Neuroanatomy - Processing Sensory Info & Intro to Special Senses Flashcards
Lists the 3 levels of processing sensory info
- Receptor level
- Circuit level
- Perceptual level
General potentials and receptors potentials are for what?
General potentials are for free dendrites or encapsulated receptors
Receptor potentials are for special senses
What is adaptation?
Reduction of sensitivity in the presence of constant stimulus - that is not painful.
Explain peripheral adaptation.
Peripheral adaptation is at the level of the receptors and reduces how much info is sent to CNS.
Explain central adaptation.
Central adaptation is at the level of the neural pathway to brain and involves brain nuclei.
Which receptors are fast adapting and what are they called?
Phasic receptors such as lamellar, tactile, special sense, which provides info on rate of change of stimulus.
Which receptors have little to no adaptation for a sustained response and what are they called?
Tonic receptors such as nociceptors & proprioceptors informs about presence and strength of stimulus.
In a chain of 3 neurons, what can the 1st order neuro do?
It can breach to lead to motor reflexes (ex. knee jerk) or branches synapse with 2nd order neuron to move up to thalamus or cerebellum.
List the 3 pathways for somatosensory info to ascend spinal cord.
- Dorsal column-medial lemniscal pathways
- Spinothalamic pathways
- Spinocerebellar pathways
Which out of the 3 ascending tracts for sensory info has the thalamus as the target, with a receptors that can be localized precisely, and there is decussation at the level of medulla?
Dorsal column-medial lemniscal pathways
Which out of the 3 ascending tracts for sensory info has the thalamus as the target, has serval receptors that don’t localize source as precisely, and there is decussation at the level of spinal cord?
Spinothalamic pathways
Which out of the 3 ascending tracts for sensory info has the cerebellum as the target, for coordination of skeletal muscle activity, is ipsilateral, and we are not aware?
Spinocerebellar pathways
What is the difference between sensation and perception?
- Sensation: aware of changes in environments
- Perception: conscious interpretations of those changes for a correct response
Lists the 6 properties of sensory perception.
- Perceptual detection
- Magnitude estimation
- Spatial discrimination
- Feature abstraction
- Quality discrimination
- Pattern recognition
What is associated with a sharp pain?
You feel aware. It is carried by small myelinated A-delta fibers.
What is associated with a burning pain?
You feel the aching and the inflammation. It is carried by slow small nonmyelinated C fibers
Explain the neurotransmitters for pain.
Glutamate & substance P in which the 2nd order axon from both ascend via spinothalamic tract.
List the two pain suppression endogenous opioids.
Endorphins and enkephalins (triggered by SNS)
What is somatic pain (musculoskeletal pain)?
Aching, cramping, easily localized because bones and muscles are well innervated.
What is visceral pain?
Pain associated with organs of thorax and abdominal cavity. Can lead to reffered pain.
What is referred pain?
Pain arising from one part of body appears to come from somewhere else.
- Ex. heart attack
What is phantom pain?
Type of hyperalgesia where the pain is ‘learned’ because of NMDA receptors (especially during amputations).
What gives tongue the bumpy surface?
Papillae
Describe the 3 types of papillae
- Fungiform: surface of tongue with 1-5 taste buds each
- Vallate: largest 8-12 vallate at the back
- Foliate: lateral, # decrease with age
Gustatory hairs have receptors for food chemicals called __________.
Tastants
What replaces taste cells during a turnover at 7-10 days?
Basal epithelial cells
What are the 5 basic tastes modalities?
Sweet, sour, salty, bitter, umami
Taste receptors are most sensitive for which modalities?
With different thresholds: bitter
For sour taste, what can occur as threshold?
H+ can go in or black leaky K+ channels, leading to depolarization
What is the G protein associated with sweet, bitter, and umani?
Gustducin
List the 3 cranial nerves associated with the gustatory pathway.
Facial nerve (VII), Glossopharangeal (IX), and Vagus (X)
What type of cells is the olfactory epithelium?
Pseudostratified columnar cells
Are olfactory sensory neurons unipolar, bipolar, or multipolar?
Bipolar - sensory neurons
Explain how odorant chemicals are captured.
The substance must be violate and dissolve in the mucus.
Non-motile cilia are covered by mucus.
The axons gather into small fascicles to form filaments of olfactory nerve, projecting trough cribriform plate to synapse in olfactory bulb.
Axons of mitral cells form olfactory tract.
Describe the olfactory transduction and the effects of Na+ and Ca++ that enters.
- influx of Na+: depolarization
- influx of Ca++: adapt and decreasing response to a sustained stimulus (opens Cl- channels)
What are the two destinations of the olfactory tracts?
Olfactory cortex & limbic system
