BIOL 1110-API-CH1-Fall 23 Introduction to the Body PDF

www.udst.edu.qa  Chapter 1 Introduction to the Body Introduction to the Body Learning Objectives Define the terms anatomy and physiology. List and discuss in order of increasing complexity the levels of organization of the body. Define the terms anatomical position, supine, and pron...

www.udst.edu.qa  Chapter 1 Introduction to the Body Introduction to the Body Learning Objectives Define the terms anatomy and physiology. List and discuss in order of increasing complexity the levels of organization of the body. Define the terms anatomical position, supine, and prone. List and define the principal directional terms and sections (planes) used in describing the body and the relationship of body parts to one another. Introduction to the Body Learning Objectives List the major cavities of the body and the subdivisions of each. List the nine abdominopelvic regions and the abdominopelvic quadrants. Discuss and contrast the axial and the appendicular subdivisions of the body. Identify a number of specific anatomical regions in each area. Explain the meaning of the term homeostasis and give an example of a typical homeostatic mechanism.  Anatomy and Physiology Anatomy: Study of the structure of an organism and relationship to its parts – Anatomists learn about the body by dissection Physiology: Study of the functions of living organisms and their parts – Physiologists use scientific experimentation Levels of Organization in the Body​ Levels of Organization Courtesy Barbara Cousins.  Levels of Organization Influence body structure and function Chemical level: Atoms and molecules – Cells: Smallest “living” units of structure and function – Tissues: Organizations of many cells that act together to perform common function Levels of Organization Chemical level: Atoms and molecules – Organs: Group of several different kinds of tissues arranged in a way that allows them to act as a unit to perform a special function – Systems: Organization of varying numbers and kinds of organs that can work together to perform complex functions for the body Anatomical Position Anatomical Position Body has bilateral symmetry Anatomical position: standing upright, arms at sides, palms facing forward (little fingers by the thigh), feet flat on the floor, face straight ahead Supine and prone are terms used to describe the position of the body when it is not in anatomical position – Supine: lying down with the face up Anatomical Directions Anatomical Directions Superior: Toward the head, upper, above Inferior: Toward the feet, lower, below Anterior: Front, in front of Posterior: Back, in back of Medial: Toward the midline of the body Lateral: Toward the side of the body or away from the midline Anatomical Directions Proximal: Toward or nearest the trunk, or nearest the point of origin Distal: Away from or farthest from the trunk, or farthest from a structure’s point of origin Superficial: Nearer the body surface Deep: Farther away from the body surface Directions and Planes of the Body Redrawn from Muscolino JE: Know the body: muscle, bone, and palpation essentials, St Louis, 2012, Mosby.  Planes of the Body Sagittal plane: Lengthwise plane that divides the body into right and left sections Midsagittal: Sagittal plane that divides the body into two equal halves Planes of the Body Frontal (coronal) plane: Lengthwise plane that divides a structure into anterior and posterior portions Transverse plane: Horizontal plane that divides a structure into upper and lower parts Planes Through the Body 2 (a) ©Eric Wise; (b) ©VideoSurgery/Science Source; (c,d) ©R.T. Hutchings  Planes Through an Organ Longitudinal: cut along the length of an organ. Transverse (cross): cut at right angle to the length of the organ. Oblique: cut at any but a right angle. Body Cavities Body Cavities Dorsal cavities – Cranial cavity: Space inside the skull that contains the brain – Spinal cavity: The space inside the spinal column Body Cavities Ventral cavities – Thoracic and abdominopelvic cavities Upper thoracic cavity, includes mediastinum and pleural cavities Lower thoracic cavity, includes the abdominal cavity and the pelvic cavity; both form the abdominopelvic cavity Body Cavities Abdominopelvic Quadrants Four quadrants – Right upper (or right superior) quadrant – Right lower (or right inferior) quadrant – Left upper (or left superior) quadrant – Left lower (or left inferior) quadrant Abdominopelvic Quadrants Abdominopelvic Quadrants Abdominopelvic Regions Upper: Right and left hypochondriac regions and the epigastric region Middle: Right and left lumbar regions and the umbilical region Lower: Right and left iliac regions and the hypogastric region Abdominopelvic Regions Courtesy Barbara Cousins. Body Regions Axial region: Head, neck, and torso or trunk Appendicular region: Upper and lower extremities Body structure and function varies among individuals and also throughout an individual's lifespan Axial and Appendicular Divisions The Balance of Body Functions Survival depends on the body maintaining relatively constant conditions – Body mechanisms act as heaters, air pumps, and the like, to maintain the relatively stable conditions Body’s Internal Environment  Examples of Homeostatic Regulation The digestive system Takes in and digests food. Provides nutrient molecules that replace used nutrients. The respiratory system Adds oxygen to the blood. Removes carbon dioxide. The liver and pancreas Stores excess glucose as glycogen. Later, glycogen is broken down to replace the glucose used. The hormone insulin regulates glycogen storage. The kidneys Under hormonal control, they excrete wastes and salts that can affect the pH of the blood. 34 Concept of Homeostasis Cells in a multicellular organism – Cannot live and function without other body cells Body Systems Maintain Homeostasis Definition : Homeostasis – Homeostasis—the ability to detect change, activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions  The Interdependence of Cells, Body Systems, and Homeostasis Maintain Body systems Homeostasis Is essential for survival of Make up Cells  Feedback Control Feedback loop: Body’s general control system Negative feedback: Opposes change in controlled condition (Example: controlling room temperature) Positive feedback: Amplifies occurring change (example: childbirth) Negative Feedback Opposes an initial change and is widely used to maintain homeostasis – Change in a controlled variable triggers a response that drives the variable in the opposite direction of the initial change, thus opposing the change Example: controlling body temperature Homeostasis in body temperature If too warm, vessels dilate in the skin and sweating begins (heat-losing mechanism) If too cold, vessels in the skin constrict and shivering begins (heat-gaining mechanism) Negative Feedback in Thermoregulation (b) Figure 1.7b Negative Feedback in Thermoregulation (a) Figure 1.7a Negative Feedback Homeostatic Compensation for a Postural Change in Blood Pressure Figure 1.8  Negative Feedback and Homeostasis 3 Receptor—structure that senses change in the body (e.g., stretch receptors above heart that monitor blood pressure) Integrating (control) center—control center that processes the sensory information, “makes a decision,” and directs the response (e.g., cardiac center of the brain) Effector— cell or organ that carries out the final corrective action to restore homeostasis (e.g., the heart) Positive Feedback Output enhances or amplifies a change so that the controlled variable continues to move in the direction of the initial change – Less common than negative feedback but is important in some instances Example: childbirth Positive Feedback Loop Disruptions in Homeostasis Can lead to illness and death – Pathophysiology: abnormal functioning of the body associated with disease – When a homeostatic disruption becomes so severe that it is no longer compatible with survival, death results Homeostasis and feedback  Thank you +974 4495 2222 [email protected] Location University of Doha for Science & Technology 68 Al Tarfa, Duhail North P.O. 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