Download Ms Gentry`s Communication ppt File

What’s the
link????
Communication & homeostasis
Links to G.C.S.E
 Endocrine system
 Negative feedback
 Homeostasis
 Circulatory system
 Adaptation
Links to AS level
 Cell signalling
 Cellular organisation
 Enzymes
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Outline the need for communication systems within
multicellular organisms (with reference to the need to
respond to changes in the internal and external
environment and to coordinate the activities of different
organs).
State that cells need to communicate with each other by
a process called cell signalling.
State that neuronal and hormonal systems are examples
of cell signalling.
Keeping cells active

What conditions need to be maintained in order
to cells to function efficiently?
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Temperature
pH
Oxygen & glucose levels
Water potential & ion levels
Blood pressure
Removal of wastes produced BY THE CELLS as a
result of respiration
Key definition
 Homeostasis
is the maintenance
of the internal environment in a
constant state despite external
changes
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Homeostasis is based on
STIMULUS: RESPONSE
A stimulus is any change in the internal or
external environment
 A response is a change in behaviour or
physiology as a result of a change in the
environment

Environments
The external environment may consist of water,
air, soil etc around the organism.
 Changes may occur slowly (seasonal) or more
rapidly (going from indoors to outdoors).

The internal environment of multicellular
organisms is the tissue fluid that bathes the cells
and tissues.
 Changes occur as cells undergo their various
metabolic activities.
 It is monitored and maintained by the
hypothalamus which takes action to alter the
blood composition
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Cell signalling
A good communication system:
Should:
-cover the whole body
-enable cells to communicate with one
another
-enable SPECIFIC communication
-enable RAPID communication
-enable short and long term responses
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Describe the physiological and behavioural
responses that maintain a constant core
body temperature in ectotherms
Key definition

An ectotherm is an organism that relies on
external sources of heat to regulate it’s
body temperature
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DO NOT SAY COLD BLOODED!!! Some
ectotherms have a body temperature of
37°C which is not cold!!
Assignment
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You will be given the name of an ‘ectotherm’ (fish,
reptiles, amphibians, invertebrates)
You need to produce a short presentation detailing
-information about the environmental conditions
that the organism has to survive in
-the upper and lower limits of temperature range
they can function at
-any behavioural or physiological adaptations that
the organism employs to aid survival
-advantages of being an ectotherm
-disadvantages of being an ectotherm
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Describe the physiological and behavioural
responses that maintain a constant core
body temperature in endotherms with
reference to peripheral temperature
receptors, the hypothalamus and effectors
in skin and muscles.
Key definition

An endotherm is an organism that can use
internal sources of heat, such as that
generated from metabolism (an exergonic
reaction) in the liver, to maintain it’s body
temperature
Key definition
Negative feedback mechanisms initiate to
maintain or regulate physiological functions
within a set and narrow range. Any change in a
parameter results in action to reverse this
change e.g. temperature or blood sugar
 The brain receives ‘negative feedback’ about the
conditions that are occurring and seeks to
change them back rather than allowing or
encouraging it to continue (positive feedback)
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Week 1
(a) Vasodilaton; (b) vasoconstriction
© Pearson Education Ltd 2009
This document may have been altered from the original
Responses may be behavioural as well as
physiological e.g.
-burrowing
-moving into the shade
-reducing surface area of body facing the
sun
-staying inactive
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Outcomes

Outline the need for communication systems within
multicellular organisms (with reference to the need to
respond to changes in the internal and external
environment and to coordinate the activities of different
organs).
 State that cells need to communicate with each other by
a process called cell signalling.
 State that neuronal and hormonal systems are examples
of cell signalling.
 Describe the physiological and behavioural responses
that maintain a constant core body temperature in
ectotherms Describe the physiological and behavioural
responses that maintain a constant core body
temperature in endotherms with reference to peripheral
temperature receptors, the hypothalamus and effectors in
skin and muscles.