science homework

Introduction: In biology, a feedback mechanism is a physiological loop that brings the body either toward or away from the normal, steady state. The feedback mechanism, also referred to as a feedback loop, either amplifies a certain biological pathway or inhibits it. These pathways most commonly return the body to homeostasis.

Title: Observing Feedback Mechanisms in Excretion

Aim: To observe excretory feedback control

Apparatus: hormone levels data, pencil, graph paper

Methods/Procedure:

· collect blood hormone level data for a patient who is thirsty

· record their levels of ADH, over a period of time

· discuss the relationship between increase in thirst [over time] and ADH production

· draw a graph to show the levels of ADH in the plasma as thirst increases

Results: ______________________________________________________

Plasma ADH (pg/ml)	Time (mins.)
0.5	0
0.5	1
2	2
4.5	5
5	6
6	7
9	10
11.5	13

Discussion:

· Discuss the function of ADH

· Define osmoregulation

· What is feedback control?

· Why are feedback mechanisms important?

· Discuss negative vs. positive feedback

· What trends do you identify from the graph?

· hints: what is the relationship between thirst and increased ADH? Is this an example of negative or positive feedback?

Conclusion:

ADH Feedback Mechanism ORR

LAYOUT:

All sections of lab completed /1

Methodology [past tense/ passive voice] /1

RESULTS:

Graph cuts more than half the page /1

Graph has appropriate title /1

Axes labeled [w/ units] /1

Suitable intervals /1

Correctly plotted points [1/2 pt. ea.] /4

/10

ADH Feedback Mechanism A/I

DISCUSSION:

Discuss the function of ADH /1

Define Osmoregulation /1

What is feedback control? /1

Why are feedbacks important? /1

Negative vs. positive feedback /2

Identify trends from the graph? /2

CONCLUSION:

Related to the aim /1

Brings closure to the lab /1

/10