An Introduction to the Structure and Function of the Body Chapter 01 An Introduction to the Structure and Function of the Body

Organization of the Body, and Anatomical Position and Directions Lesson 1.1 Organization of the Body, and Anatomical Position and Directions Define the following terms: anatomy, physiology, and pathology. Describe the scientific method. List and discuss in order of increasing complexity the levels of organization of the body. Define the term anatomical position. 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 Anatomy—study of structure of an organism and relationships of its parts (Dissection) Physiology—study of functions of living organisms and their parts Pathology—scientific study of disease

The Scientific Method

Structural Levels of Organization Organization is the most important characteristic of body structure. The body as a whole is a unit constructed of the following smaller units: Atoms and molecules—chemical level Cells—the smallest structural units; organizations of various chemicals Tissues—organizations of similar cells working together Organs—organizations of different kinds of tissues arranged for specific functions Systems—organizations of many different kinds of organs working together for complex functions Organism (body as a whole)-All systems working together

Structural Levels of Organization Courtesy of Barbara Cousins.

Anatomical Position Reference the position in which the body is standing erect with the feet slightly apart and arms at the sides with palms turned forward. Anatomical position gives meaning to directional terms.

Copyright Kevin Patton, Lion Den Inc, Weldon Springs, MO. Anatomical Position Copyright Kevin Patton, Lion Den Inc, Weldon Springs, MO.

Anatomical Directions Superior—toward the head, upper, above Inferior—toward the feet, lower, below

Anatomical Directions Anterior—front, in front of (same as ventral in humans) Posterior—back, in back of (same as dorsal in humans)

Anatomical Directions Medial—toward the midline of a structure Lateral—away from the midline or toward the side of a structure

Anatomical Directions Proximal—toward or nearest the trunk, or nearest the point of origin of a structure Distal—away from or farthest from the trunk, or farthest from a structure’s point of origin

Anatomical Directions Superficial—nearer the body surface Deep—farther away from the body surface

Planes or Body Sections Sagittal plane—lengthwise plane that divides a structure into right and left sections Midsagittal—sagittal plane that divides the body into two equal halves Frontal (coronal) plane—lengthwise plane that divides a structure into anterior and posterior sections Transverse plane—horizontal plane that divides a structure into upper and lower sections

Directions and Planes of the Body & Tissues Courtesy of Barbara Cousins.

Lesson 1.2 Body Sections, Cavities, and Regions; and the Balance of Body Functions List the major cavities of the body and the subdivisions of each, including 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.

Body Cavities Ventral cavity Thoracic cavity Mediastinum—midportion of thoracic cavity; heart and trachea located in mediastinum Pleural cavities— right lung located in right pleural cavity; left lung in left pleural cavity

Courtesy of Rolin Graphics. Body Cavities Courtesy of Rolin Graphics.

Body Cavities Ventral cavity Abdominopelvic cavity Abdominal cavity— contains stomach, intestines, liver, gallbladder, pancreas, and spleen Pelvic cavity— contains reproductive organs, urinary bladder, and lowest part of intestine Abdominopelvic regions Nine regions Four quadrants

Quadrants and Regions of Abdominopelvic Cavity Courtesy of Barbara Cousins.

Body Cavities Dorsal cavity Cranial cavity contains the brain Spinal cavity contains the spinal cord

Organs of the Major Body Cavities

Body Regions Axial region— head, neck, and torso or trunk Appendicular region— upper and lower extremities

Axial & Appendicular Divisions of the Body

The Balance of Body Functions Survival of the individual and of the genes that make up the body is of the utmost importance. Survival depends on the maintenance or restoration of homeostasis (relative constancy of the internal environment). The body uses negative feedback loops and, less often, positive feedback loops to maintain or restore homeostasis. Feedback loops involve a sensor, a control center, and an effector.

The Body's Internal Environment

Negative Feedback Loops

Positive Feedback Loop

The Balance of Body Functions All organs function to maintain homeostasis. Ability to maintain balance of body functions is related to age: Peak efficiency occurs during young adulthood; diminishing efficiency occurs after young adulthood.

Studies of the Human Body (cont.) Body Systems (Organized by Function) Protection, support, and movement Integumentary Skeletal Muscular Coordination and control Nervous Endocrine

Studies of the Human Body (cont.) Body Systems (Organized by Function) (cont.) Circulation and immunity Cardiovascular Lymphatic Energy supply and fluid balance Respiratory Digestive Urinary Production of offspring Reproductive

Effects of Aging Gradual changes occur in all body systems. Some changes are harmless. Wrinkles and gray hair Some changes may result in injury and disease. Decreased kidney function Loss of bone mass Formation of deposits within blood vessels

Key Terms anabolism intracellular fluid anatomic position metabolism anatomy negative feedback catabolism organ cell pathology disease physiology extracellular fluid system homeostasis tissue

Word Anatomy (cont.) Word Part Meaning Example Studies of the Human Body dis- apart, away from To dissect is to cut apart. -logy study of Radiology is the study and use of radioactive substances. path/o disease Pathology is the study of disease. physi/o nature, physical Physiology is the study of how the body functions. -tomy cutting, incision of Anatomy

Word Anatomy (cont.) Word Part Meaning Example Metabolism ana- upward, again, back Anabolism is the building up of simple compounds into more complex substances. cata- down Catabolism is the breakdown of complex substances. extra- outside of, beyond Extracellular fluid is outside the cells. home/o- same Homeostasis is the steady state (sameness) within an organism. intra- within Intracellular fluid is within a cell. stat, -stasis stand, stoppage, constancy In homeostasis, “-stasis” refers to constancy.