Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Elaine N. Marieb Chapter 1 The Human Body: An Orientation

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Ch 1 Performance Objectives Define Anatomy and Physiology. Describe the relationship between structure and function. Define basic directional terms. Describe the anatomical position. Describe the major cavities of the body. Describe the levels of organization of the body and give major characteristics of each level. List the organ systems. Define homeostasis and explain why it is important. Describe the negative-feedback system and the positive-feedback system and their relationship to homeostasis. Name and describe the three major planes of the body or organ.

The Human Body – An Orientation Anatomy – study of structure and shape of body and its parts Physiology – study of how body and its parts work or function

Anatomy – Levels of Study Gross Anatomy Large structures Easily observable

Anatomy – Levels of Study Microscopic Anatomy Very small structures Can only be viewed with microscope

Levels of Structural Organization

Organ System Overview Integumentary system Forms external body covering Protects deeper tissue from injury Makes vitamin D Location of cutaneous nerve receptors

Organ System Overview Skeletal system Protects, supports body organs Provides muscle attachment for movement Site of blood cell formation (in marrow) Stores minerals (Ca, Phos)

Organ System Overview Muscular system Allows locomotion Maintains posture Produces heat

Organ System Overview Nervous system Fast-acting control system Responds to internal and external changes Activates muscles and glands

Organ System Overview Endocrine system Secretes regulatory hormones for Growth Reproduction Metabolism

Organ System Overview Cardiovascular system Transports materials in body via blood pumped by heart Oxygen (O 2 ) Carbon dioxide (CO 2 ) Nutrients Wastes

Organ System Overview Lymphatic system Returns fluids to blood vessels Disposes of debris Involved in immunity

Organ System Overview Respiratory system Keeps blood supplied with (O 2 ) Removes (CO 2 )

Organ System Overview Digestive system Breaks down food Allows for nutrient absorption into blood Eliminates indigestible material

Organ System Overview Urinary system Eliminates nitrogenous wastes Maintains acid – base balance Regulation of water & electrolytes (K, Na)

Organ System Overview Reproductive system Produce offspring

Homeostasis maintenance of a stable internal environment dynamic (active, moving) state of equilibrium must be maintained for normal body functioning and to sustain life Homeostatic imbalance – disturbance in homeostasis = sickness, disease

Maintaining Homeostasis Body communicates via neural & hormonal control systems Receptor Responds to changes in environment (stimuli) Sends information to control center (brain, SC)

Maintaining Homeostasis Control center Determines set point Analyzes information Determines appropriate response Effector Provides a way to respond to the stimulus

Feedback Mechanisms Negative feedback most control mechanisms Shuts off the original stimulus, or reduces its intensity Works like thermostat

Positive Feedback Increases original stimulus to push variable farther In body, this occurs only in blood clotting and child birth

The Language of Anatomy Slide 1.21 Exact terms are used for: Position Direction Regions Structures

Orientation and Directional Terms

Anterior Body Landmarks Figure 1.5a

Posterior Body Landmarks

Body Planes

Body Cavities