LASIK
Reshapes the cornea surgically- common for myopia.
Cornea
transparent area in front of sclera; can bend light as it enters.
Vasodilation
arterioles dilate, increasing blood flow to surface of skin so more heat is lost through radiation.
Retina
layer at back containing light sensitive cells- rods and cones.
Negative Feedback
Make adjustments to bring body back to bodily norm.
Suspensory Ligament
holds lens in place.
Vasoconstriction
reduces heat loss through radiation.
Stimulus
Change in environment body reacts to.
Contact lenses
Float on the surface of the cornea, focusing and refracting light.
Sensory Neuron
Carry electrical impulse from Receptor to CNS.
Fovea
area of cones where light is bought to focus.
Optic Nerve
sends electrical signal to the brain.
Neurotransmitters
diffuse across the synapse form an area of high concentration to an area of low concentration (down the concentration gradient)
Lens
clear disc that can change shape to focus light on retina.
Motor Neuron
Transmits impulse from CNS to body tissues.
Central Nervous System (CNS)
Made up of brain and spinal cord.
Iris
controls the size of the pupil.
nerve
A(n) ________ is multiple neurons.
Pupil
hole through which light enters.
Sclera
tough, white, outer layer- protects eye.
Relay Neurons
Carry electrical impulse from one part of CNS to another.
Peripheral Nerves
All nerves EXCEPT brain and spine.
convex lens
brings light together before it reaches the eye.
Neuron
specialized cell
nervous system
The ________ is comprised of receptors, nerves, the central nervous system (CNS) and effectors.
Ciliary muscles
change the shape of the lens, which alters the refraction of light.
Neurotransmitter
binds to the receptor on the surface of the post- synaptic neuron.
retina
Light hits the ________ and stimulates the rods and cones.
Homeostasis
Maintenance of constant internal conditions
Relay Neurons
Carry electrical impulse from one part of CNS to another
Nerve
Multiple neurons
Sensory Neuron
Carry electrical impulse from Receptor to CNS
Coordinator
Brain or spine; coordinates response
Peripheral Nerves
All nerves EXCEPT brain and spine
Motor Neuron
Transmits impulse from CNS to body tissues
Stimulus
Change in environment body reacts to
Effector
Muscle or gland that reacts to nerve impulse
Receptor Cells
Specialist cells that detect impulse
Synapse
Gap between two neurons
Cornea
transparent area in front of sclera ; can bend light as it enters
Suspensory Ligament
holds lens in place
Pupil
hole through which light enters
Fovea
area of cones where light is bought to focus
Optic Nerve
sends electrical signal to the brain
Iris
controls the size of the pupil
Ciliary Muscle
contracts and relaxes to change the shape of the lens
Circular Muscles
contract to bring iris further in, opening pupil
Radial Muscles
contract to dilate pupil by pushing pupil further out
Myopia
Short-sightedness
concave lens
spreads light out before it reaches the eye
Hyperopia
Long-sightedness
convex lens
brings light rays together before it reaches the eye
Contact lenses
Float on the surface of the cornea, focusing and refracting light
shivering
muscles contract and relax rapidly with energy from respiration which is exothermic and releases heat