Immunity Coordination and Response Flashcards
What is homeostasis
The maintenance of a constant internal environment
What are the parts of the eye?
Suspensory ligament, Conjunctiva, Iris, Pupil, Cornea, Ciliary Muscle, Lens, Retina, Fovea, Optic Nerve
What is the function of the Cornea?
Transparent lens that refracts (bends) light as it enters the eye
What is the function of the Iris?
Controls how much light enters the pupil
What is the function of the Lens
A transparent disc that can change shape to focus light onto the retina
What is the function of the retina?
Contains light receptor cells- rods (detect light intensity) and cones (detect colour)
What is the function of the optic nerve?
A sensory neurone that carries impulses between the eye and the brain
What is the function of the pupil?
A hole that allows light to enter the eye
What are some examples of receptors?
The eyes, ears, nose tongue and skin
Effectors examples
Muscles, Glands
What happends to the iris when it is sunny?
Circular muscles contract, radial muscles relax
What happends to the iris when it is dark?
Circular muscles relax, Radial Muscles contract
What happends when you want to look at something close up
Ciliary muscles relax, which allows suspensory ligaments to pull tight, this makes the lens go thin (less curved). So it refracts light by a smaller amount
What happends when you want to look at something far away
Ciliary muscles contract, which slackens the suspensory ligaments, the lens becomes more fat (more curved). This increases the amount by which it refracts light
