Sponge:

When we say that the body
demonstrates homeostasis, do we
mean that conditions in the body are
unchanging?
Explain in your own words in 2-3
sentences…
Agenda

Sponge (10)
Quiz make up policy (5)
Notes: What is homeostasis? (20)
LS assignment: Circle Maps  (20)
Organ system work time (20)
Exit Pass (10)

Reminders:
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
Organ systems project due Monday
 Unit 1 Test and Notebook check Tuesday

Standards Mastery
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SAP1c- Homeostasis
SAP1c. Explain the role of homeostasis and its
mechanisms as these relate to the body as a whole
and predict the consequences of the failure to
maintain homeostasis.
Quiz Results! 2nd block
Average 75%

Truc N.
 Yolanda W.
100 Club
N.
 Mohamed S.

 Hong
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On fire (A)
Nardos A.
 Tia B.
 Iman B.
 Jermyn F.
 Asmelash G.
 Veronica K.
 Aaliyah M.


Mastery (B)
Abdur B.
 Mamoudou B.
 Chisom I.
 Reina N.
 Brenda N.
 Barbara R.
 Diante R.
 Karon T.

Quiz Makeup policy
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Question Number:___
GPS Standard:__________
Vocabulary + definitions needed to understand the
question (at least 3 words):
1. ________________________2. _______________________3. ________________________Why did you miss this question?
What is the correct answer? _______
HOMEOSTASIS!!
What is homeostasis?
Homeostasis is the state of equilibrium of the
internal environment of the body. Homeostasis
is maintained by the dynamic processes of
feedback and regulation.
•
–
Homeo = same
–
Stasis = standing still
What is homeostasis?
So, Homeostasis means
unchanging, but it is actually a
dynamic equilibrium. Dynamic
equilibrium means that
internal conditions change and
vary within narrow limits.
•
–
Homeostasis is basically the
body's natural desire to remain
unchanged.
All homeostatic mechanisms have
three components
1.
2.
3.
Receptor
Control Center
Effector
How does Homeostasis work?
Receptor –monitors and responds to changes in
the environment. Responds to stimuli by sending
information (input) into the control center.
– Afferent pathway = Receptor to control
center
2. Control Center – controls the level the variable
is supposed to be at, analyzes the situation and
determines the appropriate action.
1.
2. Control Center
– Efferent pathway = control center to
effector
3. Effector – Provides the output of the
control center. Determines which
mechanism to use.
The two feedback systems:


Positive Feedback System
Negative Feedback System
Positive Feedback System

Positive Feedbackwhen the initial stimuli
cause an increasing
reaction from the
organism, it is a
cascading reaction.
–
Each reaction from the
organism is stronger
than the last.
–
Ex: Oxytocin in child
birth
Negative Feedback System

Negative Feedback- The body has a set
range of internal conditions. When the
body is not in these optimal conditions
the organism will respond and reactions
will occur to get the person back to the
range of normalcy.
–
This type of feedback is similar to a
thermostat.
–
This is the more common type of feedback
mechanism found in living organisms.
–
Ex: Heart Rate, temperature
Quick Check:

What does the afferent
pathway connect?
 Receptor

and control center.
How does the positive
feedback system work?
 Each
reaction builds on the
previous
LS Assignment




Create two circle maps defining Positive Feedback
System and Negative Feedback System
In your outer circle include defining words, phrases,
and pictures.
CWP
Frame of reference: What are the three
components of all homeostatic mechanisms. How are
these three components connected and what do they
do?
Exit FUN
1.
What is the control center and how is it
connected to the receptor and the
effector?
2.
What is an example of a negative
feedback system?
Homeostasis Lab:
1.
2.
3.
4.
Read through the entire lab.
Pick one person on your team to conduct
the physical activity.
Only one classmate will be recording
temperature, and you will be able to
record the data into your own Lab sheet.
When you are finished… see right white
board.