Human Body Orientation (Part I) MEDI-101 Fall 2024 PDF

Orientation to the human body (Part I) MEDI-101 Fall 2024 Dr Wisam Nabeel Ibrahim M.B.Ch.B, M.Sc, Ph.D, Assistant Professor  Learning Objectives 1. Define anatomy and physiology....

Orientation to the human body (Part I) MEDI-101 Fall 2024 Dr Wisam Nabeel Ibrahim M.B.Ch.B, M.Sc, Ph.D, Assistant Professor  Learning Objectives 1. Define anatomy and physiology. 2. Describe the different branches of anatomy and physiology. 3. Describe the Levels of Structural Organization in the human body. 4. List and Describe body systems. 5. Understand the basic life processes. 6. Explain the homeostasis process. 7. Understand the feedback control of homeostasis. 8. Understand the basic anatomical terminologies. 9. Describe Positions, names, planes. 10.Describe body cavities and their contents. 11.Describe abdominal regions and their contents.  Orientation  Anatomy and physiology—provide the foundation for understanding the body’s parts and functions.  Anatomy is the science of body structures and the relationships among them.  It was first studied by the careful cutting apart of body structures to study their relationships (dissection).  Physiology is the science of body functions—how the body parts work.  The structure of a part of the body often reflects its functions. Selected Branches of Anatomy and Physiology  Microscopic anatomy (Histology) Structures are too small to be seen with the naked eye Cells and tissues can be viewed only with a microscope Let’s look at examples of microscopic anatomy Skin, kidney, intestine, lung.  Diversity of cells Differences in: Epigenetics: methylation, acetylation and MicroRNAs which lead to - Different gene expression profile leading to - different types and amounts of proteins. Which make differences in I. Cell function. II. Cytoskeleton: The cytoskeleton is a dynamic network of protein filaments within the cell that provides structural support and determines cell shape. III. Cell Junctions and Adhesion. Cellular memory (Differentiated cell). Levels of Structural Organization  Levels of Structural Organization Six levels of structural organization 1. Atoms: the smallest units of matter. 2. Cells: the basic structural and functional units of an organism. 3. Tissues: groups of cells and the materials surrounding them that work together to perform a particular function. 4. Organs: structures that are composed of two or more different types of tissues; they have specific functions and usually have recognizable shapes. 5. Organ systems: consists of related organs with a common function. 6. Organisms: All the parts of the human body functioning together constitute the total organism.  Organ System Overview  Integumentary system  Forms the external body covering (skin) and includes hair and fingernails  Waterproofs the body  Cushions and protects deeper tissue from injury  Produces vitamin D with the help of sunlight  Excretes salts in perspiration  Helps regulate body temperature  Location of cutaneous nerve receptors  Organ System Overview  Skeletal system  Consists of bones, cartilages, ligaments, and joints  Provides muscle attachment for movement  Protects vital organs.  Site of blood cell formation.  Stores minerals.  Store Fat.  Organ System Overview  Muscular system  The skeletal muscles contract (or shorten)  Produces movement of bones  Organ System Overview  Digestive system  Includes the oral cavity (mouth), esophagus, stomach, small and large intestines, rectum, and accessory organs  Breaks down food  Allows for nutrient absorption into blood  Eliminates indigestible material as feces  Organ System Overview  Nervous system  Fast-acting control system  Consists of brain, spinal cord, nerves, and sensory receptors  Responds to internal and external stimuli  Sensory receptors detect changes  Messages are sent to the central nervous system  Central nervous system assesses information and activates effectors (muscles and glands)  Organ System Overview  Cardiovascular system Includes heart and blood vessels  Heart pumps blood  Vessels transport blood to tissues Blood transports:  Oxygen and carbon dioxide  Nutrients  Hormones Blood also contains white blood cells and chemicals that provide protection from foreign invaders  Organ System Overview  Lymphatic system  Includes lymphatic vessels, lymph nodes, and lymphoid organs  Complements the cardiovascular system by returning leaked fluids back to bloodstream  Lymph nodes and other lymphoid organs cleanse the blood  Houses white blood cells, which are involved in immunity  Organ System Overview  Respiratory system  Includes the nasal passages, pharynx, larynx, trachea, bronchi, and lungs  Gases are exchanged with the blood through air sacs in the lungs Supplies the body with oxygen Removes carbon dioxide  Organ System Overview  Endocrine system Secretes chemical molecules, called hormones, into the blood Body functions controlled by hormones include Growth, Reproduction and Use of nutrients Endocrine glands include: 1. Pituitary gland 2. Thyroid and parathyroids 3. Adrenal glands 4. Thymus 5. Pancreas 6. Pineal gland 7. Ovaries (females) and testes (males)  Organ System Overview  Urinary system  Includes the kidneys, ureters, urinary bladder, and urethra  Eliminates nitrogenous wastes  Maintains acid-base balance  Regulates water and electrolyte balance  Helps regulate normal blood pressure  Organ System Overview  Reproductive system  For males, includes the testes, scrotum, penis, accessory glands, and duct system  Testes produce sperm  Duct system carries sperm to exterior  For females, includes the ovaries, uterine tubes, uterus, and vagina  Ovaries produce eggs  Uterus provides site of development for fetus  Learning Objectives 1. Define anatomy and physiology. 