Homeostasis Systems

Study Notes

Two systems that maintain homeostasis: Nervous system and Endocrine system
Nervous system controls and coordinates bodily activities that require rapid responses
Endocrine system regulates activities that require duration rather than speed, controlling concentration of nutrients and internal environment

Homeostasis is continually being disrupted by external stimuli (heat, cold, lack of oxygen, pathogens, toxins) and internal stimuli (body temperature, blood pressure, concentration of water, glucose, salts, oxygen, etc.)
If homeostasis is not maintained, death may result
Homeostatic control systems are grouped into two classes: Intrinsic controls (local controls inherent in an organ) and Extrinsic controls (regulatory mechanisms initiated outside an organ)

Types of feedback systems: Negative feedback (reverses the original stimulus) and Positive feedback (intensifies the original stimulus)
Negative feedback loop consists of: Receptor (monitors a controlled condition and detects changes), Control Centre (determines next action), and Effector (receives directions from the control centre and produces a response that restores the controlled condition)

Process of maintaining a steady body temperature
Skin and muscles regulate body temperature
Sweating: releases heat from the skin, cooling it down
Shivering: hypothalamus signals skin and muscular, respiratory, and circulatory systems to constrict blood vessels, contract muscles, and release thyroid hormones to increase metabolism

The amount of water in the blood must be kept constant to avoid cell damage
Balance is maintained between water gained and water lost by the body
ADH (anti-diuretic hormone) regulates water levels in the blood
Hypothalamus detects changes in water levels and sends messages to the pituitary gland to release ADH, which controls the kidneys to produce more or less concentrated urine