internal body environment maintenance

1. Homeostasis

2. Homeostasis
• Refers to the maintenance of constant internal environment of the
body.
Q- So what is this internal environment of the body?
- It is the extracellular fluid (ECF) in which the cells live.
- It is the fluid outside the cell and is continuously moving throughout
the body.
It includes :-
1. Blood – which circulates in the vascular system.
2. Interstitial Fluid – fluid present in between the cells.

3. Role of various systems in homeostasis
1. pH of ECF – 7.4
- tissues cannot survive alteration in pH.
Acidosis – decrease in pH
Alkalinity- increase in pH
- both affect the tissues markedly.
--- Respiratory system, blood and kidney help in regulation of
pH.

4. 2. Body temperature – 37.5 degrees.
•Increase or decrease – alters metabolic activities
of cell.
•The skin,respiratory,digestive,skeletal,nervous,ex
cretory system – maintains body temp. Within
normal limits.

5. 3. Adequate nutrients – essential for activities of
cell and growth of tissues – source of energy for
cell.
•Nutrients must be digested , absorbed into
blood and supplied to cell.
•Systems involved - digestive and circulatory.

6. 4. Adequate oxygen – metabolism of nutrients.
Carbon dioxide and other waste products should
be removed.
Systems involved – respiratory and excretory system .

7. 5. Hormonal balance – endocrine glands.
6. Water and electrolyte balance -

8. Components of homeostatic system
• Homeostatic systemin the body acts through self-regulating devices,
which operate in cyclic manner.
• This cycle includes 4 components:
1. Sensors or detectors, which recognize the deviation
2. Transmission of this message to a control center
3. Transmission of information from the control center to the effectors
for correcting the deviation
4. Effectors, which correct the deviation.

9. Mechanism of action of homeostatic system
• Homeostasis helps in maintaining the normalcy of various
body systems.
• Change in behavioral pattern of any system Effectors
bring back normalcy by inhibiting/reversing the
change or by supporting and accelerating the change.
• This is achieved by means of – Feedback signal.

10. • Whenever there is some change in the behaviour,
system receives and reacts to two types of feedback:
1. Negative feedback
2. Positive feedback

11. Negative feedback
• System arrests the change or reverse the direction of the
change.
• Receives message --- effector sends negative feedback
signals --- system.
• The system stabilizes its own function – makes an attempt to
maintain homeostasis.