Zusammenfassung der Ressource
Senses, Coordination,
Hormones and Homeostasis
- Senses
- The eye
- Cornea
- Refracts light-bends it
as it enters the eye.
- Iris
- controls how much light
enters the pupil.
- Lens
- Further refracts the light
to focus on the retina.
- Retina
- Contains the light
receptors
- Optic nerve
- carries impulses between
the eye and the brain.
- Coordination
- The iris reflex
- Low light intensity
- Radial muscles of the iris and the pupil are
opened wider so more light can enter and
reach the retina.
- High light intensity
- CIrcular muscles of iris contract and
the pupil is reduced in size so less light
can enter the retina is protected from
bleaching.
- How do we see objects?
- 1) The light is refracted when it
passes through the cornea
boundary and at the lens.
- 2) Inverted image on retina
- 3) Brain intercepts image
as correct way up.
- Nerve Impulse
- Electrical signal that passes
along the nerve cells called
neurons.
- Identify motor(effecter),
relay(connector) and sensory
neurons
- Descibe a simple reflex arc in
terms of receptor, sensory neuron,
relay neuron, motor neuron and
effector.
- The reflex arc is when the receptor receives
information through sense and the sensory
neurons go the brain and the relay neuron
helps to connect to sensory neuron to the
motor neuron which goes to the muscle which
helps us react
- Describe a reflex action
- It is a means of automatically
and rapidly integrating and
coordinating stimuli with the
responses of effectors.
- Hormones
- Chemical substances that alter the activity of
one or more specific target organs. It is
secreted by glands. Eg-insulin, adrenaline