AQA Biology Unit 5 notes (BIOL5)

So these notes are like my other ones. Ive made them mostly based on the book so everything you need to know is in there. They're more condensed than the book but i dont think there is any vital information missing. I hope they're useful good luck :)

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  • Created by: bssjonny
  • Created on: 10-06-12 20:31

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Unit 5 Biology notes

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Section 9.1 ­ Sensory Reception
Section 9.2 ­ Nervous Control
Section 9.3 ­ Control of heart rate
Section 9.4 ­ Role of receptors
Section 10.1 ­ Coordination
Section 10.2 ­ Neurons
Section 10.3 ­ The nerve impulse
Section 10.5 ­ The speed of a nerve impulse
Section 10.6/10.7 ­…

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Section 9.1 ­ Sensory Reception

A stimulus is a detectable change in the internal or external environment of an
organism that produces a response.
The ability to respond to a stimulus increases an organism's chances of survival.
Receptors transfer the energy of a stimulus into a form that can be…

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Section 9.2 ­ Nervous Control

Nervous organisation

The nervous system can be thought of as having two main divisions:

1.) The central nervous system (CNS) ­ brain and spinal cord
2.) The peripheral nervous system (PNS) ­ Made up of pairs of nerves that originate
either from the brain or…

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5.) Coordinator (intermediate neuron)
6.) Synapse
7.) Motor neuron
8.) Effecter
9.) Response

Importance of the reflex arc

Involuntary ­ does not require the decision making power of the brains
Brain can override the response if necessary
Protects the body from harmful stimuli
Effective from birth ­ does not need…

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This section then increases the number of impulses sent to the S.A node via the sympathetic
nervous system
This results in an increase in heart rate which then causes blood pH to return to normal.

Control by pressure receptors

Pressure receptors occur in the wall of the carotid arteries and…

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Different receptors respond to a different intensity of a stimulus
Light receptors of the eye are found in the retina (the inner most layer)
The light receptors in the eye can are of two types, rod and cone cells. Both receptors
convert light energy into a nervous impulse and are…

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Section 10.1 ­ Coordination

Body systems cannot work in isolation and must therefore be integrated in a coordinated

Principles of coordination

In mammals, there are two main forms of coordination:

1.) The nervous system ­ Uses nerve cells that can pass electrical impulses along
their length. The result is…

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Effect may be permanent/long lasting/ Effect is temporary and reversible

Plant growth factors

Plants respond to external stimuli by means of plant growth factors (plant hormones)
Plant growth factors:
Exert their influence by affecting growth
Are not produced by a particular organ, but are instead produced by all cells…

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Section 10.2 ­ Neurons

Specialised cells adapted to rapidly carry electrochemical changes (nerve impulses) from
part of the body to another

Neuron structure

Cell body
Large amounts of rough
endoplasmic reticulum to produce

Extensions of the cell body
subdivided into dendrites
Carry nervous impulses to the cell…




absolute legend

Yusra Ahmed


when co2  concentration is high, the ph is lowered  and when co2 concentration is low ph increases .....there is a confusion of this in the notes in the control heart rate section. 

matthew adelekan


thanks pal

matthew adelekan


these notes are not goiod enough

matthew adelekan



Lucy Chapman


thank, helps a lot!

Grace Hillsmith


Great notes, but you've spelt neurones as neurons all the way through and being the grammar Nazi I am, I had to correct every single one.



Very good notes. 

sasha fortell


link doesnt work?

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