What is Anatomy & Physiology? BIG IDEAS: How does the body maintain homeostasis? How are structure and function interdependent?

Introduction “Modern medicine began with long-ago observations on the function, and malfunction of the human body. The study of the human body probably began with our earliest ancestors, who must have been curious about how their bodies worked, as we are today. At first, their interest most likely concerned injuries and illnesses, because healthy bodies demand little attention from their owners. Their healers relied heavily on superstitions and notions about magic. However, as healers tried to help the sick, they began to discover useful ways of examining and treating the human body. They observed the effects of injuries, noticed how wounds healed, and examined cadavers to determine causes of death. They also found that certain herbs and potions could sometimes be used to treat coughs, headaches, fevers, and other common signs of illness.

Introduction (cont.) “Over time, people began to believe that humans could understand forces that caused natural events. They began observing the world around them more closely, asking questions and seeking answers. This set the stage for the development of modern medical science. As techniques for making accurate observations and performing careful experiments evolved, knowledge of the human body expanded rapidly. At the same time, early medical providers coined many new terms to name body parts, describe their locations, and explain their functions and interactions. These terms, most of which originated from Greek or Latin words, formed the basis for the language of anatomy and physiology that persists today.” –Hole’s Essentials of Human Anatomy and Physiology Review Questions: What factors probably stimulated an early interest in the human body? What kinds of activities helped promote the development of modern medical science?

Anatomy & Physiology anatomy - study of the structure of body parts and how they are organized anatomy = structure physiology – study of the functions of body parts; what they do and how they do it physiology = function Anatomy is to structure, what physiology is to function.

A & P (cont.) a body part’s function depends on the organization of its structure all physiological functions are performed by anatomical parts anatomy and physiology are interdependent and influence each other Review Questions: Why might it be difficult to separate the topics of A & P? Brainstorm 3 examples of how the structure of a body part makes possible its function. (Ex. Teeth are shaped to break solid foods into smaller pieces.)

Levels of Organization chemical  cellular  tissues  organs  organ systems  organisms complexity increases with each level each level relies on the structure and function of the level below it Review Questions: A group of cells with a common function are called ______. Using the flow chart above, define organism.

Levels of Organization (cont.) Using a different organ system, construct a flow chart demonstrating how that system is organized.

Characteristics of Life cells – basic unit of life need for energy – metabolism (chemical processes that build up or break down materials) enables us to acquire and use energy to fuel life processes response to environment reproduction and development (growth)

Maintenance of Life being alive requires certain environmental factors water – most abundant chemical in body foods – provide the body with necessary chemicals (nutrients) in addition to water oxygen, heat, and pressure quantities and qualities of these resources are important

Maintenance (cont.) vital signs – observable body functions that reflect essential metabolic activities body temperature, blood pressure Review Questions: List the 5 characteristics of life. In what ways does an organism rely on its external environment.

Homeostasis homeostasis – stable internal environment dynamic process b/c physiological variables are constantly changing to survive, every living organism must maintain homeostasis How? homeostatic regulation

Homeostatic Regulation adjustments in physiological systems to maintain a stable internal environment requires a receptor, control center, effector receptor – sensitive to specific stimuli control center – receives and processes info effector – responds (corrects or reinforces)

Negative vs. Positive Feedback negative feedback – when a stimulus rises or falls outside normal, the receptor triggers an automatic response that corrects the initial stimulus negative feedback CORRECTS the stimulus Ex. thermostat normal room temp  temp rises (stimulus)  registers with thermometer (receptor)  sends info to thermostat (control center)  turns on air conditioner (effector)  room temp drops  normal room temp

Negative Feedback – Room Temp

Negative Feedback – Body Temp

Negative vs. Positive Feedback positive feedback – initial stimulus produces a response that reinforces the stimulus positive feedback REINFORCES the stimulus accelerates processes that need to be completed quickly (blood clotting or child birth) Review Questions: Define homeostasis. What is the difference between positive and negative feedback?

Positive Feedback – Blood Clotting