Chapter 1: The Human Body: An Orientation

In chapter 1, Marieb and Hoehn of our Anatomy and Physiology book, the author goes over the basics about anatomy and physiology. They stress how anatomy and physiology go hand in hand. They state the definition of anatomy as “the study of structure of body parts and their relationship with one another.” The author continues by defining physiology as “the study of the function of different body parts.” The main point of the definitions of anatomy and physiology is that they work off each other. The structure of a body part reflects on what the function of that body part would do.  After the basic summary of what this book and chapter is about, the authors go into describing the different levels of structural organization. There is chemical organization, which are atoms, molecules, and organelles. There are cellular systems which are cells and Tissue which are groups of similar cells. Next, organs which contain 2 or more types of tissue, organ systems which are organs working closely today. Lastly, Organismal which are all the organs working together. Here is a diagram to visually understand the levels of structures. 


http://www2.lbsdk12.com/science/Anatomy/anatomyunit101.html

Human are multicellular in order to function, these cell depend on organ systems in order to survive.    Body cells are interdependent on each other which basically means that one system can’t work alone, if one thing changes then things in other systems will also have to change. The body also likes to keep homeostasis or balance in its environment, such as its internal temperature. In order to keep this homeostasis environment the body has receptors, a control center, and effectors. The receptor is a senor and its job is to monitor the environment of the body and respond to different stimuli. The receptors bring the information to the control center which determines the set point at which a variable needs to be maintained. After the control center receives the information from the receptor it determines what needs to be done to maintain balance in the body. Once it decides what needs to be done, the control center tells the effectors what needs to be done. The effector is usually a muscle or a gland which acts upon what the control center ordered them. The response the effector makes either reduces or stimulates stimuli. This is either a negative (reduces) or positive (stimulates) feedback. Negative feedback is much more common that positive feedback. Negative feedback is when the response given off reduces or shuts off the original stimulus. This is when the stimulus reaches its set point such as body temperature. Once the body researches its set point, the normal body temperature, the control center tells the receptors to stop producing the stimuli that is increasing the body temperature. Positive feedback is very rare, it is when the control center wants the response to speed up or enhance the stimuli because it isn’t doing enough. Such as giving labor, the exaggeration the production of oxytocin in a pregnant female gives a woman extreme contractions she needs in order to deliver the body. People wouldn’t be able to function if there was a lot of positive feedback. Referring back to the giving labor example, the contractions would keep getting bigger and bigger and the cervix would never go back to the normal size after the delivery.

http://www.tokresource.org/tok_classes/enviro/syllabus_content/1.1_Systems/index.htm

Here is your summary of key points for chapter 1 in the anatomy and physiology book! Hope this helped your understanding of chapter 1, or at least another review of the information to help the memorizing.