38 - Nervous Systems Flashcards
How has the nervous system evolved
It started as a nerve net, which was a very simple neuron connecting the whole organism, no central processing
Evolved
Ganglia – groups neurons that process information
Brains – large ganglia for central processing (Brain generally in the head of the organism and often protected)
Glial Cells that support neurons
White Matter – Axons, white due to glial cells
Grey Matter – Cell bodies and dendrites
Describe the divisions of the central nervous system.
CNS (Central) – Spinal Cord / Brain – information processing
PNS (Peripheral) - everything except the brain / spinal cord - movement, unconscious processing, and gathering information
Chemoreceptors
Taste, olfactory (smell) / bind to chemicals = stimulus
Thermoreceptors
Temperature change physical conformation
Mechanoreceptors
Sense of touch / physical contact
Nociceptors
Pain Receptors
Electromagnetic receptors
light waves, and other waves
How do action potentials differ based on the intensity of a stimulus?
Low frequency = small changes (Gentle pressure) / adaptation to stimuli to make us notice it less after time, like sitting in a chair.
High frequency = large changes (Higher pressure levels) / action potential tells the body the need to move immediately (increased frequency
Retina and be able to trace how information is moved.
(Slide 16)
Cone -> Rod-> Neurons -> Ganglion Cell -> Optic Nerve Fibers
Rods
Rod = Sensitive photoreceptor that detects light but not color (why we can distinguish light at night but have a hard time with detecting color)
Cones (Green)
Cone = Photorecpor that is less sensitive to light but allows perception of color. 3 types of cones to detect red, green, and blue wavelength (if color blind, one receptor has the same receptor as another, making it so they cannot distinguish colors)
How does rhodopsin detect light? Then what happens to get that signal to the brain?
Retinal molecule detects light is bent when no light and glutamate is being produced (how we know it’s dark). When light hits the retina triggers the retina to straighten and stops the production of glutamate.
Rhodopsin is activated
Signal transduction = activation of a series of proteins in the photoreceptor cells
Glutamate release stops (tells the body there is light / we saw something)
Neurons interpret lack of glutamate as light
Activate ganglion cells to send signals to the nervous system
Two definitions of sensory receptor
A cell that detects a stimulus
-Could be a neuron that directly relies on the stimulus
-Might be a cell that signals to an afferent neuron
2. A protein receptor that detects a stimulus
Generally, transmembrane proteins that are in the membrane of the sensory receptor cell (the different _____recepotrs covered Chemo, Thermo, Mechno, Electromagnetic, Nocice)
Afferent Neurons
Collect information from the environment and send signals to the CNS (Sensory)
Efferent Neurons
Neurons send signals from the CNS to the peripheral to the motor
