Orientation to the human body (Part I) MEDI-101 Spring 2024 PDF

Orientation to the human body (Part I) MEDI-101 Spring 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 h...

Orientation to the human body (Part I) MEDI-101 Spring 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. Levels of Structural Organization 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 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 Spring 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 Takes in nutrients, digests them (part of metabolism), and excretes unabsorbed matter (feces) Respiratory system Takes in oxygen, which is required for metabolism, and 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 Blood Examples of interrelationships among organ systems that illustrate life functions. CO2 O2 Heart Nutrients Urinary system Excretes nitrogencontaining wastes and excess ions Interstitial fluid Nutrients and wastes pass between blood and cells via the interstitial fluid Feces are excreted Integumentary system Protects the body as a whole from the external environment by maintaining boundaries Urine is excreted 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 glucose, their major fuel for producing cellular energy, or ATP. supply of 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 mechanism. shuts off the positive feedback 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 Orientation to the human body (Part III) MEDI-101 Spring 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. The Language of Anatomy Scientists and health-care professionals use a common language of special terms when referring to body structures and their functions. The language of anatomy they use has precisely defined meanings that allow us to communicate clearly and precisely. Special terminology is used to prevent misunderstanding ❖ Exact terms are used for: Position Direction Regions Structures Body Positions Descriptions of any region or part of the human body assume that it is in a standard position of reference called the anatomical position. Terminology refers to this position regardless of actual body position In the anatomical position, the subject stands erect facing the observer, with the head level and the eyes facing directly forward. The lower limbs are parallel, and the feet are flat on the floor and directed forward, and the upper limbs are at the sides with the palms turned forward. Two terms describe a reclining body. If the body is lying facedown, it is in the prone position. If the body is lying faceup, it is in the supine position. Regional Terms Directional Terms To locate various body structures, anatomists use specific directional terms, words that describe the position of one body part relative to another. Body Planes and Sections Sections are cuts along imaginary lines known as planes Three types of planes or sections exist as right angles to one another Frontal Transverse Sagittal Oblique Sections A sagittal section divides the body (or organ) into left and right parts A median, or midsagittal, section divides the body (or organ) into equal left and right parts A frontal, or coronal, section divides the body (or organ) into anterior and posterior parts A transverse, or cross, section divides the body (or organ) into superior and inferior parts Body Cavities Organs inside the thoracic and abdominopelvic cavities are called viscera Thoracic and Abdominal Cavity Membranes A membrane is a thin, pliable tissue that covers, lines, partitions, or connects structures. One example is a slippery, double-layered membrane associated with body cavities that does not open directly to the exterior called a serous membrane It covers the viscera within the thoracic and abdominal cavities and also lines the walls of the thorax and abdomen. The parts of a serous membrane are 1. the parietal layer, a thin epithelium that lines the walls of the cavities. 2. the visceral layer, a thin epithelium that covers and adheres to the viscera within the cavities. Between the two layers is a potential space that contains a small amount of lubricating fluid (serous fluid). The fluid allows the viscera to slide during movements, such as when the lungs inflate and deflate during breathing. Serous Membranes The serous membrane of the pleural cavities is called the pleura. The visceral pleura clings to the surface of the lungs, and the parietal pleura lines the chest wall, covering the superior surface of the diaphragm. In between is the pleural cavity, filled with a small amount of lubricating serous fluid Serous Membranes The serous membrane of the pericardial cavity is the pericardium. The visceral pericardium covers the surface of the heart; the parietal pericardium lines the chest wall. Between them is the pericardial cavity, filled with a small amount of lubricating serous fluid. Serous Membranes The peritoneum is the serous membrane of the abdominal cavity. The visceral peritoneum covers the abdominal viscera, and the parietal peritoneum lines the abdominal wall, covering the inferior surface of the diaphragm. Between them is the peritoneal cavity, which contains a small amount of lubricating serous fluid. Most abdominal organs are surrounded by the peritoneum. Some are not surrounded by the peritoneum; instead, they are posterior to it. Such organs are said to be retroperitoneal. The kidneys, adrenal glands, pancreas, duodenum of the small intestine, ascending and descending colons of the large intestine, and portions of the abdominal aorta and inferior vena cava are retroperitoneal. Other body cavities 1. 2. 3. 4. 5. the oral (mouth) cavity, which contains the tongue and teeth. the nasal cavity in the nose. the orbital cavities (orbits), which contain the eyeballs. the middle ear cavities (middle ears), which contain small bones. the synovial cavities, which are found in freely movable joints and contain synovial fluid. The four abdominopelvic quadrants. Right upper quadrant (RUQ) Left upper quadrant (LUQ) Right lower quadrant (RLQ) Left lower quadrant (LLQ) 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