B3 - organism level systems Flashcards
what is accommodation?
changing the lens shape to fine focus the image of an object regardless of its distance from the eye
what is the central nervous system?
CNS, the brain and the spinal cord
what is the cerebellum?
the region of the brain that controls unconscious functions such as posture, balance and muscular movement
what is the cerebral cortex?
the outer layer of the cerebrum
what is the cerebrum?
the highly folded region of the brain that is responsible for controlling voluntary actions such as learning, personality and memory; it is divided into the right and left hemispheres
what is the ciliary body?
an extension of the iris, it contains the ciliary muscle which can contract or relax allowing the eye to focus
what is colour blindness?
a condition where a person has a defect in the receptors or a lack of receptors in the retina
what is coordination?
the ability to use different parts of the body together smoothly and efficiently
what is the cornea?
the part of the eye that refracts light as it enters, focusing it onto the retina
what is the effector?
a gland or muscle that produces a response to the stimulus to restore optimum conditions
what is the iris?
the part of the eye that contracts or relaxes to control the amount of light entering the eye
what is the lens?
a part of the eye that further refracts light to focus it onto the retina
what is long-sightedness?
hyperopia; a defect of the eye where distant objects appear out of focus due to the convergence of light rays in front of the retina
what is the medulla?
the part of the brain responsible for non-voluntary movement such as breathing rate and heart rate
what is the motor neurone?
the neurone that transmits impulses from the relay neurone to the effector to produce a response
what is the optic nerve?
the nerve that carries impulses between the brain and the eye
what is the pituitary gland?
the gland that stores and releases hormones which regulate many bodily functions
what is the pupil?
a hole in the centre of the iris, it is controlled by the muscles of the iris and changes size depending on the brightness of the light
what is the receptor?
a cell or organ that recognises the stimulus
what is the reflex arc?
the pathway of neurones involved in a reflex action
what is the relay neurone?
the neurone that transmits electrical impulses from the sensory neurone to the motor neurone
what is the retina?
the layer at the back of the eye that contains light receptors and is sensitive to light
what is the sensory neurone?
the neurone that detects the stimulus. and transmits the electrical impulse to the rely neurone located in the spinal cord
what is short-sightedness?
myopia; a defect of the eye where distant objects appear out of focus due to the convergence of light rays in front of the retina