What is the pathway in a reflex arc in response to shining a bright light into the eye?
The constriction of pupils in response to bright light is called the pupillary light reflex. If the light is shining directly into one eye, then the pupil in that eye will constrict (a direct response), but so will the pupil in the non-illuminated eye (a consensual response).
How are impulses transmitted in a reflex arc?
Reflex arcs Sensory neuron sends electrical impulses to a relay neuron, which is located in the spinal cord of the CNS. Relay neurons connect sensory neurons to motor neurons. Motor neuron sends electrical impulses to an effector. Effector produces a response (muscle contracts to move hand away).
What are the stages of a reflex arc?
So the reflex arc consists of these five steps in order-sensor, sensory neuron, control center, motor neuron, and muscle. These five parts work as a relay team to take information up from the sensor to the spinal cord or brain and back down to the muscles.
How the brain receives information from the eye GCSE?
When focused light is projected onto the retina, it stimulates the rods and cones. The retina then sends nerve signals are sent through the back of the eye to the optic nerve. The optic nerve carries these signals to the brain, which interprets them as visual images.
How does the blink reflex work?
The corneal blink reflex is caused by a loop between the trigeminal sensory nerves and the facial motor (VII) nerve innervation of the orbicularis oculi muscles. The reflex activates when a sensory stimulus contacts either free nerve endings or mechanoreceptors within the epithelium of the cornea.
Which pathway shows how nerve impulses travel in a reflex action?
reflex arc
The nerve pathway followed by a reflex action is called a reflex arc . For example, a simple reflex arc happens if we accidentally touch something hot. Receptor in the skin detects a stimulus (the change in temperature). Sensory neurone sends electrical impulses to relay neurone, which are located in the spinal cord.
What is the stimulus response pathway?
The basic pathway for a nerve impulse is described by the stimulus response model. A stimulus is a change in the environment (either external or internal) that is detected by a receptor. Receptors transform environmental stimuli into electrical nerve impulses.
What are the 5 elements of the reflex arc?
The reflex arc consists of 5 components:
- sensory receptor.
- sensory neuron.
- integration center.
- motor neuron.
- effector target.
How does the pupil reflex work?
A greater intensity of light causes the pupil to constrict (miosis/myosis; thereby allowing less light in), whereas a lower intensity of light causes the pupil to dilate (mydriasis, expansion; thereby allowing more light in). Thus, the pupillary light reflex regulates the intensity of light entering the eye.
How does the eye work GCSE Bitesize?
The eye is a sense organ containing receptors sensitive to light, intensity and colour. Clear area of the sclera, it refracts light – bends it as it enters the eye. Muscles which alter the size of the pupil, controlling the amount of light entering the eye. Focuses light onto the retina.
Which is the efferent arm of the blink reflex?
The supraorbital branch of the ophthalmic division of the trigeminal nerve constitutes the afferent arm, while the motor fibers of the facial nerve form the efferent arm of this reflex. The diagram below depicts the pathway of the blink reflex.
Is the eye blink reflex the same as the corneal reflex?
Just as with the corneal reflex, ipsilateral electrical stimulation of the supraorbital branch of the trigeminal nerve elicits a facial nerve (eye blink) response bilaterally.
How is the blink reflex affected by demyelinating neuropathy?
25. Blink reflex can be affected in Demyelinating peripheral neuropathy. In demyelinating neuropathies, all potentialsof the blink response may be markedly delayed or absent, reflecting slowing of either or both motor and sensory pathway IM 18-07- 2012. 26.
When does blink reflex occur in multiple sclerosis?
CLINICAL APPLICATION• In hemifacial spasm or facial synkinesis following aberrant reinnervation there is spread of blink reflex into muscles other than orbicularis oris.• In multiple sclerosis, the R1- delayed on one or both the sides and alterations in the R2 component is less specific.