Organization of the Human Body Chapter 1

Definitions Anatomy: Science of Structure Physiology: Science of body functions

Levels of Organization Chemical: atoms->molecules Cellular: cells with organelles Basic unit of life Tissue: groups of cells & surround 4 basic types: epithelial, connective, muscular, nervous Organ: groups of tissues performing a common function System: group of organs with a common function Organism

Figure 1.1

Life Processes Metabolism Responsiveness Movement Growth Differentiation Reproduction

Homeostasis Maintaining a stable internal environment Dynamic process

Homeostasis (Cont.) Maintained by feedback systems Involves adjusting the value of a physiological variable Must be measured and then changed toward some goal

System Components Variable at issue=controlled variable Receptor. measures variable value Control Center. evaluates input from receptor and send output to the effector Effector. System that changes the value of the controlled variable as determined by the control center

Figure 1.2

Negative Feedback System Reverses a change in the controlled variable, bringing it back to “normal” This is the process that maintains homeostasis E.g. blood sugar levels, blood pressure, body temperature

Figure 1.3

Positive Feedback Systems This process strengthens a change. Rare but important Must be shut down by an outside force. E.g. child birth, ovulation, blood clotting

Clinical Terms Disorder: abnormality of structure/function Disease: specific illness determined by signs & symptoms Symptoms: subjective changes not observable form outside Signs: measurable observable changes

Aging & Homeostasis Normal process that includes a progressive loss in the ability to maintain homeostasis

Anatomical Terms Precise use of language to define position, direction and location in the body.

Figure 1.4a

Figure 1.4b

Figure 1.5

Figure 1.6

Figure 1.7a

Figure 1.7b

Figure 1.7c

Figure 1.8 part 1

Figure 1.8 part 2

Figure 1.10a

Figure 1.10b

Figure 1.11