2. Describe the different branches of anatomy and physiology. 3. Describe the Levels of Structural Organization in the human body. 4. List and Describe body systems. 5. Understand the basic life processes. 6. Explain the homeostasis process. 7. Understand the feedback control of homeostasis. 8. Understand the basic anatomical terminologies. 9. Describe Positions, names, planes. 10.Describe body cavities and their contents. 11.Describe abdominal regions and their contents. Thank you Orientation to the human body (Part II) MEDI-101 Fall 2024 Dr Wisam Nabeel Ibrahim M.B.Ch.B, M.Sc, Ph.D, Assistant Professor  Learning Objectives 1. Define anatomy and physiology. 2. Describe the different branches of anatomy and physiology. 3. Describe the Levels of Structural Organization in the human body. 4. List and Describe body systems. 5. Understand the basic life processes. 6. Explain the homeostasis process. 7. Understand the feedback control of homeostasis. 8. Understand the basic anatomical terminologies. 9. Describe Positions, names, planes. 10.Describe body cavities and their contents. 11.Describe abdominal regions and their contents.  Basic Life Processes 1. Metabolism: the sum of all chemical processes that occur in the body (Anabolism and catabolism). 2. Responsiveness: the body’s ability to detect and respond to changes. For example, an increase in body temperature. 3. Movement: includes motion of the whole body, individual organs, single cells, and even tiny structures inside cells. 4. Growth: is an increase in body size that results from an increase in the size of existing cells, an increase in the number of cells, or both. In addition, a tissue sometimes increases in size because the amount of material between cells increases. 5. Differentiation: is the development of a cell from an unspecialized to a specialized state. Such precursor cells, which can divide and give rise to cells that undergo differentiation, are known as stem cells. 6. Reproduction: refers either to (1) the formation of new cells for tissue growth, repair, or replacement, or (2) the production of a new individual.  Survival Needs  Nutrients  Chemicals used for energy and cell building  Include carbohydrates, proteins, lipids, vitamins, and minerals  Oxygen  Required for chemical reactions  Made available by the cooperation of the respiratory and cardiovascular systems  Water  60 to 80 percent of body weight  Most abundant chemical in the human body  Provides fluid base for body secretions and excretions  Normal body temperature  37ºC (98.6ºF)  Below this temperature, chemical reactions slow and stop Above this temperature, chemical reactions proceed too rapidly  Atmospheric pressure  Must be appropriate for gas exchange  Homeostasis  Homeostasis: is the maintenance of relatively stable conditions in the body’s internal environment.  Homeostasis occurs because of the ceaseless interplay of the body’s many regulatory systems (dynamic condition).  Main controlling systems are the Nervous system and the Endocrine system.  Necessary for normal body functioning and to sustain life  For example, the level of glucose in blood normally stays between 70 and 110 milligrams of glucose per 100 milliliters of blood.*  Homeostatic imbalance: A disturbance in homeostasis results in disease  Digestive system Respiratory system Takes in nutrients, digests them Takes in oxygen, which is (part of metabolism), and excretes required for metabolism, and unabsorbed matter (feces) excretes carbon dioxide Food O2 CO2 Cardiovascular system Via the blood, distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs Examples of interrelationships among Blood CO2 organ systems that illustrate life O2 functions. Heart Urinary system Nutrients Excretes nitrogen- containing wastes and excess ions Interstitial fluid Nutrients and wastes pass between blood and cells via the interstitial fluid Integumentary system Feces are Protects the body as a whole Urine is excreted from the external environment excreted by maintaining boundaries  Maintaining Homeostasis  All homeostatic control mechanisms have at least three components: receptor, control center, and effector Receptor Responds to changes in the environment (stimuli) Sends information to control center along an afferent pathway Control center Determines set point Analyzes information Determines appropriate response Effector Provides a means for response to the stimulus Information flows from control center to effector along efferent pathway  Mechanisms for Maintaining Homeostasis  Feed back response can be either  Depressing it (negative feedback) so that the whole control mechanism is shut off.  