The document discusses homeostasis as a fundamental aspect of human physiology, defining it as the maintenance of the body's internal environment within a narrow range of normal values. It covers the characteristics, components, and feedback systems involved in homeostatic control, emphasizing the importance of these mechanisms in health and illness. Additionally, it highlights the role of nursing in monitoring and maintaining homeostasis to ensure proper body function.

1. HOMEOSTASIS
Jamilah saad Alqahtani
CNS,MSN,NS,RGN,BSN, OR Specialist
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3. Objectives
The student will be able to
understand:
1.Def homeostasis
2.The scope of human physiology
3.Homeostasis: defining feature of
physiology
4.General characteristics of
homeostatic control system:
5.Homeostasis Control system
6.Feedback system
7.Components of homeostasis
control system
8.Process related to homeostasis
9.Nursing and homeostasis

4. Outlines
Introduction
Def homeostasis
The scope of human physiology
Homeostasis: defining feature of
physiology
General characteristics of homeostatic
control system:
1.Homeostasis Control system
2.Feedback system
Components of homeostasis control
system
Process related to homeostasis
Nursing and homeostasis
Summary

5. Homeostasis
Homeo –same
Astasis-standing still
Dynamic equilibrium
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6. Homeostasis
Is the most
fundamental of
physiology

7. Homeostasis
 Homeostasis is the maintenance of the
body's internal environment within a narrow
range of normal values. It is an ongoing
process, with changes constantly occurring in
the body.
 In health, normal homeostatic mechanisms
function to maintain fluid, electrolyte, and
acid-base balance.
 In illness, one or more of the regulating
mechanisms may be affected, or an
imbalance
 may become too great for the body to
correct without treatment.
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9. The scope of human physiology
how is the body organized ?
1.Cell(the basic unit
of living organisms)
2.Tissue
3.Organs
4.and organ system
5.Body fluid
compartments

10. Many organs are
organized into small
similar subunits
referred to as
functional units
Example:
nephrons are
function in
kideny
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11. Body Fluid compartments
1.H2o present
within and
around the cells
of the body and
within blood
vessels

12. Fluid in the body
plasma
Interstitial fluid
Intracelluer
fluid
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13. This led to concept
that homeostasis is
state of dynamic
constancy
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14. Homeostasis: defining feature of physiology
•The body’s internal
environment is the
extracellular fluid.
•The function of organ
systems is to maintain a
stable internal
environment-homeostasis.
•Numerous variables
within the body must be
maintained
homeostatically. When
homeostasis is lost for one
variable , it may trigger a
series of changes in other
variables.
•Example (consider swing
in blood glucose level over
the course of day
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15. •Homeostasis denotes the stable condition
of the internal environment that results
from operation of compensatory
homeostatic control system.
General characteristics of
homeostatic control system:

16. General characteristics of
homeostatic control system:
Homeostasis control
system
Feedback system

17. Homeostasis control system
•The activities of cells, tissue
and organs must be regulated
and integrated with each other
so that any change in extra
cellular fluid initiates a reaction
to correct the change. The
compensating mechanisms
that mediate such response
are performed by
homeostasis control system

18. Example1, Regulation of body
temperature

19. The body undergoes no net gain or loss
of heat and body temp remains constant
(a steady stat)
Intake = Output

20. Stability of
internal
environment
variables is a
achieved by
balancing of
input and
outputs.

21. Example2, Regulation of body glucose level
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23. Feed back system
Negative positive

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25. Negative feedback
•Is a change in the variable being
regulated brings about responses
that tend to push the variable in
the direction opposite to the
original change. Negative feedback
minimizes changes from set point
of the system leading to stability.

26. Negative feed back

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28. Positive feedback
Positive feedback
accelerates a
process leading to
explosive system ( in
positive feedback
no means of
stopping )
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29. Resetting of set point
Change in the external environment
can displace variable from its set
point . In additional the set point for
many regulated variables can be
physiologically reset to new value.
Common example :fever- high body
temp response to - infection is
some what analogous-to raising
the home’s thermostat homeostatic
control system still working during
fever- by maintain temp at a higher
value.

30. That is why
•This regulated rise in
the body temp is
adaptive for fighting the
infection, because
elevated temp inhibits
proliferation of some
pathogens . In fact; this
is why fever often
preceded by chills and
shivering.

