• Midterm is MDCL 1105 at 7pm.
- 20 brief question: what is most common neurotransmitter?
- 5 brief questions: short answers
- 5 comprehensive questions: like homework questions
• Referred pain: when there is a problem in internal organ, but have pain on external skin
-ie. Heart attacks can cause pain in left arm
- reason is in dorsol horn of spinal cord some axons converge/synapse onto same
neuron; ie. skin in which pain is perceived axon converges onto a neuron, but axon that
feels pain from injured organ also synapse at same neuron
• Gate hypothesis: a beta axons inhibit or reduce firing rate of second order neurons in
- a beta releases glutamate to a local circuit neuron (or inter neuron) which releases
GABA onto cell body of secondary neuron and inhibits it
- ie when you bump into something and hurt shin you rubbing it makes it feel better
• Descending pain control: how placebo effect works
- amygdala indirectly (by influencing other parts of brain) projects axons down to dorsal
horn of spinal cord.
- These axons releases glutamate onto inter neuron releases ekephalin (endorphin) onto
axon terminal of c fiber. Enkephalin opens up K+ channels and closes voltage gated Ca
channels (makes it harder for neuron to release neurotransmitters or reduced pain).
• Phantom limb: neurons in HOM fires APs and feels like limb
• Lens and ___ focus light onto retina.
- myopia is nearsightedness Light focuses before retina. When cornea is too curved or
eyeball is too curved, and hyperopia is farsightedness. Light focuses after retina. When
cornea is too flat or eyeball to short
• Snells law: different densities cause different refractions (refractive index). When light
refracts it wants to go towards the normal
- most of the refraction of the eye is done by cornea (lens is fine tuning it). This is
because light hits cornea first (ratio between air and cornea is great whereas refractive index of aqueous solution (water) behind cornea to lens is less)
• as surface gets rounder it bends light more
- lens gets rounder as you focus on something that’s closer
- lens is naturally round, ciliary muscles causes lens to become rounder
(accommodation) or more oval
- image on retina is upside down and left right flips. brain interprets this automatically
• retina is “in