Chapter 44 - Neuroscience 3: Sensory systems
What do sensory systems do?
Convert stimuli from an animal's. body of external environment to a signal that changes embrace potential of sensory neurons
What is sensory transduction?
Process by which incoming stimuli are converted into neural signals
What is Perception?
Awareness of sensation
Are all sensations consciously perceived?
What are sensory receptors and what do they do?
Neurons or specialized epithelial cells that recognize stimulus and initiate signal transduction
What happens when the response of a sensory receptor is very strong?
Depolarization of the membrane to the threshold potential at the axon hillock and production of an action potential in a sensory neuron
A stronger stimulus (Opens/CLoses) more ion channels?
Membrane potential = ?
What is the strength of the stimulus indicated by?
Frequency of action potentials?
What kind of frequency of action potentials does the brain interpret as more intense?
Why do different stimuli produce different sensations?
Because they activate specific neural pathways dedicated to processing only that type of stimulus
Where are stretch receptors most commonly found?
In the walls of organs that can be distended
- Stomach, urinary bladder, skeletal muscles
What is glaucoma?
Drainage of aqueous humor blocked and pressure inside eye rises, damaging the retina
What is macular degeneration?
Photoreceptor cells in and around macula are lost
- Causes loss of sharpness and color vision
What are cataracts?
Accumulation of protein clouds the lens
What is deafness usually caused by?
Damage to hair cells in cochlea
What is the most significant cause of deafness?
Repeated, long-term exposure to loud noise
What is the purpose of cochlear implants?
Implantation to generate electrical signals in response to sound waves