need help with biology homework

Questions

State whether each of the following processes are regulated by a positive feedback loop or a negative feedback loop.

· A person feels satiated after eating a large meal.____________

· The blood has plenty of red blood cells. As a result, erythropoietin, a hormone that stimulates the production of new red blood cells, is no longer released from the kidney.________________________

When bacteria are destroyed by leuckocytes, pyrogens are released into the blood. Pyrogens reset the body’s thermostat to a higher temperature, resulting in fever. How might pyrogens cause the body temperature to rise?____________________________________________________________________________________________________________________________________________________________

Review Questions

1.____When faced with a sudden drop in environmental temperature, an endothermic animal will:

· experience a drop in its body temperature

· wait to see if it goes lower

· increase muscle activity to generate heat

· add fur or fat to increase insulation

2.____Which is an example of negative feedback?

· lowering of blood glucose after a meal

· blood clotting after an injury

· lactation during nursing

· uterine contractions during labor

·

3.____Which method of heat exchange occurs during direct contact between the source and animal?

· radiation

· evaporation

· convection

· conduction

4.____The body’s thermostat is located in the ________.

· homeostatic receptor

· hypothalamus

· medulla

· vasodilation center

Task 11 : Essay

· Why are negative feedback loops used to control body homeostasis?

· An adjustment to a change in the internal or external environment requires a change in the direction of the stimulus. A negative feedback loop accomplishes this, while a positive feedback loop would continue the stimulus and result in harm to the animal.

· So what is positive feedback useful for and tell me how it works.

· Why is a fever a “good thing” during a bacterial infection?

· How is a condition such as diabetes a good example of the failure of a set point in humans?