this slide show how the body works!

1. •Life functions:to subtain life,organism
must be able to maintain its
boundaries,move,respond to
stimuli,digest nutrients and exrete
wastes,carry on metabolism,reproduce
itself and growth.
•Survival needs include food, oxygen,
water, appropriate temperature,and
normal atmospheric
pressure.Extremes(excesses or deficits)of
these factors can be harmful.

2.  Ability to maintain relative
stable(balance)internal condition even though
the external environment changes
 Involves keeping the parameter of the tissue
fluid such as pH,temperature and salt
concentration at the relatively constant level
 Necessary for survival and good health,its
loss result illness or diseases.

3.  Control mechanism have 3 elements:
1.Receptor that respond to environment
changes
2.Control centre that assesses those change
and produce a responds
3.Effector provides the means for control
center’s response to the stimulus.

4.  To maintain homeostasis, communication within the body
is essential. The image below is an example of how a
homeostatic control system works. Here is a brief
explanation:
 Stimulus- produces a change to a variable (the factor
being regulated).
 Receptor- detects the change. The receptor monitors the
environment and responds to change (stimuli).
 Input- information travels along the (afferent) pathway to
the control center. The control center determines the
appropriate response and course of action.
 Output- information sent from the control center travels
down the (efferent) pathway to the effector.
 Response- a response from the effector balances out the
original stimulus to maintain homeostasis.

6.  Afferent pathways- carry nerve impulses into the
central nervous system. For instance, if you felt
scorching heat on your hand, the message would
travel through afferent pathways to your central
nervous system.
 Efferent pathways- carry nerve impulses away
from the central nervous system to effectors
(muscles, glands).
 The feeling of heat would travel through an
afferent pathway to the central nervous system. It
would then interact with the effector and travel
down the efferent pathway, eventually making
the person remove their hand from the scorching
heat.

7.  A mechanism that restore the body to a normal
state.
 Shut off or reduce the intensity of the original
stimulus.
 Example::
 The control of blood sugar (glucose) by insulin is
another good example of a negative feedback
mechanism. When blood sugar rises, receptors in
the body sense a change . In turn, the control
center (pancreas) secretes insulin into the blood
effectively lowering blood sugar levels. Once
blood sugar levels reach homeostasis, the
pancreas stops releasing insulin.

8.  Mechanism that promote a condition farther
from normal level of function.
 Increase the original stimulus(disturbance)
 Usually harmful because it tends to produce
unstable conditions.
 When the negative feedback mechanism in
mammalian thermoregulation breaks
down,an increase in temperature cause death
 Sometimes be useful,for example,the release
of oxytocin during childbirth.

9.  We need homeostasis for maintance of body
temperature because most of the biochemical
process vital to life occur eficiently only
within a limited range of temperatures.
 Temperatures above or below these limits
inhibit enzyme ad thus chemical
reaction,discrupt vital functions such as
breathing and circulation ang at extreme heat
level,can denature enzyme and other protein.