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Biology Unit F214:
Spread: Specification: Content: Other:
1.1.1 Outline the need for External Environments: The environmental change is a stimulus and the Definitions:
communication systems way in which the organism changes its physiology or behaviour is its A stimulus is any change in the
within multicellular response. environment that causes…

Page 2

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Biology Unit F214:

Principles of Homeostasis (2): A positive feedback mechanism tends to homeostatic control breaks down,
push the parameter further and further away from the norm, rather than then positive feedback reinforces
keeping it constant. Examples include: further increase in core body
If a person breathes air that has…

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Biology Unit F214:

Control of temperature regulation:
Endotherms monitor the temperature of their blood in the hypothalamus of
the brain. If the core temperature falls below normal, hypothalamus sends
signals to reverse the change. This will involve several changes:
Increased rate of metabolism in order to release more heat from…

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Biology Unit F214:

1.1.5 Outline the roles of Sensory Receptors: Some sensory receptors are specialised to detect Definitions:
Sensory receptors in changes in our surroundings. They are energy transducers that change one A polarised membrane is one that
mammals in converting form of energy to another. Each change in energy…

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Biology Unit F214:

just outside the spinal cord. potential
Intermediate neurones, sometimes called relay neurones have their cell The stronger the stimulus, the
bodies and cytoplasmic processes inside the CNS. They are adapted to carry greater is the generator potential
impulses from and to numerous other neurones. When the generator…

Page 6

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Biology Unit F214:

channels in the membrane open. Na+
5 6 that was pumped out now goes back
into the cell. They do this because there
is an electrical gradient for them ­ the
membrane has a more +ve charge on
4 the outside than on the inside, so the…

Page 7

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Biology Unit F214:

The myelin sheath: It's made up largely of lipids, together with some o Repolarization of the
proteins. Myelin sheath contains myelin, a phospholipid which does not membrane when K+
conduct an electrical current. There are no transmembrane ion movement leave the axon
across myelinated membranes. Thus, the…

Page 8

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Biology Unit F214:

Transmission across the synapse (chemical synapses): glutamate occur only in the brain.
An action potential arrives at the synaptic knob Neuromuscular junction:
The voltage-gated Ca²+ channels open It's a synapse between the end of a
Ca²+ diffuse into the synaptic knob motor neurone and a muscle. Here,…

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Biology Unit F214:

and eyes. In the future, when you hear the voice, information flowing synaptic neurones. The numerous
from your ears along this pathway automatically flows into the other synaptic connections allow the
pathway too, so that your brain `pictures' the face that goes with the cell to combine…

Page 10

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Biology Unit F214:

1.1.10 Define the terms Signalling by using hormones: Many animals, including mammals, also have Definitions:
endocrine gland, another communication system (other than the nervous system), the Hormones are molecules that are
exocrine gland, endocrine system, which transmits information from one cell or organ to released by endocrine…

Comments

Adi

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amazing!!

sana

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This is really a great, sound set of notes, specific to the spec and full of detail thankyou!!

18RA41M

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It doesn't seem to open?

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