31. •In fact the points
can be reset
adaptive as in the
case of fever . Highly
important
challenges for
medicine

32. Some important generalizations about homeostatic control systems
1- stability of an internal environmental variable is achieved by balancing inputs and
outputs. It is not the absolute magnitudes of the inputs and outputs that matter but
the balance between them.
2-in negative feedback systems a change in variable being regulated brings about
responses that end to move the variable in the direction opposite the original
change- that Is back toward the initial value (set point)
3-homeostasis control systems cannot maintain complete constancy of any given
feature of internal environment. Therefore, any regulated variable will have a more-
or – less narrow range of normal values depending on the external environmental
conditions
4-the set point of some variables regulated by homeostatic control systems can be
reset—that is physiologically raised or lowered
5-it is not always possible for homeostasis control systems to maintain constancy in
every variable in response to an environmental challenges. There is hierarchy of
importance so that the constancy of certain variables may be altered marked to
maintain others within their normal range

33. Feed forward regulation
It anticipates changes in regulated
variable, improves the speed of the
body’s homeostatic responses and
minimizes fluctuations in the level
of the variable being regulated.
Work in conjunction with feedback
system

34. Feed forward regulation
•Example temp sensitive nerve cells trigger
negative feedback regulation of body temp
when it beings to fails are located inside
the body . In additional there are temp
sensitive nerve cells in skin and it is in
effect.

35. Components of homeostatic
control system
1.Reflexes
2.Local homeostatic responses
3.Intercellular chemical
messengers

36. Components of homeostatic
control system
the components of a
reflex arc are
receptor, afferent
pathway,
integrating center,
efferent pathway
and effector. The
pathway may be
neural or
hormonal.

37. Local homeostatic
responses are also
stimulus-response
sequences, but they
occur only in the
area of stimulus,
with neither nerves
nor hormones
involved.
Components of homeostatic control
system
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38. Components of homeostatic
control system
Intercellular communication is
essential to reflexes and
local responses and is
achieved by
neurotransmitters,
hormones and paracrine or
autocrine agents. Less
common is interecellular
communication through
either gap junctions or cell-
bound messengers.

39. Processes related to
homeostasis
1.Acclimatization
2.Biological rhythms
3.Balance in homeostasis of
chemical substances in the body

40. Acclimatization
Acclimatization is an improved ability to
respond to an environmental stress.
1.The improvement is induced by prolonged
exposure to the stress with no change in
genetic endowment.
2.If acclimatization occurs early in life, it may
be irreversible and is known as
developmental acclimatization.

41. Biological rhythms
Provide a feed forward component to
homeostatic control systems.
1.The rhythms are internally driven by brain
pacemakers, but are entrained by
environmental cues, such as light, which also
serve to phase-shift (reset)the rhythms when
necessary.
2.In the absence of cues, rhythms free run.

42. Balance in homeostasis of
chemical substances in the body
•Is achieved by matching inputs and outputs.
•Total-body balance of substance may be
negative, positive, or stable.

43. Nursing and homeostasis
Homeostasis is important in nursing because the body
mobilizes its fight-or-flight reaction in an attempt to maintain
homeostasis. This can result in sweating, breathlessness, rapid
heartbeat, shivering, and trembling. The internal equilibrium
of the body is the gauge of whether it is functioning properly
or not. With homeostasis, the body's systems are stable and
self-perpetuating. Many of the tests that a nurse performs on
a patient, such as taking a temperature or a blood pressure,
are tests to determine whether the patient's body is in
homeostasis or in distress. Homeostasis is highly desirable,
because it keeps the body functioning as it should be.
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44. The body as a homeostatic system maintains its
structure and functions by means of:
a multiplicity of dynamic equilibriums rigorously
controlled by interdependent regulation
mechanisms. Such a system reacts to every
change in the environment, or to every random
disturbance, through a series of modifications of
equal size and opposite direction to those that
created.
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46. Summary
We have discuss Definition of homeostasis which is
state of balance .then The scope of human
physiology in homeostasis means the feature and
characteristics of homeostasis control system and
feedback system. Negative and positive feedback
when and where it place . Also components of
homeostasis control system which include reflex arc,
local homeostatic response . And intercellular
chemical messengers .
Process related to homeostasis like acclimatization ,
biological rhythms and the balance of substances in
the body .At last Nursing and homeostasis
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47. Any questions
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49. Thank you
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