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Senses and Sensory Receptors. Sensory Receptors. Sensory receptors are located at the ends of afferent neurons. Receive stimuli from their surroundings and allow neurons to pass this information into the central nervous system. Types of receptors.
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Sensory Receptors • Sensory receptors are located at the ends of afferent neurons. • Receive stimuli from their surroundings and allow neurons to pass this information into the central nervous system.
Types of receptors • Different receptors sense different types of information • Mechanoreceptors • Thermoreceptors • Photoreceptors • Chemoreceptors • Nociceptors
Mechanoreceptors, Thermoreceptors, and Photoreceptors • Mechanoreceptors - These respond to mechanical stimuli, such as pressure or stretch • Thermoreceptors – Detect both sensations of cold and warmth • Photoreceptors respond to particular light wavelengths
Chemoreceptors and Nociceptors • Chemoreceptors – respond to particular chemicals, they are resposible for smells and taste • Nociceptors – These are pain receptors they respond to extreme heat and tissue damage.
How two point discrimination works • Nerve fibers have sensory fields • You depress two areas in the same sensory field your mind can not distinguish the areas separately • If you depress two areas in different sensory fields your mind will interpret it as two different points.
How do we tell a strong stimulus from a weak one? • Stimulus intensity can be controlled in two ways • The frequency of action potentials from a single neuron • The more action potentials a single neuron sends the larger intensity the brain will interpret it as. • More neurons firing will also increase sensation of intensity