemicals attract more platelets. 2 Platelets Positive feedback loop adhere to site and release chemicals. Feedback cycle ends when plug is formed. 4 Platelet plug is fully formed. Figure 1.12 A positive feedback loop Baby drops lower in uterus to initiate labor Cervical stretch causing stimulates Push baby against cervix Oxytocin release Positive feedback loop causes Uterine contractions Delivery of baby stops the cycle Clinical Question: Calcium levels in Mr. X’s blood are dropping to dangerously low levels. The hormone PTH is released and soon blood Ca levels begin to rise. Shortly after, PTH release slows. Form a group and answer these questions (10 min): •Positive or negative feedback? •Identify the initial stimulus, receptor, afferent, integrating center, efferent? •Result? The Scientific Method • Steps: – Make observations. – Form a hypothesis. – The hypothesis must be testable (educated guess). Variables: Independent: Factor to be changed by investigators & Dependent: Observed factor following change – Design and conduct experiments or make more observations. – Analyze the data. Results must be replicated many times before a conclusion is accepted. Several verified hypotheses may become a general theory. Interpretation of Human Experiments • Difficult to interpret results – Genetic and environmental variability • Crossover studies – Placebo effect and nocebo effect • Blind, double-blind studies, and double-blind crossover studies – Ethics of humans as test subjects Tuskegee syphilis experiment Ethics in Germany - Nazi Measurements, Controls, and Statistics • Good physiological research requires: – Quantifiable measurements – An experimental group and a control group – Statistical analysis – Review and publication by a peer-reviewed journal (pubmed.gov) Can you form a good hypothesis? Figure 1.14a FOCUS ON . . . Graphs (1 of 5) Dependent variable (units) y-axis 1 unit 1 unit x-axis Independent variables(units) Legend (Describes the information represented by the graph) The standard features of a graph include units and labels on the axes, a key, and a figure legend. Group A Group B Key Figure 1.14b FOCUS ON . . . Graphs (2 of 5) 8 Food intake (g/day) 7 6 5 4 3 2 1 A Canaries were fed one of the three diets and their food intake was monitored for three weeks. B Diet C GRAPH QUESTION Which food did the canaries prefer? Bar graph. Each bar shows a distinct variable. The bars are lined up side by side along one axis so that they can be easily compared with one another. Scientific bar graphs traditionally have the bars running vertically. Figure 1.14c FOCUS ON . . . Graphs (3 of 5) Number of students 5 4 3 2 1 0 1 2 3 4 5 6 7 8 9 10 Quiz score The distribution of student scores on a 10-point quiz is plotted on a histogram. GRAPH QUESTION How many students took the quiz? Histogram. A histogram quantifies the distribution of one variable over a range of values. Figure 1.14d FOCUS ON . . . Graphs (4 of 5) 60 Body weight (g) 50 40 30 KEY 20 Males 10 Females 0 1 2 3 4 5 6 7 Day Male and female mice were fed a standard diet and weighed daily. GRAPH QUESTION When did male mice increase their body weight the fastest? Line graph. The x-axis frequently represents time; the points represent average observations. The points may be connected by lines, in which case the slope of the line between two points shows the rate at which the variable changes. Figure 1.14e FOCUS ON . . . Graphs (5 of 5) 100 90 Exam score (%) 80 70 Game 60 50 40 30 20 10 2 4 8 6 Time spent studying (hours) 10 12 Student scores were directly related to the amount of time they spent studying. GRAPH QUESTION For graphs (d) and (e), answer the following: • What was the investigator trying to determine? • What are the independent and dependent variables? • What are the results or trends indicated by the data? Scatted plot. Each point represents one member of a test population. The individual points of a scatter plot are never connected by lines, but a best fit line may be estimated to show a trend in the date, or better yet, the line may be calculated by a mathematical equation.