Neuroscience Exam 3

Front 1

Pain can be modulated in the central nervous system by two different mechanisms

Back 1

1- Gate control theory
2- Descending control from higher brain centers

Front 2

Why does it feel better to rub an injury?

Back 2

Modulation of pain signals by "touch" pathways

Front 3

Gate neuron in the spinal cord

Back 3

- Found in substantia gelatinosa (layer 1 of spinal cord gray matter)
- Indirectly inhibited by C fibers (pain)
-- Activated by AB fibers (touch)
_ It inhibits second order neuron of ALS pathway decreasing its conduction of pain messages (releases enkephalin

Front 4

Analgesia induced by descending control from higher brain centers

Back 4

1. Not always adaptive to attend to injury-flighting, fleeing, mating
2. Temporarily decreases..., nociception, subjective experience
3. Endorphins- stress induced analgesia, another endogenous opiod
4. Blocked by naloxone

Front 5

Placebo Effect

Back 5

-Inert pills can reduce perception of pain
- The placebo effect can be blocked by naloxone, a competitive antagonist of opiod receptors
- The placebo effect is based on a biochemical change in the brain

Front 6

Endorphins (descending control from higher brain centers)

Back 6

-Mostly beta-endorphin
-31 amino acid peptide
-Synthesized from precursor that also creates melanocyte stimulating hormone and adrenalcorticotropic (adrenal cortex-stimulating hormone)
-Found in pituitary and hypothalamus
- Reduces perception of pain
- Endogenous opiod -> hyperpolarization

Front 7

Exogenous opiates Examples Morphine, codeine

Back 7

- Act by mimicking endogenous opiates
- Major actions of exogenous opiates like morphine ar via mu receptor
- Problems due to side-effects, tolerance and addiction
- Side-effects, euphoria/dysphoria, constipation, respiratory depression, nausea/ vomitting

Front 8

Antagonist

Back 8

Naloxone, naltrexone. Excellent, selective antagonists for exogenous and endogenous opiods

Front 9

Opiate receptors
Types

Back 9

Mu (MOR) (most common)
Delta (DOR) ( less common than Mu)
Kappa (KOR) (least common)

Front 10

Opiate Receptors

Back 10

-All G-protein/cAMP linked
- Can also be coupled to ion cnannels independent of G-proteins
- Mu most important for analgesics actions
- Delta predominantly analgesia
Kappa more complex, can be analgesic or hyperalgesic

Front 11

Enkephalins (gate theory and descending control)

Back 11

- Endoginous opiods
- small peptides, leucine enkephalin, methionine enkephalin, differ by one amino acid
- Synthesised in parallel, similar actions
- Inhibitory neurotransmitters
- Found mostly in small interneurons

Front 12

Synthesize dopamine. Explain the life cycle of dopamine. Explain the pathway affected in Albinism

Back 12

COMT and MOA responsible for the breakdown of dopamine. MOA react with Tyramine can induce blood vessels constriction and an increase in blood pressure
Dopamine is produced in substanical nigra and ventral Tegmentum area which gives two projections nigro-striatal projection and mesocortial projection

Front 13

The auditory system is divided into four areas

Back 13

1-External ear
2-Middle ear
3-Inner ear
4-Neural auditory pathways

Front 14

External ear

Back 14

consists of the pinna and external auditory canal

Front 15

Pinna

Back 15

collects and funnels sound into the external auditory meatus

Front 16

External auditory meatus

Back 16

small tube leading from the medial opening in the pinna to the temporal bone. bound internally by the tympanic membrane

Front 17

Middle Ear

Back 17

consists of tympanic cavity, three bones and two muscles
air filled space in the temporal bone that is bound externally by the tympanic membrane. on the medial side there are two openings into the inner ear, the oval and round window

Front 18

Three bones(ossicles) connect the tympanic membrane to the oval window

Back 18

Tympanic membrane-> malleus-> incus-> stapes-> oval window

Front 19

Why have the malleus, incus, stapes?

Back 19

Amplification

Front 20

Two skeletal muscles connected to the ossicles

Back 20

-Tensor tympani, connected to the malleus
-Stapedius, connected to the stapes

Front 21

contraction of the tensor tympani and stapedius do what

Back 21

reduce ossicular motion, thereby decreasing amplitude of sound

Front 22

Tensor tympani inervated by

Back 22

cranial nerve V used to dampen the sound of chewing

Front 23

Stapedius is innervated by

Back 23

Cranial nerve VII, has effects used when yawning and speaking