Look Mama, It’s Alive! Human Feedback Systems

Question True or False: Each body system works in isolation

Body systems are interrelated and work through a series of feedback systems

Question True or False: Feedback systems react quickly

In feedback systems, the action of a system components is typically slow in terms of time. That is, there is a build up in one direction and slowly, the body returns to homeostasis.

Negative feedback systems – homeostasis Control of blood glucose Control blood calcium Control of blood pressure Control of body temperature

Negative feedback Returns the body to equilibrium. It works like driving car down the road. Constant adjustment to the right or left is required to keep the car on the road.

A negative feedback system is one that tries to keep the body constant.

In a positive feedback system the change will continue to increase in one direction until something happens in the body to stop it.

An example of positive feedback is childbirth

The feedback cycle

Glucose: Insulin and Glucagon The receptors of the pancreas are responsible for monitoring glucose levels in the blood.

Blood Glucose Level Pancreatic Hormones regulate blood sugar level before and after meals. Islets; clusters of cells in pancreas –Alpha  secrete GLUCAGON – increases sugar –Beta  secrete INSULIN – decreases sugar

What Happens? Between meals Blood glucose low  Pancreas secretes glucagon  Liver changes glycogen to glucose  glucose sent to target tissues After a meal Blood glucose high  Pancreas secretes insulin  Glucose goes to the Liver(Glygogen) and goes to Target tissues

Fight or Flight In emergencies, adrenaline is released by the body to override the homeostatic control of glucose. This is done to promote the breakdown of glycogen into glucose to be used in the emergency. These emergencies are often known as 'fight or flight reactions'.

Fight or Flight Adrenaline is secreted by the adrenal glands. The secretion of it leads to increased metabolism, breathing and heart rate. Once the emergency is over, and adrenaline levels drop, the homeostatic controls are once again back in place

Thermoregulation

Compare the level of serotonin and serontonin receptors. Stop the video at 3:50, 3:56, and 4:03  EXPLORE

1. What is the role of serotonin? 2. What is the effect of high levels of serotonin on the body? 3. Explain how the body attempts to regulate serotonin levels? 4. Relate serotonin regulation to anorexia nervosa. EXPLAIN

Role Play: The Rise and Fall of Glucose  ELABORATE

How does the body keep from overheating? How does the body keep warm?  ELABORATE

1.Produce a sketch or graph and describe a negative feedback system. 2.Produce a labeled sketch of thermal regulation in humans. 3.Summarize the regulation of blood glucose  EVALUATE

regulates Concept Map by means of the Growth Water balance ReproductionMetabolism Calcium and glucose levels Response to stress The Endocrine System Pituitary Ovaries TestesThyroidPancreasAdrenals Parathyroids