Chapter 2- Nervous System Flashcards
Sense Organs
a specialised structure that detects stimuli (such as light, sound, touch, taste and smell) in your environment
Stimuli
changes in the environment that can be detected and responded to
Thermoreceptors
special cells located in your skin, part of your brain and body core that are sensitive to temperature
Mechanoreceptors
special cells within the skin, inner ear and skeletal muscles that are sensitive to touch, pressure and motion, enabling you to balance, hear and sense pressure and movement
Chemoreceptors
special cells within a sense organ (especially the nose and tastebuds) that are sensitive to particular chemicals, giving you the sensations of smell and taste
Photoreceptors
a receptor cell located in your eye that is stimulated by light, converting it to electrical energy that is sent to the brain, giving you the sensation of light
Pain receptors
special cells located throughout the body (except the brain) that send nerve signals to the brain and spinal cord in the presence of damaged or potentially damaged cells, resulting in the sensation of pain
Hot thermoreceptors
a type of receptor in your skin that can detect an increase in skin temperature above 37.5°C (normal body temperature)
Cold thermoreceptors
a type of receptor in your skin that can detect a decrease in skin temperature below 35.8 °C
Olfactory nerve
nerve that sends signals to the brain from the chemoreceptors in the nose
Pupil
a hole through which light enters the eye
Iris
coloured part of the eye that opens and closes the pupil to control the amount of light that enters the eye
Reflex action
a quick response to a stimulus. Reflex actions do not involve thought.
Cornea
the curved, clear outer covering of your eye
Lens
a transparent curved object that bends light towards or away from a point called the focus. The eye has a jelly-like lens.
