Anatomy Chapter 1

the existance of a stable internal environment

• Autoregulation
• Extrinsic regulation

occurs when a cell, a tissue, an organ, or an organ system adjusts its activites automatically in response to some environmental change

Whn oxygen levels decline in a tissue, the cells release chemicals that widen local blood vessles. This dilation increases the rate of blood flow and provides more oxygen to the region

results from the activites of the nervous system or endocrine system, two organ systems that control or adjust the activities of many other systems simultaneously

When you excersize, your nervous system issues commands that increase your heart rate so that blood will circulate faster

• receptor
• control center
• effector

a sensor that is sensitive to a particular stimulus or environmental change

recieves and processes the information supplied by the receptor and sends out commands

a cell or organ that responds to the commands of the control center and whose activity either opposes or enhances the stimulus

a way for counteracting an effect and provides long-term control over the body's internal conditions and systems. 

Negative feedback

an intial stimulus produces a response that exaggerates or enhances the original change in conditions rather than opposing it

they are typically found when a potentially dangerous or stressful process must be completed quickly before homeostasis can be restored