Honors Biology: Homeostasis, Graphing Analysis, and Scientific Design Assessment

biological definition of homeostasis?

The tendency of an organism to regulate its internal environment and maintain equilibrium

what is a homeostatic control system?
how does a homeostatic control system work?

It is the communication within the body that helps maintain homeostasis

1. Stimulus produces a change in variable

2. Receptor detects change

3. Input → information sent along a pathway to a control center

4. Control Center integrates/interprets the information

5. Output → information sent along a pathway to an effector (a muscle or gland)

6. Response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level

almost all homeostatic control mechanisms are _____.

negative feedback mechanisms

what do negative feedback mechanisms do?

they change the variable back to its original state or “Ideal value” or “set point” → BACK TO HOMEOSTASIS

with negative feedback systems, the output/response will _____.

reduce the original effect of the stimulus
the response reverses a change in a controlled condition in order to return to homeostasis

a positive feedback system is the exact opposite of a negative feedback mechanism. In a positive feedback system, the output _____.

enhances the original stimulus
the response strengthens the change in a controlled condition in order to enhance the stimulus and its response. When the expected “event” is complete, the feedback stops

how do organisms regulate complex systems through a chemical interaction?

By using both positive and negative feedback mechanisms

which hormone is produced and secreted by the adrenal glands in response to immediate stress?

adrenaline

briefly describe the role of the sympathetic nervous system

why is this a valuable response?

the sympathetic nervous system is the part of the nervous system that responds to stress → it focuses on what the body need do right now to get itself out of the stressful situation
for example when you running from a burning building, your body doesn’t need to focused on producing reproductive cells, or digesting the meal you had earlier
The sympathetic nervous system blasts all your energy to your brain, heart, and muscle to deal with the threat at hand

All these functions that the sympathetic nervous system activates are extremely valuable to our survival because it helps get us out of potentially life-threatening situations. It keeps us alive

briefly describe role of the parasympathetic nervous system

why is this essential?

the parasympathetic nervous system is the calming side of your autonomic system → it is an antidote to the effects of stress created by the sympathetic nervous system
compared to the sympathetic system, the parasympathetic system deals with everything else that is not the crisis of the now

the parasympathetic is essential because it allows us to do the “business of living” → to excrete waste, fight off infections, digests food, to reproduce

what is the name of the hormone released during long-term stress?

cortisol

how is long-term stress different than what is experienced during immediate stress?

short-term stress eventually goes away in a short period of time and the body will return to homeostasis, but when the body is under constant stress, or prolonged stress, the biochemical cascade continues
short-term stress only emerges in certain situations as it is apart of the flight or fight response the body undergoes, while long-term stress happens when the body is exposed to prolonged stressors and not just in certain situations
In short-term stress situations, the hormone that the body releases adrenaline, while in long-term stress situations, the body continuously releases cortisol hormones

under what circumstances will our body be purposely shifted away from homeostasis?
this is an _____ response; it is an automatic response caused by our _____.

when we are in immediate danger!
INNATE (encoded in our DNA)
sympathetic nervous system

after the short-term stressful event is over, the _____ nervous system brings our body back to _____
this system is critical in allowing our bodies _____

parasympathetic
homeostasis
to rest and conserve energy

*We would not be able to survive in such a heightened state of arousal

Parasympathetic vs. Sympathetic

Rest and Digest vs. Fight or Flight
Needed to return to homeostasis vs. needed for survival during life-threatening situations
Conserves energy vs. Utilizes energy to increase chances of survival

consequences of long-term stress

suppressed immune system → susceptible to developing more illnesses

obesity

depression

how to write a hypothesis

IF… (explain how you will incorporate the independent variable) THEN… (explain what will happen to the dependent variable) BECAUSE (reasonable explanation why