Mechanisms of Homeostasis

Homeostasis Defined: Process where the body maintains a constant internal environment Reactions & enzymes work best in specific conditions Control systems adjust to changes pH, temp, fluids Hypothalamus senses you are cold Thermostat turns heater off Thermostat senses cold room Hypothalamus turns off Room gets back to normal Body temp returns to normal Hypothalamus activates muscles to shiver Heater is activated Heat is generated Warm air released

Control Systems Sensors (aka: receptors) !*%!?%&# Sensors (aka: receptors) Gather information about the body Ex: skin senses pressure from bowling ball Communication Center Messages sent throughout the body Ex: Impulse travels through your nerves Control Center Receives information from the sensors Ex: Brain receives the impulse Targets Body part changes its activity Ex: Brain tells foot muscles to pull away

Negative Feedback Loops Regulates most of the body Reverses the change Ex: if your temp drops…you will shiver to reverse that Ex: If your temp rises…you will sweat to reverse that

How Negative Feedback Makes You Breathe

Positive Feedback Loop Does not stop the change, but… Speeds up the change Ex: Birth Contractions Contractions of a pregnant woman start slow Oxytocin released Contractions speed up to push out baby

Thermoregulation Defined: Maintenance of body temperature Example of homeostasis Many organ systems working together Skin: sensors provide feedback to brain Nervous & Endocrine system: send messages to/from brain Muscles: Start to shiver

Homeostasis disruption Some changes can be too great for your body to control Examples: Frost bite: Sensors are destroyed Paralysis: Messages from brain doesn’t reach target Infection: fever, sore throat, soreness

Long Term: Diabetes Normally (good) Glucose in blood rises after meals Pancreas releases insulin Cells remove the glucose glucose glucose glucose glucose glucose insulin insulin insulin insulin glucose glucose

Long Term: Diabetes Normally (good) Glucose in blood rises after meals Pancreas releases insulin Cells remove the glucose Type 1 (bad) Immune system destroys pancreas cells Pancreas unable to make insulin Blood pH decreases as glucose builds up glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose

Long Term: Diabetes Normally (good) Glucose in blood rises after meals Pancreas releases insulin Cells remove the glucose Type 1 (bad) Immune system destroys pancreas cells Pancreas unable to make insulin Blood pH decreases as glucose builds up Type 2 (bad) Pancreas does not make enough insulin glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose glucose insulin insulin glucose glucose glucose

Kobe Kuiz Define homeostasis. Name and describe the four parts of the “control system.” What is negative feedback? What is positive feedback? Is the following example positive or negative feedback? During heavy exercise your body loses water when you sweat. As a result of water loss, your body redirects the remaining water inside your body to vital parts of your body to replenish these vital organs. What is diabetes? How does Type I and Type II diabetes differ?