Unit 1 Biology Notes GCSE :) x

Coordination and Control




For example...

receptors in the eyes which are sensitive to light ­ `Light receptors'
receptors in the ears which are sensitive to sound ­ `Sound and balance receptors'
receptors in the ears which are sensitive to changes in position and enable us to keep our balance
receptors…

receptors in the skin that are sensitive to touch, pressure, pain and to temperature changes. `Touch,
pressure and temperature receptors'

Neurons and Reflexes

Remember: the 3 types of neurones, sensory, motor and relay.

A typical NEURONE:


Neurons transmit electrical impulses very quickly around the body.

Difference between a Sensory Neurone and a Motor Neurone:
Sensory Neurones Motor Neurones

Transmit information to the spinal cord Transmit information from the spinal cord
to an effector.


It is attached to a receptor It is attached to an effector (usually a
muscle)


Transmit the information about stimuli Transmit information…

THE REFLEX ARC
A muscle reacts by contracting, a gland responds by secreting.

Stimulus Receptor Sensory Relay neurone Motor Effector Response
neurone neurone

Example of a reflex action...


The retina is the light sensitive part of the eye and is covered in rods and cones that detect light.

Rods are more sensitive in dim light but only sense black and white.

Cones (found in the fovea) are sensitive to colour but not so good with dim light.




Control in the Human Body

Skin and Temperature
All enzymes work best at a certain temperature, so in our bodies it would be 37 degrees Celsius. To keep this you have to...

Shiver when your body is cold, this increases your metabolism to produce heat.
When you're too hot you produce sweat which cools you…

When you're too COLD
Hairs stand on end to keep you warm
No sweat is produced
The blood supply to the skin closes off.



Ion (salts) content of the body


This is
controlled to
protect cells by
avoiding too
much water

entering or
leaving them.

Ion content is controlled by…

*to provide cells with a constant supply of energy.



Hormones
Hormones are chemical substances that help processes in our body. They are secreted from GLANDS and travel to their target
organ in the bloodstream. The main gland is in the base of the brain, known as the Pituitary gland. Hormones…