Senses Flashcards
Rods
Sensitive to light, responsible for night vision
Cones
3 types: red, green, blue (each are sensitive to their corresponding light)
Phototransduction cascade
When light hits a rod, the rod turns off. This turns the bipolar cell on, which turns the retinal ganglion cell on, which sends a signal to the optic nerve
What protein do rods contain?
Rhodopsin
What protein do cones contain?
Photopsin
How do the recovery times of rods and cones compare?
Rods have a very slow recovery time (takes a while for eyes to adjust to the dark), while cones have a fast recovery time (can rapidly adjust to changes in illumination)
Are rods or cones more sensitive to light?
Rods are 1000X more sensitive to light. Rods are very good at detecting if light is present (black vs. white), while cones primarily detect color, but also some light.
Blind spot
Point at which the optic nerve connects to the periphery, no rods or cones
How does the distribution of rods and cones differ?
Rods are found mainly in the periphery, whereas cones are found mainly in the fovea.
In which part of the brain is information from the right side processed? Information from the right side?
Information from the right side is processed in the left side of the brain and vice versa
Trichromatic Theory of color
Our cones see three colors: red, blue, and green
Parallel processing
ability to detect color, form, and motion at the same time
How is form detected?
The parvoceullar pathway This pathway has good spatial resolution (shape), but poor temporal (motion)
How is motion detected?
The magnocellular pathway Has poor spatial resolution, but good temporal
Sensory adaptation
Change over time of a receptor to a constant stimulus through down regulation of a sensory receptor in the body
Amplification
The opposite of sensory adaptation, occurs through upregulation of the sensory receptors
Somatosensory Homunculus
Part of the sensory cortex, located in the parietal cortex Different parts of the body signal to different parts of the strip
Proprioception
Sense of balance/position
Kinanesthesia
The body’s sense of movement, more behavioral than proprioception
Nociception
Ability to sense pain, slow process
Thermoception
Ability to sense temperature, slow process
3 Types of Nerve Fibers (A-B, A-D, C)
A-beta fibers: fast, thick, covered in myelin A-delta fibers: smaller, less myelin C fibers: smaller, unmyelinated (give a lingering sense of pain)
Gate control theory of pain
Noxious stimuli can prevent pain from traveling to the CNS
Pheromone
Chemical signal released by one member of a species and received by another to trigger an innate response
Specialized olfactory cells
Olfactory bulb
Bundles of nerves extending from the brain
Each rececptor at the end is sensitive to one type of molecule. Receptors work through GCPR
Labeled line theory of olfaction
Each receptor binds to a specific stimuli and extends into the brain
Vibrational theory of olfaction
Vibrational frequency of a molecule gives it its odor profile
Steric theory of olfaction
Odors fit into receptors like a lock and key
Anosmia
Inability to perceive odor
What are the five tastes and what receptors do they use?
Bitter, salty, sweet, sour, umami (ability to taste glutamate)
Bitter, sweet, and umami use GCPRs
Salty and sour use ion gated channels
Labeled Lines Model of Taste
Each taste bud receptor has 5 different axons, all which send different taste information to different parts of the gustatory cortex
Describe the areas of the cerebral cortex
Frontal lobe: motor cortex, executive function, Broca’s area
Parietal lobe: somatosensory cortex
Temporal lobe: hearing, Wernicke’s area
Occipital lobe: vision
What parts of the brain make up the brainstem?
Pons, reticular formation, medulla
The pons is involved in relaxation, the reticular formation is involved in motivation and alertness,and the medulla is involved in autonomic activity of the heart and lungs
What is the role of the thalamus?
Sensory functions (all sensory pathways travel through the thalamus)
