Nervous System And Eye

Question 1

What are some examples of reflexes?

Answer 1

Knee jerk reflex pupil reflex, sneezing, changing your lens shape to focus on an object

Question 2

What happens in the reflex arc?

Answer 2

Stimulus stimulates a receptor, electric impulse to sensory neurone, passes it to relay neurone in spinal cord , skips Brian, passes it to motor neurone, which then stimulates an effector cell to do the thing, e.g. Move hand away from hot plate

Question 3

How does a nerve impulse transmit across a synapse?

Answer 3

1. Nerve impulse travels as electrical signal across axon to synapse
2. Vesicles w neurotransmitters move to membrane
3. Neurotransmitter emptied into synapse and diffuses across it
4. Neurotransmitters bind to receptor on surface of dendrite, triggering a new nerve impulse which moves from the sensor to the axon

Question 4

What is the conjunctiva and its role?

Answer 4

Layer covering eye. Helps to lubricate it.

Question 5

What is the lens and its role?

Answer 5

Transparent structure behind pupil. Helps to refract and focus light

Question 6

What is the lens and its role?

Answer 6

Transparent structure behind pupil. Refracts and focuses light

Question 7

What is the pupil and iris and their role?

Answer 7

Pupil- hole in centre of iris
Iris- lightened tissue.
Controls amount of light entering the eye