Post by Admin on Nov 23, 2016 21:50:01 GMT
The Central Nervous System
• The central nervous system consists of the brain, the spinal chord and the nerves.
• Sensory nerves carry messages to the brain.
• Motor nerves carry messages from the brain.
• In certain cases there is no time to decide what to do, e.g. if you place your hand on something hot. The message goes from your hand to the spinal chord. From there a message is sent to your arm telling it to pull your arm away.
The Eye
• Sclera: a white protective layer (3rd layer from the inside).
• Choroid Layer: a dark layer rich in blood vessels (2nd layer from the inside).
• Retina: the light sensitive layer (1st layer from the inside).
• Cornea: this allows light into the eye.
• Aqueous Humour: liquid that helps focus light onto the retina (in the area between the cornea and the lens).
• Iris: a muscle that controls the amount of light entering the eye.
• Lens: this focuses light onto the retina.
• Ciliary Muscles: hold the lens in place and controls its shape to allow us to see objects near and far away.
• Optic Nerve: brings images to the brain in the form of electric pulses.
• Fovea/Yellow Spot: the most sensitive part of the retina.
• Blind Spot: the point where the retina joins the optic nerve.
• Vitreous Humour: jelly-like fluid that gives the eye shape (in the main part of the eye).
• The central nervous system consists of the brain, the spinal chord and the nerves.
• Sensory nerves carry messages to the brain.
• Motor nerves carry messages from the brain.
• In certain cases there is no time to decide what to do, e.g. if you place your hand on something hot. The message goes from your hand to the spinal chord. From there a message is sent to your arm telling it to pull your arm away.
The Eye
• Sclera: a white protective layer (3rd layer from the inside).
• Choroid Layer: a dark layer rich in blood vessels (2nd layer from the inside).
• Retina: the light sensitive layer (1st layer from the inside).
• Cornea: this allows light into the eye.
• Aqueous Humour: liquid that helps focus light onto the retina (in the area between the cornea and the lens).
• Iris: a muscle that controls the amount of light entering the eye.
• Lens: this focuses light onto the retina.
• Ciliary Muscles: hold the lens in place and controls its shape to allow us to see objects near and far away.
• Optic Nerve: brings images to the brain in the form of electric pulses.
• Fovea/Yellow Spot: the most sensitive part of the retina.
• Blind Spot: the point where the retina joins the optic nerve.
• Vitreous Humour: jelly-like fluid that gives the eye shape (in the main part of the eye).