Enhancing it (positive feedback) so that the reaction continues at an even faster rate.  Most homeostatic control mechanisms are negative feedback, examples include regulation of body temperature, heart rate, blood pressure, breathing rate, and blood levels of glucose, oxygen, carbon dioxide, and minerals).  Positive feedback: is rare in the human body. Increases the original stimulus to push the variable farther reaction occurs at a faster rate  Examples of homeostatic positive feedback in the body occurs in blood clotting and infant birth.  Negative Feedback  Negative feedback  Includes most homeostatic control mechanisms  Reverses a change in a controlled condition  In these systems, the output shuts off the original stimulus or reduces its intensity  The variable change in a direction opposite to that of the initial change, returns to its “ideal” value  Both the nervous system (fast) and the endocrine system (slow) are important in the maintenance of homeostasis  The goal of negative feedback mechanisms is to prevent sudden, severe changes in the body  An Example of Negative Feedback: Blood Sugar To carry out normal metabolism, body cells need a continuous supply of glucose, their major fuel for producing cellular energy, or ATP. Blood sugar levels are normally maintained around 90 mg of glucose per 100 mls of blood. Rising glucose levels stimulate the insulin-producing cells of the pancreas, which respond by secreting insulin into the blood Insulin accelerates the uptake of glucose by most body cells. It also encourages storage of excess glucose as glycogen in the liver and muscles. Consequently, blood sugar levels fall back toward the normal set point, and the stimulus for insulin release diminishes An Example of Negative Feedback Blood Sugar Negative Feedback: regulating the body Temperature 36.1 C - 37.2 C Negative Feedback: regulating the blood pressure Negative Feedback: regulating the blood Calcium level.  Positive Feedback Mechanisms: Unlike a negative feedback system, a positive feedback system tends to strengthen or reinforce a change in one of the body’s-controlled conditions. In a positive feedback system, the control center still provides commands to an effector, but this time the effector produces a physiological response that adds to or reinforces the initial change in the controlled condition. The action of a positive feedback system continues until it is interrupted by some mechanism  Positive Feedback Mechanism  Enhancement of labour contractions during birth:  Oxytocin, a hypothalamic hormone, intensifies labour contractions during the birth of a baby.  Causes the contractions to become more frequent and more powerful until the baby is finally born, an event that ends the stimulus for oxytocin release and shuts off the positive feedback mechanism.  Positive Feedback Mechanism An Example of Positive Feedback: Lactation An Example of Positive Feedback: Blood Clotting  Another example of positive feedback is what happens to your body when you lose a great deal of blood. Upon severe blood loss, blood pressure drops, and blood cells (including heart cells) receive less oxygen and function less efficiently. If the blood loss continues, heart cells become weaker, the pumping action of the heart decreases further, and blood pressure continues to fall. This is an example of a positive feedback cycle that has serious consequences and may even lead to death if there is no medical intervention. Combined feedback mechanisms  Homeostatic Imbalance  lifelong good health is not something that happens effortlessly. The many factors in this balance called health include the following: The environment and your own behavior. Your genetic makeup. The air you breathe, the food you eat, and even the thoughts you think.  Many diseases are the result of years of poor health behavior that interferes with the body’s natural drive to maintain homeostasis.  Causes: As we age, our body’s control systems become less efficient and less stable which increase the risk of illness Negative feedback mechanisms become overwhelmed and destructive positive feedback mechanisms take over.  Learning Objectives 1. Define anatomy and physiology. 2. Describe the different branches of anatomy and physiology. 3. Describe the Levels of Structural Organization in the human body. 4. List and Describe body systems. 5. Understand the basic life processes. 6. Explain the homeostasis process. 7. Understand the feedback control of homeostasis. 8. Understand the basic anatomical terminologies. 9. Describe Positions, names, planes. 10.Describe body cavities and their contents. 11.Describe abdominal regions and their contents. Thank you