Homeostasis Lab

2 What are the changes you observed in body color and perspiration level in response to? As the body moves it creates heat. Skin color turns pinkish due to increased blood flow to the skin to release heat & cool the body internally. Perspiration increases & then evaporates which cools the surface of the body.

2 Explain how these changes contribute to the maintenance of homeostasis? The core body temperature needs to remain stable at 98.6 degrees. As the body temperature increases due to work these two cooling mechanisms kick in to counteract (negative feedback) and make sure the temperature stays in balance.

3 Was there a change in body temperature? There was only a slight increase in body temperature and then a return to the resting temperature. Did you find this change surprising? Why or why not? Answers vary depending on your hypothesis.

3 What mechanisms does the body use to maintain its homeostatic temperature? Sweating which evaporates & cools the skins surface. Dilation of the capillaries at the skin’s surface…bring more hot blood to the surface which releases heat at the surface & then returns cooler to the core where it picks up more heat & returns to the surface to cool.

4 Explain to the best of your knowledge, why does an increase in heart rate and breathing rate accompany exercise? The muscle cells need oxygen to convert macromolecules (typically glucose) into cellular energy (ATP) through cellular respiration to work. Breathing increases to increase oxygen intake. Blood flow also needs to increase to get the oxygen where it is needed (and carbon dioxide out), thus the heart beats faster. Both breathing and heart rate should increase and then stabilize.

TTBOYK Explain the results you obtained for diastolic (lower number) and systolic (higher number) blood pressure. As the heart pumps faster to circulate the blood the systolic pressure in the blood vessels increases. Systolic pressure is when the heart is contracting (blood is forced through arteries). Diastolic does not change much as it is the resting moment of the heart beat & thus the pressure should remain pretty stable. The systolic SHOULD stabilize after it rises. Some of you found the systolic BP to drop! Apparently it’s complicated BUT this has to do with the dilation of all blood vessels…larger vessels = more space and less pressure. It can also do with dehydration.

Is this lab an example of positive or negative feedback or both? NEGATIVE!!! All of it is negative. Stimulus occurs which unbalances your body. Your ATP (cellular energy) drops Your body then increases the production of ATP to counter balance this drop in ATP. To do this process the cells require OXYGEN. So, breathing increases to bring in O2 & get rid of CaO2 Heart rate increases to transport the O2 in and the CO2 out. Heat stimulus is also created due to friction of the muscles. This causes the body to over heat. Your body then dilates capillaries and sweats in response to counteract the increase in heat