Anatomy & Physiology Study Guide (Based on Your Lecture Notes)
Chapter 1: Organization of the Body & Homeostasis
Levels of Organization
Smallest → Largest
Chemical Level
Cellular Level
Tissue Level
Organ Level
Organ System Level
Organism Level
Example:
Chemicals → Cells → Tissues → Organs → Organ Systems → Human Body
Homeostasis
Homeostasis = maintaining a stable internal environment.
Fluids of the Body
Intracellular Fluid (ICF) = inside cells
Extracellular Fluid (ECF) = outside cells
Interstitial Fluid = between cells
Plasma = fluid portion of blood
Blood = 55% plasma
Plasma = 92% water
Systems That Maintain Homeostasis
Nervous System
Uses electrical impulses
Endocrine System
Uses hormones (chemical messengers)
Feedback Mechanisms
Negative Feedback
Returns body to normal.
Example:
Blood pressure rises
Body lowers it back to normal
Positive Feedback
Continues until an event ends
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